Crystal structure of dibromodiadeniniumcopper(II) dibromide: a complex with unidentate adenine

Abstract

The crystal structure of the title compound has been determined from three-dimensional X-ray diffractometer data by Patterson and Fourier methods. Crystals are monoclinic with unit-cell dimensions a= 18·649. b= 8·731, c= 12·028 Å, β= 113·14°, space group C2/c, and Z= 4. Full-matrix least-squares refinement by use of 1657 independent reflections has reached R 0·056.

The structure contains complex cations [Cu(adenineH)₂Br₂]²⁺ and bromide ions. In the complex cation the central copper atom lies on a diad and is co-ordinated to two N(9) atoms of unidentate adeninium ligands and to two terminal bromide atoms. The copper atom has a co-ordination intermediate between tetrahedral and square planar, with Cu–N 2·013 and Cu–Br 2·361 Å. The adenine molecule is protonated at N(1), and atoms N(1) and N(7) are involved in hydrogen bonding of the type N–H ⋯ Br^–.