Direct electrochemical synthesis of inorganic and organometallic compounds

Abstract

Although the electrochemical properties of inorganic and organometallic compounds have been widely studied, there has been comparatively little attempt to apply the results of such work in preparative chemistry.Recent eXperiments have shown that the sacrificial dissolution of either anodic or cathodic metals in non-aqueous media yields a nurober of different types of inorganic• and organometallic complexes1 examples of such syntheses are reviewed.The possible mechanisms of these reactions, and the advantages of electrochemical preparative methods, are also discussed. PREPARATIVE ELECTROCHEMISTRYThe electrochemical technique represents one of the simplestand most direct methods.ofcarrying out oxidation or reductioR reactions, since the removal or addition of electrons can be achieved without the attendant complications otherwise involved in•the addition of redox reagents.The applications of this principle in inorganic and organametallic chemistry are well-documented in the extensive literature describing the oxidation or reduction of solute species at inert electrodes to yield either direct products, or intermediate species which subsequently decompose to the required substance.Despite the inherent•simplicity, and despite the amount of information available from polarographic studies and o.ther physical measurements, preparative inorganic and organometallic ehemiste have not taken advantage of electrochemical methods to the extent which might have been expected.The reasons for this are beyond the scope of this review, but . .one obvious factor which is especially relevant to the theme of the present Conference is that experiments in aqueous media impose restrictions which it is often impossible to 'overcome, especially with organametallic compounds.Electrochemistry in non-aqueous solvente is now a mature subject in its own right, as the papers presented in Sectio.nIV of this Conference deinon'strate, and I shall concentrate in the present discussion only on those aspects which are relevant to preparative chemistry.With non-aqueous solution electrochemistry, as with aqueous systems, some thorough reviews (1-3) suggest that more effort has been aevoted to the studyof phe'r\omena such as current-voltage relationships than to'the preparative applications of the processes involved.One of the purposes of this paper will be to eiemonatrate that an iqnorance of the detailed electrochemistry, and even of such fundamental parameterB as E 0 , need be no bar to the use of electrochemical methods in non-aqueous solvehts in preparative chemistry.