Heteroarray of cobalt(II)tetrasulfophthalocyanine and cobalt(II) tetrakis(N-methyl-4-pyridyl)porphyrin: synthesis, isolation and electronic properties

Abstract

Porphyrin and phthalocyanine macrocycles with ionic substituents can form mixed assemblies with interesting electronic properties for potential application on the development of new devices. This paper reports the synthesis, isolation and purification of heteroaggregate formed by cobalt(II) 4,4′,4″,4‴-tetrasulfophthalocyanine (CoTsPc) and cobalt(II) tetrakis(N-methyl-4-pyridyl)porphyrin (CoTMPyP), followed by its spectroscopic characterization. Spectroscopic titration, performed with a CoTsPc water/acetone solution, allowed the use of Job's method for determination of the heteroaggregates stoichiometry. The Job's plot revealed the formation of only one predominant heterocomplex in solution, containing two CoTsPc molecules in terminal positions and a central CoTMPyP one. For the first time, a method for isolation and purification of a mixed ionic array has been reported in the literature. The triad's electronic spectrum is quite different from the sum of the macrocycles isolated spectra, due to the overlap of their electronic densities and a charge transfer process between CoTsPc and CoTMPyP.