[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~O)] (M = Ir,
2; M = Rh,
3), in which the ligand is P-monodentate. Complex
3 reacts with AgClO
4 to give [Rh(Nbd)(PO)]ClO
4 (
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
trans-[MCl(CO)(P~O)
2] (M = Ir,
5; M = Rh,
6) or
trans-[Rh(CO)
2(P~O)
2]ClO
4 (
7). Cyclooctadiene complexes react with PPh
2(
o-C
6H
4CHO) to afford [MClH(PPh
2(
o-C
6H
4CO))(PO] (M = Ir,
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(PPh
2(
o-C
6H
4CO))(P~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)(κ
1-PPh
2(
o-C
6H
4CHO))(P~O)] (
11),
6 and
trans-[RhCl(CO)(κ
1-PPh
2(
o-C
6H
4CHO))
2] is formed. Bubbling of nitrogen transforms
11 back into
9. Compound
2 reacts with hydrogen to give the fluxional [IrCl(H)
2(P~O)(PO)] (
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~O)
2L] (L = CO,
13; py,
14;
nPrNH
2,
15) or [Ir(H)
2(P~O)
2(en)]BPh
4 (
16, en = ethylenediamine). Abstraction of halide from
12 affords [Ir(H)
2(PO)
2]BPh
4 (
17), which is fluxional owing to interconversion between only two of the possible four diastereomers, for which Δ
H‡ = 54.7 ± 0.7 kJ mol
–1 and Δ
S‡ = 4.7 ± 0.2 J K
–1 mol
–1. The X-ray structures of
8,
15 and
16 are also reported.
[2-(1,3-Dioxolane-2-yl)phenyl]diphenylphosphane (1) coordinates to MI preferably as a κ1-P ligand. MIII may afford κ2-P,O coordination in dynamic diastereomers such as A or B. A contains a single diastereomer if M = Ir or two diastereomers in a 95:5 ratio if M = Rh. B contains a mixture of only two diastereomers.
