Cyanide-bridged complexes with Sn(II)Mn(I), Sn(II)Mn(II), Sn(IV)Mn(I) and Sn(IV)Mn(II) oxidation states

Abstract

The redox-active cyanomanganese carbonyl ligands trans- and cis-[Mn(CN)(CO)₂(PR₃)(dppm)] (R = OEt or OPh, dppm = Ph₂PCH₂PPh₂) and trans-[Mn(CN)(CO)(dppm)₂] react with SnCl₂ to give [Cl₂Sn^II(μ-NC)Mn^IL_x] [L_x = trans- and cis-(CO)₂(PR₃)(dppm), R = OEt or OPh, 1–4, and trans-(CO)(dppm)₂5]; complex 5 is oxidised by [Fe(η-C₅H₅)₂][PF₆] to give [Cl₂Sn^II(μ-NC)Mn^II(CO)(dppm)₂][PF₆] 5⁺[PF₆]⁻. X-Ray structural studies on the redox related pair 5 and 5⁺ are consistent with oxidation localised mainly at Mn although the Sn^II–NC distance increases from 2.198(3) Å in 5 to 2.303(9) Å in 5⁺. The dicarbonyl cyanomanganese ligands react with SnCl₄ to give trinuclear trans-[Cl₄Sn{(μ-NC)MnL_x}₂] [L_x = trans- and cis-(CO)₂(PR₃)(dppm), R = OEt or OPh, 6–9], X-ray studies on 7 showing octahedral geometry at Sn(IV). The reaction of cis-[Mn(CN)(CO)₂{P(OEt)₃}(dppm)] with one equivalent each of SnCl₄ and PPh₃ and of trans-[Mn(CN)(CO)(dppm)₂] with one equivalent each of SnCl₄ and [N(PPh₃)₂]Cl gives heterobinuclear [Cl₄(Ph₃P)Sn^IV(μ-NC)Mn^I(CO)₂{P(OEt)₃}(dppm)-cis] 10 and [N(PPh₃)₂][Cl₅Sn^IV(μ-NC)Mn^I(CO)(dppm)₂-trans], [N(PPh₃)₂]⁺(11⁻), respectively; the latter is oxidised with [Fe(η-C₅H₅)₂][PF₆] to give [Cl₅Sn^IV(μ-NC)Mn^II(CO)(dppm)₂-trans] 11, completing a series of cyanide-bridged complexes with core oxidation states Sn(II)Mn(I), Sn(II)Mn(II), Sn(IV)Mn(I) and Sn(IV)Mn(II).