The stereochemistry and reactivity of metal-Schiff base complexes III. The kinetic and thermodynamic stereoselectivities in the formation of N,N'-ethylenebis(.ALPHA.-methylsalicylideneaminato)cobalt(III) complexes with L-proline,hydroxy-L-proline,and allo

スポンサーリンク

概要

• 論文の詳細を見る

• Under air-oxidation conditions, the reaction of [Co(α-Me-sal<SUB>2</SUB>en)] with L-aaH, where α-Me-sal<SUB>2</SUB>en represents the dianion of <I>N</I>,<I>N</I>′-ethylenebis(α-niethylsalicylideneaniine) and where L-aaH denotes L-proline, hydroxy-L-proline, or <I>allo</I>-hydroxy-L-proline, proceeded rapidly to yield <I>Λ</I>-<I>cis</I>-β<SUB>2</SUB>–[Co(α-Me-sal<SUB>2</SUB>en)(L-aa)] stereoselectively, followed by the slow isomerization of the <I>Λ</I>-<I>cis</I>-β<SUB>2</SUB>-isomer thus formed to give the corresponding <I>Δ</I>-<I>cis</I>-β<SUB>2</SUB>-isomer in a yield of almost 100% under equilibrium conditions. The complexes thus formed were isolated and characterized by the use of their absorption, circular dichroism, and <SUP>1</SUP>H-NMR spectra. The preferential formation of the <I>Λ</I>-<I>cis</I>-β<SUB>2</SUB>-isomer in the initial reaction was found to be kinetic in origin. The kinetic stereoselectivity was determined to be 87% for L-proline, 56% for hydroxy-L-proline, and 23% for <I>allo</I>-hydroxy-L-proline by the measurement of the rotation at 435 nm of the reaction solutions. On the other hand, no kinetic differentiation was observed for the formation of the similar <I>cis</I>-β<SUB>2</SUB>-complexes with L-alanine, L-valine, L-methionine, L-phenylalanine, L-tryptophan, <I>N</I>-benzyl-L-alanine, and <I>N</I>-methyl-L-alanine. On the basis of these data, the mechanism of the initial complexation was discussed. The high thermodynamic stereoselectivity for <I>Δ</I>-<I>cis</I>-β<SUB>2</SUB>-isomer was explained in terms of the intramolecular steric interaction between the pyrrolidine ring of the coordinated L-aa and the distorted α-Me-sal<SUB>2</SUB>en ligand in the complex.

• 公益社団法人 日本化学会の論文

著者

• Isago Takashi

  Department Of Chemistry College Of Science And Engineering Aoyama Gakuin University

• Fujii Yuki

  Department Of Chemistry Faculty Of Science Ibaraki University

• Shiono Katsuji

  Department of Chemistry, Faculty of Science, Ibaraki University

• Ezuka Kuniko

  Department of Chemistry, Faculty of Science, Ibaraki University

関連論文

• Aqueous Media Effect on Molecular Recognition. II.^ Temperature Dependence of Chemical Selectivity in Alcohols amd Water
• Precise Discrimination between Butyl and Pentyl Groups in Molecular Aggregates
• Effect of Triamine Ligands (L) on the Acidity of L-Zn-OH_2 as a Model Compound of CA and AP
• Synthesis of New Cationic Schiff Base Complexes of Copper(II) and Their Selective Binding with DNA
• Thermodynamic and Kinetic Studies of Zinc(II)-Triamine Complexes as Models of CA and AP
• Preparation of Palladium (II) and Copper (II) Selective Chelating Resin Bearing 2-Acetylphenol Ligand
• TES microcalorimeter SEM-EDS system for rare-earth elements analyses
• Evidence for the similarity recognition hypothesis. Structure dependence of the selectivity in oxidation of a pair of associating thiols each having an alkyl group.
• Cobalt(III) and Chromium(III) Complexes with Ethylenediaminemonoacetic Acid
• The stereochemistry and reactivity of metal-Schiff base complexes. II. High stereoselectivity in (1S,2S)-N,N'-1,2-cyclohexylenebis(salicylideneaminato)(sal2-(S,S)-chxn) cobalt(III) complexes with amino acids and the optical resolution of amino acids with
• Preparation, crystal structure, and stereochemical properties of {N,N'-ethylenebis(1,1,1-trifluoro-4-imino-2-pentanonato)} (L-methioninato)cobalt(III).
• The stereochemistry and reactivity of metal-Schiff base complexes. V. The solvent effect on the stereoselectivity of cobalt(III) complexes containing a sal2en-type Schiff base and L-amino acid.
• The stereochemistry and reactivity of metal-Schiff base complexes III. The kinetic and thermodynamic stereoselectivities in the formation of N,N'-ethylenebis(.ALPHA.-methylsalicylideneaminato)cobalt(III) complexes with L-proline,hydroxy-L-proline,and allo
• Preparation and characterization of (iminodiacetato)cobalt(III) complexes with L-methioninate and S-methyl-L-cysteinate.
• Characterization of trans(O)-N,N'-ethylenebis(S-methyl-L-cysteinato)cobalt(III) perchlorate and the absolute configuration of the complex determined by X-ray analysis.
• An NMR Study of Metal Complexes Containing Acetylacetone and Related Compounds. III. The Preparation and Determination of the Configurations of Cobalt(III) Complexes Containing N,N′-Ethylenebis(acetylacetonimine) and N,N′-Ethyl
• The crystal and molecular structure of (N-benzyl-L-alaninato)-(n,n'-ethylenebis(.ALPHA.-methylsalicylideneaminato))-cobalt(III) trihydrate.
• A Co-59 nuclear magnetic resonance study of the interaction of lanthanoid shift reagents with tris(.BETA.-diketonato)-cobalt(III) complexes.
• The stereochemistry and reactivity of metal-Schiff base complexes. VII. Contribution of hydrophobic interligand interaction to chiral recognition of phenylalaninate and tryptophanate with (1R,2R)-N,N'-disalicylidene-1,2-cyclohexanediaminecobalt(III) compl
• The stereochemistry and reactivity of metal-Schiff base complexes. VI. The kinetics and mechanism of isomerization between .DELTA.L-.BETA.2- and .LAMBDA.L-.BETA.2-diastereoisomers of N,N'-ethylenebis(.ALPHA.-methylsalicylideneaminato)cobalt(III) complexes
• Multidentate Ligand Substitution Reactions. XI. Substitution Reactions of Nickel(II) Complexes of Diethylenetriamine and Ethylenediaminemonoacetic Acid with Diethylenetriaminepentaacetic Acid and of Nickel(II) Complexes of Diethylenetriamine and Ethylened
• An NMR Study of Metal Complexes Containing Acetylacetone and Related Compounds. I. The Preparation, Halogenation and NMR Spectra of Cobalt(III) Complexes Containing Acetylacetone and Bis(acetylacetone)ethylenediimine
• The stereoselectivity of N,N'-ethylenebis(.ALPHA.-methylsalicylideneaminato)-cobalt(III) complexes with N-benzyl-L-alanine, N-methyl-L-alanine, and N-benzyl-N-methyl-L-alanine, and the stereospecificity of N,N'-1,2-cyclohexylenebis(salicylideneaminato)-co
• Stereochemistry and reactivity of metal-schiff-base complexes. I. Preparation and thermodynamic stereoselectivity of mixed ligand cobalt(III) complexes containing N,N'-ethylenebis(salicylideneamine) dianion (sal2en) or (7,7'-Me-sal2en) and L-amino acid an
• Nickel(II) Complexes of Ethylenediaminemonoacetic Acid (EDMA). The Preparation and Thermal Decomposition of Nickel(II)-EDMA Complexes
• The Polarography of N,N′-Ethylenebis(acetylacetoniminato) and N,N′-Ethylene bis(salicylaldehydeiminato) Complexes of Cobalt(III), Nickel(II), and Copper(II) in an N,N′-Dimethylformamide Solution
• Determination of the Optical Purity of Amino Acids by Complex Formation. Determination of Optimum Condition for Rotational Measurement
• Inversion of stereoselectivity by hydrophobic interligand interactions. Preparation, structure, and stereoselectivity of {N,N'-ethylenebis(1,1,1-trifluoro-4-amino-2-pentanonato)}(L-amino acidato)cobalt(III).

もっと見る 閉じる

スポンサーリンク