ORTHOMETALATION OF 6-AMINO-1,3-DIMETHYL-5-PHENYLAZOURACIL - CRYSTAL-STRUCTURE AND SPECTROSCOPIC PROPERTIES OF TRANS-[(RHCL2)-CL-III(L)(H2O)]CENTER-DOT-3H(2)O

The preparation and spectroscopic characterization of two iso-structur al complexes trans-[Rh(III)X(2)(L)(H2O)]. 3H(2)O (HL is 6-amino-1,3-di methyl-5-phenylazouracil and X stands for Cl and Br) are reported. In addition, the crystal structure of the complex trans-[Rh(III)X(2)(L)(H 2O)]. 3H(2)O has been solved and refined to R = 0.039 (R(W) = 0.045). The compound crystallizes in the triclinic space group <P(1)over bar> (No. 2) with cell constants a = 7.395(4), b = 11.412(3), c = 11.776(4) Angstrom, alpha = 77.42(2), beta = 75.14(3), gamma = 78.67(2)degrees, V = 927(2) Angstrom(3), Z = 2, D-c = 1.74 g cm(-3), D-exp = 1.75(2) g cm(-3), F(000) = 510, mu(Mo K alpha) = 1.305 mm(-1). In this complex the ligand undergoes orthometalation, coordinating in a monodeprotonat ed tridentate fashion through an exocyclic oxo group, the azo group an d the carbon atom of the phenyl ring ortho to the azo group. The three remaining positions are occupied by two chlorine atoms in trans posit ion and a water molecule.