Copper carboxylates structure

There is an interesting technique which makes it possible to introduce carboxylic acid groups into a copper phthalocyanine structure by an economical route. Carrying out the phthalic anhydride/urea process in the presence of a small amount of trimellitic acid or another benzene polycarboxylic acid will afford a car-boxylated pigment. 

The molecular structures of these benzoates (4, 13, 16,18) are analogous to those of the copper carboxylates, including copper acetate, and our discussion makes use of the coordinate frames shown in Fig. 2. A full description of our approach (8, 7) to the magnetism of these systems is outside the scope of this review, but the following sketch illustrates some of the more important features. We consider a Hamiltonian acting upon the binuclear entity,... 

Structures of this type are especially abundant among copper carboxylate complexes ([537] and references cited therein). 

Electron spin resonance studies of the structural features of binuclear copper carboxylates suggest that the magnetic properties of biologically important molecules which contain copper may be better understood with this spectrophotometric technique [728]. Indeed, Greenaway, Norris and Sorenson used electron spin resonance to show that the copper complex of 3,5-diisopropylsalicylic acid is actually isolated as a binuclear complex, Cu(II)2(3,5-DIPS)4(H20)2, as opposed to the mononuclear structure, Cu(II)(3,5-DIPS)2, used throughout this manuscript, and organic solvates of this complex are also binuclear [729]. Electron spin resonance has also been used to study the orientation and mobility of Cu(II)[3-ethoxy-2-oxobutyralde-hyde bis(dimethylthiosemicarbazone)] in a bilayer lipid vesicle [730]. 

The third spectrum (c) was obtained from copper chloride dissolved in hydrated trioctylammonium 2-ethylhexanoate in toluene (the mixed extractant). It has a broad maximum absorbance at 725 nm, its symmetry is similar to that of copper carboxylate, and bonding of copper can be assumed to occur via the carboxylic oxygens in a manner similar to that of the dimer. Spectrum (c) bears an even greater similarity to that of the Cu-EDTA complex, the maximum absorption being at 734 nm, and which is known to have a distorted octahedral structure [12]. It is easy to convert the carboxyT ate dimer into a mixed complex. On adding trioctylamine to copper carboxylate, the maximum absorption shifts gradually from 680 to 725 nm. It is assumed that the addition of the amine converts the dimer into a monomer in which copper is bound to four monomeric carboxylic ligands and two amine molecules are located farther away in an axial position. It is of interest to note that the anion of the salt coextracted with the metal ion has no effect on the visible spectrum i.e., it is immaterial whether copper fluoride, chloride, or nitrate is extracted they all have the same spectrum. 

Copper Carboxylate Complexes. The structural literature on copper(n) carboxylate complexes prior to 1971 is extorsive a recent report on anti-ferromagnetism in dinuclear copper carboxylates makes reference to nearly forty relevant crystallographic papers a 1967 review of metal-peptide... 

Figure 28.7 (a) Dinuclear structure of copper(II) acetate, and (b) spin singlet (25 +1 = 1) and spin triplet (25 +1=3) energy levels in dinuclear Cu carboxylates. 

Structure and metal-metal interactions in copper(II) carboxylate complexes. R. J. Doedens, Prog. Inorg. Chem., 1976, 21, 209-231 (70). 

The reaction of tert-alkyl Grignard reagents with carboxylic acid chlorides in the presence of a copper catalyst provides ieri-alkyl ketones in substantially lower yields than those reported here.4,14 The simplicity and mildness of experimental conditions and isolation procedure, the diversity of substrate structural type, and the functional group selectivity of these mixed organocuprate reagents render them very useful for conversion of carboxylic acid chlorides to the corresponding secondary and tertiary alkyl ketones.15... 

Chemical analysis revealed that commercial food grade copper chlorophyllin is not a single, pure compound, but is a complex mixture of structurally distinct porphyrins, chlorin, and non-chlorin compounds with variable numbers of mono-, di-, and tri- carboxylic acid that may be present as either sodium or potassium salts. Although the composition of different chlorophyllin mixtures may vary, two compounds are commonly found in commercial chlorophyllin mixtures trisodium Cu (II) chlorin Cg and disodium Cu (II) chlorin which differ in the number of... 

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