The synthesis, cyclic voltammetry and spectroelectrochemical studies of Co(II) phthalocyanines tetra-substituted at the α and β positions with phenylthio groups

摘要

Non-peripherally substituted cobalt l,(4)-(tetraphenylthiophthalocyaninato) and peripherally substituted cobalt 2,(3)-(tetraphenylthiophthalocyaninato) complexes were synthesized. Redox processes were observed at E_(1/2) = -1.44 V (I), -0.39 V (II), +0.37 V (III), +0.78 V (IV) and 1.15 V (V) for the non-peripherally substituted and at E_(1/2) = -1.42 V (I), -0.57, -0.39 V (II), +0.27 V (III), +0.79 V (IV) and +1.10 V (V) for the peripherally substituted complexes, respectively. The couples were assigned to Co~IPc~(-2)/ Co~IPc~(-3) (I), Co~(II)Pc~(-2)/Co~IPc~(-2) (II), Co~(III)Pc~(-2)/Co~(II)Pc~(-2) (III), and Co~(III)Pc~(-1)/Co~(III)Pc~(-2) (IV) using spectroelec-trochemistry. The last process (V) could not be ascertained by spectroelectrochemistry but is associated with ring oxidation. Upon reduction or oxidation, the Q band of the non-peripherally substituted complex became less red shifted compared to that of its peripherally substituted counterpart.