Six New Coordination Polymers: from Dimer to 2D Network based on the Combination of cis‐Bis(imidazole) Spacers with Cobalt(II) Cations

Abstract

AbstractThis paper reports the first systemic investigation on the bimetallic ring coordination polymers based on two structure‐related flexible bis(imidazole) ligands, bimb as well as bix [bimb = 1, 4‐bis(imidazol‐1‐yl)‐butane, bix = 1, 4‐bis(imidazol‐1‐yl‐methylene)‐benzene)]. As expected, six new cobalt complexes were generated, namely, [Co2(SCN)4(bimb)2] (1), [Co2(L1)2(bimb)2Cl2] (2), [Co2(L2)4(bix)2] (3), [Co(SCN)2(bimb)2] (4), {Co[N(CN)2]2(bimb)2} (5), and [Co(L3)(bix)] (6) (HL1 = 4‐aminobenzoic acid, HL2 = 4‐nitrobenzoic acid, and H2L3 = succinic acid). The structures of 1–3 are three discrete dinuclear ring motifs. Especially, 1 is the first example of 1D pseudo‐polyrotaxane formed by S···S strong interactions based on bis(imidazole) ligands. 4 and 5 exhibit 1D meso‐helical chain architecture, in spite of their different space groups. In 6, the discrete dinuclear ring motifs, traversed by μ2‐η3‐chelating L3 anions, are interconnected by another μ2‐η1‐bridging L3 anions to form 2D (4, 4) network. The formation of these compounds should be undoubtedly attributed to the preference for cis‐bis(imidazole) ligands crystallization resulting in various ring architectures. In addition, compound 6 exhibits antiferromagnetic behavior.