Syntheses, crystal structures, and properties of optically active Lu(III) and Yb(III) complexes of N,N′-bis(2-hydroxybenzyl)-N,N′-bis(2-pyridylmethyl)-R-1,2-propanediamine with chloride or thiocyanate

Abstract

The reaction of N,N′-bis(2-hydroxybenzyl)-N,N′-bis(2-pyridylmethyl)-R-1,2-propanediamine (R-bbppnH₂) with LnCl₃∙6H₂O (Ln: Lu, Yb) stereoselectively gave an optically active complex, [LnCl(R-bbppn)], which crystallizes in the acentric space group of P2₁2₁2₁. The central lutetium(III) is coordinated by two oxygens from two phenolates, four nitrogens from two pyridines, and one bidentate propanediamine of R-bbppn²⁻, one chloride to form a seven-coordinate distorted pentagonal bipyramidal geometry. Although two optical isomers, ΔΛΔ and ΛΔΛ, are possible for such a structure, the absolute configuration of the complex is stereoselectively unified to ΔΛΔ. The coordinated chloride of the complex is readily replaced by other ligands, and hence the reaction with thiocyanate results in formation of another seven-coordinate complex, [Ln(NCS)(R-bbppn)].

Keywords:

• Lutetium(III) and ytterbium(III) complexes
• optically active complexes
• multidentate ligand
• crystal structures
• ligand exchange reactions