Neutral and Cationic Cyclopentadienyliron Macromolecules Containing Arylazo Chromophores Alaa S. Abd-El-Aziz,* Rawda M. Okasha, Patrick O. Shipman, Tarek H. Afifi Department of Chemistry, The University of Winnipeg, Winnipeg, Manitoba, Canada R3B 2E9 Fax: (þ1) 204 783-8910; E-mail: a.abdelaziz@uwinnipeg.ca Received: May 28, 2004; Revised: June 17, 2004; Accepted: June 18, 2004; DOI: 10.1002/marc.200400218 Keywords: arylazo chromophores; cationic cyclopentadienyliron; differential scanning calorimetry (DSC); metal-polymer complexes; thermogravimetric analysis (TGA) Introduction The discovery of ferrocene by Kealy and Pauson in the early 1950s sparked a breakthrough in the development of orga- nometallic complexes. [1] The landmark report of the poly- merization of vinylferrocene by Arimoto and Haven [2] gave birth to a new field in polymer chemistry, in which the combination of the supramolecular architectures and the metallic units created unique properties such as nonlinear optical, catalytic, electrical, preceramic, and magnetic pro- perties. [3–7] The past few decades have seen a number of reports on the synthesis, properties and applications of iron- based polymers. [8–11] Ferrocene and cationic cyclopentadie- nyliron complexes are the most prevalent organoiron groups that have been incorporated into polymeric materials. The incorporation of ferrocene units into polymers has been the target of many studies due to the unique nature of the resulting organometallic polymeric materials. These materials were found to be excellent candidates as electrocatalysts, modified electrodes, chemical sensors and photoactive molecular devices. [3–11] The design of polymers containing cationic cyclopentadienyliron moieties has been a focus of our re- search for many years due to the enhanced solubilities that these materials possess compared with their organic analo- gues, as well as the potential applications of these cationic iron-containing polymers as electrocatalysts and polyelec- trolytes. [12,13] Macromolecules incorporating azobenzene moieties have been widely investigated due to their interesting cis- trans photoisomerization behavior, which make these mate- rials suitable for optical applications such as electrooptic modulators, photorefractive switches, reversible optical storage systems, and nanoscale applications. [14–21] Man- ners and co-workers have prepared liquid crystalline poly(ferrocenylsilanes) containing azo dyes in their side chains. [22] Recently, we reported the synthesis of cationic iron-coordinated polyaromatic ethers and thioethers func- tionalized with azo dyes in their side chains. [23] In this article, the first example of neutral and cationic organoiron polymers containing arylazo chormophores in their backbones is presented. The photochemical degrada- tion of the cationic polymers has also allowed for the isolation of a novel class of ferrocene-based polymers incorporating azo dyes. Experimental Part Materials Bisphenol A, 4,4 0 -thiobis(benzenethiol), 1,8-octanedithiol and pyridine were obtained from the Aldrich Chemical Summary: A new class of macromolecules containing neu- tral and cationic organoiron moieties with arylazo chromo- phores in their backbones has been prepared. Photolysis of these polymers resulted in the removal of the cationic iron moieties leading to new polyferrocenes with azo dyes in their backbones. UV-vis studies showed l max around 419 nm in DMF with a bathochromic shift to around 530 nm upon the addition of HCl. Organoiron macromolecules containing azo dye moieties prepared in this study. Macromol. Rapid Commun. 2004, 25, 1497–1503 DOI: 10.1002/marc.200400218 ß 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Communication 1497