PYROLYSIS OF TRANSITION-METAL COMPLEXES - PREPARATION OF METAL CARBIDES (MC,M(2)C) FROM ORGANOMETAL COMPOUNDS

The following compounds were prepared and their pyrolysis in a stream of argon was studied: [Fe(eta(5)-C5H5)(CO)(2)](2) (1), [M(eta(5)-C5H5) (CO)(3)](2) (2, M = Mo; 3, M = W), [Fe(eta(5)-C5H5)(CO)(2)(C=CSiMe(3)) ] (4), [M(eta(5)-C5H5)(CO)(3)(C=CSiMe(3))] (5 M = Mo; 6, M = W), (eta( 5)-C5H5)(3)(CO)(7)(mu-eta(2:2:1)-C=CSiMe(3))] (7), Mo-2(eta(5)-C5H5)(2 )(CO)(4)(mu-eta(2:2)-HC=CC6H5)] (8), (5)-C5H5)(2)(CO)(4)(mu-eta(2:2)-R C=C-SiR'R''-C=CR] (9a, R = H, R' = R'' = CH3; 9b, R = C6H5, R'= H, R'' = CH3; 9c, R = C6H5, R'= CH=CH2, R'' = C=CC6H5), 5H5)(2)(CO)(4)(mu-et a(2:2)-Me(3)SiC=C-C=CSiMe(3))] (10), (CO)(8)(mu(4)-eta(2:2:2:2)-Me(3)S iC=C-C=CSiMe(3))] (11). The products of bulk pyrolysis of selected com pounds are formed in 20%-60% yield, based on the charged sample weight . The ceramic materials obtained consist of metal carbides (MC, M(2)C) together with small amounts of metal(0) (M = Mo, W) and amorphous car bon.