Dry sol-gel polycondensation of hydrosilanes to organosilicas catalyzed by colloidal nickel nanoparticles.
The dry sol-gel polycondensation at toluene in ambient air atmosphere of p-X-C6H4SiH3 (X = H, CH3, CH3O, F, Cl) to silica p-X-C6H4SiO15 in high yield, catalyzed by colloidal nickel nanoparticles in-situ generated from nickelocene(II), nickel(II) acetate, and bis(1,5-cyclooctadiene)nickel(0), is described. Similar catalytic activities were observed for the catalysts. Similarly, the dry sol-gel polyco-condensation p-X-C6H4SiH3 (X = CH3, CH3O, F, Cl):C6H4SiH3 (9:1 mole ratio) at toluene in ambient air atmosphere of was performed to yield co-silicas (p-X-C6H4SiO1.5)9(p-X-C6H4SiO1.5)1 in high yield using nickelocene. The co-gels with higher molecular weights and TGA residue yield were obtained when compared to the homogels. The highest yield, molecular weight, polydispersity index, and TGA residue yield were obtained for p-Cl-C6H4SiH3. Some degree of unreacted Si-H bonds still remained in the gel matrix because of steric bulkiness. All the insoluble gels adopt an amorphous structure with a smooth surface. A plausible mechanism for the dry sol-gel reaction was suggested.
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
Hong
H
Li
D011232:Chemical Precipitation; D003102:Colloids / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D005782:Gels / Q000737:chemistry; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods; D009532:Nickel / Q000737:chemistry*; D017646:Organosilicon Compounds / Q000737:chemistry*; D010316:Particle Size; D044367:Phase Transition; D011208:Powders; D012821:Silanes / Q000737:chemistry*; D013499:Surface Properties
D003102:Colloids; D005782:Gels; D046911:Macromolecular Substances; D017646:Organosilicon Compounds; D011208:Powders; D012821:Silanes; D009532:Nickel