New silicon-containing phenyleneethynylene hybrid oligomers P2, P3, and P4 were synthesized via Sonogashira cross-coupling reactions of ethynyl-terminated silazane monomer N,N′-bis（4-ethynylphenyl）-1,1-diphenylsila...New silicon-containing phenyleneethynylene hybrid oligomers P2, P3, and P4 were synthesized via Sonogashira cross-coupling reactions of ethynyl-terminated silazane monomer N,N′-bis（4-ethynylphenyl）-1,1-diphenylsilazane（M1） and corresponding bis-（4-bromo-phenyl）-ended organosilicon unit containing monomers, respectively. These new oligomers were easily soluble in common solvents. The incorporation of flexible organosilicon units in the oligomers leads to blue-shift in both the UV-Vis absorption and fluorescence emission spectra similarly. The results of differential scanning calorimetry（DSC） indicate that the flexible units relieve the rigidity of oligomeric chain and provide favorable conformation for thermal cross-linking reactions. The oligomers show good thermal and thermal-oxidative stability from the thermogravimetric analysis（TGA）, with their decomposition temperature at 10% weight loss（T10%） higher than 400 ？C under both nitrogen and air atmosphere.展开更多
The charge-doping effect on the geometric and the electronic structures of organosilicon oligomers nSix(C=C)+y has been studied using density functional theory. Charge-doping can significantly lower the excitation ene...The charge-doping effect on the geometric and the electronic structures of organosilicon oligomers nSix(C=C)+y has been studied using density functional theory. Charge-doping can significantly lower the excitation energies. Interchain hole hopping mainly occurs between the π-conjugated units. A doped nSix(C=C)+y oligomer can undergo a structural rearrangement. The simulated UV/vis absorption peak of the rearranged structure is located at higher energy than the non-rearranged one. The hole transfer rate is significantly decreased if a doped molecule undergoes a rearrangement. These results offer a basis to explain previously observed experimental phenomena.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.50673094 and 20774102)
文摘New silicon-containing phenyleneethynylene hybrid oligomers P2, P3, and P4 were synthesized via Sonogashira cross-coupling reactions of ethynyl-terminated silazane monomer N,N′-bis（4-ethynylphenyl）-1,1-diphenylsilazane（M1） and corresponding bis-（4-bromo-phenyl）-ended organosilicon unit containing monomers, respectively. These new oligomers were easily soluble in common solvents. The incorporation of flexible organosilicon units in the oligomers leads to blue-shift in both the UV-Vis absorption and fluorescence emission spectra similarly. The results of differential scanning calorimetry（DSC） indicate that the flexible units relieve the rigidity of oligomeric chain and provide favorable conformation for thermal cross-linking reactions. The oligomers show good thermal and thermal-oxidative stability from the thermogravimetric analysis（TGA）, with their decomposition temperature at 10% weight loss（T10%） higher than 400 ？C under both nitrogen and air atmosphere.
基金supported by the National Natural Science Foundation of China (51073048)the Science Foundation for Leading Experts in Academy of Harbin City of China (2010RFJGG016)+1 种基金the Science Foundation of Heilongjiang Postdoctoral Grant of China (LBHQ07058)the Science Foundation for Elitists of Harbin University of Science and Technology
文摘The charge-doping effect on the geometric and the electronic structures of organosilicon oligomers nSix(C=C)+y has been studied using density functional theory. Charge-doping can significantly lower the excitation energies. Interchain hole hopping mainly occurs between the π-conjugated units. A doped nSix(C=C)+y oligomer can undergo a structural rearrangement. The simulated UV/vis absorption peak of the rearranged structure is located at higher energy than the non-rearranged one. The hole transfer rate is significantly decreased if a doped molecule undergoes a rearrangement. These results offer a basis to explain previously observed experimental phenomena.
