Synthesis and structure of methylmercury(II) complexes of 9-methylguanine, including the X-ray structural analysis of (9-methylguanine)-methylmercury(II) nitrate
- 1 January 1980
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in J. Chem. Soc., Dalton Trans.
- No. 9,p. 1693-1697
- https://doi.org/10.1039/dt9800001693
Abstract
Methylmercury(II) nitrate reacts with 9-methylguanine (9-MeGua) in water to form solid complexes of stoicheiometry [HgMe(9-MeGuaH–1)], [HgMe(9-MeGua)][NO3], [HgMe(9-MeGua)][NO3]·H2O, and [(HgMe)2(9-MeGuaH–1)][NO3]. Comparison of i.r. spectra of the solid complexes and 1H n.m.r. spectra of [2H6]dimethyl sulphoxide-soluble (ionic) complexes with spectra of analogous guanosine (Guo) complexes indicates that complexes of 9-MeGua and Guo with similar stoicheiometry have the same mode of binding of HgIIMe to the purine ring. The spectra indicate that [HgMe(9-MeGuaH–1)] and [(HgMe)2(9-MeGuaH–1)][NO3] have HgIIMe bonded to N(1) and both N(1) and N(7), respectively, and the complexes [HgMe(9-MeGua)][NO3] and [HgMe(9-MeGua)][NO3]·H2O have HgIIMe bonded to N(7) with retention of a proton at N(1). Crystals of [HgMe(9-MeGua)][NO3] are monoclinic, with a= 4.196(1), b= 15.060(4), c= 18.288(5)Å, β= 90.17(2)°, Z= 4, and space group P21/c. The structure has been solved by conventional Patterson and Fourier methods and refined by least-squares techniques to R 0.061 for 1 152 reflections collected by diffractometer. The complex has HgIIMe bound to N(7) with Hg–C 2.06(2), Hg–N(7) 2.09(2)Å, and C–Hg–N(7) 175(1)°. Mercury interacts weakly with nearby nitrate ions, with Hg 0 2.75(2) and 2.99(2)Å; the purine ring is planar with the HgIIMe group slightly tilted from this plane, Hg being –0.168(1) and the carbon atom –0.411(25)Å from the plane.Keywords
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