Halide Substitution Reactions of the Germylidyne Complexestrans-[X(dppe)2W⋮Ge(η1-Cp*)] (X = Cl, I; dppe = Ph2PCH2CH2PPh2; Cp* = C5Me5)

The first reactions of the germylidyne complexes trans -[X(dppe) 2 W⋮Ge(η 1 -Cp*)]·[toluene] ( 1-Cl ·C 7 H 8, X = Cl; 1-I ·C 7 H 8, X = I) with nucleophiles and electrophiles are reported. Treatment of 1-I ·C 7 H 8 with KBH 4 in refluxing THF affords selectively the hydrido−germylidyne complex trans -[H(dppe) 2 W⋮Ge(η 1 -Cp*)] ( 2 ). Similarly, metathetical exchange of 1-I ·C 7 H 8 with an excess of MY (M = Na, K; Y = NCO, N 3, NCS, CN) gives the pseudohalide complexes trans -[Y(dppe) 2 W⋮Ge(η 1 -Cp*)]· x (toluene) ( 3a, Y = NCO, x = 0; 3b, Y = N 3, x = 0; 3c ·C 7 H 8, Y = NCS, x = 1; 3d ·0.5C 7 H 8, Y = CN, x = 0.5). Chloride abstraction from 1-Cl ·C 7 H 8 with Li[B(C 6 F 5 ) 4 ]·2.5Et 2 O yields in the presence of acetonitrile the first cationic germylidyne complex, trans -[(MeCN)(dppe) 2 W⋮Ge(η 1 -Cp*)][B(C 6 F 5 ) 4 ] ( 4 ). All new complexes were well characterized. The molecular structures of 2 ·1.5C 6 D 6, 3a ·THF, 3d ·0.5C 7 H 8, and 4 were determined by single-crystal X-ray diffraction studies. The germylidyne complexes reveal very short W−Ge distances ( d W - Ge = 229.91(9)−231.84(6) pm), an almost linear geometry at the triply bonded germanium atom (W−Ge−C Cp* = 172.0(1)−176.8(1)°) and a η 1 -bonded Cp* substituent.