Synthesis and Kinetics of Isomerization of mer and fac[CoCO3(en)(Amino Acidato)] Isomers

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Title:Synthesis and Kinetics of Isomerization of mer and fac[CoCO3(en)(Amino Acidato)] Isomers
Creators:
Tyle, Pavel
Jursík, František
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 60, 6, pp. 983-989

Abstract

<p>Reaction of [CoXY(en)(AB)]<sup>n+</sup> (AB = glycinato or (S)-α-alaninato anion, X = H<sub>2</sub>O, Y = Cl; AB = (S)-valinato anion, X = Y = Cl) with HCO<sup>-</sup><sub>3</sub>) or Ag(<sub>2</sub>CO)<sub>3</sub> gives mixture of <i>mer-</i> and <i>fac-</i>[CoCO(<sub>3</sub>(en)(AB)] isomers, ratio of which is temperature dependent. Both isomers undergo in aqueous solution to spontaneous isomerization which does not occur when carbonato group is replaced by oxalato or malonato one. This suggests that the source of stereolability in these complexes is a strain imposed by the four-membered carbonato chelate ring. The equilibrium constants (K = <i>fac/mer</i>) increase in the order KGly &lt; KVal &lt; KAla. The total rate constants obtained at 45 °C and 55 °C increase in the order kAla &lt; kVal &lt; kGly. λ-<i>mer-</i>[CoCO<sub>3</sub>(en)(S)-Val)] isomer undergoes at 22 °C racemization at the octahedral centre yielding the mixture of 59% δ and 41% λ isomers.

Title:Synthesis and Kinetics of Isomerization of mer and fac[CoCO3(en)(Amino Acidato)] Isomers
Creators:
Tyle, Pavel
Jursík, František
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:6
Page Range:pp. 983-989
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19950983UNSPECIFIED
ID Code:792
Item Type:Article
Deposited On:06 Feb 2009 17:04
Last Modified:06 Feb 2009 16:04

Citation

Tyle, Pavel; Jursík, František (1995) Synthesis and Kinetics of Isomerization of mer and fac[CoCO3(en)(Amino Acidato)] Isomers. Collection of Czechoslovak Chemical Communications, 60 (6). pp. 983-989. ISSN 0010-0765

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