LAUSR

Chromium in compounds can exist in various oxidation states, ranging from II to VI. In particular, chromium(VI) in CrO4 or Cr2O7 is highly cytotoxic substance and a potential carcinogen. A number of treatment methods for the removal of toxic heavy metal ions in water have been described. It may be possible that the [Cr(urea)6] is suitable to target the oxoanion. In a recent communication, we described concerning synthesis and crystal structure of the [Cr(urea)6][Cr2O7]Br·H2O (Scheme 1). The complex crystallized in the monoclinic space group P2/n with Z = 4. It consists of the isolated complex cation [Cr(urea)6], together with Cr2O7 and Br− counter ions. For convenience, a perspective drawing together with the atomic labeling is depicted in Fig. 1. It is found that the Cr(III) ion is coordinated by six urea ligands through oxygen atoms with the CrA-OA bond lengths ranging from 1.9534 (13) to 1.9776 (12) Å, and with OA–CrA–OA bond angles in the range of 85.10 (5)°–92.95 (5)°. The Cr2O7 anion is in a nearly staggered conformation. The Cr1B– O7B–Cr2B bridging angle in the anion is 130.26 (10)°. However, the detailed physical properties of the complex have not been published yet. In the present work we are reporting on the spectroscopic and magnetic studies of title complex by using UVvisible and IR spectroscopy and by measuring magnetic susceptibility. EXPERIMENTAL