Polyhedral metallacarbaborane chemistry: preparation, molecular structure, and nuclear magnetic resonance investigation of [3-(η5-C5Me5)-closo-3,1,2-MC2B9H11] (M = Rh or Ir)

Abstract
Reaction between Cs[nido-7,8-C2B9H11] and [{M(η5-C5Me5)Cl2}2] (M = Rh or Ir) yielded orange-yellow, air-stable crystals of [3-(η5-C5Me5)-closo-3,1,2-RhC2B9H11] [compound (2), 34%] or [3-(η5-C5Me5)-closo-3,1,2-IrC2B9H11] [compound (3), 96%] both of which were characterized by their assigned 11B and 1H n.m.r. spectra and by single-crystal X-ray diffraction analyses. Crystals of (2) were orthorhombic, space group P212121, with a = 1 081.0(2), b = 1 278.2(1), c = 1 278.4(2) pm, and Z = 4; R = 0.0197, R′ = 0.0204 for 1 756 observed reflections [I > 2.0σ(I)]. Crystals of (3) were also orthorhombic, space group P212121, with a = 1 076.3(1), b = 1 282.9(1), c = 1 292.8(2) pm, and Z = 4; R = 0.0286, R′ = 0.0307, for 1 712 observed reflections [I > 2.0σ(I)]. The n.m.r. properties of the C2B9H11 fragments of (2) and (3) are compared with the 11B and hitherto unreported 1H n.m.r. characteristics of the corresponding fragments of [3-(η5-C5H5)-closo-3,1,2-CoC2B9H11] (4), closo-1,2-C2B10H12, nido-7,8-C2B9H13, and [nido-7,8-C2B9H12], in order to assess any n.m.r. shielding patterns that might reveal bonding trends. The unique endo/bridging open-face hydrogen atom in [nido-7,8-C2B9H12] is discussed in the light of its n.m.r. properties.

This publication has 37 references indexed in Scilit: