Phosphorescent Acentric Cuprous Halide Coordination Polymers for Nolinear Optical Materials

Three phosphorescent acentric cuprous halide coordination polymers, namely, [Cu 2 (pyt)Cl] ( 1 ), [Cu 2 (pyt)Br] ( 2 ), and [Cu 5 (pytH) 3 Cl 5 ] ( 3 ) have been synthesized through the treatment of copper halides with achiral ligand pyridine-4-thiol (pyHt) by the hydro(solvo)thermal method. Complexes 1 and 2 are isostructural and exhibit three-dimensional (3-D) pillar-layered structures constructed by [Cu 2 SCl] ∞ /[Cu 2 SBr] ∞ layers and pyridine pillars. The [Cu 2 SCl] ∞ layer can be viewed as a fusion of zigzag [CuS] ∞ and [CuCl] ∞ chains. Alternately, the [Cu 2 SCl] ∞ layers can be viewed as a fusion of six-membered Cu 3 S 2 Cl and Cu 3 Cl 2 S rings. Complex 3 shows a [Cu 5 S 3 Cl] ∞ chain decorated by terminal chlorides and pyridine rings, in which the six Cu(I) atoms are linked by three μ 3 -S atoms and one μ 3 -Cl into a Cu 6 S 3 Cl cage, and a fusion of Cu 6 S 3 Cl cages via sharing Cu sites results in a one-dimensional [Cu 5 S 3 Cl] ∞ chain. At ambient temperature, 1, 2, and 3 show a strong yellow or red emission assigned from ligand-to-metal charge transfer (LMCT) and/or metal-to-ligand charge-transfer (MLCT) character and a weak higher energy blue emission band assigned from halide to pyridine π* charge transfer. Their noncentrosymmetric structures are confirmed by measurement of second harmonic generation efficiency.