One-dimensional helical Zn(II) and repeated rhomboidal Fe(II) coordination chains containing the twisted ligand 4,4′-di(4-pyridyl-4-pyrimidinyl)disulfide

Reactions of 4-PPDS (4-PPDS = 4,4′-di(4-pyridyl-4-pyrimidinyl)disulfide) with Zn(OAc)2 and FeCl2 produced a one-dimensional helical chain {[Zn(CH3CO2)2(4-PPDS)]·H2CO3}n (1) and a one-dimensional repeated rhomboidal coordination chain [FeCl2(4-PPDS)2]n (2), respectively. One-dimensional helical chain (1) is built from the alternating links of one Zn(II) ion and one 4-PPDS ligand with the same chirality whereas one-dimensional repeated rhomboidal chain (2) is constructed by alternated linking of one Fe(II) ion and two enantiomers of 4-PPDS ligands. Complex (1) has the unexpected carbonic acid in its crystal structure, which is assumed to be transformed from carbon dioxide. The solvent-accessible volume in complex (2) is approximate 151.4 Å3 per unit cell volume. Both complexes in the solid state exhibit intense photoluminescences with the emission maxima around 365 nm upon excitation at 260 nm.