Transition metal compounds containing alkynylsilyl groups − complexes with a metal-silicon bond

Abstract Two transition metal complexes containing alkynylsilyl groups and a metal−silicon bond (CpFe(CO) 2 SiMe 2 C CPh ( 1 ), Co(CO) 4 SiMe 2 C CPh ( 2 )) have been synthesized by nucleophilic substitution (salt elimination) using both strongly and weakly nucleophilic metallates. No disturbing interactions of the metallate with the C C bond were observed. The synthesis of a third complex ((Ph 3 P) 2 RhClHSiMe 2 C CPh ( 3 )) by oxidative addition was hampered by transition metal catalyzed reactions of the Si−H with the C C triple bond. The reactivity of 1 toward complexation and hydrosilylation of the C C triple bond was studied, leading to the trinuclear dicobaltatetrahedrane compound 1 ∗ Co 2 (CO) 6 ( 4 ) and the vinylsilyl complex CpFe(CO) 2 SiMe 2 CH=CPh(SiEt 3 ) ( 5 ), respectively. The complexes were characterized by NMR ( 1 – 5 ), IR ( 1 – 5 ), and UV/VIS spectroscopy ( 1 , 3 , 4 ) as well as X-ray crystallography ( 1 – 4 ).