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Nuclease activity of diaza-crown ether complexes of cerium(III) with different functional groups as side arms

Posted on 15. May, 2018.

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Cerium(III) complexes of two ligands of a diaza-crown ether with different functional groups as side arms were synthesised and characterised. The catalytic ability of the cerium(III) complexes for pUC19 DNA cleavage was investigated and compared using agarose gel electrophoresis. 

The results indicate that the catalytic activity of the complex CeL2 [L2 = 2,2'-(1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diyl)diacetamide] with two carbamoylmethyl groups is significantly higher than the complex CeL1 [L1 = 2,2'-(1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diyl)diethanol] with two hydroxyethyl groups under the same conditions. The optimum catalytic concentrations of CeL1 and CeL2 were 7.69 × 10–5 and 3.08 × 10–5 mol L–1 respectively and excessively high concentrations of the complexes can reduce their catalytic efficiency due to the formation of inactive µ-hydroxo dimers. The optimum catalytic acidities of CeL1 and CeL2 were pH 7.0 and 7.5 respectively and excessively high pH of the reaction system can reduce the catalytic efficiency of the complexes due to the formation of cerium(III) hydroxide. DNA cleavage promoted by the two complexes takes place via the same hydrolytic pathway and so the activity difference of the two complexes is attributed to the stability of the complexes, rather than the catalytic mechanism.

Read the full article in Progress in Reaction Kinetics and Mechanism, Volume 43, Number 1, 2018, pp. 91-99(9).

DOI: https://doi.org/10.3184/146867818X15161889114448

Authors: Bingying Jianga, Shulan Caib, Jiaqing Xieb and Fa-mei Fengb*
aCollege of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing 400054, P.R. China
bCollege of Chemistry and Environmental Engineering, Sichuan University of Science and Engineering, Zigong, Sichuan 643000, P.R. China
*E-mail: ffmei@163.com

Keywords: diaza-crown ether, functional group, cerium(III) complex, DNA hydrolysis

Image: Equilibrium between three forms of the cerium complexes, R = acetamide or ethanol.