Bis[4-amino-N-(pyrimidin-2-yl)benzenesulfonamido]diamminecopper(II): aqua or ammine ligands?

Abstract

Diffraction results obtained at 100 and 291 K, the former at high resolution, are reported for the title compound, [Cu(C10H9N4O2S)2(NH3)2] or [Cu(sulfa)2(NH3)2] [Hsulfa is 4-amino-N-(pyrimidin-2-yl)benzenesulfonamide]. The Cu(II) cation is coordinated by two N-atom donors from a bidentate sulfa ligand, by two ammonia molecules in the equatorial plane and by a monohapto (η(1)) sulfadiazine at the apex of a distorted square pyramid. The present interpretation and two earlier reports [Brown, Cook & Sengier (1987). Acta Cryst. C43, 2332-2334; Tommasino, Renaud, Luneau & Pilet (2011). Polyhedron, 30, 1663-1670] disagree about the nature and geometry of the ligands. The relationship between the present result and the former is discussed, and evidence is provided that the latter erroneously assigned an ammine as an aqua ligand.

Sulfonamide-containing copper(II) metallonucleases: Correlations with in vitro antimycobacterial and antiproliferative activities

“…The equatorial bonds of the three complexes are on average of length 2.0 Å. This is consistent with bond lengths of copper(II)-sulfonamide-(N^N) in ternary complexes reported in the literature [24,[39][40][41]. The copper(II)-N phen values observed for complexes 1 and 2 are within the range of short lengths for such bonds (< 2.05 Å) [42].…”

“…Beloso et al reported crystal structures of similar complexes in which axial CueN interactions were of the order of 2.5 Å [39]. The copper(II) complex with sulfadimethoxine and ammonia molecules instead of a (N^N) ligand, previously reported in the literature, was clearly a 5-coordinate complex, since the sixth theoretical axial CueN "bond" is longer than 3.0 Å [24,40]. The copper complexes with benzothiazole-derived sulfonamides showed a similar coordination geometry to the complexes of this work, but the axial bond lengths longer than 2.8 Å were not considered effective bonds by the authors [10].…”