Luminescent copper(ı) (pseudo)halide complexes with neocuproine and a novel bulky tris (aminomethyl) phosphine derived from 2-piperazinopyridine

A novel bulky phosphine derived from 2-piperazinopyridine P(CH2N(CH2CH2)2N-2-py)3 (1) and its chalcogenide derivatives (oxide, sulfide and selenide) have been synthesized and characterized by elemental analysis, NMR spectroscopy and mass spectrometry. Next, two new copper(I) iodide or isothiocyanate complexes with 1 and 2,9-dimethyl-1,10-phenanthroline (dmp): [CuI(dmp)(1)] (1I) and [CuNCS(dmp)(1)] (1T), have been also synthesized and characterized by elemental analysis and studied by NMR, UV–vis, IR and luminescence spectroscopies. The X-ray structure of the complex 1T·1.81(CH3COCH3) was determined. The coordination geometry around the Cu(I) center is pseudo-tetrahedral with distortions resulting mostly from the molecular packing in the crystal cell. Both complexes exhibit orange photoluminescence in the solid state, which is much stronger for 1I than for 1T. The luminescence spectra of both complexes at room and 77 K temperatures show relatively large bands with a typical batochromic shift accompanying the lowering of the temperature. On the basis of TDDFT calculations we interpreted these bands as of (MX,MPR3)LCT type resulting mainly from the transitions from the copper–iodine (or isothiocyanate) bonds and a small admixture of copper–phosphine bonds to antibonding orbitals of dmp diimine.