Assessing the Effect of Ligand Proximity on Chiroptical and Other Properties in Cobalt(III) Model, Tyrosine-Like Complexes

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Title:Assessing the Effect of Ligand Proximity on Chiroptical and Other Properties in Cobalt(III) Model, Tyrosine-Like Complexes
Creators:
Jursík, František
Archer, Ronald D.
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 60, 12, pp. 2097-2106

Abstract

<p>A series of new cobalt(III) octahedral complexes of the general formula Na[Co(ohb-aa)<sub>2</sub>] (ohb-aa = <i>N</i>-(<i>o</i>-hydroxybenzyl)amino acid anion); amino acid = glycine, (S)-α-alanine, α-aminoisobutyric acid, (S)-valine, (S)-norvaline and (S)-leucine) were prepared by the charcoal catalyzed reaction of the appropriate ligand with [Co(NH<sub>3</sub>)<sub>6</sub>]<sup>3+</sup> in alkaline aqueous solution. Complexes obtained have, regardless of the amino acid used, the same <i>facial all</i>-<i>trans</i> symmetry (CoN<sub>2</sub>O<sub>4</sub> chromophore) with the vicinal effects as the entire source of the optical activity. <sup>13</sup>C NMR spectra reveal that the leucine derivative has, due to the steric reasons, a different ground state structure. Absorption maxima reflect a positive inductive effect from the amino acid side chain carbon atoms. Complexes of the ligands bearing electrophobic alkyl groups exhibit more negative <i>E</i><sub>1/2</sub> in comparison with the glycine derivative, reduction of which occurs at a more positive potential. Reduction potentials do not correlate with cobalt(III) Lewis acidity modulated by ligands.

Title:Assessing the Effect of Ligand Proximity on Chiroptical and Other Properties in Cobalt(III) Model, Tyrosine-Like Complexes
Creators:
Jursík, František
Archer, Ronald D.
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:60
Number:12
Page Range:pp. 2097-2106
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19952097UNSPECIFIED
ID Code:896
Item Type:Article
Deposited On:06 Feb 2009 17:04
Last Modified:06 Feb 2009 16:04

Citation

Jursík, František; Archer, Ronald D. (1995) Assessing the Effect of Ligand Proximity on Chiroptical and Other Properties in Cobalt(III) Model, Tyrosine-Like Complexes. Collection of Czechoslovak Chemical Communications, 60 (12). pp. 2097-2106. ISSN 0010-0765

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