CRYSTAL AND MOLECULAR-STRUCTURES AND SYNTHESES OF 9,9-(PPH3)2-6,9-SPTB8H10 AND 8-OET-9,9-(PPH3)2-6,9-SPTB8H9 - RELATED PLATINATHIADECABORANES

Platinathiaboranes were prepared by the reaction of L4Pt (L=PMe2Ph, PEt3, and PPh3) with 1-SB9H9 in ethanol. X-ray crystallographic characterization left an ambiguity regarding the formulation of the thiaborane ligand as SB8H8 or SB8H10. Mass spectrometry and 'H NMR characterization showed that the complexes had the general formulation L2Pt (SB8H10). Therefore, the framework electron count corresponds with the nido skeletal structure found crystallographically, and the structure is not “unexpected” as found for other d8 and d9 metallaheteroboranes. In addition to the three 9,9-L2-6,9-SPtB8H10 molecules, 8-OEt-9,9-(PPh3)2-6,9-SPtB8H9 was characterized, and the relationship of these four platinathiadecaboranes to the previously reported L2M (SB9H9) (M=Pd, Pt) is discussed. It appears that the synthetic method is a degradative insertion. Even treatment of SBuHn with L4Pt in ethanol leads to the kinetically stable L2Pt(SB8H10) molecule. The reactants behave differently in benzene or cyclohexane, and the nature of these products is discussed. The crystals of 9,9-(PPh3)2-6,9-SPtB8H10,1, and 8-OEt-9,9-(PPh3)2-6,9-SPtB8H9, II, both form in the monoclinic space group P21/n with a=11.522 (5) υ,b = 20.005 (5) υ, c=16.398 (4) υ, β=95.74(3)°, and Z=4 for I and a=13.336 (4) υ, b=21.034 (5) υ, c=14.545 (3) υ, β=103.04 (2), and Z=4 for II. The conventional R index converged at 0.043 and 0.051 for I and II, respectively, with full matrix refinement including the scale factor, positional and anisotropic thermal parameters for all nonhydrogen atoms, and fixed phenyl hydrogen positions. © 1979, American Chemical Society. All rights reserved.