Molybdenum complexes cyclic voltammetry

The reaction between [MoCl4(NCPr)2] and dithiocarboxylic acids is a general route to the preparation of eight-coordinate [Mo(S2CR)4] complexes.168 The crystal structure of [Mo(S2CPh)4] reveals these compounds to be isostructural with the dithiocarbamates, with a dodecahedral coordination around the molybdenum and average Mo—S distances of 2.475(1) and 2.543(1) A to the two different sulfur sites.170 Cyclic voltammetry has shown that in [Mo(acda)4] (Hacda = 2-aminocyclopent-l-ene-l-dithiocarboxylic acid) the Mo can be reversibly oxidized and reversibly reduced in one-electron processes.171... 

Cyclic voltammetry and controlled-potential electrolysis are the techniques that have been used to investigate the electrochemistry of oxo-chromium and oxo-molybdenum corrolates. The data have been related to those obtained for similar porphyrin complexes. Redox potentials are reported in Table 17. 

Electrochemical method [54] Silicate is determined in sea water by four different electrochemical methods based on the detection of the silicomolybdic complex formed in acidic media by the reaction between silicate and molybdenum salts. The first two methods are based on the addition of molybdate and protons in a seawater sample in an electrochemical cell. A semiautonomous method was developed based on the electrochemical anodic oxidation of molybdenum, the complexation of the oxidation product with silicate and the detection of the complex by cyclic voltammetry. Finally a complete reagent-less method with a precision of 2.6% is described based on the simultaneous formation of the molybdenum salt and protons in a divided electrochemical cell. 

Molybdenum complexes containing these ligands were prepared and cyclic voltammetry was carried out, but no evidence for electropolymerization was observed. 

Chromium, Molybdenum and Tungsten The intramolecular rotational behaviour of a series of highly substituted Ti -arene chromium and molybdenum compounds has been examined in detail. Dynamic processes in the solid state, using spin-lattice relaxation time measurements, have been studied for two structurally characterised polymethyl benzenechromium tricarbonyl complexes. The mechanism of migration of the Cr(CO)3 unit from the six to the five membered ring in indenyl anions has been reported. The synthesis and cyclic voltammetry of (Ti -phenylmethylsila-14-crown-5)chromiumtricarbonyl has appeared. ... 

Related to the latter, abstraction of an 0x0 ligand from [MoO(S2CNR2)3]-[BF4] (R = Me, Et) by PPha yields the dimeric mixed oxidation state [Mo(IV)/ Mo(V)] complexes, [Mo2(S2CNR2)6(p-0)] (Eq. 63). The equivalence of the molybdenum-oxygen bonds [Mo—O 1.848(2) A] leads to their classification as class Ilia compounds on the Robin and Day scheme (436,811,812). Cyclic voltammetry shows that they undergo a reversible one-electron reduction, however, oxidation results in irreversible cleavage of the 0x0 bridge. 

---