Electrochemistry SYNTHESIS, CO-POLYMERIZATION, AND ELECTROCHEMICAL EVALUATION OF NOVEL FERROCENE-PYRROLE DERIVATIVES Geok Hong Soon, 1 Mary Deasy, 1 Oliver Worsfold, 2 and Eithne Dempsey 1 1 Centre for Research in Electroanalytical Technologies (CREATE), Institute of Technology Tallaght, Dublin, Ireland 2 Business Development Directorate, Stephenson Building, Newcastle University, Newcastle Upon Tyne, United Kingdom New ferrocene derivatives, (6-(4-(1H-pyrrol-1-yl)phenoxy)hexyl) ferrocene (1) and ((4-(1H-pyrrol-1-yl)phenoxy)carbonyl) ferrocene (2) were synthesized, characterized, and electrochemically evaluated as redox active films formed via anodic oxidation with pyrrole. Thin film studies were conducted and films formed from both compounds resulted in a stable Fe II/III redox couple with E o ¼ 0.035 V and 0.365 V vs. Ag/Ag þ for (1) and (2), respectively. Both potential sweeping and chronocolometry were employed for film forma- tion with the former resulting in controllable, reproducible film deposition. Growth conditions and solution concentrations were varied in order to assess influence on electro- chemical behavior. Surface coverage was of the order 10 8 –10 9 mol cm 2 , surface confined behavior (i p vs. n) was evident up to 0.2 V s 1 with semi-infinite diffusion (i p vs. n 1/2 ) dominating at higher scan rates. Laviron theory was employed where possible for the determination of electron transfer co-efficient and rate constants. Keywords: Co-polymerization; Ferrocene pyrrole derivatives; Thin film deposition INTRODUCTION Organometallic compounds, particularly metallocenes, have established a significant role in a range of sensor applications over recent decades (Forrow and Bayliff 2005). Unlike other organometallic compounds, the properties of metallo- cenes, in terms of electrochemistry in particular, can readily be modified by substi- tution on one or both cyclopentadienyl rings. A recent review described polymers Received 12 March 2010; accepted 18 May 2010. This paper is part of a Special Issue of Analytical Letters focusing on papers presented at the 10th International Symposium on Kinetics in Analytical Chemistry (KAC-10). Address correspondence to Eithne Dempsey, Centre for Research in Electroanalytical Technologies (CREATE), Institute of Technology Tallaght, Tallaght, Dublin 24, Ireland. E-mail: Eithne.dempsey@ ittdublin.ie Analytical Letters, 44: 1976–1995, 2011 Copyright # Taylor & Francis Group, LLC ISSN: 0003-2719 print=1532-236X online DOI: 10.1080/00032719.2010.539729 1976