Esr in macrocyclic complexes: supehyperfine interaction of cu (ii) in 5,7,7,12,14,14- hexamethyl -1,4,8,11- tetraazacyclo -tetradeca-4,11 -dienenickel (ii) perchlorate - Rodrigues, Edson; Lorencetti, L (Meeting of the International Society of Magnetic Resonance, 1986)