SYNTHESIS AND SPECTROSCOPIC CHARACTERIZATION OF THE [FE4P(CO)13HM-N]N-(M=3, N=0, 1, 2, 3, M=2, N=2) CLUSTERS - CRYSTAL-STRUCTURE OF [PPH4]2[FE4P(CO)13H]

The new [Fe4(mu-4-P)(CO)13H(m-n)]n-(m = 3, n = 0, 1, 2, 3; m = 2, n = 2) clusters have been indirectly obtained by the reaction of PCl3 with either [Fe3(CO)11]2- or [Fe4(CO)13]2-, and have been spectroscopically and chemically characterized. The [Fe4P(CO)13H]2- dianion has been isolated in a crystalline state as a [PPh4]+ salt and its structure has been determined by single crystal X-ray diffraction studies. The compound is triclinic, Space Group P1BAR with unit cell dimensions a = 10.968(2), b = 11.886(2), c = 25.397(4) angstrom, alpha = 97.84(2), beta = 95.86(1), gamma = 113.59(1)-degrees, Z = 2, R = 0.052 for 2874 reflections having I > 3-sigma(I). The anion consists of a triangular Fe3(CO)9(mu-H) moiety capped by a phosphorus atom, which binds a dangling Fe(CO)4 group. The unique hydrogen atom could not be directly located by X-ray and its coordination was inferred from stereochemical and spectroscopical considerations.