formation-human-periodontal-ligament-cell-spheroids-on-chitosan

Formation of Human Periodontal Ligament Cell Spheroids on Chitosan Films

Periodontal ligament (PDL) cells hold great promise for periodontal tissue regeneration. Conventionally, PDL cells are cultured on two-dimensional (2D) ...

Tongji University

We have successfully achieved the stereoselective synthesis of a specific cis-diene moiety through a dehalogenative homocoupling of alkenyl bromides on the Cu(110) surface, where the formation of a cis-form organometallic intermediate is the key to such a stereoselectivity as determined by DFT calculations. 

The stereoselective synthesis of dienes through dehalogenative homocoupling of terminal alkenyl bromides on Cu(110).

From the interplay between high-resolution scanning tunneling microscopy imaging/manipulations and density functional theory calculations, we display the hierarchical formation of supramolecular networks by codeposition of 9eG molecules and Fe atoms on Au(111) based on the flexible coordination bonds (the adaptability and versatility in the coordination modes). In the first step, homochiral islands composed of homochiral GFe motifs are formed; and then in the second step, thermal treatment results in the transformation into the porous networks composed of heterochiral GFe motifs with the ratio of the components being constant. In situ STM manipulations and the coexistence of some other heterochiral GFe motifs and clusters also show the flexibility of the coordination bonds involved. These studies may provide a fundamental understanding of the regulations of multilevel supramolecular structures and shed light on the formation of designed supramolecular nanostructures.

Hierarchical formation of Fe-9eG supramolecular networks via flexible coordination bonds.

Conductive polymers are of great importance in a variety of chemistry-related disciplines and applications. The recently developed bottom-up on-surface synthesis strategy provides us with opportunities for the fabrication of various nanostructures in a flexible and facile manner, which could be investigated by high-resolution microscopic techniques in real space. Herein, we designed and synthesized molecular precursors functionalized with benzal  gem-dibromomethyl groups. A combination of scanning tunneling microscopy, noncontact atomic force microscopy, high-resolution synchrotron radiation photoemission spectroscopy, and density functional theory calculations demonstrated that it is feasible to achieve the direct formation of C-C double-bonded structural motifs via on-surface dehalogenative homocoupling reactions on the Au(111) surface. Correspondingly, we convert the sp-hybridized state to an sp-hybridized state of carbon atoms, i. e., from an alkyl group to an alkenyl one. Moreover, by such a bottom-up strategy, we have successfully fabricated poly(phenylenevinylene) chains on the surface, which is anticipated to inspire further studies toward understanding the nature of conductive polymers at the atomic scale.

Article	Year
The stereoselective synthesis of dienes through dehalogenative homocoupling of terminal alkenyl bromides on Cu(110). Chemical communications (Cambridge, England)\| PubMed ID: 27063567	2016
Hierarchical formation of Fe-9eG supramolecular networks via flexible coordination bonds. Physical chemistry chemical physics : PCCP\| PubMed ID: 29345265	2018
Direct Formation of C-C Double-Bonded Structural Motifs by On-Surface Dehalogenative Homocoupling of gem-Dibromomethyl Molecules. ACS nano\| PubMed ID: 30016072	2018

Chunxue Yuan

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