Crystal structure of a dimeric 1-methylcytosine mercuric chloride complex

Abstract

Di-μ-chloro-bis[chloro(1-methylcytosine-O,N3)mercury(II)] belongs to space group P21/c with cell dimensions a = 9.932(2), b = 14.051(3), c = 9.198(2) Å, and β = 135.41(2)°. The structure was solved by the heavy-atom method and refined to an R factor of 0.027 for 1271 independent reflections. The crystal is composed of centrosymmetric dimeric molecules in which two mercury atoms are attached by a pair of symmetrical chlorine bridges. The 1-methylcytosine ligand is bidentate via N(3) and O(2). The metal atom has a (2 + 3) coordination with a very distorted trigonal bipyramid geometry. A chlorine atom at 2.322(3) Å and ring nitrogen N(3) at 2.17(1) Å form strong axial bonds with mercury. Two bridging chlorine atoms at 2.719(2) and 2.745(3) Å, and carbonyl oxygen O(2) at 2.84(1) Å form weaker equatorial bonds. The amino group is hydrogen-bonded to a bridging chlorine of the same molecule [Formula: see text] and a carbonyl oxygen of a neighboring molecule [Formula: see text]