РФС благодарит Национальный научный фонд (CHE-0844946) для поддержки этой работы.

1. Синтез SmI 2 (0,1 M) <ol><li> Пламя высохнуть 50 мл круглодонную колбу и промойте его с аргоном. Добавить мешалкой и покрывать колбы с перегородками. Взвесить самария металла (0,2 г, 1,3 ммоль) и добавьте в колбу, снова промывки колбы с аргоном. </li><li> Добавить 10 мл сухого, тщательно дегазировали тетрагидрофуран (ТГФ), затем кристаллы йода (0,254 г, 2,0 ммоль). Добавить воздушном шаре аргона через перегородку, это сохраняет положительное давление в атмосфере Ar на реакцию. </li><li> Раствор перемешивают энергично при комнатной температуре в течение 3 часов. Как SmI 2 порождается раствор проходит через различные изменения цвета, оранжевый следуют желтые (45 мин), и зеленый (1 час), которая в конечном итоге превращается в синий цвет. </li><li> Окончательный темно-синего цвета является признаком того, что однократно ионизованного самария сформировался. В целях обеспечения полного преобразования, перемешать раствор в течение по крайней мере 3 часа перед использованием SmI 2 в синтезе. </li></ol> 2. SaMarium Барбье Реакция-гексаметилфосфорамида (ГМФА) Сложение <ol><li> Для того, чтобы SmI 2-HMPA комплекса, принимают свежеприготовленный SmI 2 в атмосфере аргона (10 мл, 0,1 М, 1,0 ммоль) и добавляют 1,75 мл HMPA (10 экв., 10 ммоль) с помощью шприца по каплям в атмосфере аргона. Темно-фиолетового цвета формы. </li><li> Отдельно в чистой, сухой флакон в атмосфере аргона, добавляют iodododecane (0,45 ммоль, 110 мкл), 3-пентанон (0,45 ммоль, 48 мкл) и 2 мл сухого ТГФ. </li><li> Добавьте смесь раствора субстрата по каплям к SmI 2 / HMPA комплекса. </li><li> В течение 5 мин перемешивания фиолетовый цвет начнет искать облачность, указывающий на конец реакции. </li><li> После завершения реакции, подвергать решение в воздух, чтобы утолить ее, при перемешивании дальнейшие изменения цвета на желтый. </li><li> Реакция затем обрабатывают промывкой насыщенным водным раствором хлорида аммония. Добавить решение в делительную воронку и добавляют диэтиловый эфир (5 мл). После энергичного встряхивания удалитьверхний органический слой, добавьте еще диэтиловый эфир. Из водный слой еще два раза, а затем объединить все органические слои. </li><li> Вымойте органического слоя насыщенным раствором водного раствора тиосульфата натрия. Снимите нижний водный слой, а затем промыть водой, а затем последней промывки рассолом. Получить верхнего органического слоя и добавить сульфат магния, чтобы впитать в последнюю количество воды, присутствующей в растворе. </li><li> Передайте решение через пробку Florisil для того, чтобы удалить излишки HMPA. </li><li> Концентрат раствора на роторном испарителе для получения Барбье продукта. Продукт был определен GCMS и 1 Н ЯМР 23. </li></ol> 3. Самарий Барбье реакция-Ni (АРКГА) 2 Catalyst <ol><li> Взвесить Ni (АРКГА) 2 (1 моль%, 0,01 ммоль, 0,0026 г) и добавить в чистый, сухой флакон, содержащий 3 мл дегазированной ТГФ в атмосфере аргона. Добавить Ni (АРКГА) 2 раствор через шприц свежеприготовленного сЕШЕНИЕ 0,1 М SmI 2 (1,0 ммоль, 10 мл). </li><li> Отдельно в чистой, сухой флакон в атмосфере аргона, добавляют iodododecane (0,45 ммоль, 110 мкл), 3-пентанон (0,45 ммоль, 48 мкл) и 2 мл сухого ТГФ. </li><li> Добавить раствор субстрата по каплям к SmI 2 / Ni смеси. </li><li> В течение пятнадцати минут перемешивания, синий цвет будет рассеиваться, образуя желто-зеленого цвета, указывающий на конец реакции. </li><li> После завершения реакции, подвергать решение в воздух, чтобы утолить ее, при перемешивании дальнейшие изменения цвета на желтый. Работа на реакцию промывкой 0,1 М водного. Соляная кислота (3 мл). Добавить решение в делительную воронку и добавляют диэтиловый эфир (5 мл). </li><li> Вымойте органический слой используя протокол, описанный ранее с водным раствором тиосульфата натрия, водой и рассолом, а затем сушат над сульфатом магния. Концентрат раствора для получения Барбье продукта. Продукт может быть идентифицирован по GCMS и 1 Н ЯМР 28. </sдо&gt; </li></ol>

<ol>
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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrochemical+investigation+of+the+reducing+power+of+SmI2+in+THF+and+the+effect+of+HMPA+cosolvent.">Electrochemical investigation of the reducing power of SmI2 in THF and the effect of HMPA cosolvent.</a> Tetrahedron Lett. 38, 1137-1140 (1997).</li><li>Enenaerke, R. J., Hertz, T., Skrydstrup, T., Daasbjerg, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evidence+for+ionic+samarium(II)+species+in+THF/HMPA+solution+and+investigation+of+Their+electron-donating+properties.">Evidence for ionic samarium(II) species in THF/HMPA solution and investigation of Their electron-donating properties.</a> Chem. Eur. 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Chem. 65, 8333-8339 (2000).</li><li>Molander, G. A., Alonso-Alija, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sequenced+reactions+with+samarium(II)+iodide.+Sequential+intermolecular+carbonyl+addition/intramolecular+nucleophilic+acyl+substitution+for+the+preparation+of+seven-,+eight-,+and+nine-membered+carbocycles.">Sequenced reactions with samarium(II) iodide. Sequential intermolecular carbonyl addition/intramolecular nucleophilic acyl substitution for the preparation of seven-, eight-, and nine-membered carbocycles.</a> J. Org. Chem. 63, 4366-4373 (1998).</li><li>Machrouhi, F., Hamann, B., Namy, J. L., Kagan, K. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+reactivity+of+diiodosamarium+by+catalysis+with+transition+metal+salts.">Improved reactivity of diiodosamarium by catalysis with transition metal salts.</a> Synlett. 7, 633-634 (1996).</li><li>Choquette, K. A., Sadasivam, D. V., Flowers, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Catalytic+Ni(II)+in+reactions+of+SmI2:+Sm(II)-+or+Ni(0)-+based+chemistry?.">Catalytic Ni(II) in reactions of SmI2: Sm(II)- or Ni(0)- based chemistry?.</a> J. Am. Chem. Soc. 133, 10655-10661 (2011).</li></ol>

Нет конфликта интересов объявлены.

Простая процедура для создания SmI 2 решения и его применение в органическом синтезе с использованием двух из наиболее распространенных добавок, представленные здесь. Эти два примера описан изобразить важность механистического понимания реакции для тонкой настройки реактивности SmI 2. Знание основу механизма реакции позволяет использовать этот реагент быть адаптированы синтетические химиков в соответствии с требованиями их реакции. Это единственный электрон однородной восстановителя прост в обращении и могут быть приобретены из коммерческих источников. Хотя приведенные выше протоколе прямо вперед, когда сделано в инертных условиях, некоторые общие процедуры устранения неисправностей являются: (а) убедиться, что ТГФ правильно дегазации и сухая, (б) если Sm металла была длительным воздействием воздуха она может иметь окисленных внешний слой, растереть металла с раствором и pestal, чтобы разоблачить чистую поверхность металла, (с)пламени высушить всю стеклянную посуду и прохладной атмосфере аргона, (г) аргона предпочтительнее инертной атмосфере азота в течение, как позже было показано, что взаимодействие с металлом, (д) ​​наличие избыточного Sm-металл помогает поддерживать концентрацию SmI 2, (е) resublime кристаллы йода.

<table border="1"><tbody><tr><td> Название реагента </td><td> Компания </td><td> Номер в каталоге </td><td> Комментарии (по желанию) </td></tr><tr><td> Самарий металла </td><td> Acros </td><td> 29478-0100 </td><td> -40 Сетки, 99,9% (металлы основе) </td></tr><tr><td> ТГФ </td><td> OmniSolv </td><td> TX0282-1 </td><td> Очищенная с помощью инновационных технологий растворителя системы очистки. В качестве альтернативы может быть дегазацию путем свободного насос-оттаивания метод </td></tr><tr><td> Йод </td><td> Alfa Aesar </td><td> 41955-22 </td><td> Resublimed кристаллы, 99,8% </td></tr><tr><td> Iodododecane </td><td> Acros </td><td> 25009-0250 </td><td> 98% </td></tr><tr><td> 3-пентанона </td><td> Alfa Aesar </td><td> AAA15297-AE </td><td> 99% </td></tr><tr><td> HMPA </td><td> Alderich </td><td> H11602 </td><td> 98%, Перегонять из CaO в атмосфере аргона </td></tr><tr><td> NiI 2 </td><td> Alfa Aesar </td><td> 22893 </td><td> 99,5% (металлы основе) </td></tr></tbody></table>

preparation and use of samarium diiodide (smi2) in organic synthesis: the mechanistic role of hmpa and ni(ii) salts in the samarium barbier reaction

Although initially considered an esoteric reagent, SmI2 has become a common tool for synthetic organic chemists. SmI2 is generated through the addition of molecular iodine to samarium metal in THF.1,2-3 It is a mild and selective single electron reductant and its versatility is a result of its ability to initiate a wide range of reductions including C-C bond-forming and cascade or sequential reactions. SmI2 can reduce a variety of functional groups including sulfoxides and sulfones, phosphine oxides, epoxides, alkyl and aryl halides, carbonyls, and conjugated double bonds.2-12 One of the fascinating features of SmI-2-mediated reactions is the ability to manipulate the outcome of reactions through the selective use of cosolvents or additives. In most instances, additives are essential in controlling the rate of reduction and the chemo- or stereoselectivity of reactions.13-14 Additives commonly utilized to fine tune the reactivity of SmI2 can be classified into three major groups: (1) Lewis bases (HMPA, other electron-donor ligands, chelating ethers, etc.), (2) proton sources (alcohols, water etc.), and (3) inorganic additives (Ni(acac)2, FeCl3, etc).3
Understanding the mechanism of SmI2 reactions and the role of the additives enables utilization of the full potential of the reagent in organic synthesis. The Sm-Barbier reaction is chosen to illustrate the synthetic importance and mechanistic role of two common additives: HMPA and Ni(II) in this reaction. The Sm-Barbier reaction is similar to the traditional Grignard reaction with the only difference being that the alkyl halide, carbonyl, and Sm reductant are mixed simultaneously in one pot.1,15 Examples of Sm-mediated Barbier reactions with a range of coupling partners have been reported,1,3,7,10,12 and have been utilized in key steps of the synthesis of large natural products.16,17 Previous studies on the effect of additives on SmI2 reactions have shown that HMPA enhances the reduction potential of SmI2 by coordinating to the samarium metal center, producing a more powerful,13-14,18 sterically encumbered reductant19-21 and in some cases playing an integral role in post electron-transfer steps facilitating subsequent bond-forming events.22 In the Sm-Barbier reaction, HMPA has been shown to additionally activate the alkyl halide by forming a complex in a pre-equilibrium step.23
Ni(II) salts are a catalytic additive used frequently in Sm-mediated transformations.24-27 Though critical for success, the mechanistic role of Ni(II) was not known in these reactions. Recently it has been shown that SmI2 reduces Ni(II) to Ni(0), and the reaction is then carried out through organometallic Ni(0) chemistry.28
These mechanistic studies highlight that although the same Barbier product is obtained, the use of different additives in the SmI2 reaction drastically alters the mechanistic pathway of the reaction. The protocol for running these SmI2-initiated reactions is described.

На рисунке 1 показана реакция самария Барбье. Без добавок Sm-опосредованной реакции занимает 72 часов, получая 69% желаемого продукта с остальными бытия исходных материалов. С добавлением 10 или более экв. из HMPA реакции почти количественным и завершается в течение нескольких минут. 15,23 с добавлением 1 мол% Ni (АРКГА) 2, реакция завершена в течение 15 мин, с выходом 97% 28. Когда HMPA добавляют в SmI 2, сорастворитель вытесняет координируется ТГФ с образованием SmI 2 - (HMPA) 4. С добавлением еще более HMPA (6-10 экв.), Йодид-ионов смещаются к внешней сфере (рис. 2). 19-21 Механистические исследования показывают, что при HMPA используется в Sm-Барбье реакции сорастворителя также взаимодействует с алкилгалогенидом подложки формирования комплекса, который удлиняет углерод-галоидных связей, активизации сpecies что делает его более восприимчивым к сокращению на Sm (рис. 3). Благодаря этому глубокому пониманию роли HMPA, механизм Sm-Барбье реакции с HMPA было предложено (рис. 4) 23. Алкилгалогенидом-HMPA комплекса, образованного в предравновесных шаг уменьшается на Sm / HMPA, чтобы сформировать радикала в определении скорости шага. Радикальное подвергается дальнейшему сокращению сформировать organosamarium видов, которые пары с карбонильной и на протонирования дает конечный продукт. В случае Ni (II) добавка, SMI 2 сначала уменьшается Ni (II) с Ni (0) преимущественно за снижение одной из подложек. На основании кинетических и механистические исследования следующий механизм был предложен (рис. 5). 28 После сокращения на SmI 2, растворимый Ni (0) видов вставляет в алкилгалогенидом образования связи organonickel видов. Под влиянием высокой oxophilic характер Sm (III)<html> , Transmetallation сформировать organosamarium промежуточных релизов Ni (II) обратно в каталитического цикла. Organosamarium то пары с карбонильной, и после протонирования формирует желаемое третичного спирта. Было также отмечено, что Ni (0) наночастицы образуются в результате Sm-опосредованного снижения Ni (II), однако эти частицы оказались неактивными и источник дезактивации катализатора. <img alt="Рисунок 1" fo:content-width="4in" fo:src="/files/ftp_upload/4323/4323fig1highres.jpg" src="/files/ftp_upload/4323/4323fig1.jpg" /> Рисунок 1. Самария Барбье реакции с iodododecane и 3-пентанона. <img alt="Рисунок 2" fo:content-width="4in" fo:src="/files/ftp_upload/4323/4323fig2highres.jpg" src="/files/ftp_upload/4323/4323fig2.jpg" /> Рисунок 2. SmI 2-HMPA комплекса. ontent &quot;FO: Keep-together.within-страница =&quot; Всегда &quot;&gt; <img alt="Рисунок 3" fo:content-width="3.5in" fo:src="/files/ftp_upload/4323/4323fig3highres.jpg" src="/files/ftp_upload/4323/4323fig3.jpg" /> Рисунок 3. HMPA и алкильные сложные йодида. <img alt="Рисунок 4" fo:content-width="4.5in" fo:src="/files/ftp_upload/4323/4323fig4highres.jpg" src="/files/ftp_upload/4323/4323fig4.jpg" /> Рисунок 4. Предложенный механизм реакции самария Барбье с избыточным HMPA. <img alt="Рисунок 5" fo:content-width="4in" fo:src="/files/ftp_upload/4323/4323fig5highres.jpg" src="/files/ftp_upload/4323/4323fig5.jpg" /> Рисунок 5. Предлагаемый механизм для реакции самария Барбье содержащих каталитических Ni (II).

Watch this Scientific Journal Video about Preparation and Use of Samarium Diiodide SmI2 in Organic Synthesis: The Mechanistic Role of HMPA and NiII Salts in the Samarium Barbier Reaction at JoVE.com

Preparation and Use of Samarium Diiodide SmI2 in Organic Synthesis: The Mechanistic Role of HMPA and NiII Salts in the Samarium Barbier Reaction

Простой процедуры по подготовке самария дииодида (SMI<sub&gt; 2</sub&gt;) В ТГФ описано. Роль два основных добавок именно гексаметилфосфорамида (ГМФА) и Ni (АРКГА)<sub&gt; 2</sub&gt; В Sm опосредованной реакции продемонстрировано в Sm-Барбье реакции.

Подготовка и использование самария дииодида (SMI<sub&gt; 2</sub&gt;) В органическом синтезе: Механистические Роль HMPA и Ni (II) соли в реакции самария Барбье

Although initially considered an esoteric reagent, SmI2 has become a common tool for synthetic organic chemists. SmI2 is generated through the addition of ...

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Preparation and Use of Samarium Diiodide (SmI2) in Organic Synthesis: The Mechanistic Role of HMPA and Ni(II) Salts in the Samarium Barbier Reaction

32.7K Views.  Lehigh University. Простой процедуры по подготовке самария дииодида (SMI 2) В ТГФ описано. Роль два основных добавок именно гексаметилфосфорамида (ГМФА) и Ni (АРКГА) 2 В Sm опосредованной реакции продемонстрировано в Sm-Барбье реакции.

Video: Preparation and Use of Samarium Diiodide SmI2 in Organic Synthesis: The Mechanistic Role of HMPA and NiII Salts in the Samarium Barbier Reaction

Synthesis, Cellular Delivery and In vivo Application of Dendrimer-based pH Sensors

The development of fluorescent indicators represented a revolution for life sciences. Genetically encoded and synthetic fluorophores with sensing abilities allowed the visualization of biologically relevant species with high spatial and temporal resolution. Synthetic dyes are of particular interest thanks to their high tunability and the wide range of measureable analytes. However, these molecules suffer several limitations related to small molecule behavior (poor solubility, difficulties in targeting, often no ratiometric imaging allowed). In this work we introduce the development of dendrimer-based sensors and present a procedure for pH measurement in vitro, in living cells and in vivo. We choose dendrimers as ideal platform for our sensors for their many desirable properties (monodispersity, tunable properties, multivalency) that made them a widely used scaffold for several biomedical devices. The conjugation of fluorescent pH indicators to the dendrimer scaffold led to an enhancement of their sensing performances. In particular dendrimers exhibit reduced cell leakage, improved intracellular targeting and allow ratiometric measurements. These novel sensors were successfully employed to measure pH in living HeLa cells and in vivo in mouse brain.

Synthesis, Cellular Delivery and In vivo Application of Dendrimer-based pH Sensors

Fluorescence sensors are powerful tools in life science. Here we describe a methodology to synthesize and use dendrimer-based fluorescent sensors to measure pH in living cells and in vivo. The dendritic scaffold enhances the properties of conjugated fluorescent dyes leading to improved sensing properties.

Синтез, Сотовый Доставка и<em&gt; В естественных условиях</em&gt; Применение датчиков рН Дендримеров основе

The development of  fluorescent indicators represented a revolution for life sciences. Genetically  encoded and synthetic fluorophores with sensing ...

Amide Coupling Reaction for the Synthesis of Bispyridine-based Ligands and Their Complexation to Platinum as Dinuclear Anticancer Agents

Amide coupling reactions can be used to synthesize bispyridine-based ligands for use as bridging linkers in multinuclear platinum anticancer drugs. Isonicotinic acid, or its derivatives, are coupled to variable length diaminoalkane chains under an inert atmosphere in anhydrous DMF or DMSO with the use of a weak base, triethylamine, and a coupling agent, 1-propylphosphonic anhydride. The products precipitate from solution upon formation or can be precipitated by the addition of water. If desired, the ligands can be further purified by recrystallization from hot water. Dinuclear platinum complex synthesis using the bispyridine ligands is done in hot water using transplatin. The most informative of the chemical characterization techniques to determine the structure and gross purity of both the bispyridine ligands and the final platinum complexes is 1H NMR with particular analysis of the aromatic region of the spectra (7-9 ppm). The platinum complexes have potential application as anticancer agents and the synthesis method can be modified to produce trinuclear and other multinuclear complexes with different hydrogen bonding functionality in the bridging ligand.

This protocol describes the use of amide coupling reactions of isonicotinic acid and diaminoalkanes to form bridging ligands suitable for use in the synthesis of multinuclear platinum complexes, which combine aspects of the anticancer drugs BBR3464 and picoplatin.

Амид Реакция сочетания для синтеза биспиридина основе лигандов и их комплексообразования платины как двухъядерные противораковые агенты

Amide coupling reactions can be used to synthesize bispyridine-based ligands for use as bridging linkers in multinuclear platinum anticancer drugs. ...

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.

Синтеза и характеристики функционализированным Металл-органические каркасы

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

Preparation and Use of Carbonyl-decorated Carbenes in the Activation of White Phosphorus

Here we present a protocol for the synthesis of two distinct carbonyl-decorated carbenes. Both carbenes can be prepared using nearly identical procedures in multi-gram scale quantities. The goal of this manuscript is to clearly detail how to handle and prepare these unique carbenes such that a synthetic chemist of any skill level can work with them. The two carbenes described are a diamidocarbene (DAC, carbene 1) and a monoamidoaminocarbene (MAAC 2). These carbenes are highly electron-deficient and as such display reactivity profiles that are atypical of more traditional N-heterocyclic carbenes. Additionally, these two carbenes only differ in their electrophilic character and not their steric parameters, making them ideal for studying how carbene electronics influence reactivity. To demonstrate this phenomenon, we are also describing the activation of white phosphorus (P4) using these carbenes. Depending on the carbene used, two very different phosphorus-containing compounds can be isolated. When the DAC 1 is used, a tris(phosphaalkenyl)phosphane can be isolated as the exclusive product. Remarkably however, when MAAC 2 is added to P4 under identical reaction conditions, an unexpected carbene-supported P8&#160;allotrope of phosphorus is isolated exclusively. Mechanistic studies demonstrate that this carbene-supported P8allotrope forms via a [2+2] cycloaddition dimerization of a transient diphosphene which has been trapped by treatment with 2,3-dimethyl-1,3-butadiene.

Here, we present a protocol for the synthesis of two carbonyl-decorated carbenes. The protocol makes these interesting compounds readily available to chemists of all skill levels. In addition to the synthesis of these two carbenes, their use in the activation of white phosphorus is also described.

Получение и применение Карбонильное оформленных карбенов в активации белого фосфора

Here we present a protocol for the synthesis of two distinct carbonyl-decorated carbenes. Both carbenes can be prepared using nearly identical procedures ...

Metal-free Synthesis of Ynones from Acyl Chlorides and Potassium Alkynyltrifluoroborate Salts

Ynones are a valuable functional group and building block in organic synthesis. Ynones serve as a precursor to many important organic functional groups and scaffolds. Traditional methods for the preparation of ynones are associated with drawbacks including harsh conditions, multiple purification steps, and the presence of unwanted byproducts. An alternative method for the straightforward preparation of ynones from acyl chlorides and potassium alkynyltrifluoroborate salts is described herein. The adoption of organotrifluoroborate salts as an alternative to organometallic reagents for the formation of new carbon-carbon bonds has a number of advantages. Potassium organotrifluoroborate salts are shelf stable, have good functional group tolerance, low toxicity, and a wide variety are straightforward to prepare. The title reaction proceeds rapidly at ambient temperature in the presence of a Lewis acid without the exclusion of air and moisture. Fair to excellent yields may be obtained via reaction of various aryl and alkyl acid chlorides with alkynyltrifluoroborate salts in the presence of boron trichloride.

The goal of this manuscript is to demonstrate a straightforward method for the preparation of ynones from acyl chloride and potassium alkynyltrifluoroborate salt starting materials. The one-pot reaction proceeds rapidly in the presence of boron trichloride without exclusion of air and moisture.

Безметалловая Синтез Ynones от ацилхлориды и калия Alkynyltrifluoroborate солей

Ynones are a valuable functional group and building block in organic synthesis. Ynones serve as a precursor to many important organic functional groups ...

Synthesis and Reaction Chemistry of Nanosize Monosodium Titanate

This paper describes the synthesis and peroxide-modification of nanosize monosodium titanate (nMST), along with an ion-exchange reaction to load the material with Au(III) ions. The synthesis method was derived from a sol-gel process used to produce micron-sized monosodium titanate (MST), with several key modifications, including altering reagent concentrations, omitting a particle seed step, and introducing a non-ionic surfactant to facilitate control of particle formation and growth. The resultant nMST material exhibits spherical-shaped particle morphology with a monodisperse distribution of particle diameters in the range from 100 to 150&#160;nm. The nMST material was found to have a Brunauer-Emmett-Teller (BET) surface area of 285 m2g-1, which is more than an order of magnitude higher than the micron-sized MST. The isoelectric point of the nMST measured 3.34 pH units, which is a pH unit lower than that measured for the micron-size MST. The nMST material was found to serve as an effective ion exchanger under weakly acidic conditions for the preparation of an Au(III)-exchange nanotitanate. In addition, the formation of the corresponding peroxotitanate was demonstrated by reaction of the nMST with hydrogen peroxide.

The surfactant mediated sol-gel synthesis of nanosized monosodium titanate is described, along with preparation of the corresponding peroxide modified material. An ion-exchange reaction with Au(III) is also presented.

Синтез и реакции химии наноразмерных Monosodium титаната

This paper describes the synthesis and peroxide-modification of nanosize monosodium titanate (nMST), along with an ion-exchange reaction to load the ...

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.

Синтез и характеристика супрамолекулярных коллоидов

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

Synthesis of Protein Bioconjugates via Cysteine-maleimide Chemistry

The chemical linking or bioconjugation of proteins to fluorescent dyes, drugs, polymers and other proteins has a broad range of applications, such as the development of antibody drug conjugates (ADCs) and nanomedicine, fluorescent microscopy and systems chemistry. For many of these applications, specificity of the bioconjugation method used is of prime concern. The Michael addition of maleimides with cysteine(s) on the target proteins is highly selective and proceeds rapidly under mild conditions, making it one of the most popular methods for protein bioconjugation.
We demonstrate here the modification of the only surface-accessible cysteine residue on yeast cytochrome c with a ruthenium(II) bisterpyridine maleimide. The protein bioconjugation is verified by gel electrophoresis and purified by aqueous-based fast protein liquid chromatography in 27% yield of isolated protein material. Structural characterization with MALDI-TOF MS and UV-Vis is then used to verify that the bioconjugation is successful. The protocol shown here is easily applicable to other cysteine - maleimide coupling of proteins to other proteins, dyes, drugs or polymers.

Synthesis of Protein Bioconjugates via Cysteine-maleimide Chemistry

This protocol details the important steps required for the bioconjugation of a cysteine containing protein to a maleimide, including reagent purification, reaction conditions, bioconjugate purification and bioconjugate characterization.

Синтез белка биоконъюгатов<em&gt; с помощью</em&gt; Цистеин-малеимид химии

The chemical linking or bioconjugation of proteins to fluorescent dyes, drugs, polymers and other proteins has a broad range of applications, such as the ...

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.

Синтез циклических полимеров и характеристика их диффузионное движение в расплавленном состоянии на уровне отдельной молекулы

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 ...

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.

палладий<em&gt; N</em&gt; -Гетероциклические карбеновые комплексы: синтез из бензимидазолиевых солей и каталитическая активность в углерод-углеродных связующих реакциях

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