Tetra conducting materials

In addition octaethylporphyrin (OEPHj), tetramethyl- and tetraphenylpor-phyrin (TMPHj and TPPH2), dihydrodibenzotetraaza[14]-annulene (taaH2) and hemiporphyrazine (HPH2) are other examples of macrocycles which have been investigated in efforts to construct new types of conducting materials. In the following we will concentrate on phthalocyaninatometal complexes, tetrabenzoporphyrins, 1,2- and 2,3-naphthalocyanines and tetra(2,3-naphtho)-porphyrins. 

Saito et at.130 studied the salts of TMTSF and the sulfur analogue tetra-methyltetrathiafulvalene, TMTTF, with a polycyano dianion. Although the conductivity of both compounds was low (crrt = 10-5 Scm-1 for TMTSF vs. 10-7 Scm-1 for TMTTF) the conductivity of the Se-donor salt was improved by two orders of magnitude. Optical absorption spectroscopy was also used to assess the materials. The electronic transition between radical cations within the segregated donor columns occurred at considerably lower energy (8800 cm-1) in the TMTSF salt than in the TMTTF (11500 cm-1). A concurrent improvement... 

Due to their structural and electrochemical properties, it would appear almost obvious to combine ferrocene-containing fragments and derivatives of tetra-thiafulvalene to construct new donors for conducting CT complexes. This approach would lead to new multistage redox systems that are likely to display different solid state properties to those of their congeners. However, only very few derivatives of this type have been so far reported. What appears to be the first compound belonging to this class was prepared by Ueno et al. in 1980 [64]. Bis(ferrocenyl)tetrathiafulvalene was obtained as a transjcis isomeric mixture (6 and 7, respectively) and was shown to form 1 1 CT complexes with TCNQ and DDQ. These materials possess... 

Polypyrrole complexed with cobalt-phthalocyanine [128] synthesized from the aqueous solution containing pyrrole and sodium salt of tetra- or mono-sulphonated cobalt-phthalocyanine, resulted in a highly electrochro-mic composite material. The electrical conductivity of the composite increased by two orders of magnitude more than that of the initial value on storage in ambient air for two months, whereas in the case of polypyrrole containing BF4, a 30-40% loss of electrical conductivity was observed. 

Several types of porphyrin and phthalocyanine ligand modification have been performed to create a new family of electrochemically polymerizable complexes. The most commonly used porphyrins are the amino " hydroxy methoxy ° ° , vinyl- and other " substituted macrocyclic complexes (see examples in Figure 8.13). In the case of phthalocyanine, tetra-amino-substituted macrocycle was exclusively and intensively developed. Studies of these complexes have focused on the electrochemical synthesis and characterization of conductive polymeric or copolymeric materials. 

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