Reaction of Molybdenocene and Tungstenocene Derivatives with the Divalent Silicon Species SiNtBuCHCHNtBu and (C5Me5)2Si

The divalent organosilicon compounds (C 5 Me 5 ) 2 Si (Cp* 2 Si) and (SiL N 2 ) have been compared concerning their reactivity toward metallocene derivatives of molybdenum and tungsten. While Cp* 2 Si does not react with Cp 2 MH 2 (M = Mo, W), either thermally or photochemically, the reaction of SiL N 2 with Cp 2 MH 2 leads via silanediyl insertion to Cp 2 M(H)(SiL N 2 H) (M = Mo ( 1a ), W ( 1b )). Irradiation of a mixture of Cp 2 Mo(PEt 3 ) and Cp* 2 Si yields only decomposition products, whereas photolysis of equimolar amounts of Cp 2 Mo(PEt 3 ) and SiL N 2 results in the formation of the silanediyl complex Cp 2 Mo(SiL N 2 ) ( 2 ). 2 is extremely moisture sensitive and easily adds one molecule of water to yield the metallosilanol Cp 2 Mo(H)(SiL N 2 OH) ( 3 ). 1a and 2 have been characterized by X-ray crystallography. 2 is the first molybdenum silanediyl complex with a tricoordinated silicon atom. The silicon−molybdenum interaction in 2 has to be described as a dative bond from the silicon to the metal atom.