Blue fluorescence of three metal-organic zinc polymers containing tetrazinc units and asymmetric ligand of btc(3-)

摘要

Three new zinc coordination polymers [Zn-2(btc)(2)(H2O)(2)](n)(.)n[Zn(H2O)(6)] (1), [Zn-3(btc)(2)(2,2'-bipy)(2)(H2O)(3)](n)(.)2nH(2)O (2) and [Zn-3(btc)(2)(H2O)(6)](n)(.)nH(2)O (3) (H(3)btc = 1,2,4-benzenetricarboxylic acid, 2,2-bipy = 2,2-bipyridine) were obtained by the diffusion method and their crystal structures were determined by single-crystal X-ray diffraction. Compounds 1-3 have the similar tetrametallic unit [Zn-4(btC)(2)] SBUs and these SBUs are further connected into stair-like structure, 2-D layer and 3-D framework for 1, 2 and 3, in which the btc(3-) ligands adopt mu(3), mu(4) and mu(5) coordination modes, respectively. The title compounds show strong blue fluorescence, which may be assigned as pi*-> n transition of the ligand mixed with the ligand-to-metal change transfer (LMCT), indicating the fluorescence, indicates the title compounds may be good candidates for blue-light photoactive materials. (c) 2005 Elsevier Inc. All rights reserved.