Aggregation of phthalocyanine derivatives in liquid solutions and human blood

The aggregation of the copper (II) 4,4′,4′′,4′′′-tetrasulfonated phthalocyanine anion (Cu(tsPc)^?4) has been studied in aqueous solutions, DMSO and in human blood by UV–VIS absorption spectroscopy and resonance Raman spectroscopy (RRS). The vibrational mode ν₄ (1530 cm^?1) has been used as a probe in RRS. It has been shown that the dimerization equilibrium constant K is shifted significantly towards monomeric forms when human blood is added to the solution. The life-time of the singlet excited state S_n of (Cu(tsPc)^?4) in aqueous solution has been estimated to be shorter than 500 fs using femtosecond pump-probe absorption spectroscopy.