Preparation and infrared spectra of some Group IV metal–tricarbonylnitrosyliron derivatives

Various complexes of the types [(R3M)Fe(CO)2(NO)L]. [R = Ph, Me, Et, Bun, Cl, or Br; M = Ge, Sn, or Pb; L = CO, Ph3P, (PhO)3P, or PhEt2As] and [(Ph2M){Fe(CO)2(NO)L}2][M = Sn or Pb; L = CO, (PhO)3P, or PhEt2As] are described, and a new method of preparing compounds containing transition metal to tin bonds is reported. On the basis of their i.r. spectra, it is suggested that these compounds have trigonal bipyramidal coordination about the iron atom, and a linear M–Fe–L system. When R3M is Ph2ClSn or PhCl2Sn, or L is PhEt2As isomerism is observed owing to restricted rotation about the Fe–Sn or Fe–As bond. In solution in acetonitrile [(Ph3M)Fe(CO)3(NO)] and [(Ph2M){Fe(CO)3(NO)}2](M = Sn or Pb) dissociate completely, and reversibly to give the [Fe(CO)3(NO)]– ion.