Syntheses, crystal structures and anion-exchange properties of novel coordination polymers with imidazole-containing tripodal ligands

Abstract

Six novel coordination polymers, [Cu(tib) 2(N 3) 2] · 2H 2O ( 1), [Cd(tib) 2(H 2O) 2](NO 3) 2 ( 2), [Cu(dien)(tib)](ClO 4) 2 · tib · CH 3CN ( 3), [Mn(ibimb) 2(H 2O) 2]Cl 2 · 2H 2O ( 4), [Zn(titmb) 2](NO 3) 2 · 2MeOH ( 5) and [Cd 3(titmb) 2Br 6] ( 6), where tib = 1,3,5-tris(1-imidazolyl)benzene, dien = diethylenetriamine, ibimb = 1-(1-imidazolyl)-3,5-bis(imidazol-1-ylmethyl)benzene, titmb = 1,3,5-tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene, were obtained by self-assembly of tripodal ligands with the corresponding metal salts, and their structures were determined by single crystal X-ray diffraction analyses. Complexes 1 and 2 have similar 2D network structure in which only two of three imidazole groups of each tib ligand coordinated to the metal atoms and the additional one did not participate in the coordination. Complex 3 has a 1D chain structure in which there are two kinds of tib ligands, one kind of tib serves as a two-connecting (bridging) ligand using its two arms. The other kind of tib acts as guest molecule filled in the void of cationic 1D chains. Complex 4 has an infinite 1D hinged chain structure and ligand ibimb serves as a two-connecting (bridging) ligand using its two flexible arms. Complex 5 has a 2D honeycomb network structure with (6,3) topology in which titmb acts as a three-connecting ligand. Complex 6 has an infinite 1D chain structure in which each titmb ligand connects three metal atoms. Ligand titmb has cis, trans, trans-conformation in 6, which is different from that in complex 5( cis, cis, cis). The anion-exchange properties of complex 5 were investigated.