Dehydropolymerization of 1,1-dihydrotetraphenylsilole and 1,1-dihydrotetraphenylgermole to optoelectronic copolymers catalyzed by colloidal silver nanoparticles.
The co-dehydrocoupling at ambient air atmosphere of 1,1-dihydrotetraphenylsilole 1 and 1,1-dihydrotetraphenylgermole 2 (9:1 mole ratio) with 2 mol% of AgNO3 in toluene at 90 degrees C produces optoelectronic poly(silole-co-germole)s 3 in high yield. The copolymer mainly has Si-Si bonds (and Si-Ge/Ge-Ge bonds in minor) along with the small portion of Si-O/Ge-O bonds in the polymer backbone chain. While Ag2SO4 is also a good catalyst as AgNO3 for the co-dehydrocoupling, AgI is a moderate catalyst. However, CP2Co, Cp2Ni, Cp2ZrCl2/Red-Al, AgX (X = F, Cl, Br) and AgI@MWCNT do not show appreciable catalytic activity. The silver complexes (AgNO3, Ag2SO4, AgI) transformed to colloidal silver nanoparticles during the catalytic reaction. The co-dehydrocoupling of 1 and 2 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. All cyclodextrins (sigma, beta, and gamma forms) considerably deteriorated the co-dehydrocoupling of 1 and 2 probably by forming toluene-insoluble inclusion complexes and by encapsulating SiH2 moiety. The resulting copolymer emits green light at 521 nm and is electroluminescent at 523 nm, which is similar to the polysilole.
Kim
Myoung-Hee
MH
Alan G. MacDiarmid Energy Research Institute (AMERI), Nanotechnology Research Center (NTRC), and Department of Chemistry, Chonnam National University, Gwangju 500-757, Korea.
Woo
Hee-Gweon
HG
Park
Woo Jin
WJ
Sohn
Honglae
H
Chu
Bryan Tsu-Te
BT
Li
Hong
H
Ko
Young Chun
YC