The crystal structure of triammine(orotato)zinc(II) monohydrate

Abstract

The crystal structure of triammine(orotato)Zn(II) monohydrate, C 4H 13N 5O 5Zn, has been determined by X-ray diffraction. The compound crystallizes in space group P 1 with cell parameters a = 7.052(4), b = 8.722(5), c = 9.616(6) Å, α =114.34(5), β = 104.63(5), γ = 92.43(5)°, V = 514.2(5) Å 3, Z = 2. The structure was refined on 1924 reflections to R = 0.040 and R w = 0.045. The deprotonated orotato ligand coordinates to the Zn(II) ion by the N1 nitrogen and by the oxygen atom of the adjacent carboxylate group. The coordination sphere around the zinc is trigonal bipyramid with the carboxylate oxygen and one ammonia molecule occupying the axial sites and two ammonia molecules and the heterocyclic N1 nitrogen of the orotato anion at equatorial sites. The conformation of the orotato anion differs slightly from that of uncomplexed orotic acid, the C6N1C2 angle being 4.6° smaller and the adjacent angles 3.0° and 3.2° larger. The crystal structure is dominated by columnar packing of the complex molecules. The columns are held together by an extensive hydrogen bond network.