Hydrated lanthanides picrate complexes with cis-1,3-dithiane-1,3-dioxide (cis-DTSO2). Structure of the Ho compound

Compounds with composition [Ln(cis-DTSO2)(4)(H2O)(2)](pic)(3) (pic=picrate, Ln=Pr-Lu and Y) were obtained by reaction of hydrated lanthanide picrate w ith cis-DTSO2 in absolute ethanol. The adducts were characterized by elemen tal analyses and IR spectra. The parameters obtained from the absorption sp ectrum of the solid Nd compound indicate that the metal-ligand bonds presen t weak covalent character. The low intensity emission spectrum obtained at 77 K for the Eu compound indicates the existence of dimeric species. X-ray powder patterns show only one isomorphous series. X-ray single-crystal data of the holmium compound showed that the crystal system is triclinic, space soup P (1) over bar a = 13.387(1) Angstrom, b = 14.243(1) Angstrom, c = 14 .965(1) Angstrom, alpha = 99.879(8)degrees, beta = 102.063(9)degrees, beta = 101.620(1). The Ho ion achieves a coordination number of eight by the bon ding of two oxygens of one bidentate cis-DTSO2, four oxygens of four monode ntate cis-DTSO2 one of which acts as a bridge between two neighboring Ho io ns, and two water molecules, giving rise to a distorted square antiprism po lyhedron. The picrate anions are not bonded to the Ho(III) ion. The crystal packing is governed by an intricate net of hydrogen bonds. (C) 2001 Elsevi er Science B.V. All rights reserved.