Synthesis and electropolymerization of the phthaocyanines with 4-(2,5-di-2-thiophen-2-yl-pyrrol-1-yl) substituents

Novel tetrakis (4-(2,5-di-2-thiophen-2-yl-pyrrol-1-yl)) substituted metal-free (H2Pc-SNS) and zinc phthalocyanine (ZnPc-SNS) complexes were synthesized and characterized by elemental analysis, Fourier Transform Infrared (FTIR) and UV–vis spectroscopies. The solution redox properties of these complexes were also studied by using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in dichloromethane (DCM) solution containing 0.1 M tetrabutylammonium perchlorate (TBAP) on platinum electrode. Both of the complexes showed two reversible reduction peaks having ligand-based character and one irreversible oxidation peak. Also, the electrochemical polymerization of these newly synthesized complexes were performed in DCM/TBAP solvent/electrolyte couple. Insoluble turquoise green and black films were deposited on the electrode surface both during repetitive cycling and constant potential electrolysis of H2Pc-SNS and ZnPc-SNS, respectively. Resulting polymer films, P(H2Pc-SNS) and P(ZnPc-SNS), were characterized by UV–vis and FTIR spectroscopic techniques and their electrochemical behavior was investigated utilizing CV. In situ spectroelectrochemical investigations revealed that both P(H2Pc-SNS) and P(ZnPc-SNS) films can be reversibly cycled and exhibit electrochromic behavior. Furthermore, the band gap of P(H2Pc-SNS) and P(ZnPc-SNS) were calculated as 2.38 eV and 2.25 eV, respectively from the on set of π–π* transition of the conjugated backbone. Moreover, the fluorescence property of the P(ZnPc-SNS) was investigated in dimethyl sulfoxide (DMSO) and toluene.