Reactivity of the unsaturated manganese dihydrides [Mn 2(μ-H) 2(CO) 6(μ-L 2)] [L 2 = (EtO) 2POP(OEt) 2, Ph 2PCH 2PPh 2, Me 2PCH 2PMe 2] toward silicon and tin hydrides

Abstract

The dimanganese hydride complexes [Mn 2(μ-H) 2(CO) 6(μ-L 2)] [L 2 = (EtO) 2POP(OEt) 2 (tedip), Ph 2PCH 2PPh 2 (dppm)] react with primary and secondary silanes H 2SiPhR (R = Ph, Me, H) to give the corresponding derivatives [Mn 2(μ-H 2SiPhR)(CO) 6(μ-L 2)] having a silane molecule displaying a relatively unusual μ-κ 2:κ 2 coordination mode (averaged values are ca. Mn–H = 1.59 Å, H–Si = 1.69 Å and Mn–Si = 2.381 Å, when R = Ph and L 2 = tedip). These complexes display in solution cis and/or trans arrangement of the bridging silane relative to the diphosphorus ligands (and facial and/or meridional arrangements of the corresponding carbonyl ligands), depending on the bridging groups. The novel unsaturated dihydride [Mn 2(μ-H) 2(CO) 6(μ-dmpm)] (dmpm = Me 2PCH 2PMe 2) has been prepared through the reaction of [Mn 2(μ-Cl) 2(μ-dmpm)(CO) 6] and 5 equiv of Li[BH 2Me 2] in tetrahydrofuran followed by addition of water. The dihydride complexes [Mn 2(μ-H) 2(CO) 6(μ-L 2)] (L 2 = tedip, dppm, dmpm) react with HSnPh 3 to give different mixtures of products strongly dependent on the particular reaction conditions. We have thus been able to isolate and characterize five new types of dimanganese-tin derivatives: [Mn 2(μ-SnPh 2) 2(CO) 6(μ-L 2)], [Mn 2(μ-H)(μ-Ph 2SnO(H)SnPh 2)(CO) 6(μ-L 2)] (average values are Mn–Sn = 2.54 Å, Sn–O = 2.11 Å, when L 2 = tedip), [Mn 2(μ-H)(μ-κ 1:κ 2-HSnPh 2)(CO) 6(μ-L 2)], [Mn 2(μ-H)(μ-κ 1:κ 1-O(H)SnPh 2)(CO) 6(μ-L 2)], and [Mn 2(μ-H)(SnPh 3)(CO) 7(μ-L 2)] (Mn–Mn = 3.237(1) Å, Mn–Sn = 2.642(1) Å, when L 2 = dppm).