Organic hgands

Much remains to be done to develop the chemistry of organic hgands on supported metal clusters, and substantial progress is to be expected as the samples are well suited to characterization, by IR, NMR, and neutron scattering (F. Li, J. Eckert, and B.C. Gates, unpubhshed results) spectroscopies, as well as density functional theory. 

Impressive improvements in our knowledge of thermodynamic properties of the various organic hgands and of our capability of calculating metal-organic complexation constants at the various P and T conditions of interest come from the systematizations of Shock and Helgeson (1990) and Shock and Koretsky (1995), which evaluated equation of state parameters to be used in the revised... 

The organic hgands of the actinide and lanthanide organometallics will be used here as an arbitrary basis of classification. The emphasis will be on the structure and bonding of these compounds rather than their S5uithetic chemistry. Several earher reviews exist which cover the chemical aspects of the organoactinides and -lanthanides [1—7). 

Bearing in mind that the synthesis of the first Mo/Bi alkoxides could be achieved by shielding part of the coordination sphere at the Mo centres by organic hgands [43-50], a similar approach was pursued in order to prepare the first Mo - O - Bi complexes. 

Geipel, G., Acker, M., Vulpius, D., Bernhard, G., Nitsche, H., and Fanghanel, T. (2004). An ultrafast time-resolved fluorescence spectroscopy system for metal ion complexation studies with organic hgands. Spectrochim. Acta Part A—Mol. Biol. Spectrosc. 60(1-2), 417-424. 

Muller, F.L.L. (1999) Evaluation of the effects of natural dissolved and colloidal organic hgands on the electrochemical lability of Cu, Pb, and Cd in the Arran Deep, Scotland. Mar. Chem. 67, 43-60. 

Finally, anion activation can also be achieved by the complexation of the cation using suitable macro(poly)cyclic Hgand molecules [643]. Organic Hgands that contain enforced cavities of dimensions at least equal to those of the smaller cations (and anions) have been called cavitands [644]. Cation complexation by such macro(poly)cyclic ligands leads to dissociation of the ion pairs as well as to salt solubilization. Complex... 

Rue, E. L., and BrrJand, K. W. (1995). Complexation of iron(III) by natural organic hgands in the Central North Pacific as determined by a new competitive hgand equihbrium/absorptive cathodic stripping voltammetric method. Mar. Chem. 50, 117—138. 

Saito M. A. and Moffet J. W. (2001) Complexation of cobalt by natural organic hgands in the Sargasso Sea as determined by a new high-sensitivity electrochemical colbalt speciation method suitable for open ocean water. Mar. Chem. 75, 49-68. 

Both Fe and Fe complexes undergo two-electron oxidations to yield Fe" " and Fe states, respectively. The Fe state, in particular, is achievable with inorganic and small organic hgands because both electrons needed for oxidation come from the Fe. This doesn t happen with hemes, where one electron comes from the iron and the other is taken from the porphyrin or apoprotein (81). 

Violante, A., and Huang, P. M. (1985). Influence of inorganic and organic hgands on the formation of aluminum hydroxides and oxyhydroxides. Clays Clay Miner. 33, 181-192. 

Naidu, R.. and Harter. R. D. (1998). Effect of different organic hgands on cadmium sorption by and extractability from soils. Soil Sci. Soc. Am. J. 62, 644-650. 

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