Anion-dependent construction of a series of fluorescent coordination polymers based on 1D zinc∩4,4′-bis(imidazol-1-yl)-biphenyl substrates

Abstract

In this work, the rod-like ligand 4,4′-bis(imidazol-1-yl)-biphenyl (bibp) has been utilized as a building block to carry out counterion effects on the structural diversities of coordination polymers. A series of new zinc complexes, [Zn(trans-bibp)Cl2]∞ (1), [Zn(trans-bibp)Br2]∞ (2), {[Zn(cis-bibp)(Ac)2]·(H2O)}∞ (3), [Zn(trans-bibp)SO4]∞ (4), {[Zn2(cis-bibp)2(ipa)2]·(H2O)}∞ (5, H2ipa=isophthalic acid) and {[Zn(trans-bibp)(cis-bibp)]·(ClO4)2(CHCl3)2(CH3OH)}∞ (6) have been successfully synthesized. Complexes 1 and 2 are iso-structural, which show a 1D W-type chain [Zn(trans-bibp)]∞. Complex 3 exhibits a 2D wave-like layer formed by the hydrogen bond among the 1D linear chain [Zn(cis-bibp)]∞. Complex 4 displays a 2D fish-bone lattice, which is generated from connecting the 1D W-type chain [Zn(trans-bibp)]∞ by the μ2-SO42-. Complex 5 presents an interesting 2D–3D 65·8 architecture, including two 1D chains [Zn(ipa)]∞ and [Zn(cis-bibp)]∞. Complex 6 demonstrates a 2D wave-like layer [Zn(trans-bibp)(cis-bibp)]∞. The structural diversities among 1–6 have been carefully discussed, and the role of counterion in the self-assembly of coordination polymer have also been well documented from the coordination affinity and bridging mode. Furthermore, the solid-state fluorescence properties of 1–6 at room temperature have been studied.