Acta Phys. -Chim. Sin. ›› 2010, Vol. 26 ›› Issue (12): 3322-3328.doi: 10.3866/PKU.WHXB20101215


Stability of Complexes Combined by Metal Ions (Na+, K+, Ca2+, Mg2+, Zn2+) and Guanine Isomers

ZHAO Yong-Ping, AI Hong-Qi, CHEN Jin-Peng, YANG Ai-Bin, QI Zhong-Nan   

  1. School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P. R. China
  • Received:2010-08-13 Revised:2010-09-24 Published:2010-12-01
  • Contact: AI Hong-Qi
  • Supported by:

    The project was supported by National Natural Science Foundation of China (20973084, 20573047), Natural Science Foundation of Shandong Province, China (Y2008B56) and Research Fund for Young and Middle-aged People of Shandong Province, China (2007BS02009).


The order of stability for complexes of differently coordinated metal ions (M+/2+=Na+, K+, Ca2+, Mg2+, Zn2+) with thirteen guanine isomers in gas (g) and aqueous (a) phases was systematically investigated at the B3LYP/6-311++G** level in combination with the polarized continuum model (PCM). Special effort was devoted to differences in the order of stability for aGnxM+/2+ (n is the label of guanine isomers, x denotes binding site of M+/2+ and guanine isomers) complexes that were obtained in aqueous solutions. An analysis was also performed to determine the reason for these differences with respect to the solute-solvent effect, binding energy, deformation energy, and relative free energy of the guanine isomers. The most stable complexes generated by the five metal ions were: aG1N2,N3Na+ , aG1N2,N3K+ , aG1O6,N7Ca2+ , aG1N2,N3Mg2+ (aG1O6,N7Mg2+), and aG2N3,N9Zn2+. The isomer of guanine in the most stable Zn2+ complex in the aqueous solution was G2 whereas in the other four most stable complexes it was G1, i.e., the different active sites in G1 generate the four most stable complexes. Additionally, we report on stable complexes in the gas phase such as gG3N1,O6K+, gG5N1,O6K+, gG3N1,O6Ca2+/Mg2+, and gG4O6,N7Ca2+/Mg2+.

Key words: Guanine isomer, Stability, Metal ion, Solute-solvent effect, Binding energy