Structural and EPR Studies of Pyrophosphate-Bridged Dinuclear CuII Complexes

SARTORIS, ROSANA P; CALVO, RAFAEL; SANTANA, RICARDO; NASCIMENTO, OTACIRO R; PEREC, MIREILLE; BAGGIO, RICARDO

POLYHEDRON

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2014 vol. 79 p. 178 - 185

0277-5387

Two new pyrophosphate-bridged copperII complexes, [Cu(dpa)(H2O7P2)]2 1 and  [Cu2(terpy)2(HO7P2).(H2O4 P).(H3O4 P).(H2 O)] 2 (dpa = 2,2´-dipyridylamine and terpy = 2,2´:6´,2"-terpyridine) were isolated and their crystal structures determined by single- crystal X-ray diffraction. The compounds are triclinic and contain dinuclear copperII units bridged by pyrophosphate anions. Their EPR spectra observed in single crystal samples as a function of field orientation at 293 K display a single resonance, as in mononuclear spin systems, without hyperfine structure and their g-factors and line widths were measured. The relations between the principal directions of the g-matrices and the molecular structures are discussed and compared with related compounds. The absence of dinuclear splitting and of hyperfine structure of the dinuclear units is explained in terms of averaging out by the interdinuclear interactions