Cyclometallated Palladium(II) Complexes: An Approach to the First Dinuclear Bis(iminophosphorane)phosphane-[C,N,S] Metallacycle

Abstract

Treatment of bis(iminophosphorane)phosphane ligands 2a–2e with Li2PdCl4 gave a set of novel diphosphane-derived complexes bearing two metallacycle rings, each one enclosing a P=N double bond: the unprecedented bis(iminophosphorane)phosphane-[C,N,S] palladacycles. In the case of the ligand derived from bis(diphenylphosphino)methane, 2a, both the single and the double palladacycle complexes were obtained. Reaction of 3a with bis(diphenylphosphino)ethane did not yield the expected product with the diphosphane bonded to both palladium atoms, but rather the novel coordination compound 5. The crystal structures of 3c and 5 are described.

Efficient and Sustainable Electrosynthesis of N-Sulfonyl Iminophosphoranes by the Dehydrogenative P–N Coupling Reaction

“…Further, unsymmetrical iminophosphorane 12 could be isolated in a high yield of 80%, illustrating that both aryl- and alkyl-substituted phosphines are suitable for the reaction. Lastly, diiminophosphorane 11 , which is an interesting ligand for organometallic complexes, , was accessible in 68% yield by reacting 1,2-bis(diphenylphosphino)ethane (dppe) with 2 equiv of TsNH 2 .…”

“…Iminophosphoranes, also referred to as phosphinimines, are nitrogen analogues of phosphonium ylides and represent powerful reagents in organic synthesis . They serve as nitrene donors in aziridine synthesis and in aza-Wittig reactions, ,− which are frequently used for the construction of N-heterocyclic compounds such as drugs (Scheme a). − Furthermore, they are utilized as superbasic organocatalysts for versatile transformations, − as ligands for transition metal catalysts, − and as intermediates for amino group protection and optical resolutions. , Moreover, several iminophosphoranes showed biological activity and were investigated as potential anticancer agents − and acetylcholinesterase (AChE) inhibitors targeting the treatment of Alzheimer’s disease (Scheme b) …”