Ionothermal synthesis of a 3D zinc(II)-carboxylate coordination polymer with bcu topology based on heptanuclear [Zn7(μ4-O)2] cluster

Compound {(EMIM)(2)[Zn-7(mu(4)-O)(2)(1,4-ndc)(6)]}(n) (1) (EMIM=1-ethyl-3-methylimidazolium and 1,4-ndc=1,4-naphthalenedicarboxylate) has been synthesized by using the mixed ionic liquids of 1-ethyl-3-methylimidazolium tetrafluoroborate and 1-ethyl-3-methylimidazolium t-lactate as solvent. Compound 1 has a 3D anionic framework with bcu-(4(24).6(4)) topology based on a unique heptanuclear [Zn-7(mu(4)-O)(mu(2)-COO)(10)] cluster as secondary building unit. The imidazolium cation [EMIM](+) of the ionic liquid acting as extra framework charge-balancing species occupies the channels of the 3D anionic framework. The roles of the ionic liquid in ionothermal synthesis and crystallization of compound 1 are briefly discussed. The thermal and photoluminescent properties of compound 1 have also been investigated. (C) 2011 Elsevier BM. All rights reserved.