Carbonato copper complexes

A suspension of polymeric cupric dimethoxide in pyridine reacts with CO2 to yield the cupric methyl carbonate. The CO2 moiety is, however, very labile the insertion could be reversed by heating the reaction mixture at 80" under a stream of nitrogen [SO]. Another reversible carbon dioxide carrier was found in copper(I) rerr-butoxide, which was stabilized by rerr-butyl isocyanide. The rerr-butyl carbonato complex was formed during the reaction with CO2 [811. Carbon dioxide also reacts with ROCu(PPh3)2 0 produce (ROCOj)Cu(PPhj>3, Hydrolysis or thermolysis of these alkylcarbonato complexes gives the binuctear carbonato copper (I) complex (PPhj>2 CuCK Oj Cu(PPhj)2, which can be further convened into the bicarbonate complex f(HC)C02)Cu(PPh3)3] by reaction with CO2 in moist solvents [82],... 

If the numbers were accepted at face value, the data indicate that the species involved account for S0-S % of the toxicity, the carbonato complexes do not contribute to toxicity, the anionic hydroxo copper complexes contribute 13-18 to the total toxicity, and the free copper ion and/or the neutral and cationic hydroxo complexes of copper are responsible for 60-70 of the toxicity of copper to aquatic life. 

If the carbonato complexes are accepted as being non-toxic, a set of experiments are needed in which the toxicity of copper to Daphnia magna is measured at equal intervals over the pH range 6.0-8.0. The speciation curves shown in Figure 1 would predict that this set of experiments plus inclusion of all copper complexes involved in the speciation calculations should allo separation of the species of concern into four groups, (Cu ),... 

The p3-bridged carbonato complex posseses a pseudo-3-fold molecular symmetry. Each of the Cu atoms is five coordinate with the four nitrogen atoms of tren and one oxygen atom of the carbonate ligand (C). The coordination polyhedron of the Cu atom can be described as almost (TBP), the copper ions being slightly out of the plane (0.15 A) of the three primary amine groups (Fig. 5). 

Fixation of atmospheric C02 by the dinuclear di-/n-hydroxo copper(II) complex [CuHB(3,5-Pr 2pz)3]2(/Li-OH)2 gives the corresponding carbonato complex106 7-XX. 

Figure 3. Titration data for complexation of copper by carbonate. Solution contained lOmM NaHCOs and 5/xM CuSO. pH varied by adjusting Pco Curve calculated according to hydroxo and carbonato stability constants determined in...

Johri, K. N., Kaushik, N. K., Bakshi, K. Thin-layer chromatographic separation of copper (II), nickel(II), and cobalt(II) as thio-carbonato-complexes and determination by ring colorimetry. Chromatographia 5, 326 (1972)... 

The syntheses and the crystal structures of the new tetranuclear P4-CO3 complexes of copper(II), [(p4-C03)(p-Br)2 Cu4(bapa)4 ]Br4 and [(p4-C03)(p-Cl)2 Cu4(bapma)4 ]Cl4-12H20, were also reported by Escuer and co-workers 62) to elucidate the multiple bridging mode of COg. The analogous compound [(p-C03)(p4-Cl)2 Cu4(bapa)4 ]Cl4 was also synthesized by them for comparative purposes. All these carbonato complexes showed very strong antiferromagnetic coupling. 

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