MOSSBAUER AND MAGNETIC STUDIES OF COPPER(II)-PHTHALOCYANINE EFFECT ONTHE SPIN STATES OF BIS(N-O-TOLYL-2-IMIDAZOLALDIMINE)IRON(II) DITHIOCYANATE

The mononuclear complex of general formula [Fe-II(TIA)(2)(NCS)(2)] (1) and the heterotrinuclear complex of (Cu-Pc)(2)[Fe(TIA)(2)(NCS)(2)] (2 ), where TIA = N-o-tolyl-2-imidazolaldimine and Pc = phthalocyanine, h ave been synthesized. The X-ray crystal structure of 1 shows it to con sist of two NCS groups in the cis position. The magnetic properties of the complexes have been measured down to 4.2 K and Mossbauer spectra have been recorded down to 20 K. In 1, the iron(II) is pure high-spin S = 2 (T-5(2)) over the whole temperature range. In 2, a gradual spin crossover (T-5(2)<->(1)A(1)) occurs below 298 K and the spin crossover is incomplete since it still presents a high-spin fraction about 0.35 , even at 4.0 K.