摘要:
Two couples of chiral tri- and tetranuclear Cd(II) clusters, namely [Cd-4(S-L-1)(6)]center dot(ClO4)(2) (1) and [Cd-4(R-L1-)(6)]center dot(ClO4)(2) (2), and [Cd-3(S-L-2)(4)]center dot(ClO4)(2) (3) and [Cd-3(R-L-2)(4)]center dot(ClO4)(2) (4) (L-1 = 1-(1-(2-pyridine)-ethylimino)-2-naphtho, L-2 = 2-(1-(2-pyridine)-ethylimino)-5-bromo-6-methoxy-pheno) have been synthesized via the solution reaction of chiral Schiff-base ligands with Cd(ClO4)(2)center dot 6H(2)O, and characterized by single-crystal X-ray analyses, IR and circular dichroism (CD) spectra. Complexes 1 and 2 are a couple of tetranuclear Cd(II) complex enantiomers crystallized in the chiral space group P4(2)22, and 3 and 4 are also a couple of trinuclear Cd(II) complex enantiomers crystallized in another chiral space group P2(1). The CD measurements further confirmed that 1-2, and 3-4 are a pair of enantiomers with Cotton effects of the opposite sign at the same wavelengths, respectively. The strong solid-state fluorescence emissions were observed at around 465 nm for 1 and 2, and 485 nm for 3 and 4, respectively. Furthermore, complex 3 exhibits a ferroelectric behavior related to the polar point group C-2. (C) 2014 Elsevier Ltd. All rights reserved.