1D Coordination Polymers from Zinc(II) and Cadmium(II) Halides and 2,2-Dithiobis(pyridine N-oxide): Isostructurality and Structural Diversity

Group 12 halides and 2,2-dithiobis(pyridine N-oxide) (dtpo) form the crystalline the 1D coordination polymers [ZnX2(-dtpo-O-2:O)](n) [X = Cl (1), Br (2), I (3)], [Cd-3(-Cl)(4)Cl-2(-dtpo-O-2:O)(2)(CH3OH)(2)](n) (4), [(CdBr2)(2)((3)-dtpo-O-3,O:O)(2)(H2O)(2)](n) (5), and [(CdI2)(2)(-dtpo-O-2:O)(3)](n) (6) in methanol. The compounds were structurally characterized by single-crystal X-ray analysis. Compounds 1-3 represent an isomorphous series of single-stranded coordination polymers, whereas the Cd-II derivatives are structurally diverse. The metal nodes in 4 and 5 are trinuclear and dinuclear cadmium clusters, respectively. In 4 and 5, the metal nodes are linked into double-stranded 1D coordination polymers by two dtpo bridging ligands. Compound 6 contains mononuclear CdI2 units as nodes and can be viewed as an alternating copolymer of CdI2(-dtpo-O-2:O)(2) and CdI2(-dtpo-O-2:O) entities. Owing to the disulfide moiety, the dtpo bridging ligand inevitably exhibits an axially chiral angular structure. The dtpo ligand adopts various coordination modes through the pyridine N-oxide oxygen atoms.