Notes. Preparation and spectroscopic characterization of pseudo-tetrahedral [NiX2{Ph2P(CH2)8PPh2}](X = Cl, Br, or I) and planar [Ni(NCS)2{Ph2P-(CH2)8PPh2}]

Abstract

The long-chain diphosphine 1,8-bis(diphenylphosphino)octane, dpo, forms pseudo-tetrahedral [Ni(dpo)X₂] complexes (X = Cl, Br, or I). Molecular-weight data indicate that [Ni(dpo)I₂] is dimeric in chloroform, and thus contains bridging bidentate diphosphine ligands. The complex [Ni(dpo)(NCS)₂] is diamagnetic and square planar. The donor properties of dpo are compared to those of 1,8-bis(diphenylphosphino)-3,6-dioxaoctane, a potentially P₂O₂ donor ligand.