首页 | 本学科首页   官方微博 | 高级检索  
     


Synthesis and x-ray structure of a Hg(II) complex with adenine N(1)-oxide. A model for mercury binding to DNA
Authors:M.Damodara Poojary  H. Manohar
Affiliation:Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
Abstract:The synthesis and crystal structure of the adenine N(1)-oxide complex with mercury(II) chloride, (C5H5N5O)HgCl2 are reported. Crystals of the coordination compound belong to the monoclinic system, space group P21/n with the following primary crystallographic data: a = 6.685(1) Å, b = 11.798(2) Å, c = 10.155(1) Å, β = 100.22(1)°, V = 906.04 Å3, Z = 4. The structure was elucidated by conventional Patterson and Fourier methods and refined by the full matrix least-squares technique on the basis of 1977 observed reflections to an R value of 0.074. The basic unit of the structure is a dimer, with a centre of symmetry, consisting of two HgCl2 moieties and two adenine N(1)-oxide ligands. A polymeric structure results from the bridging interactions of chloride ions. Adenine N(1)-oxide acts as a bidentate bridging ligand, coordinating through N(7) and O(1). The coordination geometry around the mercury ion is a distorted square pyramid with N(7) and three chlorines (two of which are centro-symmetrically related) forming the square plane and O(1) occupying the axial position. Hg also interacts indirectly with N(6) through a Cl
/></figure>HN hydrogen bond. Principal intracomplex geometrical parameters are as follows: HgN(7) = 2.61(1) Å, HgO(1) = 2.55(1) Å, HgCl(1) = 2.330(3) Å, HgCl(2) = 2.318(3) Å, HgCl(2′) = 3.347(3) Å. The <em>cis</em> angles range from 77.5° to 107.9° and the two <em>trans</em> angles are 155.5° and 163.1°. The centro-symmetrically related bases overlap partially and pack at a distance of 3.2 Å. The glide-related bases are linked by a hydrogen bond, N(9)H<figure class=/></figure>O(1) and are inclined to one another by 109.7°. The results are compared with those derived from spectroscopic and other physicochemical studies on metal interaction with adenine N(1)-oxide. Based on the present structural observations and earlier experimental results a possible mechanism is proposed for mercury interaction with DNA.</td>
		  </tr> 
		  <tr>
		   <td align=
Keywords:Author to whom correspondence should be addressed.
本文献已被 ScienceDirect 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号