Synthesis and properties of ZnII and CdII complexes with chiral N-derivatives of aminoacetic acid based on natural monoterpenes (+)-3-carene and (−)-α-pinene. Crystal structure of coordination polymer [Zn(HL)Cl·2H2O] n

Abstract

Chiral sodium salts of N-derivatives of aminoacetic acid based on (+)-3-carene (HLNa) and (−)-α-pinene (HLNa) were synthesized. Complexes Zn(HL)Cl (1), Cd(HL)Cl·0.5H2O (3), Zn(HL′)Cl·0.5H2O (4), and Cd(HL′)Cl·0.5H2O (5) were obtained. The single crystals of the coordination polymer [Zn(HL)Cl·2H2O] n (2) were grown. According to the X-ray diffraction analysis, the crystal structure of 2 consists of 1D chains built of Zn(HL)Cl and water molecules. The coordination polyhedron ClN2O2 is a distorted square pyramid. The HL− ligand performs the chelating tetradentate-bridging function, and the COO− group binds two adjacent Zn atoms. The IR spectroscopy data for compounds 1 and 3–5 indicate the coordination of the COO−, NOH, and NH functional groups. The excitation and photoluminescence (PLM) spectra of the solid samples of compounds HLNa, HL’Na, 1, and 3–5 were recorded at room temperature. The compounds exhibit blue PLM. The intensity of PLM of the CdII complexes is higher than that of the ZnII complexes, which is a characteristic feature of PLM of the studied compounds.