Preparation and thermal decomposition of hexa(amino amide) organosilicon cobalt carbonyl gels based on 3-aminopropyltriethoxysilane, dicobalt octacarbonyl, and methyl(phenyl)trimethoxysilanes

Hexa(amino amide) organosilicon cobalt carbonyl gels {[(RNH2)-N-2](6-x)[(RN HC)-N-2(O)H](x)Co} [Co(CO)(4)](2)(O15SiR3)(6) (R-2 = O1.5SiCH2CH2CH2, R-3 = Me, Ph, CH2CH2CH2NH2) were prepared by coprecipitation of {[(RNH2)-N-1](6- x)[(RNHC)-N-1(O)H](x)Co}[Co(CO)(4)](2) [R-1 (EtO)(3)SiCH2CH2CH2] with organ oalkoxysilanes (MeO)(3)SiMe, (MeO)(3)SiPh, and (EtO)(3)SiCH2CH2CH2NH2. The cobalt-free analogs [(O1.5SiCH2CH2CH2NH2) (O1.5SiR)] (R = Me, Ph) were prep ared by cohydrolysis of (EtO)(3)SiCH2CH2CH2NH2 with (MeO)(3)SiMe and (MeO)( 3)SiPh. Their thermal and oxidative thermal degradation were studied in the range 150-1000 degreesC. Of the three types of groups forming the structur e of the cobalt-containing xerogels, the least thermostable is the cobalt c arbonyl anion which completely decomposes at 250 degreesC. Heating to 600 d egreesC results in complete decomposition of the cobalt(II) hexa(amino amid e) cation and profound transformation of the organosilsesquioxane skeleton. Phenyl groups undergo carbonization, and Si-CH3 groups dimerize to give, i n the first stage, disilyl-ethane bridges. Thermal decomposition of the cob alt-containing compounds is accompanied by liberation of large amount of ga ses (H-2, CO, CH4, CO2, NH3, C2H6, C2H4, C3H8, C3H6, C4H8) and volatile org anic substances and yields highly porous silica-carbon-cobalt or silica-car bon-cobalt oxide materials with specific surface area ranging from 18 to 47 8 m(2) gl. The cobalt-free xerogels under similar conditions give silica-ca rbon adsorbents with S-sp from about 35 to 595 m(2) g(-1).