Synthetic Metals 196 (2014) 166–172 Contents lists available at ScienceDirect Synthetic Metals jo ur nal homep age: www.elsevier.com/locate/synmet New electropolymerizable metal-free and metallophthalocyanines bearing {2-[3-(diethylamino)phenoxy]ethoxy} substituents Zekeriya Bıyıklıo˘ glu a,∗ , Volkan C ¸ akır a , Faruk Demir b , Atıf Koca b a Department of Chemistry, Faculty of Science, Karadeniz Technical University, 61080 Trabzon, Turkey b Department of Chemical Engineering, Engineering Faculty, Marmara University, Göztepe, 34722 ˙ Istanbul, Turkey a r t i c l e i n f o Article history: Received 20 March 2014 Received in revised form 21 July 2014 Accepted 29 July 2014 Keywords: Phthalocyanine Synthesis Diethylamino Electropolymerization Electrochemistry Spectroelectrochemistry a b s t r a c t In this work, metal-free and metallophthalocyanines (Ni, Co, Cu) bearing peripherally tetra substituted 4-{2-[3-(diethylamino)phenoxy]ethoxy}groups were synthesized by cyclotetramerization of the corre- sponding phthalonitrile derivative and their electrochemical, spectroelectrochemical properties were investigated. Phthalocyanines were characterized by a combination of IR, 1 H-NMR, UV–vis and MS spec- tral data. Diethylamino groups on the substituents of the complexes cause electropolymerization of the complexes on the working electrode during the oxidation reactions. Changing the potential window of the voltammetric cycles alters the electropolymerization mechanisms. Types of the metal center of the complexes also affect the electropolymerization mechanism. Spectroelectrochemical measurements were performed to assign the redox processes and spectroscopic responses of the electropolymerization processes. © 2014 Elsevier B.V. All rights reserved. 1. Introduction Metal-free and metallophthalocyanines are one of the most useful heterocyclic materials. They show a wide range of techno- logical applications in different scientific areas for example solar cells [1], electronic devices [2], liquid crystals [3], gas and chemi- cal sensors [4], photo dynamic therapy (PDT) [5–9], electrochromic and electroluminescent displays [10], non-linear optics [11], semi- conductors [12], photovoltaics [13] and their electrochemical properties [14,15] are utilized for electrochemical applications such as electrocatalytic [16,17], electrosensing [18], electrochromic fields [19]. Electrochromism is an electrochemically produced stable and reversible color changes due to changing the opti- cal responses of the electro-chromophores in the visible region of the light spectrum. Electrochromic materials which include electropolymerizable phthalocyanines [20] are used in different applications, such as various display technologies, energy-saving smart windows, sensors and data storage [21,22]. However, the applications of metal-free and metallophthalocyanines is limited by their low solubility in common organic solvents and water. Because of this, one of the goals of research on the phthalocya- nines is to increase their solubility in common organic solvents ∗ Corresponding author. Tel.: +90 462 377 36 64; fax: +90 462 325 31 96. E-mail address: zekeriya 61@yahoo.com (Z. Bıyıklıo˘ glu). and water. The solubility of metal-free and metallophthalocyanines can be enhanced by introducing different kinds of substituents such as alkyl, alkoxy, phenoxy, macrocyclic groups [23–26] in com- mon organic solvents and amino, sulfo or carboxyl groups leads to phthalocyanine derivatives soluble in water [27–30]. Metallophthalocyanines (MPcs) are intensely studied as elec- trochemically functional materials due to the excellent redox properties [31–33]. Their electrochemical properties are easily arranged by changing the metal center and types, number and position of substituents. It is well documented that functional materials should be coated on a substrate for their practical appli- cations [34–38]. Although many film coating techniques were studies for the preparation of composite electrodes, prepara- tion of modified electrodes with electropolymerization is one of the most preferred techniques [39–43]. Since it is easy to control many of the film characters, such as morphology, thick- ness, conductivity, and polymer structure of the films [44,45]. Although numerous different conjugated polymers, such as poly- thiophene [46–49], polyaniline [50–52], polypyrrole [50–52], were studied for different applications, nowadays metal-containing conjugated polymers, especially polymerized MPcs have taken condensed attentions [53–59] Some examples of porphyrin and phthalocyanine-containing conjugated polymers have been also reported [60–67]. Applications of modified electrodes based on electropolymerization of functional materials canalized our stud- ies to synthesis of MPcs bearing electropolymerizable substituents. http://dx.doi.org/10.1016/j.synthmet.2014.07.023 0379-6779/© 2014 Elsevier B.V. All rights reserved.