Structural and spectroscopic studies of neodymium complexes with S(+)-mandelic acid

Abstract

► Syntheses of neodymium S(+)-mandelate monocrystals. ► X-ray crystal structure determination. ► TG–DTA analyses. ► Spectroscopic UV–vis–NIR–IR measurements. ► Neodymium S(+)-mandelate crystals as metal–organic frameworks. The crystal structure of tetraaquahexakis-S(+)-mandelatodineodymium trishydrate was determined by the X-ray diffraction method. The compound crystallizes in the monoclinic space group P2 1 with the following unit cell parameters: a = 10.536(2), b = 16.089(3), c = 15.316(3) Å, β = 97.96(2)°. The structure consists of polymeric [Nd 2 (Man) 6 (H 2 O) 4 ·3H 2 O] ∞ chains (where ManH = S(+)-2-hydroxy-2-phenylacetic acid or S(+)-mandelic acid), with two symmetry independent Nd +3 ions. Both neodymium ions are nine-coordinate but differ in their environments. Nd(1) is surrounded by two water molecules, five carboxylate and two hydroxyl oxygen atoms, Nd(2) is coordinated by two water molecules, four carboxylate and three hydroxyl oxygen atoms. Crystals of neodymium mandelate complex were characterized by thermal analysis as well as by IR and UV–vis–NIR absorption spectroscopy.