SYNTHESIS, CHARACTERIZATION, AND CONFORMATIONAL ASPECTS OF CHIRAL COBALT(III) ETA-5-INDENYL AND ETA-5-CYCLOPENTADIENYL PHOSPHONATE AND PHOSPHINATE COMPLEXES

Reactions of (eta5-Cp)CO(C3F7)(L)(I) (1: L = P(OMe)3, PMe3) and (eta5-indenyl)Co(Rf)(L)(1) (4: Rf = C3F7, C6F13; L = P(OMe)3, PMe3, PPhMe2, PPh2Me, PPh(OMe)2) with PR(OMe)2 (R = OMe, Ph) initially afford the corresponding labile ionic intermediates [(eta5-CP)CO(C3F7)(L)(PR(OMe)2)]+ (2) and [(eta6-indenyl)Co(R(f))(L)(PR(OMe)2)]+ (5), respectively, which subsequently dealkylate with loss of MeI in benzene via Arbuzov rearrangement to give the phosphonate and phosphinate complexes (eta5-CP)CO(C3F7)(L)(P(O)R(OMe)) (3) and (eta5-indenyl)Co(Rf)(L)(P(O)R(OMe)) (6) (R = OMe, Ph). In most cases intermediates 2 and 5 are directly observable by H-1 NMR in acetone-d6. The solid-state structure of [(eta5-indenyl)Co(C3F7)(P(OMe)3)2)]+SbF6-(5aalpha-SbF6) was determined by X-ray diffraction. 5aalpha-SbF6 crystallizes in the monoclinic system, space group P2(1)/c (No. 14), with a = 12.821(4) angstrom, b = 12.057(3) angstrom, c = 18.835(4) angstrom, beta = 99.74(2)-degrees, V = 2869(1) angstrom3, Z = 4, and R = 0.055 (R(w) = 0.039) for 1913 reflections with I > 2.00sigma(I). Crystal structures of several phosphonate and phosphinate derivatives establish characteristic conformational preferences in the solid state which are demonstrated by H-1 NOED data to persist in solution. Crystal data: 6balpha crystallizes in the monoclinic system, space group P2(1)/c (No. 14), with a = 8.235(2) angstrom, b = 16.983(3) angstrom, c = 15.795(2) angstrom, beta = 101.88(1)-degrees, V = 2161.6(7) angstrom3, Z = 4, and R = 0.038 (R(w) = 0.034) for 2455 reflections with I > 3.00sigma(I); 6bbeta-1 crystallizes in the monoclinic system, space group P2(1)/c (No. 14), with a = 12.626(2) angstrom, b = 14.017(7) angstrom, c = 14.380(2) angstrom, beta = 107.46(1)-degrees, V = 2428(1) angstrom3, Z = 4, and R = 0.051 (R(w) = 0.040) for 2158 reflections with I > 3.00sigma(I); 6cbeta-2-CHCl3.2.85H2O crystallizes in the monoclinic system, space group C2/c (No. 15), with a = 21.794(8) angstrom, b = 15.214(2) angstrom, c = 21.115(3) angstrom, beta = 92.33(2)-degrees, V = 6995(3) angstrom3, Z = 8, and R = 0.052 (R(w) = 0.036) for 3961 reflections with I > 2.00sigma(I); 3bbeta-1 crystallizes in the monoclinic system, space group P2(1)/c (No. 14), with a = 8.481(4) angstrom, b = 17.916(3) angstrom, c = 14.518(2) angstrom, beta = 97.31(2)-degrees, V = 2188(1) angstrom3, Z = 4, and R = 0.036 (R(w) = 0.033) for 2780 reflections with I > 3.00sigma(I). The dominant conformation places the highest trans-influence ligand, P(O)R(OMe), anti to the indenyl six-ring and staggers the substituents along the Co-P(O) bond with the phosphoryl P=O bond aligned anti to the indenyl or cyclopentadienyl plane. Empirical correlations between chromatographic relative R(f) values, NMR parameters, and the relative configuration of the phosphinates, which provide a simple way to determine the stereochemistry of chiral cobaltiophosphinates, were established.