Novel conducting polymers incorporating covalently bound metal–tetraazamacrocycle complexes

Abstract

The syntheses of a tetraazamacrocycle functionalized at nitrogen with a pendant 3-thiophene, 1 -[2-(3thienyl)ethyl]-l,4,8,1 I-tetraazacyclotetradecane (cyclamN-CH2CH2-thiophene), and its complexes with Nil1 and Cull, are described. Electro-oxidation of the pure Nil1 complex in acetonitrile electrolytes afforded only soluble oligomers. Novel conducting polymer-modified electrodes were fabricated, however, by electrocopolymerization of the Nil' complex with 3-methylthiophene. These are unusual in that both the metal centre [Ni1l-NiI1l at +I . I 5 V (saturated calomel electrode)] and the conducting polymer backbone show stable, reversible redox behaviour, with no apparent oxidative degradation of the poly(thiophene) backbone. The Ni1I-Ni1l1 redox behaviour appears unaffected by incorporation into the conducting polymer matrix. However, the NilI-Nil wave, observed at -1.40 V in solution, is entirely suppressed in the polymer, which at that potential is an electronic insulator.

Hybrid Organic–Inorganic Materials—In Search of Synergic Activity

“…[72] This covalent link approach has been most extensively applied to PPy, [73±84] and also to PT. [85,86] It has also been used for PAni [87] but in this case a general application of the method is much restricted due to the high reactivity of the amino group.…”

Transition-Metal-Polythiophene Hybrid Materials

“…Sable et al reported the formation of a poorly conducting film, [16] while Higgins found under similar conditions that soluble oligomers were formed. [17,18] Both groups have prepared electrochromic copolymers from mixtures of 4 and 3-methylthiophene. The films are red-orange when neutral, green when only the thiophene backbone is oxidized, and blue upon oxidation of both the Ni centers and the backbone.…”

“…The films are red-orange when neutral, green when only the thiophene backbone is oxidized, and blue upon oxidation of both the Ni centers and the backbone. [17] A thiophene derivative with a porphyrin attached (5) has been electropolymerized. [19] The resulting films were reacted with Ni 2+ after deposition, and a Ni 2+/3+ redox wave was observed at 0.45 V vs. saturated calomel electrode (SCE) in the modified films, even though the backbone is insulating at this potential.…”

The effect of Pd(ii) coordination on the properties of an alkylsulfanyl substituted polythiophene. Comparison with the corresponding monomer

“…Hybrid materials, combining conductivity of conducting polymers and redox properties of transition metal ions, represent an appealing alternative to the redox polymers, taking advantage of synergic electronic interactions. 2 Conducting polymers bearing different residues capable of coordinating different metal ions, such as cyclams, [3][4][5] porphyrins, [6][7][8] bipyridines, 9 and Schiff-bases, 10 are reported in several studies. However, the long-chain 'spacer' used to link the polymer and binding residue leads to a degree of separation between the polymer p-electron system and the metal.…”