Syntheses, characterization and luminescence properties of five entangled coordination polymers based on bis(4-imidazolphenoxy)methane and various dicarboxylic acids

Abstract

Five novel entangled coordination polymers, namely, [Cd(sdc)(bipm)(H₂O)]·DMF (1), [Cd₂(bdc)₂(bipm)₂(DMF)₂] (2), [Cd₂(ndc)₂(bipm)₂]·2H₂O (3), [Cd(bdc)(bipm)] (4) and [Cd₂(bpdc)₂(bipm)₂] (5) [bipm = bis(4-imidazolphenoxy)methane, H₂sdc = 4,4′-sulfonyldibenzoic acid, H₂bdc = 1,4-benzenedicarboxylic acid , H₂bpdc = biphenyl-4,4′-dicarboxylic acid, and H₂ndc = naphthalene-2,6-dicarboxylic acid], have been synthesized and structurally characterized. Compound 1 exhibits a 2-fold interpenetration of (4,4)-connected sql network. Compound 2 displays an inclined catenation of (6,3)-connected hcb network. Compound 3 features an unusual twofold interpenetrating polyrotaxane motif composed of two interlocked sets of identical pcu nets. Compounds 4 and 5 both show 3D polycatenane motifs generated by the 2D → 2D parallel → 3D parallel interpenetration of (4,4)-connected sql network. But in 4, one net is interpenetrated by five others, while in 5, unusually, one net is interpenetrated by eight others. The thermal stabilities and photochemical properties of these compounds have also been studied.