Luminescent cadmium 1,3-adamantanedicarboxylate coordination polymers with diverse topologies depending on dipyridylamide ligands

Hydrothermal reaction of cadmium nitrate, 1,3-adamantanedicarboxylic acid (adcH(2)), and a hydrogen-bonding capable dipyridylamide ligand afforded five crystalline coordination polymers whose dimensionality depends on the dipyridylamide length and nitrogen donor disposition. The five new phases were structurally characterized via single-crystal X-ray diffraction. [Cd(adc)(4-pmina)](n) (1, 4-pmina = 4-pyridylmethylisonicotinamide) displays a (4,4) grid topology with [Cd(adc)](n) chains pillared by the dipodal dipyridylamide ligands. {[Cd(adc)(4-pmna)(H2O)]center dot 4H(2)O}(n) (2, 4-pmna = 4-pyridylmethylnicotinamide) displays a similar layered topology, but with octameric water molecule clusters residing in the interlamellar regions. {[Cd(adc)(3-pna)(H2O)]center dot 6H(2)O}(n) (3, 3-pna = 3-pyridylnicotinamide) possesses 1-D ribbon submotifs due to the syn-conformation and shorter tether length of the dipyridylamide ligands. Compound 3 entrains intriguing ''infinite" water molecule tapes comprised of 4- and 5-membered rings. {[Cd-2(adc)(2)(3-pina)(2)]center dot H2O}(n) (4, 3-pina = 3-pyridylisonicotinamide) manifests a 4-connected 3D 6(5)8 cds topology. The minor coordination polymer chain product {[Cd(adc)(3-pyram)(2)(H2O)]center dot 2H(2)O}(n) (5) was isolated along with 4 (3-pyram = 3-pyridylamine). Luminescent behavior in 1-4 is attributed to intra-ligand molecular orbital transitions. The new phases were also surveyed for the ability to detect nitrobenzene in ethanol suspension. Thermal decomposition behavior is also discussed herein. (C) 2017 Elsevier B.V. All rights reserved.