Available online at www.sciencedirect.com Spectrochimica Acta Part A 69 (2008) 291–303 Synthesis and characterization of polyketanils with 3,8-diamino-6-phenylphenanthridine moieties exhibiting light emitting properties Molecular and supramolecular engineering concept Agnieszka Iwan ∗ , Zbigniew Mazurak, Bozena Kaczmarczyk, Bozena Jarzabek, Danuta Sek Centre of Polymer and Carbon Materials, Polish Academy of Sciences, 34 M. Curie-Sklodowska Street, 41-819 Zabrze, Poland Received 18 December 2006; received in revised form 30 March 2007; accepted 2 April 2007 Abstract Relationship between structures and properties of new conjugated polyketanils (PKs) with special architectures, synthesized from three diketones, i.e. p-dibenzoylbenzene, dibenzyl, trans-1,2-dibenzoylethylene and 3,8-diamino-6-phenylphenanthridine, was investigated. The photolumines- cence (PL) of green, yellow and red emitting light polymers and their blend was studied. These included the effects of excitation wavelength, concentration and film thickness on the PL. Photoluminescence properties of the PKs before and after protonation with 10-Camphorsulfonic acid (CSA) were tested. The structure formation of (PKs) 1 (CSA) 2 complexes are discussed on the basis of FTIR spectroscopy. © 2007 Elsevier B.V. All rights reserved. Keywords: Polyketanils; Protonation; Photoluminescence; FTIR; UV–vis 1. Introduction Since the CH N group is isoelectronic with the CH CH group, the incorporation of nitrogen atoms into the conjugated system leads to another class of conjugated polymers closely related to poly(p-phenylenevinylene)s, namely aromatic polya- zomethines which are also extensively studied in recent years because of their interesting electronic and optical properties [1–5]. Conjugated polyketanils, abbreviated in the subsequent text as PKs, can be considered as simple derivatives of the cor- responding polyazomethines in which the hydrogen atom of the azomethine group is replaced by an aryl group. The literature data concerning the synthesis and the investigation of optical properties of PKs are scarce [6–8]. This is rather surprising because PKs seem to be excellent candidates for various appli- cations such as optical sensors or organic semiconductors in plastic electronics and optoelectronics devices [9]. In particular, they should combine a rather facile tuning of their spectroscopic properties with improved thermal stability as compared to other ∗ Corresponding author. Tel.: +48 32 271 6077; fax: +48 32 271 29 69. E-mail address: aiwan@cchp-pan.zabrze.pl (A. Iwan). conjugated polymers. This last property is of significant tech- nological importance since conjugated polymer based materials used, for example, in organic electronics and opto-electronics frequently suffer from insufficient thermostability and photo- stability [10–21]. They can be also protonated with Bronsted acids and complexed with Lewis acids. Nevertheless, according to our best knowledge, photoluminescence of polyketanils espe- cially after protonation was not reported before the authors of this paper started their study [22–24]. It is well-known that properties of the polyketanils could be modified by “chain engineering” consisting of appropri- ate design of chain building blocks via using monomers: diamines and diketones with various chemical structures. Our previous papers [22–24] reported the synthesis and prop- erties of some aliphatic and aromatic polyketanils. In this article novel conjugated polyketanils containing 3,8-diamino-6- phenylphenanthridine unit in the main polymer chain have been synthesized by melt polycondensation and their structure was proved by spectroscopic methods. Additionally the relationship between polyketanil structures and their photoluminescence (PL) along with the influence of solvents and protonating agent on luminescence emission wavelength and its relative inten- sity have been presented. Additionally the effect of excitation 1386-1425/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.saa.2007.04.001