Catalytic Si-Si/Si-O dehydrocoupling of 1,1-dihydrotetraphenylsilole to optoelectronic polysiloles with colloidal silver nanoparticles.
The combinative Si-Si/Si-O dehydrocoupling at ambient air atmosphere of 1,1-dihydrotetraphenylsilole 1 with 2 mol% of AgNO3 and Ag2SO4 in toluene at 90 degrees C produces optoelectronic polysiloles 2 in high yield. The complexes such as Cp2Co, Cp2Ni, Cp2ZrCl2/Red-Al, and AgCl were found to be ineffective for the dehydrocoupling of 1. The polysiloles mainly have Si-Si bonds along with the small portion of Si-O bonds in the polymer backbone chain. Interestingly, the Si-O linkage increased with increasing the concentration of catalyst AgNO3, implying that while Ag(0) species catalyze the Si-Si dehydrocoupling, Ag(I) species catalyze the Si-O dehydrocoupling along with the simultaneous oxidation of NO3 ion to NO2. The silver complexes transformed to colloidal silver nanoparticles during the catalytic reaction. The Si-Si/Si-O dehydrocoupling of 1 with AgNO3 even at dry nitrogen atmosphere is occurred, supporting that the oxidation of NO3- ion to NO2 is only the possible oxygen source, but not from the adventitious moisture in air. sigma-, beta-, and gamma-Cyclodextrins considerably deteriorated the dehydrocoupling of 1 probably due to both the formation of insoluble inclusion complexes in toluene and the encapsulation of SiH2 moiety. The resulting silole polymer 2 emits green light at 520 nm and is electroluminescent at 520 nm.
Department of Korean Medicinal Supply, Dongshin University, Naju 520-714, Korea.
Bo-Hye
BH
Kim
Myong-Shik
MS
Cho
So-Yeun
SY
Kim
You-Jeong
YJ
Kim
Hee-Gweon
HG
Woo
Do-Heyoung
DH
Kim
Honglae
H
Sohn
D003102:Colloids / Q000737:chemistry; D003460:Crystallization / Q000379:methods; D049408:Luminescent Agents / Q000737:chemistry*; D008163:Luminescent Measurements / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods; D010316:Particle Size; D012825:Silicon / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D013499:Surface Properties
D003102:Colloids; D049408:Luminescent Agents; D046911:Macromolecular Substances; D012834:Silver; D012822:Silicon Dioxide; D012825:Silicon