Copper(II) and silver(I) complexes with chiral N-substituted aminoacetic acid derivatives containing the natural monoterpenes (+)-3-carene and (–)-α-pinene: Synthesis and structures

Abstract

The complexes [Cu(HL)Cl] · 0.25H2O (I), [Cu(HL1)Cl] · 0.5H2O (II), [Ag(HL)] · 0.5H2O (III) were obtained; HL– and (HL1)– are the anions of the chiral N-substituted aminoacetic acid derivatives containing the natural monoterpenes (+)-3-carene and (–)-α-pinene, respectively. The µeff values for paramagnetic complexes I and II are 1.92 and 1.81 µB, respectively. Single crystals of the coordination 1D polymer [Cu(HL)Cl · 2H2O]n (IV) were grown. According to the X-ray diffraction data (CIF file CCDC No. 1035219), the crystal structure of complex IV is made up of the zigzag chains [Cu(HL)Cl]n and water molecules. The coordination polyhedron of the Cu atom is a distorted square pyramid (ClN2O2). The anion HL– acts as a chelating and bridging tetradentate ligand coordinated through the N atoms of the NH and NOH groups as well as through the O atoms of the COO–groups linking two adjacent Cu atoms together. The IR spectra of complexes I and II also provide evidence for the coordination of the functional COO–, NOH, and NH groups. In complex III, the coordination sphere of the Ag atom is made up of the O atoms of the COO–group. Complex III shows weak green photoluminescence (λmax = 530 nm).