Synthesis and structures of copper(II), copper(I,II) and copper(l) complexes with 4-(3,5-dipheny1-1H-pyrazol-1-y1)-6-(piperidin-l-y1)pyrimidine. Luminescence of copper(I) complexes

A series of Cu(ll), Cu(1,11) and Cu(I) halide complexes, [CuL2Br]2[Cu2Br6]. ICuL2Br2], I Cu(2)L2(B)r(31).EtOH, I cu(2) L2Br3].CHCl3, [Cu(2)L2(C)l(3)].MeCN, [Cu2L2Cl3].CHCl3, [CuLCl1, [CuLBr] and [Cu(2)L(2)l(2)] with 4-(3,5-dipheny1-1Hpyrazol-1-y1)-6-(piperidin-1-y1)pyrimidine (L) have been synthesized. Copper(II) compounds, [CuL(2)B(1)l(2) [Cu2Br6] and [CuL2Br2], were obtained by the reactions of CuBr2 with L in the Cu:L = 1:1 and 1:2 molar ratios, respectively, in EtOH solutions at room temperature. In the structure of [CuL(2)Br(2)l, the double intermolecular lone pair- interactions were observed between N(piperidine) atom and Tr-deficient pyrimidine ring. Dinuclear mixed-valence copper(1,11) bromide compounds, [Cu2L2Br3I.EtOH and [Cu2L2Br3]-CHCl3, were prepared (i) by the reaction of CuBr2 and L in a 1:1 molar ratio upon heating in EtO1-1 either CHCl3/MeCN solutions, and (ii) by recrystallizing [CuL2BrI2[Cu2Br6] from CHCl3/MeCN mixture. Their analogs, mixed-valence copper(I,11) chloride compounds, [Cu2L2Cl3].MeCN and [Cu2L2Cl3].CHCl3, were prepared by reacting the complex [CuL2Cl2] with CuCl in MeCN/CHCI3 mixtures (various v/v ratios of the solvents). The frozen solutions of copper(11) and copper(1,11) complexes in CHCI3 were studied by EPR spectroscopy at 77 K. These data revealed that mixed valence compounds are type 1 systems. In the structures of [Cu(2)L(2)BrACHCI(3) and [Cu2L2Cl3].CHCI3, lone pair-7r interactions were observed between CI atom of chloroform solvent molecule and the phenyl group. The Cu(I) complexes, [CuLC1], [CuLBr] and [Cu(2)L(2)l(2)], were obtained by the reactions of CuHal (Hal = Cl, Br, I) and L in a 1:1 molar ratio in MeCN solutions. The complex [Cu(2)L(2)l(2)] has dinudear structure with rather short Cu-Cu distance, 2.59 degrees, within (Cu(mu-l)(2)Cu) central unit, while its chloride and bromide analogs seem to be mononuclear compounds. The complexes [CuLC1], [CuLBr] and [Cu(2)L(2)l(2)] were found to show bright yellow luminescence in the solid state at room temperature. The relative intensity of emission increases across the series: [CuLC1] < [CuLBr] < [Cu(2)l(2)l(2)]. At 77 K, there is a noticeable red shift (ca. 20 nm) in emission for [Cu(2)l(2)l(2)] (C) 2013 Elsevier Ltd. All rights reserved.