3D supramolecular networks of Mn(II)-5-sulfosalicylate assembled with 4,4′-dipyridyl N,N′-dioxide and 4,4′-dipyridyl: Structure, photoluminescence and DFT calculations

The supramolecular complexes {[Mn2(HSsal)2(dpyo)3(H2O)6]2(H2O)} (1) and {[Mn(4,40-bipy)(H2O)4] (HSsal)(H2O)}n (2) [dpyo = 4,40-dipyridyl N,N0-dioxide; 4,40-bipy = 4,40-bipyridine and HSsal = 5-sulfosalicylate dianion] have been synthesized and structurally characterized. Complex 1 is a rare Mn dinuclear species realized with bridging dpyo and coordinated HSsal ligands to form a 3D architecture through H-bonding and p p interactions. In complex 2, Mn(H2O)4 fragments are bridged by 4,40-bipy, giving rise to a 1D chain. The adjoining chains encapsulate HSsal anions to give a 3D structure through a R2 2 (12) H-bonding synthon and p p interactions. The complexes were tested in association with several aromatic compounds, since they exhibit intense fluorescence (kex = 223 nm, kem = 308, 325, 353 and 393 nm for 1; kex = 237 nm, kem = 312, 335, 348 and 394 nm for 2). The outcome of DFT calculations on model compounds is discussed and compared with the experimental X-ray structural data.