Structure and photoluminescence of Zn(II) and Сd(II) complexes with chiral bis-pyridine containing fragments of natural (–)-α-pinene

Complexes ZnLCl2 (I) and [CdLCl2] n (IV), where L is chiral bis-pyridine containing fragments of natural monoterpenoide (–)-α-pinene are synthesized. Single crystals of [ZnLCl2]·CH2Cl2 (II), [ZnLCl2]·i-PrOH (III), and IV compounds are grown. The crystal structures of II and III are composed of mononuclear ZnLCl2 complex molecules and solvate CH2Cl2 and i-PrOH molecules; the coordination polyhedron of the zinc atom Cl2N2 is a distorted tetrahedron. According to the single crystal XRD data, complex IV is a 1D coordination polymer; the coordination core CdN2Cl4 is a distorted octahedron and Cl atoms are bridging ligands. In the structures of II, III, and IV the L molecule functions as a bidentate chelate ligand. In the solid phase, complexes I and IV exhibit photoluminescence in the visible range (λmax 505 nm and 460 nm respectively). The band intensity in the photoluminescence spectra of I and IV complexes considerably exceeds the band intensity in the spectrum of free L.