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SYNTHESIS AND STRUCTURE OF METHYLMERCURY(II) COMPLEXES OF 9-METHYLGUANINE, INCLUDING THE X-RAY STRUCTURAL-ANALYSIS OF "(9-METHYLGUANINE)-METHYLMERCURY(II) NITRATE

Version 2 2025-06-13, 03:25
Version 1 2023-05-25, 22:56
journal contribution
posted on 2025-06-13, 03:25 authored by Allan CantyAllan Canty, RS TOBIAS, N CHAICHIT, BM GATEHOUSE

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 ⋯ O 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.

History

Publication title

Journal of the Chemical Society, Dalton Transactions

Volume

0

Issue

9

Pagination

1693-1697:5

ISSN

1477-9226

Department/School

Chemistry

Publisher

ROYAL SOC CHEMISTRY

Publication status

  • Published

Rights statement

Copyright 1980 Royal Society of Chemistry

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