Carboxylic acid complexes

Entries where the oxidation state of a metal has been specified occur after all the entries for the unspecified oxidation state, and the same or similar entries may occur under both types of heading. Thus cyanide appears under Chromium complexes, Chromium(O) complexes, Chromium(I) complexes, etc. More specific entries, such as Chromium, hexacyano-, may also occur. Similar ligands may also occur in different entries. Thus a carboxylic acid-metal complex may occur under Carboxylic acid complexes, under entries for specific carboxylic acids, and under the specific metal. Coordination complexes may also be listed in the Cumulative Formula Index. 

The location of protons in intermolecularly hydrogen-bonded carboxylate-carboxylic acid complexes, for example sodium hydrogen bis(acetate) [1],... 

Carboxylic acid complexes, 199-203 Catalysis, see also Organoselenium compounds ... 

Garcia Tellado F, Goswami S, Chang SK, Geib SJ, Hamilton AD (1990) J Am Chem Soc 112 7393 therein is also described the complex of a macromonocycle with diethylmalonate. Carboxylic acid complexation by a synthetic vancomycin analogue Pant N, Hamilton AD (1988) J Am Chem Soc 110 2002... 

Asymmetric induction to main-chain chiral centers can also be achieved by the radical polymerization of sorbates having chiral ester groups [80,81] and 1,3-butadiene-l-carboxylic acid complexed with optically active amines [82,83]. 

The reaction of Cp2LnCl with sodium carboxylates yields the corresponding dicyclopen-tadienyl lanthanide carboxylates, which on the basis of molecular weight determinations are dimers with /i-carboxylate bridges [57]. Some of the carboxylic acid complexes are summarized. 

Treatment of nF salts with acetic acid affords trans-[Ni(02CMe)2(H20)4] (79) incorporating monodentate acetate ligands. By altering the reaction conditions and the carboxylic acid, complexes of type trans andcri [Ni(02CR)2(L)2]... 

This chapter will cover the synthetic, structural, and solution chemistry of rare earth complexes with carboxylic acids, polyaminopolycarboxylic acids, and amino acids, with an emphasis on their structural chemistry. As the carboxylate groups play the key roles in the metal-ligand coordination bonding in these complexes, we will start the chapter with the coordination chemistry of rare earth-carboxylic acid complexes, followed by rare earth-polyaminopolycarboxylic acid and rare earth-amino acid coordination chemistry. Owing to length limitations, an exhaustive citation of the large amount of research activities on the subjects is not possible. Instead, only selected examples are detailed to highlight the key features of this chemistry. 

Rare earth-carboxylic acid complexes are sometimes called rare earth carboxylates. This section will focus on the synthetic methods, structural modes and connectivity, and solution chemistry. Distinct structural features and the general trends in structural change with various RE or ligands will be emphasized. 

Many synthetic methods have been developed to prepare pure rare earth-carboxylic acid complexes with high yields. Based on the starting materials, the methods can be put into two categories (i) rare earth oxides and (ii) rare earth salts. The synthesis can be done in aqueous solutions, organic media, or mixtures of the two, depending on the solubility and the nature of the ligands and the complexes, under ambient conditions, by hydro(solvo)thermal synthesis, or by gel synthesis. Under hydro(solvo)thermal conditions (in aqueous or non-aqueous media... 

Compared with their polyaminopolycarboxylic acid analogs, the solution chemistry of RE(III)-carboxylic acid complexes have received much less attention. However, from the data reported so far, we can already see some of the general aspects of the complexes in solution, the species formed, their stability, and the thermodynamic properties, as well as their evolution with the change of the central atoms. 

In a typical dimeric 1 2 complex, the two RE(III) ions are linked through a quadruple bridge (P2-iiN )4- Each of the metal ions is further coordinated by four water molecules, CN = 8. A representative structure, [Eu2(Ala)4(H20)8] " ", is shown in Figure 3.31a. While most dimeric RE(III)-carboxylic acid complexes are centrosymmetric, with amino acids as ligands, similarly structured complexes are only obtainable when the racemic form of the ligands are used for the synthesis [127]. 

G. E. Coates. Chem. and Ind. London) 1941, 185. Theory piperidine-carboxylic acid complexes. 

R. Malpas, F. R. Mayers, and A. G. Osborne, The chemical modification of small band gap semiconductor electrodes using chromium-carboxylic acid complexes of redox couples, J. Electroanal. Chem. 153, 97, 1983. 

As stated, hydrogen bonds have been used to construct the majority of finite molecular assemblies. Thus, most synthons used to form finite assemblies in the solid state have been based on hydrogen bonds. Many such synthons have also been used to form networks.2 Examples include single-point hydrogen bonds based on phenols and imidazoles, as well as multi-point hydrogen bonds based on carboxylic acid dimers, pyridone dimers, urea dimers, cyanuric acid-melamine complexes, and pyridine-carboxylic acid complexes.2... 

Although the solid state reactivity of one class of metal-carboxylic acid complexes--those of acrylic acid and methacryllc acid--has been known for some time ( ), little convincing Information exists as to whether the structural basis for reactivity can be... 

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