Preparation,crystal and molecular structure of,and NMR parameters for,the exopolyhedral heterocyclic platinaundecaborane [μ-2,7-(SCSNEt2)-7-(PMe2Ph)-NIDO-7-PtB10H11]

The compound [μ-2,7-(SCSNEt₂)-7-(PMe₂Ph)-nido-7-PtB₁₀H₁₁] has been obtained in a yield of 52% from the reaction of [7,7-(PMe₂Ph)-nido-7-PtB₁₀H₁₂] and [AuBr₂(S₂CNEt₂)], and identified by single crystal X-ray diffraction analysis and multi-element single and double resonance NMR spectroscopy. The yellow-orange compound crystallizes in the monoclinic space group P2₁/n with a 1179.2(2), b = 1244.9(5), c = 1641.4(2) pm, β = 95.45(1)°, Z = 4, and the structure (R 0.0209, R_w = 0.0211 for 3719 observed reflections) is that of a nido-7-platinaundecaborane with an exopolyhedral N,N-diethyldithiocarbamate ligand bridging the Pt(7) and B(2) positions to give a $\text{-Pt-B-C-S-}$ five-membered ring. The tetrahapto platinum-to-borane bonding has a considerable twist distortion relative to other nido-7-platinaundecaboranes which do not possess this cyclic feature. The NMR parameters exhibit no anomalies and are consistent with the crystal molecular structure. A plot of δ(¹¹B) vs δ(¹H) for directly bound exo-terminal hydrogen atoms shows good correlation with the slope 16 : 1.