Complexation of tris(2-pyridyl)phosphine chalcogenides with copper(I) halides: The selective formation of scorpionate complexes, [Cu(N,N′,N-2-Py3P=X)Hal] (X = O, S and Se)

A series of copper(I) scorpionates, [Cu(N,N',N ''-2-Py3P=X)Hal] (X = O, S and Se; Hal = Cl, I), has been synthesized in 67-88% yields by the reaction of tris(2-pyridyl)phosphine chalcogenides with Cu(I) halides (CH2Cl2, r.t., 10 min). These complexes were characterized by X-ray crystallography, NMR and UV-Vis techniques to reveal that the ligand coordinates with Cu(I) ion via three pyridine nitrogen atoms to form near-C-3-symmetrical [Cu(N-C)(3)P=X] cage. The halogen atoms are bonded with metal so that the latter adopts a distorted trigonal pyramidal geometry. The DFT computations confirm that the observable kappa(3)-N,N',N ''-binding of the ligands is energetically more favorable than the alternative coordination modes, i.e. kappa(1)-X-monodentate, kappa(2)-N,N'- or kappa(2)-N,X-bidentate and kappa(3)-N,N',X-tridentate. (C) 2015 Elsevier Ltd. All rights reserved.