Tuning Haptotropic Rearrangements of Arene–Chromium Complexes: Steric and Electronic Effects of Phosphorus Coligands

Abstract

(Eta6-arene)tricarbonylchromium 2 was synthesised by [3+2+1] benzannulation of the Fischer carbene complex 1 and converted to the thermodynamically more favorable regioisomer 3 by haptotropic metal migration. Photo-induced ligand-exchange reactions in both regioisomers with triphenylphosphine, triphenylphosphite, trimethylphosphine, and trimethylphosphite afforded dicarbonyl(phosphine or phosphite)arene complexes 4-11. The regioisomers were separated by high-performance liquid chromatography (HPLC), and kinetic analyses of the thermo-induced haptotropic metal shift were performed with regioisomers 4, 6, 8, and 10. The kinetic parameters were compared with those obtained for the parent tricarbonyl complex 2 and were discussed in terms of the steric and electronic properties of the phosphorus ligands by applying a quantitative analysis of ligand effects (QALE). The molecular structures of regioisomeric PPh3 and P(OPh)3 complexes 4/5 and 6/7 as well as of P(OMe)3 complex 10 have been established by single-crystal X-ray analysis.

Conformation analysis of triphenylphosphine in trans and cis triphenylphosphine-substituted Fischer carbene complexes

“…The synthesis and purification of monophosphinated Fischer carbenes with various ligands and metals had been described in literature [25][26][27][28][29][30]. of molybdenum, chromium and tungsten but no crystal structures were determined [25].…”

Syntheses of chromium tricarbonyl organometals of 1-methyl-naphthalene and different polycyclic aromatic hydrocarbons, characterisation of the (C11H10)Cr(CO)3 isomers and the crystal structure of the [(η6-5,6,7,8,9,10-C11H10)Cr(CO)3] complex

“…This reaction has been reported for the substituted naphthalene Cr(CO) 3 complexes [33] and accounts for the presence of regioisomers of different thermodynamic stability [28].…”

“…The complex provides a structural example for the methyl-substituted polycyclic molecule coordinated to the CTC unit, similar to those already reported [28]. A modelled simulation of the vibrational features of complexes has been outputted by DFT methods, matching with satisfactory precision the experimental FT-IR and Raman results.…”

A density functional study of intra- and interring haptotropic η2,η2 rearrangements in rhodium, ruthenium, and osmium naphthalene complexes

“…For instance, such processes in Cr tricarbonyl and triphosphine complexes [12] and also chromium bis arene derivatives with a PAL (for instance, naphthalene or fluoranthene [13]) as an arene have well been studied. In certain cases, the kinetic experimental data were used to very accurately calculate the activation parameters of haptotropic rearrangements for η 6 ,η 6 Inter HR in polyaromatic ligand complexes [5,14].…”