Structure of μ₃-(adeninato-N ³,N ⁷,N ⁹)-tris[methylmercury(II)] nitrate

Abstract

CsH13Hg3NTO6, M r = 905.01, monoclinic, space group C2/c, a = 20.939 (7), b = 23.976 (3), c = 7.073 (6) A, fl = 94.29 (4) °, Z = 8, dc= 3.394 Mg m -3. The structure was refined on 1603 independent nonzero reflections to an R factor of 0-045. Ring sites N(3), N(7) and N(9) of a deprotonated adenine ligand are occupied by linearly coordinated methylmercury groups as observed in the corresponding perchlorate salt. Layers parallel to the ac plane contain parallel [adeninato(CH3Hg)3] 2+ cations bridged by nitrate ions interacting with the metal atoms. The remaining nitrate ions form strong hydrogen bonds with amino groups in the interlayer region.

Reactions of the methylmercury cation with xanthine and crystal structures of μ-(xanthinato-N3,N7,N9)tris(methylmercury(II)) nitrate and μ-(xanthinato-N1,N3,N7,N9)tetrakis(methylmercury(II)) nitrate

“…The Hg-C and Hg-N distances (ave. 2.07(3) A in both cases) are normal (1,20) and the linear two-coordination commonly found for Hg(I1) is again found. In one case, significant departure from linearity is observed (N(9)-Hg(9)-C(9) = 174.2(8)"), but distortions of this magnitude are often noted, presumably in response to packing constraints.…”

“…In one case, significant departure from linearity is observed (N(9)-Hg(9)-C(9) = 174.2(8)"), but distortions of this magnitude are often noted, presumably in response to packing constraints. The presence of two CH3Hgt groups on adjacent N(3) and N(9) sites has previously been found for several adenine complexes, namely the nitrate and perchlorate salts of [(CH,Hg),(Ade-H:lIZt, a cation showing the CH3Hgt similarly distributed on N(3), N(7), and N(9) of the purine (20). The C-N-Hg angles at both N(3) and N(9) are unequal (1 l7(1)" vs. 13 l(1)" at N(3), 124(1)" vs. 13 l(1)" at N(9)) and the two CH,Hg groups have slipped away from the xanthine plane in opposite directions.…”

“…Binding of the imidazolic CH3Hg+ group at N(7) in compound 2 is proposed by analogy, although coordination to N(9) or tautomeric exchange between N(7) and N(9) in solution cannot be ruled out, since position N(3) is occupied by a CH,Hg+ unit in this case, and simultaneous CH3Hg+ binding to N(3) and N(9) has been observed (ref. 20, and X-ray work below). I3C nmr could provide more information, but the spectrum could not be obtained because of the low solubility of the complex in DMSO.…”

Structure du perchlorate de μ-(méthyl-9 adéninato-N1,N6)-bis[méthylmercure(II)]

“…Les contributionsf' etf" ~ la dispersion anomale pour Hg et C1 sont tir~es de Cromer (1965). La liste des programmes utilisSs a dSj~, 8t8 prSsentSe (Hubert & Beauchamp, 1980a). (Prizant et al, 1982).…”

Structure of μ-(9-methyladeninato-μ-N6)-bis[methyl-mercury(II)], C8H11Hg2N5

“…Anomalousdispersion correction for Hg from Cromer (1965). The computer programs used are listed elsewhere (Hubert & Beauchamp, 1980). Table 1.…”