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 pi-pi* transition of the conjugated backbone. Moreover, the fluorescence property of the P(ZnPc-SNS) was investigated in dimethyl sulfoxide (DMSO) and toluene. (C) 2009 Elsevier B.V. All rights reserved.