Synthesis of Ethylene‐bridged Heterocyclic Bidentate P(III)N‐Ligands — Oxidation and Complexation Studies

Abstract

AbstractA series of phosphor(III)inanone ligands 4‐7, linked by ethylene bridges between the nitrogen atoms of the heterocyclic rings, were synthesized by the reaction of the bis‐PCl derivative 3 with the appropriate trimethylsilylamines. The bis‐phosphor(V)inanone compounds 8‐11 were obtained by the oxidation of 4‐7 with hexafluoroacetone (HFA). Oxidation of 4 and 6 with tetrachloro‐orthobenzoquinone (TOB) gave the bis‐phosphor(V)inanones 12 and 13. The reaction of 4‐6 with [Pt(COD)Cl2] led to the platinum complexes 14‐16. All the σ3‐phosphorinanone compounds 4‐7 and the σ5‐phosphorinanone compounds 8‐10, 12 and 13 exist as a mixture of two conformers, as indicated by two signals in the 31P‐NMR spectra. However, compounds 9 and 11 exist as single conformers, both display only one sharp singlet in the 31P‐NMR spectra. The Pt‐complexes 15 and 16 contain two conformers; one conformer of 16 could be isolated by crystallization. X‐ray crystal structure determinations for compounds 8, 14 and 16 were conducted, revealing inversion symmetry for 8 and cis arrangement for 14 and 16.