Luminescent coordination polymers with anthracene chromophores: Syntheses, crystal structures and luminescent properties

Abstract

Five luminescent coordination polymers, namely, [Cd(DIA)(1,2-chdc)]n (1), [Cd(DIA)1.5(cdc)]n (2), [Cd(DIA)(sdba)(H2O)]n (3), [Zn(DIA)0.5(nda)]n (4) and [Zn(DIA)(1,4-chdc)·2H2O]n (5), where 1,2-chdcH2 = 1,2-cyclohexanedicarboxylic acid, H2cdc = 4,4′-carbonyldibenzoic acid, H2sdba = 4,4′-dicarboxybiphenyl sulfone, H2nda = 2,6-naphthalenedicarboxylic acid, 1,4-chdcH2 = 1,4-cyclohexanedicarboxylic acid and DIA = 9,10-di(1H-imidazol-1-yl)anthracene, have been obtained under solvothermal conditions and characterized by IR, elemental analyses, thermogravimetric analyses and single crystal X-ray diffraction. In 1, adjacent Cd(II) ions are linked by 1,2-chdc anions to generate [Cd(1,2-chdc)]2 units, which are further extended by DIA ligands to form a puckered sheet. Complex 2 represents an unusual 2D + 2D → 3D metal–organic polyrotaxane framework entangled in a highly rare parallel fashion. Complex 3 has a two-dimensional (2D) layer structure with a topology of (44.62). Complex 4 affords a three-dimensional (3D) two-fold interpenetrating α-Po network, whereas complex 5 features a 2D two-fold interpenetrating layer structure. The structural variation was achieved by tuning the organic carboxylate ligand. Five complexes indicate high thermal stabilities and different photoluminescent behavior in the solid state.