Synthesis and Structures of Zeise‐type Complexes with Vinylsilane Ligands and Quantum Chemical Analysis of the Platinum–Vinylsilane Bonding

Zeise‐type complexes with vinylsilanes as π‐ligands [K(18C6)][PtCl 3 (η 2 ‐CH 2 =CHX)] (X = SiMe 3 , 4 ; SiPh 3 , 5 ; Si(OMe) 3 , 6 ; 18C6 = 18‐crown‐6) and [K(18C6)] 2 [(PtCl 3 ) 2 {η 2 ,η 2 ‐(CH 2 =CHSiMe 2 ) 2 O}] ( 7 ) have been prepared by the reaction of [K(18C6)] 2 [Pt 2 Cl 6 ] ( 3 ) with the appropriate vinylsilanes. The identities of the complexes have been confirmed by NMR spectroscopy as well as for 4 , 5 and (PPh 4 )[PtCl 3 {η 2 ‐CH 2 =CHSi(OMe) 3 }] ( 6′ ) also by single‐crystal X‐ray diffraction measurements. DFT calculations exhibited, that the coordination induced C=C bond lengthenings and the pyramidalization angles of the olefins in the vinylsilane complexes [PtCl 3 (η 2 ‐CH 2 =CHX)] − (X = SiMe 3 , 4c ; SiPh 3 , 5c ; Si(OMe) 3 , 6c ) are the same as in Zeise's anion [PtCl 3 (η 2 ‐CH 2 =CH 2 )] − ( 8c ) while the amount of the π back‐donation in the vinylsilane complexes 4c–6c is higher than that in the ethylene complex 8c .