Amino acids as CH-acids 17. Increase in the amino acid ?-proton mobility in Schiff base copper complexes with pyridine or N-2-pyridinecarbonyl-2?-aminobenzaldehyde ligands

1978 ◽  
Vol 27 (10) ◽  
pp. 2014-2020
Author(s):  
Yu. N. Belokon' ◽  
V. M. Belikov ◽  
V. A. Maksakov ◽  
V. I. Tararov
Keyword(s):  
Amino Acids ◽  
Schiff Base ◽  
Amino Acid ◽  
Copper Complexes ◽  
Proton Mobility ◽  
Ch Acids ◽  
Acid Proton

scholarly journals Correction: Photochemical reduction of Cr(vi) compounds by amino acid Schiff base copper complexes with a hydroxyl group and titanium oxide composites in aqueous solutions

2020 ◽  
Vol 44 (39) ◽  
pp. 17129-17129
Author(s):  
Yoshito Miyagawa ◽  
Arshak Tsaturyan ◽  
Tomoyuki Haraguchi ◽  
Igor Shcherbakov ◽  
Takashiro Akitsu
Keyword(s):  
Schiff Base ◽  
Amino Acid ◽  
Aqueous Solutions ◽  
Titanium Oxide ◽  
Copper Complexes ◽  
Hydroxyl Group ◽  
Photochemical Reduction ◽  
Amino Acid Schiff Base ◽  
Oxide Composites

Correction for ‘Photochemical reduction of Cr(vi) compounds by amino acid Schiff base copper complexes with a hydroxyl group and titanium oxide composites in aqueous solutions’ by Yoshito Miyagawa et al., New J. Chem., 2020, DOI: 10.1039/d0nj02481c.

scholarly journals Enantioselectivity-Evaluation of Chiral Copper(II) Complexes Coordinated by Novel Chiral Tetradentate Ligands for Free Amino Acids by Mass Spectrometry Coupled With the Isotopically Labeled Enantiomer Method

2020 ◽  
Vol 8 ◽  
Author(s):  
Takashi Nakakoji ◽  
Kaori Yoshino ◽  
Kazuki Izutsu ◽  
Hirofumi Sato ◽  
Hiroyuki Miyake ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Amino Acids ◽  
Amino Acid ◽  
Copper Complex ◽  
Free Amino Acids ◽  
Free Amino ◽  
Copper Complexes ◽  
Ionization Mass ◽  
Tetradentate Ligand ◽  
Tetradentate Ligands

A series of copper(II) complexes with chiral tetradentate ligands, N,N′-ethylene- bis(S-amino acid methyl amide or methyl ester) prepared from S-alanine, S-phenylalanine, S-valine or S-proline, was generated in methanol. The copper complexes provided three component complexes in the presence of a free chiral amino acid. The enantioselectivity for the amino acid was evaluated by electrospray ionization-mass spectrometry coupled with the deuterium-labeled enantiomer method and these copper complexes were found to exhibit high enantioselectivity for free amino acids having bulky side chains. This result suggests that steric interaction between the tetradentate ligand and free amino acid was a major factor in chiral recognition. The copper complex with a chiral tetradentate ligand prepared from S-proline showed opposite enantioselectivity to copper complexes consisting of tetradentate ligands prepared from other S-amino acids. The conformational difference of the tetradentate ligand in the copper complex was found to be significant for enantioselectivity.

Diphenoxo-Bridged Copper(II) Complexes of Reduced Schiff Base Ligands as Functional Models for Catechol Oxidase

2009 ◽  
Vol 62 (9) ◽  
pp. 968 ◽  
Author(s):  
Bellam Sreenivasulu
Keyword(s):  
Amino Acids ◽  
Schiff Base ◽  
Amino Acid ◽  
Unnatural Amino Acids ◽  
Short Review ◽  
Catechol Oxidase ◽  
Schiff Base Ligands ◽  
Functional Models ◽  
Reduced Schiff Base ◽  
Reduced Schiff Base Ligands

The design and development of synthetic analogues for the active dicopper(ii) sites of catechol oxidase, with the help of binucleating ligands in particular, is an attractive strategy to generate relevant information on structure–function relationships. Dicopper(ii) complexes of different yet closely related series of reduced Schiff base ligands (N-(2-hydroxybenzyl)-amino acids; N-(2-hydroxybenzyl)-amino amides, N-(2-hydroxybenzyl)-aminomethane or ethanesulfonic acids, and N-(2-hydroxy-5-substituted-benzyl)-cyclopentane or hexanecarboxylic acids) derived from various substituted salicylaldehydes and natural or unnatural amino acids or amides explored as functional models for the Type 3 copper enzyme catecholase oxidase are reviewed in the present paper. The catalytic activity of different series of dicopper(ii) complexes to oxidize the model substrate 3,5-di-tert-butylcatechol to the corresponding 3,5-di-tert-butylquinone is discussed with respect to the various ligand properties such as the length and chelating ability of the amino acid side-arm of the ligands, conformation of the ligand, nature of the donor groups on the amino acid backbone and role of different para-substituents. This article provides a short review summarizing the trend observed in the catecholase activity of different series of dicopper(ii) complexes investigated in our laboratory.

Photochemical reduction of Cr(vi) compounds by amino acid Schiff base copper complexes with a hydroxyl group and titanium oxide composites in aqueous solutions

2020 ◽  
Vol 44 (38) ◽  
pp. 16665-16674
Author(s):  
Yoshito Miyagawa ◽  
Arshak Tsatsuryan ◽  
Tomoyuki Haraguchi ◽  
Igor Shcherbakov ◽  
Takashiro Akitsu
Keyword(s):  
Schiff Base ◽  
Amino Acid ◽  
Titanium Oxide ◽  
Copper Complexes ◽  
Reduction Reaction ◽  
Hydroxyl Group ◽  
Photochemical Reduction ◽  
Methanol Solutions ◽  
Amino Acid Schiff Base ◽  
Oxide Composites

The photo-driven reduction reaction of Cr(vi) to Cr(iii) by Schiff base Cu(ii) complexes was studied in aqueous and methanol solutions. The Cr(vi) reduction ratio with the CuVDB–TiO2 system reached 91%.

Stereoselective interaction of a tridentate Schiff base complex of nickel(II) and amino acids

1979 ◽  
Vol 57 (8) ◽  
pp. 883-885 ◽  
Author(s):  
B. Erno ◽  
R. B. Jordan
Keyword(s):  
Amino Acids ◽  
Schiff Base ◽  
Amino Acid ◽  
Schiff Base Complex ◽  
Salt Crystallization ◽  
Sensitive Test ◽  
Dilute Acid ◽  
Base Complex ◽  
Tridentate Schiff Base ◽  
Perchlorate Salt

It has been observed that a tridentate Schiff base complex of nickel(II), triaquotribenzo-[b,f,j][1.5.9]-triazacyclodecinenickel(II), commonly called (TRI)Ni(OH2)32+, shows substantial stereoselectivity on complexing with several amino acids. This provides a convenient way to resolve (TRI)Ni(OH2)32+ using histidine as a resolving agent, and either ion exchange or perchlorate salt crystallization techniques.The resolved (TRI)Ni(OH2)32+ may then be used to resolve other amino acids or as a sensitive test of the stereochemistry of an amino acid. The test can be done on milligram quantities because of the insolubility of the complex perchlorate salt and because of the relatively large molecular rotation (2 × 105 deg at 283 nm) of (TRI)Ni(OH2)32+. The amino acid is easily released by treatment of the complex with dilute acid (Ph ≈ 2). The procedure has been tested with histidine, tyrosine, methionine, and phenylglycine.

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