Synthesis of Silicon-Containing Unsaturated Polymers by Hydrosilylation Reactions. Photophysical Studies

Co-Crystal Formation of Partially Fluorinated 1,3,5-Tris(phenylethynyl)benzenes

Several rigid 1,3,5-tris(phenylethynyl)benzenes with different fluorination patterns were synthesized through selective Sonogashira-Hagihara coupling reactions to analyze the packing behavior in solid-state structures. The aggregation is dominated by various intermolecular interactions between aryl substituents, triple bonds, C-H bonds and H⋅⋅⋅F contacts. Co-crystallization experiments for the analysis of preferred aryl-aryl-interactions led to 1 : 1 complexes. Intermolecular phenyl-perfluorophenyl interactions with short centroid-centroid distances are dominating these co-crystal structures. They lead to melting point increases of up to 49 °C for the co-crystals compared to the pure substances.

Synthesis and thermal properties of silicon-containing benzoxazine

A novel benzoxazine, containing silicon (Si) in the main chain and bonded to two benzene ring, was synthesized from aniline, bis( p-hydroxyphenyl)dimethylsilane, and paraformaldehyde. The structure was characterized by proton nuclear magnetic resonance and Fourier transform infrared (FTIR) spectra. The curing behavior of the benzoxazine was evaluated by differential scanning calorimeter and in situ FTIR. The thermal stability of the resulting polybenzoxazine was studied by thermogravimetric analysis under nitrogen and air atmospheres. The results indicated that the Si-containing polybenzoxazine possessed significantly higher initial degradation temperature and char yield than conventional bisphenol A/aniline-based polybenzoxazine.

Unusual emission properties of the selected organosilicon compounds containing a styryl-carbazole chromophore: inversion of the singlet excited states

The presence of the silicon atom in a trimethylsilyl-styryl-carbazole derivative induced the inversion of the lowest excited states in polar solvents.

Studies on homologous random and alternating segmented conjugated polymers with and without silicon synthesized by ADMET

Using acyclic diene metathesis (ADMET), we synthesized homologous luminescent conjugated polymers with two aromatic segments based on thiophene and substituted phenylene, either alternating or randomly distributed, and either directly connected or separated by Si-linkers.

Studies of Silicon-Containing Bismaleimide Resins – Preparation and Characteristics of Reactive Blends of Silicon-Containing Bismaleimide and Epoxy

Three kinds of silicon-containing bismaleimide (4,4′-Bismaleimido phenoxy silane) monomers were synthesized and added through blending to general epoxy system for the study of their applications as reactive flame retardants. The thermal analysis of the BMI monomers in bisphenol type epoxy system had been discussed. An increase in the BMI contents decreased the storage modulus and glass-transition temperature and slightly reduced the mechanical strength of the epoxy blends. Although the initial pyrolysis temperatures of all the blending systems gradually decreased as the silicon-content increased, all the silicon-containing epoxy systems still had good thermal stability and the flame retardancy was promoted significantly by increasing contents of BMI. The LOI values of all the blend types were increased to about 30 as the BMI concentration reached 20%.

Alternating divinylarene–silylene copolymers

A summary of recent advances on the chemistry and photophysics of silylene-spaced divinylarene copolymers is presented. The silicon moieties have been shown to serve as an insulating spacer in these copolymers. The photophysical studies have provided useful insights into how chromophores in polymers interact intramolecularly. Because different chromophores can be regioregularly introduced into the polymeric chain, these copolymers have been extensively used as models for studying energy transfer, light harvesting as well as chiroptical transfer.