A series of chiral coordination polymers containing helicals assembled from a new chiral (R)-2-(4′-(4′′-carboxybenzyloxy)phenoxy)propanoic acid: syntheses, structures and photoluminescent properties?

Dalton Transactions Pub Date: 2012-07-06 DOI: 10.1039/C2DT30863K

Abstract

Ten new chiral coordination polymers, namely, [Ni(L)(H2O)2] (1), [Co(L)(H2O)2] (2), [Cd(L)(H2O)] (3), [Cd(L)(phen)] (4), [Mn2(L)2 (phen)2]·H2O (5), [Cd2(L)2(biim-4)2] (6), [Zn2(L)2(biim-4)2] (7), [Cd(L)(pbib)] (8), [Cd(L)(bbtz)] (9) and [Cd(L)(biim-6)] (10), where phen = 1,10-phenathroline, biim-4 = 1,1′-(1,4-butanediyl)bis(imidazole), pbib = 1,4-bis(imidazole-1-ylmethyl)benzene, bbtz = 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene, biim-6 = 1,1′-(1,6-hexanedidyl)bis(imidazole), and H2L = (R)-2-(4′-(4′′-carboxybenzyloxy)phenoxy)propanoic acid, have been synthesized under hydrothermal conditions. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by infrared spectra (IR), powder X-ray diffraction (PXRD), elemental analyses and thermogravimetric (TG) analyses. Compounds 1 and 2 exhibit similar 1D left-handed helical chains, which are further extended into 3D supramolecular structures through O–H?O hydrogen-bonding interactions, respectively. Compound 3 shows a 2D double-layer architecture containing helical chains. Compound 4 features two types of 2D undulated sheets with helical chains, which are stacked in an ABAB fashion along the c direction. Compound 5 possesses a 1D double chain ribbon structure containing unusual meso-helical chains, which is linked by π–π interactions into a 2D supramolecular layer. These layers are further extended by hydrogen-bonding interactions to form a 3D supramolecular assembly. Compounds 6 and 7 are isostructural and exhibit 2D (44)-sql networks with helical chains. Neighboring sheets are further linked by C–H?O hydrogen-bonding interactions to generate 3D supramolecular architectures. Compounds 8–10 are isostructural and display 3D 3-fold interpenetrating diamond frameworks with helical chains. The effects of coordination modes of L anions, metal ions and N-donor ligands on the structures of the coordination polymers have been discussed. The luminescent properties of 3, 4 and 6–10 have also been investigated in detail.

Graphical abstract: A series of chiral coordination polymers containing helicals assembled from a new chiral (R)-2-(4′-(4′′-carboxybenzyloxy)phenoxy)propanoic acid: syntheses, structures and photoluminescent properties
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