138826-98-9Relevant academic research and scientific papers
Metallaheteroborane Chemistry. Part 9. Syntheses and Spectroscopy of Platinum and Palladium Phosphine Complexes containing η5--based Cluster Ligands. Crystal Structures of (L = PPh3 or PMe2Ph) and
McGrath, Marguerite,Spalding, Trevor R.,Fontaine, Xavier L. R.,Kennedy, John D.,Thornton-Pett, Mark
, p. 3223 - 3234 (2007/10/02)
The reaction between and closo-1,2-As2B10H10 in ethanol gives 1 in low yield (9percent).Reaction of - and in tetrahydrofuran (thf) in the presence of a ten-fold excess of NEt3 affords (M = Pt, R3 = Me2Ph 2; M = Pd, R3 = Ph3 3 or Me2Ph 4) and (R3 = Ph3 5; or R3 = Me2Ph, 6) in low-to-moderate (20-45percent) yields.X-Ray diffraction analyses of 1, 2 and 5 confirm the closo icosahedral MAs2B9 cage structures and the presence of a MAs2 triangulated face in each of these molecules.Both compounds 1 and 2 crystallise in the monoclinic space group P21/n with Z = 4.Cell dimensions: 1, a = 1230.0(2), b = 1736.5(4), c = 1881.0(3) pm and β = 91.44(2) deg; 2, a = 1308.6(3), b = 1058.0(2), c = 1934.7(3) pm and β = 104.45(2) deg.The structure of 1 was refined to a final R of 0.0574 (R' 0.0532) for the 4160 reflections with I >= 2.0?(I).One of the As atoms is disordered over two sites.Calculated Pt-As distances are 259.1(5), 255.7(5) and 264.0(6) pm, As-As 251.5(6) and 243.5(5) pm.Structure 2 had a final R of 0.0384 (R' 0.0376) for 3778 reflections with I >= 2.0?(I).The Pt-As distances are 265.5(4) and 254.5(4) pm and As-As is 249.7(3) pm.Compound 5 crystallises in the triclinic space group P1/ with Z = 2, a = 1037.8(2), b = 1321.9(3), c = 1712.9(3) pm, α = 103.67(1), β = 93.19(1) and γ = 110.86(1) deg; final R = 0.392 (R' 0.0408) for 4688 reflections with I >= 2.0?(I).The Pd-As distances are 256.3(4) and 253.9(4) pm and As-As is 247.7(3) pm.Compounds 1-6 were characterised by multielement NMR spectroscopy.Variable-temperature 1H studies of 2, 4 and 6 show the metal to As2B9 ligand bonding is fluxional at room temperature with ΔG(excit.)298 -1 for 2 and 4 and possibly slightly higher for 6 at ca. 32 kJ mol-1.An analysis of the frontier molecular orbitals of the model ligand P2B9H9 and their possible interactions with a Pt(PH3)2 group shows no clear preference between the two possible conformations that the PtP2 unit could adopt above the P2B3 face to which it bonds.
