Chlorogold(I) and gold(III) complexes of 6-Amino-1,3-dimethyl-5-arylazouracil derivatives: IR spectroscopy, growth inhibition of hela cells and X-ray crystal structure of 6-amino-1,3-dimethyl-5-phenylazoniumuracil dichloroaurate(I) sesquihydrate

Abstract

The preparation and X-ray crystal structure of the complex formed between 6-amino-1,3-dimethyl- 5-phenylazouracil (DZH) and gold(I) chloride, [DZH 2] [AuCl 2]· 1.5H 2O, are described. The complex crystallizes in the monoclinic system: space group C2/ c, a = 17.865(4), b = 16.333(3), c = 14.014(2) Å, β = 118.59(1)°, Z = 8, R = 0.049. The structure is ionic and consists of AuCl 2 − anions, DZH + cations and crystal water molecules bonded together by hydrogen bonds. The anion AuCl 2 − is almost linear [ClAuCl = 179.1(1)°], with AuCl distances of 2.245(3) and 2.255(4) Å. The cation is essentially co-planar and the protonation takes place at the nitrogen atom N(10) of the azo group bonded to the phenyl ring. Likewise, three gold(III) complexes of type AuLCl 2 were prepared from NaAuCl 4·2H 2O and 6-amino-l,3-dimethyl-5-arylazouracil derivatives (LH). A cis-square-planar structure is proposed for these complexes on the basis of IR data. Tests of the isolated gold(I) and gold(III) complexes for their growth inhibition of HeLa cells showed considerable inhibition for the compounds [DZH 2][AuCl 2]· 1.5H 2O, Au(DZ)Cl 2 and Au(DZC)Cl 2.