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Abstract:
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The primary aim of these investigations was to probe the elecnuchemical
and material science aspects of some selected metal phthalocyanines(MPcs).Metal phthalocyanines are characterised by a unique planar molecular structure. As a single
class of compounds they have been the subject of ever increasing number of physicochemical and
technological investigations. During the last two decades the literature on these compounds was
flooded by an outpour of original publications and patents. Almost every branch of materials science
has benefited by their application-swface coating, printing, electrophotography, photoelectrochemistry,
electronics and medicine to name a few.The present study was confined to the electrical and electrochemical properties of cobalt,
nickel, zinc. iron and copper phthalocyanines. The use of soluble Pes as corrosion inhibitor for
aluminium was also investigated.In the introductory section of the thesis, the work done so far on MPcs is reviewed. In this
review emphasis is given to their general methods of synthesis and the physicochemical properties.In phthalocyanine chemistry one of the formidable tasks is the isolation of singular species.
In the second chapter the methods of synthesis and purification are presented with necessary
experimental details.The studies on plasma modified films of CoPe, FePc, ZnPc. NiPc and CuPc are also presented.Modification of electron transfer process by such films for reversible redox systems
is taken as the criterion to establish enhanced electrocatalytic activity.Metal phthalocyanines are p- type semiconductors and the conductivity is enhanced by
doping with iodine. The effect of doping on the activation energy of the conduction process is
evaluated by measuring the temperature dependent variation of conductivity. Effect of thennal
treatment on iodine doped CoPc is investigated by DSC,magnetic susceptibility, IR, ESR and
electronic spectra. The elecnucatalytic activity of such doped materials was probed by cyclic
voltammetry.The electron transfer mediation characteristics of MPc films depend on the film thickness.
The influence of reducing the effective thickness of the MPc film by dispersing it into a conductive
polymeric matrix was investigated. Tetrasulphonated cobalt phthalocyanine (CoTSP) was
electrostatically immobilised into polyaniline and poly(o-toluidine) under varied conditions.The studies on corrosion inhibition of aluminium by CoTSP and CuTSP and By virtue of their anionic character they are soluble in water and are strongly adsorbed on aluminium.
Hence they can act as corrosion inhibitors. CoTSP is also known to catalyze the reduction of
dioxygen.This reaction can accelerate the anodic dissolution of metal as a complementary reaction.
The influence of these conflicting properties of CoTSP on the corrosion of aluminium was studied
and compared with those of CuTSP.In the course of these investigations a number of gadgets like cell for measuring the electrical
conductivity of solids under non-isothermal conditions, low power rf oscillator and a rotating disc
electrode were fabricated. |