Cadmium(II) Complexes with 2-Hydroxy-1-naphthoate Ligand: Syntheses, Crystal Structures, and Emission Properties

Two new Cd-II complexes [Cd(L)(2)(phen)](2) (1) and {Cd(L)(2)(4bpy)(1.5)}(infinity) (2) (L = 2-hydroxy-1-naphthoate, phen = 1,10-phenanthroline, and 4bpy = 4,4'-bipyridine) were prepared by slow solvent evaporation from mixtures of 2-hydroxy-1-naphthoic acid (HL) and Cd(ClO4)(2)center dot 6H(2)O in the presence of auxiliary phen and 4bpy co-ligands. Single-crystal X-ray analyses show that complex 1 features a dinuclear structure, which is assembled into a one-dimensional (1D) chain, and further into a two-dimensional (2D) network by intermolecular pi center dot center dot center dot pi stacking and C-H center dot center dot center dot pi supramolecular interactions. Complex 2 has a 1D ladder-like chain, which is further interlinked to form a 2D network by the co-effects of the interchain C-H center dot center dot center dot O hydrogen bonds as well as C-H center dot center dot center dot pi interactions. The structural differences between 1 and 2 are attributed to the different N-donor auxiliary ligands, phen for 1 and 4bpy for 2. Moreover, complexes 1 and 2 exhibit strong solid-state luminescences at room temperature, which mainly originate from the intraligand pi ->pi* transitions of L.