On possible reasons of Mo-Sn σ-bond shortening in heterometallic complexes of (η5-C5H5)2Mo(H)Sn(CH3)nCl3-n composition

As possible reasons of Mo-Sn σ-bond shortening in heterometallic complexes of (η5-C5H5)2Mo(H)Sn(CH3)n composition, dative π-interaction of d-electron unshared pairs of a transition metal with vacant d-orbitals of tin atoms and redistribution of electron densities at Mo and Sn atoms, leading to a high S-character of this bond, are discussed. The most important structure characteristics of Cp2Mo(H)Sn(CH3)2Cl and Cp2Mo(H)Sn(CH3)3 complexes (interatomic distances, valence angles) and a structure model are presented. The conclusion is made that structure peculiarities and spectral properties of this complexes are explained by higher than usual S-character of Mo-Sn bond, that doesn't exclude certain participation of π-dative interaction in formation of metal-metal bond