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 C3v local symmetry at MnI, 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 1JMnPca. 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.