Alkinyl-substituierte Chlorsilane als Clusterbausteine

Abstract

The reaction of phenylethynyl-substituted chlorosilanes with dicobaltoctacarbonyl is discussed. Co 2(CO) 8 (II) yields selectively with (R)(PhCC)Si(H)(Cl) (R = Me: I; R = CCPh: V) (R)[(η 2- CCPh)Co 2(CO) 6]Si(H)(Cl) (R = Me: III; R = CCPh: VI), in which the phenylethynyl group is η 2 side-on co-ordinated to “Co 2(CO) 6”. III affords with further Co 2(CO) 8 under oxidative addition (Me)[(η 2-CCPh)Co 2(CO) 6]Si(Cl)[Co(CO) 4] (IV); IV may also be obtained directly by the reaction of I with 1.5 equivalents of II. VI contains a non-coordinated CCPh group and yields with one equivalent of II the tetranuclear complex [(η 2-CCPh)Co 2(CO) 6] 2Si(H)(Cl) (VII) in which the two CCPh ligands form sterically-hindered carboncobalt tetrahedrane cluster units. Compounds VIII and X show the same reaction behaviour as I and V: (R)(PhCC)Si(Cl) 2 (R = Ph: VIII; R = H: X) reacts with one equivalent of II to yield in the first step (R)[(η 2-CCPh)Co 2(CO) 6]Si(Cl) 2 (R = Ph: IX; R = H: XI). Addition of 0.5 parts of II to XI affords in high yields complex [Co(CO) 4][η 2- CCPh)Co 2(CO) 6]Si(Cl) 2 (XII). In a similar manner, compound (Me)(PhCC)Si(H) 2 (XIII) yields with one equivalent of II the dinuclear complex (Me)[(η 2-CCPh)Co 2(CO) 6]Si(H) 2 (XIV) which slowly decompose to form oligomeric compounds as well as (η 2-PhCCH)Co 2(CO) 6 (XV). All new compounds were characterized by analytical and spectroscopic data (IR, 1H, 13C NMR, MS), and (Me)[(η 2-CCPh)Co 2(CO) 6]Si(Cl)[Co(CO) 4] (IV) by X-ray analysis.