Synthesis of Half‐Sandwich Tungsten Chlorogermyl and Chlorostannyl Complexes

The reaction of the dichlorogermane Me 2 GeCl 2 and stannanes R 2 SnCl 2 (R = Me, Bu) with the alkali tungsten salts M[(η 5 ‐C 5 R′ 5 )L(OC) 2 W] (L = CO, PPh 3 ; M = Li, Na; R′ = H, Me) yields via alkali salt elimination a range of novel chlorostannyl‐ and chlorogermyl‐functionalized tungsten complexes of the general formula [(η 5 ‐C 5 R′ 5 )L(OC) 2 W(ER 2 Cl)] (R′ = H, Me; L = CO, PPh 3 ; E = Ge, Sn; R = Me, Bu) ( 3a – e ). The use of the phosphane‐substituted tungsten anion Na[(η 5 ‐C 5 Me 5 )(Ph 3 P)(OC) 2 W] ( 1c ) and Me 2 SnCl 2 leads to a mixture consisting of the mono‐ ( 3e ) as well as the di‐substituted stannyl compound [{(η 5 ‐C 5 H 5 )(Ph 3 P)(OC) 2 W} 2 (SnMe 2 )] ( 4 ). Access to 3a is also given by reaction of ClMe 2 Sn–C 5 H 5 ( 5 ) with [(MeCN) 3 W(CO) 3 ] which includes chemoselective tin shift from the cyclopentadiene to the tungsten atom. In addition, a successive chlorination of [(η 5 ‐C 5 H 5 )(OC) 3 W(SnMe 3 )] ( 6 ) via [(η 5 ‐C 5 H 5 )(OC) 3 W(SnMe 2 Cl)] ( 3a ) and [(η 5 ‐C 5 H 5 )(OC) 3 W(SnMeCl 2 )] (7) to [(η 5 ‐C 5 H 5 )(OC) 3 W(SnCl 3 )] ( 8 ) is presented. All new compounds have been fully characterized by elemental analyses and in solution by IR and multinuclear NMR spectroscopy. The crystal structures of complexes 3b – d and 8 were presented and discussed, showing bond lengths of 2.6272(4) Å for Ge–W, 2.7959(5) ( 3b ), 2.7866(3) ( 3d ) and 2.7244(3) ( 8 ) Å for the Sn–W bonds.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)