Amines chelation

The use of monodentate and bidentate polar ligands such as ethers, amines, chelating diethers, and diamines in RLi diene polymerization has been studied by a number of workers (23-28). For example, the effect of... 

Johansson and Davidsson47 have reported on the NMR studies of a mixture of two different chelating lithium amides, one with an ether chelate, derived from (R)-l-methylamino-2-methoxy-l-phenylethane (9), and one with an amine chelate (Li-4). It was found that the Et20 solution contained different dimers, both homo and hetero dimers. Based on NMR data it was concluded that a mixture of the two hetero dimers, both symmetrically ((Li-4/Li-9) 2Et20) and unsymmetrically ((Li-4/Li-9) Et20) solvated, dominated in solution. 

Molochnikov LS, Kovalyova EG, Zagorodni AA, Muhammed M, Sultanov YM, Efendiev AA (2003) Coordination of Cu(II) and Ni(II) in polymers imprinted so as to optimize amine chelate formation. Polymer 44 4805... 

Several amino acids are speculated to be effective in increasing iron absorption and can be divided into three categories. These are 1) amino acids which act as buffering agents in the Intestine and delay the increase of the pH towards neutrality where iron is oxidized and forms insoluble precipitates 2) amino acids which form iron-amine chelates that act to enhance iron absorption and 3) amino acids which act to stimulate iron transport systems within the animal (3). A wide variety of soy products ranging from soy meal to soy protein isolates were found to have a strong inhibitory effect on... 

POLY AMINE-CHELATED ALKALI METAL COMPOUNDS... 

Because of the exceptional reactivity and chemical importance of the amine-chelated organolithium reagents, their stereochemical properties are of special significance. Our interest centered on six points ... 

Magnetic Resonance Studies of Polytertiary Amine Chelated Alkali Metal Compounds... 

Table I. Skeletal Structures of Poly tertiary amine Chelating Agents...

Our background with chelate complexes suggested the use of Group IA and IIA metal salts for selective polyamine complexation. The specificity of the interaction between alkali-metal and alkaline-earth salts and certain polyamines provides a sensitive technique for separating single polyamines from multicomponent samples. These separations, the factors that affect complex formation, and the unique properties of the poly-tertiary amine chelates of inorganic lithium compounds are discussed in this paper. 

Telomerization Reactions Involving Amine-Chelated Lithium Catalysts... 

Diamine complexes. The pK values determined for a range of cobalt(iii)-amine chelates indicated enhanced acidity for the protic chelate complexes compared with those with related unidentate ligands." Complete resolution of rac-[Co(en)3] cations has been achieved by paper electrophoresis in a background of d-tartrate and AlC. The crystal structure of (-H)D-[Co(en)3](N03)3 has been determined. The very low quantum yields for the photoreactions of [Co(en)3] have been explained as due to the lack of ligand field excitation for this ion. However, convincing evidence is presented for the reaction of [Co(en)3] " and [Fe(CN)g] under photochemical conditions indicating that this is an efficient photochemical reaction of the cobalt-amine complex in a ligand field excited state (quantum yield ca. 0.2). ... 

The most stable Cr(IV) complexes are the diperoxy(amine) chelates and [Cr(02)2(dien)] has now been investigated as an oxidant in glycine or acetate buffers. " With Ti(III) and [Fe(CN)6] ", both the peroxo groups and the Cr(IV) center are reduced but with only the Cr(IV) center. The Cr(III) products contain coordinated dien, but not all the N-donor atoms are coordinated. 

In the absence of phosphine ligands and amines, chelation of the allylic hydroxy group to Pd(II) may yield a flve-membered cyclic o--complex. This chelate ring makes it difficult to achieve the conformation required for elimination of H and preferentially directs the elimination of the hydridopalladium species to give the enol. 

Hahn, E. Rupprecht, S. Kramp, W. Nenmeier, R. Preparation of poly(aryloxyalkyl)amine chelating agents and their technetinm and rheninm complexes for diagnosis and therapy. Ger. Offen. DE 4025788, 1992 Chem. Abstr. 1992,117, 130916. 

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