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

Two transition metal complexes containing alkynylsilyl groups and a metal−silicon bond (CpFe(CO)2SiMe2CCPh (1), Co(CO)4SiMe2CCPh (2)) have been synthesized by nucleophilic substitution (salt elimination) using both strongly and weakly nucleophilic metallates. No disturbing interactions of the metallate with the CC bond were observed. The synthesis of a third complex ((Ph3P)2RhClHSiMe2CCPh (3)) by oxidative addition was hampered by transition metal catalyzed reactions of the Si−H with the CC triple bond. The reactivity of 1 toward complexation and hydrosilylation of the CC triple bond was studied, leading to the trinuclear dicobaltatetrahedrane compound 1 ∗ Co2(CO)6 (4) and the vinylsilyl complex CpFe(CO)2SiMe2CH=CPh(SiEt3) (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).

Graphical abstractThis cobalt silyl compound and two related Fe and Rh complexes with directly metal bound alkynylsilyl moieties were synthesized. Their reactivity patterns with respect to addition of Co2(CO)6 and to hydrosilylation with Et3SiH were studied.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The synthesis of iron, cobalt, and rhodium alkynylsilyl complexes is studied. ► Both strongly and weakly nucleophilic metal complex anions can be applied. ► Metal-silicon bonds can be preserved in subsequent reactions of the CC triple bonds. ► Four compounds are fully characterized, including a free cobalt alkynylsilyl complex.