REACTIONS OF 12-TUNGSTOC0BALTATE(III) ANION WITH SOME ORGANIC AND INORGANIC LIGANDG IN AQUEOUS SOLUTION
REACTIONS OF 12-TUNGSTOC0BALTATE(III) ANION WITH SOME ORGANIC AND INORGANIC LIGANDG IN AQUEOUS SOLUTION
| dc.contributor.author | AYOKO, GODWIN ADEFIKAYO | |
| dc.date.accessioned | 2014-02-06T10:57:31Z | |
| dc.date.available | 2014-02-06T10:57:31Z | |
| dc.date.issued | 1981-04 | |
| dc.description | A Thesis submitted to the Department of Chemistry, Ahmadu Bello university, Zaria for the degree of Master of Science. APRIL, 1981 | en_US |
| dc.description.abstract | The kinetics of the reduction of 12-tungstooobaltate(iii) anion by some organic and inorganic substrates have been investigated in perchlorate acid media. These reactions are shown to proceed by series of univalent changes involving free radical intermediates. Both spectrophotometer and kinetic observations indicate that inner-sphere complex formation is absent and the inertness of the oxidant to substitution is advanced as the major reason for the operation of the outer sphere mechanism in these reactions. in the oxidation's of butane 1,4-diiol and pennant 1,5- idol by 12-tungstocobaltate (III) anion, only one of the two hydroxide groups in the idols is oxidized. In contrast to the reaction of butane 1,4-diol where no hydrogen ion dependence is observed, the rate of oxidation nf pontnna 1, 5-diol is catalyses by acid and retarded by added 12-tungs tocobaltate (II) ions. Rates of oxidation of pennant 1,5-diol also correlated well with Hammett»s and Bunncttis relations in the acid concentration range used. Mechanistic interpretation of these observations is advanced. One mole each of L-cysteine, Meritocratic acid and Methamphetamine is required to reduce 12-tungstocobal Tate (III) to 12-tungstocobaltate(II) with the disulphide of the ligand as the other product. The rates of the reactions decrease with increasing (H+) .This is attributed to the dissociation of the hydrogen of the -SH group in the thistles prior to electron transfer. possible mechanic for the reactions and the significance of the second-order Lindy dependent pathways observed in these reaction are discussed. Finally, the reactions of 12-tungstocobal tats (III) with nitrous acid, thiocyanate and iodide ions Ara first order in both the oxidant and the reluctant in each case. Although simple electron transfer from SCN- or _I to 12- laughingstock (III) to give SCN or I radicals in not thermodynamically feasible, it is kinetically favored. possible driving forces for the reactions are suggested. Excellent agreement is obtained between observed rate constants and those calculated on the basis of Marcus theory far the reactions of l- and SCN- with the oxidant,, The i- reduction of 12-tungstocobaltate (III) is catalyzed by bromide and chloride ions and this is rationalized in terms of possible stabilization of atomic iodine by these ho-lido ions. | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/441 | |
| dc.language.iso | en | en_US |
| dc.subject | REACTIONS, | en_US |
| dc.subject | 12-TUNGSTOC0BALTATE, | en_US |
| dc.subject | ANION, | en_US |
| dc.subject | ORGANIC, | en_US |
| dc.subject | INORGANIC, | en_US |
| dc.subject | LIGANDG, | en_US |
| dc.subject | AQUEOUS, | en_US |
| dc.subject | SOLUTION | en_US |
| dc.title | REACTIONS OF 12-TUNGSTOC0BALTATE(III) ANION WITH SOME ORGANIC AND INORGANIC LIGANDG IN AQUEOUS SOLUTION | en_US |
| dc.type | Thesis | en_US |