Oxalato-copper complexes

Cation-deficient partial oxidation has been effected on the Pt(ox)2 system. Oxidation of Pt(ox)2 with either nitric acid (380), chlorine (244, 245), dichromate (244, 245), hydrogen peroxide (394), or tetracyanodihaloplatinate-(IV) (244, 245, 273) yields copper colored needless of the Pt(ox)2 ion. Oxygen readily oxidizes aqueous solutions of H2Pt(ox)2 to the violet Hi.64-Pt(ox)2(H20)a (273). Table IX lists a variety of partially oxidized bis (oxalato)-platinate complexes. 

Reaction of Cytochrome cIinn with Bis(ferrozine)copper(II) Knowledge of the redox properties of cytochrome c was an encouragement to initiate a kinetics investigation of the reduction of an unusual copper(II) complex species by cyt c11. Ferrozine (5,6-bis(4-sulphonatophenyl)-3-(2-pyridyl)-1,2.4-triazine)286 (see Scheme 7.1), a ligand that had come to prominence as a sensitive spectrophotometric probe for the presence of aqua-Fe(II),19c,287 forms a bis complex with Cu(II) that is square pyramidal, with a water molecule in a fifth axial position, whereas the bis-ferrozine complex of Cu(I) is tetrahedral.286 These geometries are based primarily upon analysis of the UV/visible spectrum. Both complexes are anionic, as for the tris-oxalato complex of cobalt in reaction with cytochrome c (Section 7.3.3.4), the expectation is that the two partners will bind sufficiently strongly in the precursor complex to allow separation of the precursor formation constant from the electron transfer rate constant, from the empirical kinetic data. 

C1CuC4H6CuC1, 6 217 Copper (II) complex compounds, anions, oxalato, K2[Cu(C204)2], 6 1... 

The magnetic properties of complexes of these anions have been studied, particularly copper(n) complexes, and have been compared with the results obtained with analogous oxalato complexes the squarato and croconato bridges are... 

Chelated Cu complexes are generally more stable than the simple complexes. Examples are the ethylenediamine, oxalato, catechol and jS-diketone complexes bis(acetylacetonato)copper(II) is shown ... 

The intermediate produced in the flash photolysis of copper(ii) oxalato complexes in deaerated aqueous solution has been identified as CUCO2. This species, which is also generated by pulse radiolysis of the Cu -oxalate-formate system, decays by first-order kinetics. A dependence of the rate constant on pH and on the concentrations of Cu and oxalate ions is established and this is interpreted in terms of competing reactions of CUCO2 [equations (7) and (8)]. 

Chromium(m) and Cobalt(iii) Complexes.—Just as copper(ii) catalyses aquation of oxalato-complexes of chromium(iii) (cf. Section 3, ref. 117), so do a variety of cations catalyse isomerisation of fra 5-[Cr(oxalate)2(OH2)2] . Rate constants are a function of the charge, radius, and structure of the... 

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