Cationic manganese(I) tricarbonyl complexes with group 15 and 16 donor ligands: synthesis, multinuclear NMR spectroscopy and crystal structures

Abstract

The compound [MnBr(CO)₅] reacted with [10]aneS₃ (1,4,7-trithiacyclodecane) in dmf solution to yield fac-[Mn(CO)₃([10]aneS₃)]Br. The compounds fac-[Mn(CO)₃(L)]CF₃SO₃ (L = MeS(CH₂)₂S(CH₂)₂SMe, MeSe(CH₂)₃Se(CH₂)₃SeMe, MeC(CH₂SMe)₃, MeC(CH₂SeMe)₃, MeC(CH₂TeMe)₃, MeC(CH₂TePh)₃, MeC(CH₂PPh₂)₃ MeC(CH₂AsMe₂)₃ or Ph₂P(CH₂)₂PPh(CH₂)₂PPh₂) were readily obtained by treatment of fac-[Mn(CO)₃(Me₂CO)₃]CF₃SO₃ with L at room temperature in Me₂CO solution. Similar reactions using three molar equivalents of PPh₂H, PCy₂H or PPhH₂ (L) yielded fac-[Mn(CO)₃(L)₃]CF₃SO₃ as pale yellow solids. The compounds have been characterised by analysis, IR and multinuclear NMR spectroscopy (¹H, ¹³C-{¹H}, ³¹P-{¹H}, ⁵⁵Mn, ⁷⁷Se-{¹H} and ¹²⁵Te-{¹H}), mass spectrometry and by single crystal X-ray diffraction studies on seven examples. The compounds all adopt a distorted octahedral arrangement with C_3v local symmetry at Mn^I, and three mutually fac carbonyl ligands. The δ(⁵⁵Mn) linewidths are very dependent upon subtle changes in the electric field gradient and for some of the phosphine complexes quartet coupling to ³¹P is clearly resolved giving ¹J_MnPca. 200 Hz. The spectroscopic data are discussed in terms of the relative bonding properties of the Group 15 or 16 donor ligands within the manganese(I) cation.