NEUTRON-DIFFRACTION STUDY OF FAC-]IRH3(PPH2ME)3]CENTER-DOT-MEOH

The structure of the methanol solvate of the facial isomer of [IrH3(PPh2Me)3] has been analysed by neutron diffraction. Data were obtained at 55 +/- 0.1 K using a single crystal of volume 17.6 mm3 and the structure refined to final agreement factors of R(F2) = 0.053 and R'(F2) = 0.064 for 1615 reflections. The Ir atom is situated on a three-fold rotation axis. Distances and angles correspond well to those expected for a complex with normal terminal H atoms: Ir-H 1.627(4). Ir-P 2.314(2) angstrom; H-Ir-H 83.4(2), P-Ir-P 98.6(l), and H-Ir-P 88.5(2). 169.1 (2)-degrees. As expected, the overall geometry of the complex is distorted octahedral, with the hydrogen ligands compressed together by the steric bulk of the phosphines, as evidenced by the H-Ir-H (< 90-degrees) and P-Ir-P (> 90-degrees) angles. The compound crystallizes in the rhombohedral space group R3, with a = 10.367(1) angstrom and alpha = 108.19(6)-degrees at T = 55 +/- 0.1 K.