Jerry L. Reddinger

Molecular Engineering of π-Conjugated Polymers

An extensive review of the synthesis of π-conjugated polymers is presented using a tutorial approach to provide an introduction to the field intended for the undergraduate student and the experienced chemist alike. The many synthetic methodologies that have been used for the synthesis of conjugated polymers are outlined for each class of polymers with a focus on research from the 1990s. The effect of structure on electrical properties is detailed. Specific systems reviewed include the polyacetylenes, polyanilines, polypyrroles, polythiophenes, poly(arylene vinylenes), and polyphenylenes.

Redox active electrochromic polymers from low oxidation monomers containing 3,4-ethylenedioxythiophene (EDOT)

Abstract Here we report the synthesis of several new low oxidation monomers with the external rings being 3,4-ethylenedioxythiophene (EDOT). These monomers were prepared via NiCI2(dppp) catalyzed Grignard coupling in good yields and were found to exhibit low oxidation potentials with the lowest having an onset of 0.14 V for 2,2′:5′,2″-ter(3,4-ethylenedioxythienyl)thiophene (TER-EDOT). The polymers were found to be stable electrical conductors and were found to exhibit band gaps ranging from 1.4 eV for trans-1,2-bis(2-(3,4-ethylenedioxy)thienyl)vinylene (BEDOT-V) to 2.5 eV for the series of 3,6-bis(2-(3,4-ethylenedioxy)-thienyl)N-substituted carbazoles (BEDOT-NCz). BEDOT-V was found to be opaque purple in the reduced state and transmissive sky blue in the oxidized state while the BEDOT-NCzs are transmissive yellow in the reduced state, green upon mild oxidation and deep opaque blue in the oxidized state. Both the BEDOT-V and BEDOT-NCzs were found to exhibit fast response times and high contrast ratios upon redox stepping, thereby proving them useful for electrochromic coatings.

Electroactive,π-Conjugated Polymers based on Transition Metal-Containing Thiophenes

A series of heterocycle-based bis(salicylaldimine) complexes have been synthesized and their electrochemical properties investigated. Both nickel and copper complexes of the simplest ligand 1 (SALOTH) were found to undergo electropolymerization to yield durable electro-active films under oxidizing condition. In both cases polymerization desisted upon blocking of the para position of the phenol ring. Hence, it appears that the polymer formed from complexes 2a-b is comprised of phenylene linkages at this site. In stark contrast when the conjugation of the monomer is extended by utilizing a terthiophene core, blocking of the para (complex 6) and both the ortho and para (complex 7) positions did not preclude polymerization. Furthermore, the metal-based oxidation moves to higher potentials, and additional redox processes, not seen in the other systems, grow in at lower potentials. Thus, we believe the polymer structure in these cases to be that of a polythiophene.

Muticoloured electrochromic polymers derived from easily oxidized bis[2-(3,4-ethylenedioxy)thienyl]carbazoles

Two bis[2-(3,4-ethylenedioxy)thienyl]carbazole-based polymers are synthesized by the electropolymerization of highly conjugated, low-oxidation potential monomers; these polymers exhibit multicolour electrochromic behaviour, each possessing three separate accessible states.