Synthesis and Polymerization of Cationic bis(cyclopentadienyliron)arene Complexes Containing Arylazo Dyes w Alaa S. Abd-El-Aziz, 1,2 Nelson M. Pereira, 1 Waleed Boraie, 1 Erin K. Todd, 1 Tarek H. Afifi, 1 Wes R. Budakowski, 1 and Ken J. Friesen 1 The synthesis of the title complexes was achieved via the reaction of g 6 -p-dichlorobenzene-g 5 - cyclopentadienyliron cations with 4,4¢-bis(4-hydroxyphenyl)valeric acid to produce the diiron complexes which were then reacted with a number of arylazo dyes to give cationic bis(cy- clopentadienyliron)arene complexes containing the arylazo dyes. These iron-containing monomers were subsequently polymerized via nucleophilic aromatic substitution using 1,8- octanedithiol, 4,4¢-thiobisbenzenethiol, or bisphenol A to produce the desired coloured cat- ionic organoiron polymers. The weight – average molecular weights were estimated to range from 11,800 to 31,600. UV–vis studies conducted in dimethylformamide (DMF) showed that the metallated polymers exhibited k max of 412–491 nm. Addition of HCl to the polymer solution caused a bathochromic shift into the range of 515–530 nm. Thermogravimetric analysis (TGA) revealed that the iron moieties were cleaved between 205 and 248 °C while the polyether/thioether backbone degraded between 380 and 613 °C. Differential scanning calo- rimetry (DSC) showed that the polymers exhibited glass transition temperatures (Tg) ranging from 106 to 184°C. KEY WORDS: Cyclopentadienyliron complexes; organoiron polymers; arylazo dyes; nucleophilic aroma tic substitution; UV–vis studies; thermal properties. . 1. INTRODUCTION Over the past 15 years there has been an exponential growth in the field of organoiron con- taining polymers [1–3]. Ferrocene and cationic cyclo- pentadienyliron-containing polymers have been by far the most common organoiron polymers; many research groups have developed new techniques and uses for these materials [4–6]. Due to their unique electrical and optical properties, organoiron polymers have potential uses in such applications as modified electrodes, electrocatalysts, chemical sensors and photoactive molecular devices [1–18]. A number of research groups have focused their efforts on the development of new synthetic methodologies for the preparation of iron-containing polymers [19–23]. For example, Astruc and co-workers prepared many different classes of ferrocene-based star-shaped mol- ecules and dendrimers [24–27]. A number of dendri- mers containing up to about 360 ferrocenyl units at their periphery were synthesized [28]. Electrochemical studies of some of the dendrimers that contain 54 ferrocenyl groups showed reversible oxidation of all 54 iron centres [24]. Manners’ group has developed efficient routes for the preparation of high molecular w This paper is dedicated to Professor Richard J. Puddephatt in recognition of his outstanding contribution to the field of metal- containing polymers. 1 Department of Chemistry, The University of Winnipeg, Winni- peg, Manitoba, R3B 2E9, Canada. 2 To whom correspondence should be addressed. E-mail: a.abdelaziz@uwinnipeg.ca Journal of Inorganic and Organometallic Polymers and Materials, Vol. 15, No. 4, December 2005 (Ó 2006) DOI: 10.1007/s10904-006-9004-4 497 1574-1443/05/1200-0497/0 Ó 2006 Springer Science+Business Media, Inc.