Iridium and Rhodium Complexes with the Hemilabile Ligand [2-(1,3-Dioxolane-2-yl)phenyl]phenylphosphane - Behaviour in Solution and Structural Characterization

[MCl(L-2)](2) (M = Ir, L-2 = 1,5-cyclooctadiene; M = Rh, L-2 = norbornadiene) reacts with [2-(1,3-dioxolane-2-yl)phenyl]diphenylphosphane (1) to afford [MCl(L-2)(P similar to O)] (M = Tr, 2; M = Rh, 3), in which the ligand is P-monodentate. Complex 3 reacts with AgClO4 to give [Rh(Nbd)((PO)-O-boolean AND)]ClO4 (4), in which the ligand is P,O-bidentate. Complex 2 is static at room temp., whereas 3 and 4 undergo intramolecular exchanges, which are fast at room temperature and slow at 223 K. The conformational changes in 4 are still fast at 223 K. Complexes 2-4 react with CO to afford transIMC1(CO)(P similar to O)21 (M = Tr, 5; M = Rh, 6) or trans-Rh[(CO)(2)(P similar to O)(2)]ClO4 (7). Cyclooctadiene complexes react with PPh2(o-C6H4CHO) to afford [MClH(PPh2(o-C6H4CO))((PO)-O-boolean AND] (M = Tr, 8; M = Rh, 9), in which 1 is chelating. Complex 8 contains a single diastereomer, is static in the 303-213 K range and reacts with CO to form [IrClH(PPh2(o-C6H4CO))(P similar to O)(CO)] (10). Complex 9 contains two diastereomers 9a/9b in a 95:5 ratio that undergo interconversion, which is slow at low temperature, and reacts with CO to undergo reductive elimination of aldehyde, cleavage of the Rh-O bond and scrambling of phosphanes. A mixture of trans-[RhCl(CO)(kappa(1)-PPh2(o-C6H4CHO))(P similar to O)] (11), 6 and transiRhCl(CO)(kappa(1)-PPh2(o-C6H4CHO))(2)] is formed. Bubbling of nitrogen transforms 11 back into 9. Compound 2 reacts with hydrogen to give the fluxional [IrCl(H)(2)(P similar to O)(PA0)] (12) with trans P atoms and cis H atoms, which attains coalescence at 203 K. Complex 12 reacts with mono- or bidentate ligands to afford static [IrCl(H)(2)(P similar to O)21,1 (L = CO, 13; py, 14; nPrNH(2), 15) or [Ir(H)(2)(P similar to O)(2)(en)BPh4 (16, en = ethylenediamine). Abstraction of halide from 12 affords [Tr(H)(2)((PO)-O-boolean AND)]BPh4 (17), which is fluxional owing to interconversion between only two of the possible four diastereomers, for which Delta H* = 54.7 0.7 kJmol(-1) and Delta S* = 4.7 +/- 0.2 JK(-1)mol(-1). The X-ray structures of 8, 15 and 16 are also reported.