Photoinduced Decomposition of Dibenzoyldiethylgermane: A Photochemical Route to Polygermanes

Synthesis, Properties, and Derivatization of Poly(dihydrogermane): A Germanium-Based Polyethylene Analogue

Polygermanes are germanium-based analogues of polyolefins and possess polymer backbones made up catenated Ge atoms. In the present contribution we report the preparation of a germanium polyethylene analogue, polydihydrogermane (GeH₂)_n, via two straightforward approaches that involve topotactic deintercalation of Ca ions from the CaGe Zintl phase. The resulting (GeH₂)_n possesses morphologically dependent chemical and electronic properties and thermally decomposes to yield amorphous hydrogenated Ge. We also show that the resulting (GeH₂)_n provides a platform from which functionalized polygermanes can be prepared via thermally induced hydrogermylation-mediated pendant group substitution.

Visible light induced radical coupling reactions for the synthesis of conventional polycondensates

We herein report a facile visible light induced synthetic method for preparing a series of conventional polycondensates, namely polyesters, polyurethanes and polyamides.

Photoinduced Electron Transfer Reactions for Macromolecular Syntheses

Photochemical reactions, particularly those involving photoinduced electron transfer processes, establish a substantial contribution to the modern synthetic chemistry, and the polymer community has been increasingly interested in exploiting and developing novel photochemical strategies. These reactions are efficiently utilized in almost every aspect of macromolecular architecture synthesis, involving initiation, control of the reaction kinetics and molecular structures, functionalization, and decoration, etc. Merging with polymerization techniques, photochemistry has opened up new intriguing and powerful avenues for macromolecular synthesis. Construction of various polymers with incredibly complex structures and specific control over the chain topology, as well as providing the opportunity to manipulate the reaction course through spatiotemporal control, are one of the unique abilities of such photochemical reactions. This review paper provides a comprehensive account of the fundamentals and applications of photoinduced electron transfer reactions in polymer synthesis. Besides traditional photopolymerization methods, namely free radical and cationic polymerizations, step-growth polymerizations involving electron transfer processes are included. In addition, controlled radical polymerization and "Click Chemistry" methods have significantly evolved over the last few decades allowing access to narrow molecular weight distributions, efficient regulation of the molecular weight and the monomer sequence and incredibly complex architectures, and polymer modifications and surface patterning are covered. Potential applications including synthesis of block and graft copolymers, polymer-metal nanocomposites, various hybrid materials and bioconjugates, and sequence defined polymers through photoinduced electron transfer reactions are also investigated in detail.

Polymers and the p-block elements

A survey of the state-of-the-art in the development of synthetic methods to incorporate p-block elements into polymers is given. The incorporation of main group elements (groups 13-16) into long chains provides access to materials with fascinating chemical and physical properties imparted by the presence of inorganic groups. Perhaps the greatest impedance to the widespread academic and commercial use of p-block element-containing macromolecules is the synthetic challenge associated with linking inorganic elements into long chains. In recent years, creative methodologies have been developed to incorporate heteroatoms into polymeric structures, with perhaps the greatest advances occurring with hybrid organic-inorganic polymers composed of boron, silicon, phosphorus and sulfur. With these developments, materials are currently being realized that possess exciting chemical, photophysical and thermal properties that are not possible for conventional organic polymers. This review focuses on highlighting the most significant recent advances whilst giving an appropriate background for the general reader. Of particular focus will be advances made over the last two decades, with emphasis on the novel synthetic methodologies employed.

Dibenzoyldiethylgermane as a visible light photo-reducing agent for CuAAC click reactions

A highly active, versatile and visible light-responsive system for CuAAC click reaction using the dibenzoyldiethylgermane photoinitiator with Cu(ii) has been developed.

Polygermanes: bandgap engineering via tensile strain and side-chain substitution

Polygermanes: bandgap engineering by strain and side-chain substitution.

Bis(germyl)ketones: Toward a New Class of Type I Photoinitiating Systems Sensitive Above 500 nm?

The ability of a bis(germyl)ketone Ph(3) GeCOGePh(3) to act as a photoinitiator of free radical polymerization under visible light is investigated. The results suggest that this compound could be the starting point of a new high performance class of photoinitiators. The excited state processes, as well as the generation and the reactivity of the germyl radicals, are studied by laser flash photolysis, ESR spin trapping experiments, and molecular orbital calculations; they are compared to the results obtained on a mono- (germyl)ketone CH(3) COGePh(3) . Time dependent density functional theory calculations allow discussion of the strongly red-shifted ground state absorption of Ph(3) GeCOGePh(3) .