Syntheses, Structures, and Luminescent Properties of a Series of Coordination Compounds Based on (4-Carboxylphenyl) (4-(2′-Carboxylphenyl)benzyl) Ether and Different N-Donor Ligands

Abstract

Fourteen novel coordination compounds based on (4-carboxylphenyl) (4-(2′-carboxylphenyl)benzyl) ether (H2L) and different N-donor ligands have been hydrothermally synthesized and structurally determined by single-crystal X-ray diffraction analyses, namely, [Zn3(L)3(biim-4)2]·H2O (1), [Cd(L)(H2O)(biim-4)0.5] (2), [Zn(L)(BIE)] (3), [Co(L)(BIE)] (4), [Cd(L)(BIE)] (5), [Ni(L)(BIE)] (6), [Ni(L)(phen)]·H2O (7), [Co(L)(phen)]·H2O (8), [Co(HL)2(phen)2]·3H2O (9), [Cd(L)(H2O)(phen)] (10), [Co(L)(H2O)(phen)] (11), [Cd(L)(phen)2] (12), [Pb(L)] (13), and [Pb(L)(phen)]·H2O (14), where biim-4 = 1,1′-(1,4-butanediyl)bis(imidazole), BIE = 2,2′-bis(1H-imidazolyl)ether, and phen = 1,10-phenanthroline. Compound 1 displays an unusual three-dimensional (3D) binodal (4,5)-connected net with a point symbol of (43·62·8)(45·5·64). Compound 2 exhibits one-dimensional (1D) looplike chain structures, which are further extended into a 3D supramolecular architecture through π–π interactions. Compounds 3–6 are isomorphous and feature similar two-dimensional (2D) layer structures. Compounds 7 and 8 are isomorphous and show the same zero-dimensional (0D) structures, which are further extended by π–π interactions into 2D supramolecular layers. Compound 9 displays a discrete [Co2(L)2(phen)2] dimer. Neighboring dimers are further linked by π–π interactions to form a 1D double chain. Compounds 10 and 11 exhibit similar 1D double chain structures. The chains are further linked via π–π interactions to generate 2D supramolecular layers. Compound 12 shows a discrete [Cd2(L)2(phen)2] dimer. The π–π stacking and hydrogen-bonding interactions further extend the dimers into a 3D supramolecular architecture. Compound 13 displays a typical (44)-sql network structure. Neighboring networks are further linked by the π–π interactions, leading to an unusual 3D supramolecular architecture. Compound 14 exhibits a discrete [Pb2(L)2(phen)2] dimer. Neighboring dimers are further linked by the π–π interactions to form a 2D supramolecular layer. The thermal stabilities and luminescent properties of the complexes have also been investigated in detail.