Synthesis, Structure, and Reactivity of [RuCl(PP)L]PF(6) (PP = (PPh(3))(2), Ph(2)P(CH(2))(4)PPh(2); L = P(py)(3), PPh(py)(2), py = 2-pyridyl). The "Missing" P,N,N'-Coordination Mode for 2-Pyridylphosphines.

The complexes [RuCl(PPh(3))(2)(P,N,N'-PPh(3-)(x)()(py)(x)())]PF(6) (x = 2, 1b; 3, 1c; py = 2-pyridyl) were isolated from the reaction of RuCl(2)(PPh(3))(3) with 1 equiv of PPh(3-)(x)()(py)(x)() and NH(4)PF(6) in acetone. Crystals of 1b (C(52)H(43)ClF(6)N(2)P(4)Ru) are monoclinic, a = 17.795(2), b = 11.375(4), and c = 23.343(2) Å, beta = 97.012(8) degrees, Z = 4, space group P2(1)/c; those for 1c (C(51)H(42)ClF(6)N(3)P(4)Ru) are monoclinic, a = 17.812(1), b = 11.353(2), and c = 23.391(1) Å, beta = 97.738(5) degrees, Z = 4, space group P2(1)/c. The isomorphous structures were solved by the Patterson method and were refined by full-matrix least-squares procedures to R = 0.036 and 0.033 (R(w) = 0.035 and 0.031) for 7690 and 8121 reflections with I >/= 3sigma(I), respectively. The P,N,N'-coordination mode for 2-pyridylphosphines is previously unreported. The P,N-coordinated complexes cis-RuCl(2)(dppb)(PPh(3-)(x)()(py)(x)()) (x = 1-3; dppb = Ph(2)P(CH(2))(4)PPh(2)) were made by isomerization of the corresponding trans-dichloro isomers, which are themselves synthesized from RuCl(2)(dppb)(PPh(3)). The cis complexes in CHCl(3) or CH(2)Cl(2) dissociate chloride reversibly with formation of P,N,N'-coordinated PPh(3-)(x)()(py)(x)() species, which were isolated as [RuCl(dppb)(PPh(3-)(x)()(py)(x)())]PF(6) (x = 2, 3). Reactions of CO with the species containing the strained P,N,N'-coordination mode lead to displacement of a coordinated pyridyl and formation of the P,N-coordinated complexes [RuCl(CO)(PP)(PPh(3-)(x)()(py)(x)())]PF(6) (PP = (PPh(3))(2), x = 2, 3; and PP = dppb, x = 2, 3). The CO reactions are partially reversible. Solution structures of the complexes were determined by NMR, IR, and UV-visible spectroscopies and conductivity.