Metal ion complexes of the optically pure bi(4-phenyl-1,3-oxazoline) ligand. Synthesis, characterization and X-ray crystal structures

Abstract

Several new complexes of optically pure 2,2′-bis-[(4 R)-phenyl-1,3-oxazoline] ( L) with Mn(II), Co(II), Cu(II), Zn(II), Cd(II) and Ag(I) metal ions have been synthesized and thoroughly characterized by IR, UV–Vis and 1H NMR spectroscopy, as well as by single-crystal X-ray diffraction. These compounds include [MnL 3][MnCl 4] ( 1), [CoL 3][Co(NCS) 4] ( 2), [CuL 3](ClO 4) 2 ( 3), [ZnL 3](ClO 4) 2 ( 4), [CdL 3](ClO 4) 2 ( 5) and [AgL](CF 3SO 3)·1/2C 6H 6 ( 6). In 1 and 2 the anionic part contains the metal ions as well. In the cationic part, the metal ions Mn(II), Co(II) have an octahedral coordination geometry of the six nitrogen atoms of the three ligands ( L). In the anionic part, Mn(II) and Co(II) adopt a tetrahedral coordination with chloride and thiocyanate species, respectively. Complexes 3– 5 are homoleptic octahedral complexes with Cu(II), Zn(II) and Cd(II) metal ions, respectively. Complex 6 is an infinite one-dimensional chain polymer composed of alternating Ag + and L units. The optical purity of these materials was assessed from the crystallographic data to reveal that crystalline 1 is optically pure, while 2– 6 are quasi-racemates.