Tungsten(0) and rhodium(I) complexes of a series of 2-(2′-halo)triarylphosphinines

Abstract

A series of halo substituted triarylphosphinines have been synthesised and coordinated to tungsten(0) and rhodium(I) to give [(2-(2'-halo)-triarylphosphinine)W(CO)(5)] and [(2-(2'-halo)-triarylphosphinine)Rh(COD)Cl] respectively. The complexes have been examined by NMR and IR spectroscopy in an effort to elucidate the nature of the bonding between the phosphinines and the respective metal centre. The W(CO)(5)(L) systems reveal restricted C-C bond rotation as evidenced by temperature-dependent (31)P{(1)H} NMR spectra. Thermodynamic barriers to the rotation are dependent upon the nature of the halide with DeltaG(double dagger) values of 72.5 kJ mol(-1) and 50.8 kJ mol(-1) being obtained for the chloro- and fluoro-derivatives, respectively; activation barriers for the iodo- and bromo- derivatives were beyond the accessible temperature range of the NMR experiment.

Cyclometalation of Aryl‐Substituted Phosphinines through CH‐Bond Activation: A Mechanistic Investigation

“…Modified literature procedure 43 for the preparation of 2,4,6‐aryl‐substituted phosphinines : P(SiMe 3 ) 3 (1–2.2 equiv) was added drop‐wise to a slurry of the functionalized pyrylium salt (1 equiv) in 1,2‐dimethoxyethane (DME) and the resulting mixture was heated at reflux ( T =90 °C) for 16 h. During that time the pyrylium salt dissolved completely. The DME was subsequently removed in vacuo and the brown residue was filtered through a pad of neutral alumina using diethyl ether as eluent.…”

PdII and PtII Complexes of 2‐(2′‐Pyridyl)‐4,6‐diphenylphosphinine: Synthesis, Structure, and Reactivity

“…The elemental analyses were performed on a Perkin-Elmer 2400 Series II CHNSO Analyzer within the Department of Chemical Engineering and Chemistry (TU/e). 1 H, 13 Reaction of 6 with DPEphos: A solution of 6 (30 mg, 0.056 mmol) in CD 2 Cl 2 (0.6 mL) was added to DPEphos (30 mg, 0.056 mmol). A red solution formed that was immediately analyzed by 31 P NMR spectroscopy.…”

“…We recently started to investigate the synthesis and coordination chemistry of functionalized 2,4,6-triaryl-substituted l 3 -phosphinines, which are generally accessible by the modular pyrylium salt route. [11][12][13] It turned out that 2-(2'-pyridyl)-4,6-diphenylphosphinine (1, Scheme 1) is readily available from the corresponding pyridyl-functionalized pyrylium salt and PA C H T U N G T R E N N U N G (SiMe 3 ) 3 and we have recently investigated its coordination chemistry with Rh I . [14,15] We anticipated that the additional phenyl group at the 6-position of the heterocyclic framework might lead to a kinetic stabilization of the corre-sponding metal complexes as the P = C double bond is sterically more shielded for addition reactions.…”

Cobalt, rhodium and iridium

“…28 Complexes 25a-25c were prepared by stirring the appropriate phosphinine with [Rh(m-Cl)(COD)] 2 in CH 2 Cl 2 . 29 Comparison of the 1 J RhP coupling constants suggests that the phosphinine ligands possess donor properties between those of arylphosphines and arylphosphites. An unusual bonding mode of a new bis-phosphine-borane alkyl ligand to Rh(I) has been reported.…”