Rare earth metal carboxylate complexes

Fig. 21 Stoichiometric reaction of C02 with rare-earth metal alkyl complexes to produce carboxylate dimeric catalysts...

Ion chromatography can be used for the determination of ionic solutes such as inorganic anions, inorganic cations (including alkali metals, alkaline earth metals, transition metals, and rare earth metals), carboxylic, phosphonic and sulfonic acids, detergents, carbohydrates, low molecular weight organic bases, and ionic metal complexes. 

Lanthanides in Living Systems Lanthanides Coordination Chemistry Lanthanides Luminescence Applications Lmninescence Lanthanides Magnetic Resonance Imaging Lanthanide Oxide/Hydroxide Complexes Carboxylate Lanthanide Complexes with Multidentate Ligands Rare Earth Metal Cluster Complexes Supramolecular Chemistry from Sensors and Imaging Agents to Functional Mononuclear and Polynuclear Self-Assembly Lanthanide Complexes. 

The use of carboxylic acids for the removal of iron(III) from solutions of the rare-earth metals has been reported,38 but has not been described in detail. The stoichiometries of the extracted complexes of iron(III) have not been clearly established. The n-decanoic acid complex has been variously described as (FeA3)3 and Fe3A9 x(OH) (HA) 51 or [Fe(OH)A2]2 and [Fe(OH)2A-HA]2,57 the H-octanoic acid complex as (FeA3-H20)3,58 the naphthenic acid complex as FeA3,47 and that of Versatic 10 acid as [FeA3(HA)J>, or [Fe(OH)A2]3.59... 

Although heterobimetallic complexes with alkylated rare-earth metal centers were proposed to promote 1,3-diene polymerization via an allyl insertion mechanism, details of the polymerization mechanism and of the structure of the catalytically active center(s) are rare [58,83,118-125]. Moreover, until now, the interaction of the cationizing chloride-donating reagent with alkylated rare-earth metal centers is not well-understood. Lanthanide carboxylate complexes, which are used in the industrial-scale polymerization of butadiene and isoprene, are generally derived from octanoic, versatic, and... 

First structural evidence for the formation of heterobimetallic Ln/Al complexes in carboxylate-based catalytic systems was obtained from the reaction of homoleptic rare-earth metal trifluoroacetates with equimolar amounts of z -Bu2A1H and EtsAl, respectively [132], Alkylated yttrium, neodymium, and... 

Most of the knowledge about aluminate and alkylaluminum coordination stems from X-ray crystallographic studies. The basic idea of this section is to compile a rare-earth metal aluminate library categorizing this meanwhile comprehensive class of heterobimetallic compounds. Main classification criteria are the type of homo- and heterobridging aluminate ligand (tetra-, tri-, di-, and mono alkylaluminum complexes), the type of co-ligand (cyclopen-tadienyl, carboxylate, alkoxide, siloxide, amide), and the Ln center oxidation state. In addition, related Ln/Al heterobimetallic alkoxide complexes ( non-alkylaluminum complexes) are surveyed. Emphasis is not put on wordy structure discussions but on the different coordination modes (charts) and important structural parameters in tabular form. An arbitrary collection of molecular structure drawings complements this structural report. 

The primarily ionic nature of the RE(III)-carboxylate interaction suggests that a direct relationship between the ionic radii of the RE(III) and the stability of their complexes with car-boxylates should exist the stability constants of the complexes would increase monotonously from La(III) to Lu(III). However, the experimental results obtained indicate that this is only true for light rare earth metals from La(III) to Eu(III). Three different trends are observed for heavy rare earths from Gd(III) to Lu(III), that is, upward, flat, and downward. This is the so called gadoliniumbreak. Acetate, malonate, succinate, glutarate, and adipate complexes fall into the second category. The log Pi of the complexes remain almost unchanged from Gd(III) to Lu(III) (Table 3.2). There have been various interpretations of these trends, and the most widely accepted one is the change in the number of the hydration water molecules [98, 99]. 

When aqueous solutions of rare earth salts are treated with solutions of ammonium carbonate in hydrazine hydrate (N2H5COON2H3), rare earth metal hydrazine carboxylate hydrate complexes are formed [15]. Initially, a precipitate forms that dissolves with the addition of excess reagent. On keeping the solution for a couple of days crystalline solids separate. The crystals are washed with alcohol and then diethyl ether and stored in a vacuum desiccator. The composition of the crystals determined by chemical analysis and infrared spectra has been found to be Ln(N2H3C00)3-3H20 ... 

As the crystal structures of all the rare earth metal hydrazine carboxyl-ates are isomorphous, it is possible to prepare solid solutions of Pr-Ce hydrazine carboxylates. The complexes Cei xPr (N2H3C00)3-3H20, with X = 0-0.5, are prepared by the same procedure used in preparing rare earth metal hydrazine carboxylates as mentioned in Section 4.3.2. Stoichiometric amounts of cerium nitrate and praseodymium nitrate are dissolved in doubly distilled water, and to this a solution of hydrazine carboxylate in hydrazine is added slowly. The mixture is allowed to... 

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. 

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