Some iridium(I) and iridium(III) complexes with the tripod-like ligand CH 3C(CH 2PPh 2) 3 (triphos) and the X-ray crystal structure of [IrCl(CO)(triphos)

Abstract

The compound [IrCl(CO)(triphos)] ( 1), has been reinvestigated and its X-ray crystal structure is reported. The crystals are orthorhombic, space group Pbca, with a 18.941(6), b 22.193(8), c 17.501(7) Å, Z = 8. The structure was solved by the heavy atom method and refined by full-matrix least-squares to the conventional R factor value of 0.074 for 6462 reflections. The metal atom coordination is trigonal bipyramidal, with the three phosphorus atoms occupying one axial and two equatorial positions. The other equatorial position is occupied by CO while Cl is coordinated axially. Compound 1 readily undergoes a series of oxidative-addition reactions with H 2, HCl and Cl 2, giving [IrH 2(CO)(triphos)] + ( 4) [IrHCl(CO)(triphos)] + ( 3), and [IrCl 3(triphos)] ( 5), respectively. Compounds [IrH(CO)(triphos)] ( 2) and [IrH n Cl 3- n (triphos)] ( n = 1, 2, 3) have also been obtained from 1 and 5, respectively, by treating them with a variety of hydride sources.