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

Abstract

Keywords: Rhodium / Iridium / Phosphane ligands / Hemilabile ligands / Fluxionality[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)(P ∧ O)]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 6 H 4 CHO) to afford [MClH(PPh 2 (o-C 6 H 4 CO))(P ∧ O] (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 6 H 4 CO))(P~O)(CO)] (10). Complex 9 contains two diastereomers 9a/9b in a 95:5 ratio that [a]

On the Reactivity of Platina‐β‐diketone and Acetylplatinum(II) Complexes toward 2‐(Diphenylphosphanyl)benzaldehyde and Its Dioxolane Derivative

“…Overall, these findings prove a κ P ,κ O coordination of ligand L1 , as also found in crystals of 4 (vide infra). At room temperature, a fast decoordination and recoordination of the acetal O atom may occur, as also described for rhodium complexes with a κ P ,κ O ‐coordinated ligand L1 14…”

“…2‐[2‐(Diphenylphosphanyl)phenyl]‐1,3‐dioxolane ( L1 ) is a potentially hemilabile PO ligand12 and may coordinate as a mono‐ (κ P ) or bidentate (κ P ,κ O ) ligand to a metal centre as has been exemplified with the platinum group metals Ru, Rh and Ir,13,14 but not yet with platinum itself. The non‐acetal‐protected analogue 2‐(diphenylphosphanyl)benzaldehyde ( L2 ) can coordinate in the same way, as has been observed for Pd, Ru and Rh,15 but for platinum only P coordination has been observed to date 16,17.…”

Iridium PCsp3P-type Complexes with a Hemilabile Anisole Tether

“…The drastic difference in chemical shift is associated with the trans substituent: the moderately π donating ether ligand shifts the trans hydride resonance upfield. 44,46 The presence of symmetrical phosphines is also supported by a singlet in the corresponding 31 P NMR spectrum at 58.6 ppm. Compound 7 was easily recrystallized from a saturated hexanes solution at −35 °C as light yellow crystals.…”

“…The upfield resonance at −11.39 ppm is attributed to the hydride trans to the sp 3 backbone carbon, and the resonance at −31.9 ppm is attributed to the hydride trans to the methoxy oxygen. The drastic difference in chemical shift is associated with the trans substituent: the moderately π donating ether ligand shifts the trans hydride resonance upfield. , The presence of symmetrical phosphines is also supported by a singlet in the corresponding 31 P NMR spectrum at 58.6 ppm. Compound 7 was easily recrystallized from a saturated hexanes solution at −35 °C as light yellow crystals.…”

“…Single crystals of 6 were grown from the diffusion of npentane into a saturated toluene solution (Figure 4). 43,44 The distances Ir−P(1) = 2.2684(9) Å, Ir− P(2) = 2.3032(9) Å, and Ir−Cl = 2.4541(9) Å are in the common range for iridium PC sp3 P pincer complexes. 45 The chloride ligand occupies the trans position with respect to the central sp 3 carbon, while the hydride ligand, which was found in the electron difference map at 1.42(4) Å from iridium, is found trans to the anisole substituent, consistent with the fact that the two strong σ donors (R 3 C − and H − ) occupy positions trans with respect to the weaker σ donors (O ether and Cl − ).…”