STRUCTURE AND THERMAL-BEHAVIOR OF THANOL-N,O)-BIS(THEOPHYLLINATO)COPPER(II)DIHYDRATE - A MODEL FOR DNA-METAL INTERACTIONS

The title compound (1) is obtained by mixing aqueous 2-aminoethanol so lutions of theophylline and copper(II) salt. According to the single c rystal data the CU2+ ion is pentacoordinated and located in a slightly distorted square pyramidal configuration. Four short Cu-N bonds to tw o N(7) of the theophyllinate anions and to two nitrogen atoms of a mon odentate and a bidentate 2-aminoethanol ligands are almost in the plan e, while a longer Cu-O bond to oxygen of the bidentate 2-aminoethanol in the apex at distance 2.350(8) Angstrom A. When heated in air or in an inert atmosphere, 1 undergoes a five-step decomposition process stu died by TG, DSC and evolved gas detection (EGD). The solid intermediat es of the thermal decomposition were detected by FTIR and powder X-ray diffraction. First the water molecules then the mono-and bidentate 2- aminoethanol ligands are released in the order of their binding energy , showing a strong structure-stability correlation. Afterwards chemica l degradation of theophyllinato ligands occurs and is accompanied in a ir by an intense oxidation process resulting in CuO formation. (C) 199 7 Elsevier Science Ltd.