Interaction of [(dien)Cu(ONO2)]NO3 and [(dien)Cu(Br)]Br with guanosine and adenine.: Crystal structure of [(dien)Cu(Guo-N7)(ONO2)]NO3

The reaction of [(dien)Cu(ONO2)]NO3 and [(dien)CuBr]Br with Guanosine(Guo) gave the compounds [(dien)Cu(Guo-N-7) (ONO2)]NO3 [dien = diethylenetriamine and [(dien)Cu(Guo) (Br)]Br, respectively. The reaction of [(dien)Cu(ONO2)]NO3 with Adenine(A) afforded the compound [(dien)Cu(A)(ONO2)]NO3. The complexes have been characterized by elemental analyses, molar conductance and magnetic measurements, as well as by electronic and IR spectral studies. According to the spectral data the ligands (Guo and A) bind to the copper atom via N-7. The crystal structure of the [(dien)Cu(Guo-N-7)(ONO2)]NO3 complex has been determined by X-ray diffraction. Copper(II) is five coordinated with three nitrogen atoms from the dien molecule [2.015(6) Angstrom, 2.007(4) Angstrom, 2.038(6) Angstrom], the N-7 atom from guanosine [2.006(4) Angstrom] and an oxygen atom from a nitrate group [2.251(6) Angstrom]. The five donor atoms form a distorted square pyramid with the four nitrogen atoms on its basal plane and the oxygen atom at the apical position. All the complexes are electrolytes as indicated by their molar conductance in methanol or water. The magnetic moments are consistent with monomeric copper(II) units. (C) 1998 Elsevier Science Ltd. All rights reserved.