AP is grateful to Imperial College London for a PhD studentship via the Frankland Chair endowment. Johnson Matthey plc are also thanked for the loan of the precious metal salts used in this work.

Remarque: Effectuer toutes les synthèses dans une hotte, et seulement après que les questions de sécurité appropriées ont été identifiés et des mesures prises pour protéger contre eux. Équipement de protection individuelle comprend une blouse de laboratoire, des gants et des lunettes de sécurité et doit être porté en tout temps. 1. Synthèse de la N, N, (diphenylphosphinomethylene) de l&#39;amine N, N (CH 2 PPh 2) 3 (de la N Ph) (1) <ol><li> Pour 200 ml séché au four ballon de Schlenk ajouter diphényl chlorure (hydroxyméthylène) phosphonium 11 (6,99 g, 24,7 mmol) et le lieu sous azote par trois cycles séquentiels vide-azote sur une ligne Schlenk collecteur double. </li><li> Ajouter du methanol dégazé (30 ml) et de triéthylamine (9,5 ml, 68,1 mmol) et agiter à TA pendant 1 heure pour assurer la conversion du sel de phosphonium de la phosphine hydroxymethene. Ensuite, ajouter la solution d&#39;ammoniac dans le méthanol dégazé (2 M, 4,1 ml, 8,2 mmol). </li><li> Chauffer le mélange réactionnel pendant 2 heures au refluxAu cours de laquelle le ligand se précipiter sous forme de solide blanc. </li><li> Bien que la N Ph le ligand est stable à l&#39;oxydation dans l&#39;air sur de courtes périodes de temps, pour une pureté optimale, éliminer le solvant via une canule filtration 26 sous azote, et rincer avec du méthanol dégazé (3 x 10 ml) pour obtenir un produit analytiquement pur et stocker sous une atmosphère d&#39;azote. </li></ol> 2. Synthèse de [Ru (CO) 2 {N (CH 2 PPh 2) 3} 3 -κ P] (2) <ol><li> Dans un ballon de Schlenk de 200 ml séché au four, ajouter -Triphos Ph N (1,0 g, 1,63 mmol) et de [Ru 3 (CO) 12] (347 mg, 0,54 mmol), sous atmosphère d&#39;azote et le lieu via trois cycles séquentiels vide-azote sur une ligne à collecteur double Schlenk. </li><li> Ajouter 30 ml de sec, le toluène dégazé et porter le mélange à reflux pendant 12 heures. </li><li> Après cette 12 h reflux, filtrer la solution via une canule à un deuxième flacon de Schlenk àenlever de petites quantités de ruthénium métallique qui forment au cours de la réaction. </li><li> Réduire le volume du solvant à environ 10 ml sous vide à l&#39;aide d&#39;une ligne à double collecteur de Schlenk muni d&#39;un piège refroidi à l&#39;azote liquide, pour induire la précipitation du complexe. </li><li> On recristallise le précipité en chauffant légèrement (80-90 ° C) dans un bain d&#39;huile jusqu&#39;à ce que la redissolution complète se produit, et le refroidissement lent subséquent à la température ambiante en retirant la chaleur du bain d&#39;huile, mais permettant au ballon de Schlenk de rester submergé. Laissez O / N pour donner un solide cristallin orange. </li><li> Isoler les cristaux orange appropriés pour diffraction des rayons X par l&#39;intermédiaire de la canule filtration du surnageant dans un autre ballon de Schlenk séché au four. Ensuite, rincer les cristaux avec du toluène sec et dégazé (2 x 5 ml) et sèche sous vide O / N. Enregistrer le surnageant et les lavages combinés dans un ballon de Schlenk séparé. </li><li> Obtenir un second lot de cristaux à partir du surnageant combiné et la solution de rinçages par un procédé de recristallisation similaire aux étapes 2,5 et 2,6 afin d&#39;améliorer le rendement global de la réaction. </li><li> Stocker le complexe sous azote que l&#39;exposition à l&#39;air conduit à la conversion lente au complexe de carbonate oxydé (voir ci-dessous). </li></ol> 3. Synthèse du [Ru (CO 3) (CO) {N (CH 2 PPh 2) 3} 3 -κ P] (3) <ol><li> Pour un ballon de Schlenk de 200 ml, ajouter 2 (280 mg, 0,364 mmol) et 5 ml de toluène pour générer une suspension orange partiellement dissous. </li><li> Insérer une aiguille fixée à un ballon d&#39;oxygène dans la suspension et de bulles d&#39;oxygène à un débit de 2 à 3 bulles par seconde à travers le mélange réactionnel pendant 10 min. </li><li> Comme il se forme un précipité orange, de les recueillir par filtration dans l&#39;air et on l&#39;a lavé avec du toluène (2 x 5 ml) et de l&#39;éther diéthylique (2 x 5 ml) et on sèche sous vide pour donner une poudre à écoulement orange libre qui est stable à l&#39;air. </li><li> Pour grandir des cristaux appropriés pour Diffr X-rayl&#39;action, dissoudre 100 mg de 3 à 3 ml de dichlorométhane dans un flacon et la couche 3 ml de toluène sur le dessus en permettant lentement ce solvant afin de fonctionner sur le côté de la fiole. <ol><li> Laissez cette O / N pour obtenir des cristaux. Isoler les cristaux par décantation du surnageant, et le lavage du toluène (2 x 3 ml) et de l&#39;éther diéthylique (2 x 3 ml). Sec sous vide sur un tube de Schlenk à double collecteur. </li></ol></li></ol> 4. Synthèse du [Ru (H) 2 (CO) {N (CH 2 PPh 2) 3} 3 -κ P] (4) <ol><li> Préparer une solution de 3 (763 mg, 0,953 mmol) dans 20 ml de sec, dégazé THF et les injecter dans 100 ml de réacteur à haute pression de l&#39;ingénieur autoclave sous une pression positive (0,2 bar) d&#39;azote. </li><li> Changez le gaz de l&#39;espace de tête du réacteur à 100% d&#39;hydrogène et sous pression à 15 bars à température ambiante, puis chauffer à 100 ° C sous agitation pendant 2 heures. Attention! Se assurer que toutes les procédures de sécurité ont été respectées lors de l&#39;utilisation de hautsystèmes de pression! </li><li> Après refroidissement à TA, vent attentivement le gaz d&#39;hydrogène en excès dans l&#39;espace de tête du réacteur et modifier à l&#39;azote. </li><li> Transvaser la solution de réaction à un ballon de Schlenk de 100 ml sous atmosphère d&#39;azote et, après la reconnexion à un tube de Schlenk à collecteur double, filtre via une canule et dilué avec 20 ml de sec, dégazé methanol. </li><li> Enlever le solvant sous vide à l&#39;aide d&#39;une ligne à double collecteur de Schlenk muni d&#39;un piège à azote liquide refroidi pour donner une poudre orange. Laver cette poudre orange avec sec, le methanol dégazé (3 x 5 ml) et on sèche, on dégaze l&#39;éther diéthylique (3 x 5 ml) et on sèche sous vide. </li><li> Cultiver des cristaux appropriés pour l&#39;analyse de diffraction des rayons X O / N à partir d&#39;une solution de toluène saturé sec et dégazé de quatre couches avec une quantité de équivolumique sec, dégazé méthanol. </li><li> Rangez le complexe sous azote. </li></ol> 5. La réaction de [RuH 2 (CO) {N (CH 2 PPh 2) 3} 3 P -κ] (4) avec du NH 4 PF 6 et l&#39;acide lévulinique <ol><li> Préparer une solution de 4 (48,4 mg, 65,2 pmol) dans 2 ml de toluène dégazé anhydre dans un ballon de Schlenk séché à l&#39;étuve, et ajouter via une seringue à une solution agitée de NH 4 PF 6 (10,6 mg, 65,0 umoles) dans de l&#39;acétonitrile (2 ml) dans un four séparé ballon de Schlenk séché. </li><li> On agite le mélange réactionnel à température ambiante pendant 2 h. Après, éliminer le solvant sous vide en utilisant une ligne à collecteur double Schlenk muni d&#39;un azote liquide refroidi piège pour donner l&#39;intermédiaire complexe [RuH (CO) (MeCN) {N (CH 2 PPh 2) 3} -κ 3 P] ( 5). </li><li> Laver à sec, dégazé de l&#39;hexane (3 x 3 ml) et on sèche sous vide pour isoler complexe 5 forme d&#39;une poudre brune. </li><li> A une solution de 5 0,5 ml dégazé dans de l&#39;acétone-d6, ajouter de l&#39;acide lévulinique (10,8 mg, 93,0 umol, 1,43 équiv.) Dans 0,5 ml de dégazé acétone-d6. On agite le mélange réactionnel pendant 2 min à l&#39;aideun agitateur à vortex. </li><li> Fiche 1 H et 30 P {1 H} de spectres RMN de la réaction toutes les heures pendant 16 heures pour observer la réaction. 27 </li></ol>

<ol>
	<li>Bruneau, C., Dixneuf, P. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Ruthenium Catalysis and Fine Chemicals. , (2004).</li><li>Naota, T., Takaya, H., Murahashi, S. -. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ruthenium-Catalyzed+Reactions+for+Organic+Synthesis.">Ruthenium-Catalyzed Reactions for Organic Synthesis.</a> Chem. Rev. 98 (7), 2599-2660 (1998).</li><li>Arockaim, P. B., Bruneau, C., Dixneuf, P. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ruthenium(II)-Catalyzed+C-H+Bond+Activation+and+Functionalization.">Ruthenium(II)-Catalyzed C-H Bond Activation and Functionalization.</a> Chem. Rev. 112 (11), 5879-5918 (2012).</li><li>Trost, B. M., Toste, F. D., Pinkerton, A. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Non-metathesis+ruthenium-catalyzed+C-C+bond+formation.">Non-metathesis ruthenium-catalyzed C-C bond formation.</a> Chem. Rev. 101 (7), 2067-2096 (2001).</li><li>Vougioukalakis, G. C., Grubbs, R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ruthenium-Based+Heterocyclic+Carbene-Coordinated+Olefin+Metathesis+Catalysis.">Ruthenium-Based Heterocyclic Carbene-Coordinated Olefin Metathesis Catalysis.</a> Chem. Rev. 110 (3), 1746-1787 (2010).</li><li>Lozano-Vila, A. M., Monsaert, S., Bajek, A., Verpoort, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ruthenium-based+olefin+metathesis+catalysts+derived+from+alkynes.">Ruthenium-based olefin metathesis catalysts derived from alkynes.</a> Chem. Rev. 110 (8), 4865-4909 (2010).</li><li>Samojlowicz, C., Bieniek, M., Grela, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ruthenium-based+olefin+metathesis+catalysts+bearing+N-heterocyclic+carbene+ligands.">Ruthenium-based olefin metathesis catalysts bearing N-heterocyclic carbene ligands.</a> Chem. Rev. 109 (8), 3708-3742 (2009).</li><li>Alcaide, B., Almedros, P., Luna, A. G. r. u. b. b. s. &. #. 8. 2. 1. 7. ;. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ruthenium-Carbenes+Beyond+the+Metathesis+Reaction:+Less+Conventional+Non-Metathetic+Utility.">Ruthenium-Carbenes Beyond the Metathesis Reaction: Less Conventional Non-Metathetic Utility.</a> Chem. Rev. 109 (8), 3817-3858 (2009).</li><li>Conley, B. L., Pennington-Boggio, M. K., Boz, E., Discovery Williams, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Applications,+and+Catalytic+Mechanisms+of+Shvo&#8217;s+Catalyst.">Applications, and Catalytic Mechanisms of Shvo&#8217;s Catalyst.</a> Chem. Rev. 110 (4), 2294-2312 (2010).</li><li>Miller, P. W., White, A. J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+preparation+of+multimetallic+complexes+using+sterically+bulky+N-centered+tipodal+dialkyl+phosphine+ligands.">The preparation of multimetallic complexes using sterically bulky N-centered tipodal dialkyl phosphine ligands.</a> J. Organomet. Chem. 695 (8), 1138-1145 (2010).</li><li>Hanton, M. J., Tin, S., Boardman, B. J., Miller, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ruthenium-catalysed+hydrogenation+of+esters+using+tripodal+phosphine+ligands.">Ruthenium-catalysed hydrogenation of esters using tripodal phosphine ligands.</a> J. Mol. Catal. A. 346 (1-2), 70-78 (2012).</li><li>Phanopoulos, A., Brown, N. J., White, A. J. P., Long, N. J., Miller, P. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis,+Characterization,+and+Reactivity+of+Ruthenium+Hydride+Complexes+of+N-Centered+Triphosphine+Ligands.">Synthesis, Characterization, and Reactivity of Ruthenium Hydride Complexes of N-Centered Triphosphine Ligands.</a> Inorg. Chem. 53 (7), 3742-3752 (2014).</li><li>Jin, G. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N.N.N-tris(phosphinomethylen)amine+N.N.N&#8217;-tris(phosphinomethylene)hydrazine+N.N.N&#8217;.N&#8217;-tetra(phosphinomethylene)hydrazine.">N.N.N-tris(phosphinomethylen)amine N.N.N&#8217;-tris(phosphinomethylene)hydrazine N.N.N&#8217;.N&#8217;-tetra(phosphinomethylene)hydrazine.</a> Tetrahedron Lett. 22 (12), 1105-1108 (1981).</li><li>Walter, O., Huttner, G., Kern, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+and+Characterisation+of+N(CH2PPh2)3.+N(CH2PPh2)3Mo(CO)3+and+[HN(CH2PPh2)3Mo(CO)3]BF4.">Preparation and Characterisation of N(CH2PPh2)3. N(CH2PPh2)3Mo(CO)3 and [HN(CH2PPh2)3Mo(CO)3]BF4.</a> Z. Naturforsch. 51b, 922-928 (1996).</li><li>Fillol, J. L., Kruckenberg, A., Scherl, P., Wadepohl, H., Gade, L. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stitching+Phospholanes+Together+Piece+by+Piece:+New+Modular+Di-+and+Tridentate+Stereodirecting+Ligands.">Stitching Phospholanes Together Piece by Piece: New Modular Di- and Tridentate Stereodirecting Ligands.</a> Chem. Eur. J. 17 (50), 14047-14062 (2011).</li><li>Rodr&#237;guez, L. -. I., Roth, T., Fillol, J. L., Wadepohl, H., Gade, L. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+More+Gold&#8211;The+More+Enantioselective:+Cyclohydroaminations+of+&#947;-Allenyl+Sulfonamides+with+Mono+Bis,+and+Trisphospholane+Gold(I)+Catalysts.">The More Gold&#8211;The More Enantioselective: Cyclohydroaminations of &#947;-Allenyl Sulfonamides with Mono Bis, and Trisphospholane Gold(I) Catalysts.</a> Chem. Eur. J. 18 (12), 3721-3728 (2012).</li><li>Scherl, P., Kruckenberg, A., Mader, S., Wadepohl, H., Gade, L. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ruthenium+&#951;4-Trimethylenemethane+Complexes+Containing+Tripodal+Phosphanomethylamine+Ligands.">Ruthenium &#951;4-Trimethylenemethane Complexes Containing Tripodal Phosphanomethylamine Ligands.</a> Organometallics. 31 (19), 7024-7027 (2012).</li><li>Scherl, P., Wadepohl, H., Gade, L. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrogenation+and+Silylation+of+a+Double-Cyclometalated+Ruthenium+Complex:+Structures+and+Dynamic+Behavior+of+Hydrido+and+Hydridosilicate+Ruthenium+Complexes.">Hydrogenation and Silylation of a Double-Cyclometalated Ruthenium Complex: Structures and Dynamic Behavior of Hydrido and Hydridosilicate Ruthenium Complexes.</a> Organometallics. 32 (15), 4409-4415 (2013).</li><li>Geilen, F. M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selective+and+Flexible+Transformation+of+Biomass-Derived+Platform+Chemicals+by+a+Multifunctional+Catalytic+System.">Selective and Flexible Transformation of Biomass-Derived Platform Chemicals by a Multifunctional Catalytic System.</a> Angew. Chem. Int. Ed. 49 (32), 5510-5514 (2010).</li><li>Geilen, F. M. A., Engendahl, B., H&#246;lscher, M., Klankermayer, J., Leitner, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selective+Homogeneous+Hydrogenation+of+Biogenic+Carboxylic+Acids+with+[Ru(TriPhos)H]+:+A+Mechanistic+Study.">Selective Homogeneous Hydrogenation of Biogenic Carboxylic Acids with [Ru(TriPhos)H]+: A Mechanistic Study.</a> J. Am. Chem. Soc. 133 (36), 14349-14358 (2011).</li><li>Van Engelen, M. C., Teunissen, H. T., de Vries, J. G., Elsevier, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Suitable+ligands+for+homogeneous+ruthenium-catalyzed+hydrogenolysis+of+esters.">Suitable ligands for homogeneous ruthenium-catalyzed hydrogenolysis of esters.</a> J. Mol. Catal. A. 206 (1-2), 185-192 (2003).</li><li>Wesselbaum, S., vom Stein, T., Klankermayer, J., Leitner, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrogenation+of+Carbon+Dioxide+to+Methanol+by+Using+a+Homogeneous+Ruthenium&#8211;Phosphine+Catalyst.">Hydrogenation of Carbon Dioxide to Methanol by Using a Homogeneous Ruthenium&#8211;Phosphine Catalyst.</a> Angew. Chem. Int. Ed. 51 (30), 7499-7502 (2012).</li><li>Fillol, J. L., Kruckenberg, A., Scherl, P., Wadepohl, H., Gade, L. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stitching+Phospholanes+Together+Piece+by+Piece:+New+Modular+Di-+and+Tridentate+Stereodirecting+Ligands.">Stitching Phospholanes Together Piece by Piece: New Modular Di- and Tridentate Stereodirecting Ligands.</a> Chem. Eur. J. 17 (50), 14047-14062 (2011).</li><li>Rodr&#237;guez, L. -. I., Roth, T., Fillol, J. L., Wadepohl, H., Gade, L. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+More+Gold&#8211;The+More+Enantioselective:+Cyclohydroaminations+of+&#947;-Allenyl+Sulfonamides+with+Mono+Bis-,+and+Trisphospholane+Gold(I)+Catalysts.">The More Gold&#8211;The More Enantioselective: Cyclohydroaminations of &#947;-Allenyl Sulfonamides with Mono Bis-, and Trisphospholane Gold(I) Catalysts.</a> Chem. Eur. J. 18 (12), 3721-3728 (2012).</li><li>Scherl, P., Wadepohl, H., Gade, L. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrogenation+and+Silylation+of+a+Double-Cyclometalated+Ruthenium+Complex:+Structures+and+Dynamic+Behavior+of+Hydrido+and+Hydridosilicate+Ruthenium+Complexes.">Hydrogenation and Silylation of a Double-Cyclometalated Ruthenium Complex: Structures and Dynamic Behavior of Hydrido and Hydridosilicate Ruthenium Complexes.</a> Organometallics. 32 (15), 4409-4415 (2013).</li><li>Bennett, B. K., Richmond, T. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+Inexpensive,+Disposable+Cannula+Filtration+Device.">An Inexpensive, Disposable Cannula Filtration Device.</a> J. Chem. Educ. 75 (8), 1034 (1998).</li><li>Judd, C. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proton+NMR+Basics.">Proton NMR Basics.</a> J. Chem. Educ. 72 (8), 706 (1995).</li><li>Rhodes, L. F., Venanzi, L. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ruthenium(II)-Assisted+Borohydride+Reduction+of+Acetonitrile.">Ruthenium(II)-Assisted Borohydride Reduction of Acetonitrile.</a> Inorg. Chem. 26 (16), 2692-2695 (1987).</li><li>Bakhmutov, V. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In-depth+NMR+and+IR+study+of+the+proton+transfer+equilibrium+between+[{MeC(CH2PPh2)3}Ru(CO)H2]+and+hexafluoroisopropanol.">In-depth NMR and IR study of the proton transfer equilibrium between [{MeC(CH2PPh2)3}Ru(CO)H2] and hexafluoroisopropanol.</a> Can. J. Chem. 79, 479-489 (2001).</li></ol>

The authors have nothing to disclose.

Ici, nous avons décrit des procédures de synthèse efficaces pour la synthèse d&#39;un ligand tridenté de phosphine et d&#39;une série de complexes du ruthénium. Le N de la Ph ligand (1) peut être facilement préparé avec un rendement élevé une procédure de travail-up minimaliste. Cette réaction de Mannich à base de phosphore utilisé pour la synthèse de ces types de ligands est tout à fait générale et peut être utilisé pour d&#39;autres ligands qui se différencie...

Complexes à base de ruthénium phosphine sont quelques-uns des catalyseurs moléculaires les plus étudiés et chimiquement polyvalents. 1-9 Typiquement, ces catalyseurs ruthénium contiennent soit des ligands mono- ou bi-denté qui dictent l&#39;électronique, sterics, la géométrie et la solubilité du complexe, et qui avoir un impact profond sur l&#39;activité catalytique. Systèmes de phosphine multidentés ont été moins largement étudiée pour la catalyse, comme ils sont connus pour conférer une plus grande stabilité sur le centre métallique en raison de la plus grande effet chélate de plusieurs bailleurs de fonds de phosphore sur le centre métallique. Cette stabilisation peut être indésirable pour la catalyse, cependant, dans des conditions plus sévères (températures de réaction plus élevées et des pressions) les propriétés stabilisatrices complexes de tels ligands peuvent être avantageux en assurant l&#39;intégrité du catalyseur. Un tel système de ligand polydenté de phosphine que nous et d&#39;autres de 10 à 12 13 à 18 ont étudié pour conférer la stabilité du complexe et du visage coorgéométries de coor- est ce qu&#39;on appelle le série de ligand -triphos N où trois bras phosphine sont liés à un atome pontant apicale d&#39;azote formant un ligand tridentate potentiellement. L&#39;une des caractéristiques clés de ces ligands particuliers est ainsi facile qu&#39;ils peuvent être synthétisés par l&#39;intermédiaire d&#39;un phosphore à base de réaction de Mannich à partir de phosphines secondaires aisément disponibles (figure 1), les phosphines avec une variété de groupes R peuvent être préparés en général à des rendements élevés d&#39;où et avec un minimum de travail-up. L&#39;objectif global de cette méthodologie est de présenter un itinéraire facile par lequel complexes de ruthénium dihydrure comportant les ligands de N peut être consultée pour les applications catalytiques ultérieures. Récemment, des complexes à base de Ru-triphos ont attiré l&#39;attention en tant que catalyseurs pour les réactions d&#39;hydrogénation de la biomasse produits dérivés, tels que l&#39;acide lévulinique, 19,20 11,21 bio-esters et de dioxyde de carbone supérieures à 22 produits chimiques de valeur. Il serait avantageuxd&#39;élargir la portée des dérivés Ru-triphos qui sont soit en tant que, ou plus actif que les systèmes déjà déclaré, surtout si elles sont synthétiquement plus facile d&#39;accès, tels que le ligand de la N. L&#39;analogue centrée sur du carbone le plus étudié souffre généralement de faible rendement et de synthèse comprend des réactifs de phosphure métallique hautement sensibles à l&#39;air, à la différence de ligand de la N, qui est plus souple et plus facile à préparer. 18/10 Les ligands de N restent relativement sous-étudié, avec des complexes ne molybdène, tungstène, ruthénium, rhodium et d&#39;or ayant été signalés dans neuf publications. Ceci est en contraste frappant avec les analogues du bore et centré-carbone, pour lesquels il existe environ 50 et 900 articles, respectivement, avec un grand nombre de composés uniques. Néanmoins, N -triphos contenant des complexes ont trouvé une application dans l&#39;hydrogénation catalytique asymétrique des oléfines pro-chiraux 23 que nousll cyclohydroamination comme asymétrique de N-protégé sulfamides γ-allényle. 24 En outre, un complexe de ruthénium coordonné par le ligand d&#39;un encombrant N avec phospholane coordination des fragments a été trouvé pour activer silanes, une étape clé dans le développement de la chimie du silicium. 25 Dans le cadre du programme de recherche en cours dans la catalyse, nous avons cherché à préparer une gamme de ruthénium N de Ph les précatalyseurs et d&#39;étudier leurs réactions stoechiométriques et le potentiel catalytique. Malgré complexes de molybdène de la N Ph ayant d&#39;abord été rapporté il ya plus de 25 ans, à leur application catalytique ou autrement n&#39;a pas été étudiée. Ce travail démontre l&#39;applicabilité de l&#39;échafaud de la N, qui, malgré étant généralement sous-développés, possèdent de nombreuses fonctions intéressantes telles que la stabilité du complexe. Nous rapportons ici la voie de synthèse et la caractérisation de laune série de complexes de ruthénium Ph N de qui peuvent trouver une application dans les réactions d&#39;hydrogénation catalytique.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Methanol</td>
			<td rowspan="5">&#8211;</td>
			<td rowspan="5">&#8211;</td>
			<td rowspan="5">Obtained from in-house solvent purification system: Innovative Technology, inc &#34;pure solv&#34; drying tower. Stored in ampules over activated molecular sieves under nitrogen.</td>
		</tr>
		<tr>
			<td>Toluene</td>
		</tr>
		<tr>
			<td>Diethyl Ether</td>
		</tr>
		<tr>
			<td>Tetrahydrofuran (THF)</td>
		</tr>
		<tr>
			<td>Acetonitrile</td>
		</tr>
		<tr>
			<td>d6-Acetone</td>
			<td>VWR</td>
			<td>VWRC87152.0011</td>
			<td>Store in fridge</td>
		</tr>
		<tr>
			<td>Triethylamine</td>
			<td>Sigma-Aldrich</td>
			<td>TO886-1L</td>
			<td>Distilled and stored over activated molecular sieves under N2</td>
		</tr>
		<tr>
			<td>2M Ammonia solution in methanol</td>
			<td>Sigma-Aldrich</td>
			<td>341428-100ML</td>
			<td>Solution comes in a &#34;Sure-Seal&#34; bottle</td>
		</tr>
		<tr>
			<td>NH4PF6</td>
			<td>Sigma-Aldrich</td>
			<td>216593-5G</td>
			<td>Store in desiccator</td>
		</tr>
		<tr>
			<td>Levulinic Acid</td>
			<td>Acros Organics</td>
			<td>125142500</td>
			<td>Solid but melts close to room temperature</td>
		</tr>
		<tr>
			<td>3 &#197; Molecular sieves</td>
			<td>Alfa Aesar</td>
			<td>LO5359</td>
			<td>Activate by heating over night under vacuum</td>
		</tr>
		<tr>
			<td>Schlenk flasks</td>
			<td>GPE</td>
			<td>Custom design</td>
			<td>&#8211;</td>
		</tr>
		<tr>
			<td>Dual-manifold Schlenk line</td>
			<td>GPE</td>
			<td>Custom design</td>
			<td>Dual-manifold of i) N2 that has been passed through a silica drying column and ii) vacuum.</td>
		</tr>
		<tr>
			<td>Rotary vacuum pump</td>
			<td>Edwards</td>
			<td>RV3 A652-01-903</td>
			<td>&#8211;</td>
		</tr>
		<tr>
			<td>100 ml Autoclave Engineer&#39;s high pressure reactor</td>
			<td>Autoclave Engineer</td>
			<td>Custon design</td>
			<td>&#8211;</td>
		</tr>
		<tr>
			<td>Vortex Stirrer</td>
			<td>VWR</td>
			<td>444-1378</td>
			<td>&#8211;</td>
		</tr>
	</tbody>
</table>

the synthesis, characterization and reactivity of a series of ruthenium n-triphosph complexes

Nous rapportons ici la synthèse d&#39;un ligand tridenté de phosphine N (CH 2 PPh 2) 3 (de la N Ph) (1) via une réaction de Mannich à base de phosphore de la phosphine hydroxylmethylene précurseur avec de l&#39;ammoniac dans du methanol sous une atmosphère d&#39;azote. Le N de la Ph ligand précipite de la solution au bout d&#39;environ 1 heure de reflux et on peut isoler analytiquement pur par procédé de filtration de canule simple, sous atmosphère d&#39;azote. La réaction de la N Ph avec le ligand [Ru 3 (CO) 12] au reflux donne une solution rouge foncé qui montrent l&#39;évolution de gaz CO à la complexation du ligand. Cristaux orange du complexe [Ru (CO) 2 {N (CH 2 PPh 2) 3} 3 -κ P] (2) ont été isolées par le refroidissement à la température ambiante. Le 31 P {1 H} spectre RMN a montré un pic caractéristique unique à la fréquence inférieurepar rapport au ligand libre. La réaction d&#39;une solution de toluène d&#39;un complexe 2 avec de l&#39;oxygène conduit à la précipitation instantanée du carbonate complexe [Ru (CO 3) (CO) {N (CH 2 PPh 2) 3} -κ 3 P] (3) en tant que stable de l&#39;air solide orange. Une hydrogénation subséquente de trois sous 15 bars d&#39;hydrogène dans un réacteur à haute pression a donné le complexe de dihydrure [RuH 2 (CO) {N (CH 2 PPh 2) 3} 3 -κ P] (4), qui a été entièrement caractérisé par X cristallographie -ray et spectroscopie RMN. Complexes 3 et 4 sont potentiellement précurseurs de catalyseurs utiles pour une variété de réactions d&#39;hydrogénation, y compris les produits dérivés de la biomasse tels que l&#39;acide lévulinique (LA). Complexe 4 se est révélé réagir avec LA proprement en présence de l&#39;additif de la source de proton NH 4 PF 6 pour donner [Ru (CO) N {(CH 2 PPh 2) 3} 3 -κ P {CH 3 CO (CH 2) 2 CO 2 H} -κ 2 O] (PF 6) (6).

Le N Ph le ligand (1) et la série complexe de ruthénium Ru (CO) 2 {N (CH 2 PPh 2) 3} -κ 3 P] (2), [Ru (CO 3) (CO) {N (CH 2 PPh 2) 3} 3 -κ P] (3) et [Ru (H) 2 (CO) {N (CH 2 PPh 2) 3} 3 -κ P] (4) ont été caractérisés par une H, 13 C {1 H}...

Watch this Scientific Journal Video about The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes at JoVE.com

The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes

Des complexes ruthénium phosphine sont largement utilisés pour des réactions catalytiques homogènes comme les hydrogénations. La synthèse d&#39;une série de nouveaux complexes du ruthénium tridentate portant le ligand N de N (CH 2 PPh 2) 3 est rapporté. En outre, la réaction stoechiométrique du complexe d&#39;un dihydrure Ru N avec de l&#39;acide lévulinique est décrite.

La synthèse, la caractérisation et la réactivité d&#39;une série de ruthénium<em&gt; N</em&gt; -triphos<sup&gt; Ph</sup&gt; Complexes

Herein we report the synthesis of a tridentate phosphine ligand N(CH2PPh2)3 (N-triphosPh) (1) via a phosphorus based Mannich reaction of the ...

the-synthesis-characterization-reactivity-series-ruthenium-n

Research

JoVE Journal

Chemistry

The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes

12.0K vues.  Imperial College London.  Des complexes ruthénium phosphine sont largement utilisés pour des réactions catalytiques homogènes comme les hydrogénations. La synthèse d'une série de nouveaux complexes du ruthénium tridentate portant le ligand N de N (CH 2 PPh 2) 3 est rapporté. En outre, la réaction stoechiométrique du complexe d'un dihydrure Ru N avec de l'acide lévulinique est décrite. 

Vidéo: The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes

Production of Disulfide-stabilized Transmembrane Peptide Complexes for Structural Studies

Physical interactions among the lipid-embedded alpha-helical domains of membrane proteins play a crucial role in folding and assembly of membrane protein complexes and in dynamic processes such as transmembrane (TM) signaling and regulation of cell-surface protein levels. Understanding the structural features driving the association of particular sequences requires sophisticated biophysical and biochemical analyses of TM peptide complexes. However, the extreme hydrophobicity of TM domains makes them very difficult to manipulate using standard peptide chemistry techniques, and production of suitable study material often proves prohibitively challenging. Identifying conditions under which peptides can adopt stable helical conformations and form complexes spontaneously adds a further level of difficulty. Here we present a procedure for the production of homo- or hetero-dimeric TM peptide complexes from materials that are expressed in E. coli, thus allowing incorporation of stable isotope labels for nuclear magnetic resonance (NMR) or non-natural amino acids for other applications relatively inexpensively. The key innovation in this method is that TM complexes are produced and purified as covalently associated (disulfide-crosslinked) assemblies that can form stable, stoichiometric and homogeneous structures when reconstituted into detergent, lipid or other membrane-mimetic materials. We also present carefully optimized procedures for expression and purification that are equally applicable whether producing single TM domains or crosslinked complexes and provide advice for adapting these methods to new TM sequences.

Biophysical and biochemical studies of interactions among membrane-embedded protein domains face many technical challenges, the first of which is obtaining appropriate study material. This article describes a protocol for producing and purifying disulfide-stabilized transmembrane peptide complexes that are suitable for structural analysis by solution nuclear magnetic resonance (NMR) and other analytical applications.

La production de disulfure stabilisées complexes peptide transmembranaire pour des études structurales

Physical  interactions among the lipid-embedded alpha-helical domains of membrane  proteins play a crucial role in folding and assembly of membrane ...

Recherche

Chimie

Isolation and Chemical Characterization of Lipid A from Gram-negative Bacteria

Lipopolysaccharide (LPS) is the major cell surface molecule of gram-negative bacteria, deposited on the outer leaflet of the outer membrane bilayer. LPS can be subdivided into three domains: the distal O-polysaccharide, a core oligosaccharide, and the lipid A domain consisting of a lipid A molecular species and 3-deoxy-D-manno-oct-2-ulosonic acid residues (Kdo). The lipid A domain is the only component essential for bacterial cell survival. Following its synthesis, lipid A is chemically modified in response to environmental stresses such as pH or temperature, to promote resistance to antibiotic compounds, and to evade recognition by mediators of the host innate immune response. The following protocol details the small- and large-scale isolation of lipid A from gram-negative bacteria. Isolated material is then chemically characterized by thin layer chromatography (TLC) or mass-spectrometry (MS). In addition to matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) MS, we also describe tandem MS protocols for analyzing lipid A molecular species using electrospray ionization (ESI) coupled to collision induced dissociation (CID) and newly employed ultraviolet photodissociation (UVPD) methods. Our MS protocols allow for unequivocal determination of chemical structure, paramount to characterization of lipid A molecules that contain unique or novel chemical modifications. We also describe the radioisotopic labeling, and subsequent isolation, of lipid A from bacterial cells for analysis by TLC. Relative to MS-based protocols, TLC provides a more economical and rapid characterization method, but cannot be used to unambiguously assign lipid A chemical structures without the use of standards of known chemical structure. Over the last two decades isolation and characterization of lipid A has led to numerous exciting discoveries that have improved our understanding of the physiology of gram-negative bacteria, mechanisms of antibiotic resistance, the human innate immune response, and have provided many new targets in the development of antibacterial compounds.

Isolation and characterization of the lipid A domain of lipopolysaccharide (LPS) from gram-negative bacteria provides insight into cell surface based mechanisms of antibiotic resistance, bacterial survival and fitness, and how chemically diverse lipid A molecular species differentially modulate host innate immune responses.

Isolement et caractérisation chimique du lipide A de bactéries à Gram négatif

Lipopolysaccharide (LPS) is the major cell surface molecule of gram-negative bacteria, deposited on the outer leaflet of the outer membrane bilayer. LPS ...

Anticancer Metal Complexes: Synthesis and Cytotoxicity Evaluation by the MTT Assay

Titanium (IV) and vanadium (V) complexes are highly potent anticancer agents. A challenge in their synthesis refers to their hydrolytic instability; therefore their preparation should be conducted under an inert atmosphere. Evaluation of the anticancer activity of these complexes can be achieved by the MTT assay.
The MTT assay is a colorimetric viability assay based on enzymatic reduction of the MTT molecule to formazan when it is exposed to viable cells. The outcome of the reduction is a color change of the MTT molecule. Absorbance measurements relative to a control determine the percentage of remaining viable cancer cells following their treatment with varying concentrations of a tested compound, which is translated to the compound anticancer activity and its IC50 values. The MTT assay is widely common in cytotoxicity studies due to its accuracy, rapidity, and relative simplicity.
Herein we present a detailed protocol for the synthesis of air sensitive metal based drugs and cell viability measurements, including preparation of the cell plates, incubation of the compounds with the cells, viability measurements using the MTT assay, and determination of IC50 values.

A method for synthesis of air-sensitive titanium and vanadium anticancer agents is described, along with the evaluation of their cytotoxic activity towards human cancer cell line by the MTT Assay.

Complexes métalliques anticancéreux: Synthèse et évaluation de la cytotoxicité par le dosage au MTT

Titanium (IV) and vanadium (V) complexes are highly potent anticancer agents. A challenge in their synthesis refers to their hydrolytic instability; ...

Split-and-pool Synthesis and Characterization of Peptide Tertiary Amide Library

Peptidomimetics are great sources of protein ligands. The oligomeric nature of these compounds enables us to access large synthetic libraries on solid phase by using combinatorial chemistry. One of the most well studied classes of peptidomimetics is peptoids. Peptoids are easy to synthesize and have been shown to be proteolysis-resistant and cell-permeable. Over the past decade, many useful protein ligands have been identified through screening of peptoid libraries. However, most of the ligands identified from peptoid libraries do not display high affinity, with rare exceptions. This may be due, in part, to the lack of chiral centers and conformational constraints in peptoid molecules. Recently, we described a new synthetic route to access peptide tertiary amides (PTAs). PTAs are a superfamily of peptidomimetics that include but are not limited to peptides, peptoids and N-methylated peptides. With side chains on both &#945;-carbon and main chain nitrogen atoms, the conformation of these molecules are greatly constrained by sterical hindrance and allylic 1,3 strain. (Figure 1) Our study suggests that these PTA molecules are highly structured in solution and can be used to identify protein ligands. We believe that these molecules can be a future source of high-affinity protein ligands. Here we describe the synthetic method combining the power of both split-and-pool and sub-monomer strategies to synthesize a sample one-bead one-compound (OBOC) library of PTAs.

Peptide tertiary amides (PTAs) are a superfamily of peptidomimetics that include but are not limited to peptides, peptoids and N-methylated peptides. Here we describe a synthetic method which combines&#160;both split-and-pool and sub-monomer strategies to synthesize a one-bead one-compound library of PTAs.

Split-et-piscine Synthèse et caractérisation de peptides tertiaire Amide Bibliothèque

Peptidomimetics are great sources of protein ligands. The oligomeric nature of these compounds enables us to access large synthetic libraries on solid ...

Nucleoside Triphosphates - From Synthesis to Biochemical Characterization

The traditional strategy for the introduction of chemical functionalities is the use of solid-phase synthesis by appending suitably modified phosphoramidite precursors to the nascent chain. However, the conditions used during the synthesis and the restriction to rather short sequences hamper the applicability of this methodology. On the other hand, modified nucleoside triphosphates are activated building blocks that have been employed for the mild introduction of numerous functional groups into nucleic acids, a strategy that paves the way for the use of modified nucleic acids in a wide-ranging palette of practical applications such as functional tagging and generation of ribozymes and DNAzymes. One of the major challenges resides in the intricacy of the methodology leading to the isolation and characterization of these nucleoside analogues.
	
	In this video article, we present a detailed protocol for the synthesis of these modified analogues using phosphorous(III)-based reagents. In addition, the procedure for their biochemical characterization is divulged, with a special emphasis on primer extension reactions and TdT tailing polymerization. This detailed protocol will be of use for the crafting of modified dNTPs and their further use in chemical biology.

The protocol described herein aims to explain and abridge the numerous obstacles in the way of the intricate route leading to modified nucleoside triphosphates. Consequently, this protocol facilitates both the synthesis of these activated building-blocks and their availability for practical applications.

Nucléosidiques Triphosphates - de la synthèse à caractérisation biochimique

The  traditional strategy for the introduction of chemical functionalities is the  use of solid-phase synthesis by appending suitably modified ...

Synthesis and Characterization of Functionalized Metal-organic Frameworks

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and technological applications. Their signature property is their ultrahigh porosity, which however imparts a series of challenges when it comes to both constructing them and working with them. Securing desired MOF chemical and physical functionality by linker/node assembly into a highly porous framework of choice can pose difficulties, as less porous and more thermodynamically stable congeners (e.g., other crystalline polymorphs, catenated analogues) are often preferentially obtained by conventional synthesis methods. Once the desired product is obtained, its characterization often requires specialized techniques that address complications potentially arising from, for example, guest-molecule loss or preferential orientation of microcrystallites. Finally, accessing the large voids inside the MOFs for use in applications that involve gases can be problematic, as frameworks may be subject to collapse during removal of solvent molecules (remnants of solvothermal synthesis). In this paper, we describe synthesis and characterization methods routinely utilized in our lab either to solve or circumvent these issues. The methods include solvent-assisted linker exchange, powder X-ray diffraction in capillaries, and materials activation (cavity evacuation) by supercritical CO2 drying. Finally, we provide a protocol for determining a suitable pressure region for applying the Brunauer-Emmett-Teller analysis to nitrogen isotherms, so as to estimate surface area of MOFs with good accuracy.

Synthesis, activation, and characterization of intentionally designed metal-organic framework materials is challenging, especially when building blocks are incompatible or unwanted polymorphs are thermodynamically favored over desired forms. We describe how applications of solvent-assisted linker exchange, powder X-ray diffraction in capillaries and activation via supercritical CO2 drying, can address some of these challenges.

Cadres de synthèse et la caractérisation de fonctionnalisé métal-organique

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and ...

Synthesis and Characterization of Supramolecular Colloids

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical properties for applications in photonics, drug delivery and coating technology. Here we present a new family of colloidal building blocks, coined supramolecular colloids, whose self-assembly is controlled through surface-functionalization with a benzene-1,3,5-tricarboxamide (BTA) derived supramolecular moiety. Such BTAs interact via directional, strong, yet reversible hydrogen-bonds with other identical BTAs. Herein, a protocol is presented that describes how to couple these BTAs to colloids and how to quantify the number of coupling sites, which determines the multivalency of the supramolecular colloids. Light scattering measurements show that the refractive index of the colloids is almost matched with that of the solvent, which strongly reduces the van der Waals forces between the colloids. Before photo-activation, the colloids remain well dispersed, as the BTAs are equipped with a photo-labile group that blocks the formation of hydrogen-bonds. Controlled deprotection with UV-light activates the short-range hydrogen-bonds between the BTAs, which triggers the colloidal self-assembly. The evolution from the dispersed state to the clustered state is monitored by confocal microscopy. These results are further quantified by image analysis with simple routines using ImageJ and Matlab. This merger of supramolecular chemistry and colloidal science offers a direct route towards light- and thermo-responsive colloidal assembly encoded in the surface-grafted monolayer.

A protocol for the synthesis and characterization of colloids coated with supramolecular moieties is described. These supramolecular colloids undergo self-assembly upon the activation of the hydrogen-bonds between the surface-anchored molecules by UV-light.

Synthèse et caractérisation de supramoléculaires Colloids

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical ...

Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level

We demonstrate a method for the synthesis of cyclic polymers and a protocol for characterizing their diffusive motion in a melt state at the single molecule level. An electrostatic self-assembly and covalent fixation (ESA-CF) process is used for the synthesis of the cyclic poly(tetrahydrofuran) (poly(THF)). The diffusive motion of individual cyclic polymer chains in a melt state is visualized using single molecule fluorescence imaging by incorporating a fluorophore unit in the cyclic chains. The diffusive motion of the chains is quantitatively characterized by means of a combination of mean-squared displacement (MSD) analysis and a cumulative distribution function (CDF) analysis. The cyclic polymer exhibits multiple-mode diffusion which is distinct from its linear counterpart. The results demonstrate that the diffusional heterogeneity of polymers that is often hidden behind ensemble averaging can be revealed by the efficient synthesis of the cyclic polymers using the ESA-CF process and the quantitative analysis of the diffusive motion at the single molecule level using the MSD and CDF analyses.

A protocol for the synthesis and characterization of diffusive motion of cyclic polymers at the single molecule level is presented.

Synthèse des polymères cycliques et caractérisation de leur mouvement Diffusive dans l&#39;État Melt à la molécule unique Level

We demonstrate a method for the synthesis of cyclic polymers and a protocol for characterizing their diffusive motion in a melt state at the single ...

Combining Solid-state and Solution-based Techniques: Synthesis and Reactivity of Chalcogenidoplumbates(II or IV)

The phases of &#34;PbCh2&#34; (Ch = Se, Te) are obtained from solid-state syntheses (i.e., by the fusion of the elements under inert conditions in silica glass ampules). Reduction of such phases by elemental alkaline metals in amines affords crystalline chalcogenidoplumbate(II) salts comprised of [PbTe3]2- or [Pb2Ch3]2- anions, depending upon which sequestering agent for the cations is present: crown ethers, like 18-crown-6, or cryptands, like [2.2.2]crypt. Reactions of solutions of such anions with transition-metal compounds yield (poly-)chalcogenide anions or transition-metal chalcogenide clusters, including one with a &#181;-PbSe ligand (i.e., the heaviest-known CO homolog).
In contrast, the solid-state synthesis of a phase of the nominal composition &#34;K2PbSe2&#34; by successive reactions of the elements and by the subsequent solvothermal treatment in amines yields the first non-oxide/halide inorganic lead(IV) compound: a salt of the ortho-selenidoplumbate(IV) anion [PbSe4]4-. This was unexpected due to the redox potentials of Pb(IV) and Se(-II). Such methods can further be applied to other elemental combinations, leading to the formation of solutions with binary [HgTe2]2- or [BiSe3]3- anions, or to large-scale syntheses of K2Hg2Se3 or K3BiSe3 via the solid-state route.
All compounds are characterized by single-crystal X-ray diffraction and elemental analysis; solutions of plumbate salts can be investigated by 205Pb and 77Se or 127Te NMR techniques. Quantum chemical calculations using density functional theory methods enable energy comparisons. They further allow for insights into the electronic configuration and thus, the bonding situation. Molecular Rh-containing Chevrel-type compounds were found to exhibit delocalized mixed valence, whereas similar telluridopalladate anions are electron-precise; the cluster with the &#181;-PbSe ligand is energetically favored over a hypothetical CO analog, in line with the unsuccessful attempt at its synthesis. The stability of formal Pb(IV) within the [PbSe4]4- anion is mainly due to a suitable stabilization within the crystal lattice.

Combining Solid-state and Solution-based Techniques: Synthesis and Reactivity of ChalcogenidoplumbatesII or IV

The synthesis of chalcogenidoplumbates(II,IV) via the in situ reduction of nominal "PbCh2" (Ch = Chalcogen) and via a solid-state reaction and subsequent solvothermal reactions is presented. Additionally, reactivities of plumbate(II) solutions are portrayed, which yield the heaviest-known CO homolog known to date: the &#181;-PbSe ligand.

La combinaison de semi-conducteurs et des techniques à base de Solution: Synthèse et réactivité de Chalcogenidoplumbates (II ou IV)

The phases of &#34;PbCh2&#34; (Ch = Se, Te) are obtained from solid-state syntheses (i.e., by the fusion of the elements under inert conditions in silica ...

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Detailed and generalized protocols are presented for the synthesis and subsequent purification of four palladium N-heterocyclic carbene complexes from benzimidazolium salts. Detailed and generalized protocols are also presented for testing the catalytic activity of such complexes in arylation and Suzuki-Miyaura cross-coupling reactions. Representative results are shown for the catalytic activity of the four complexes in arylation and Suzuki-Miyaura type reactions. For each of the reactions investigated, at least one of the four complexes successfully catalyzed the reaction, qualifying them as promising candidates for catalysis of many carbon-carbon bond-forming reactions. The protocols presented are general enough to be adapted for the synthesis, purification and catalytic activity testing of new palladium N-heterocyclic carbene complexes.

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Detailed and generalized protocols are presented for the synthesis and subsequent purification of four palladium N-heterocyclic carbene complexes from benzimidazolium salts. The complexes were tested for catalytic activity in arylation and Suzuki-Miyaura reactions. For each reaction investigated, at least one of the four complexes successfully catalyzed the reaction.

Palladium<em&gt; N</em&gt; - Complexes de carbène hétérocyclique: synthèse des sels de benzimidazolium et activité catalytique dans les réactions de formation de liaison carbone-carbone

Detailed and generalized protocols are presented for the synthesis and subsequent purification of four palladium N-heterocyclic carbene complexes from ...