Coordination Chemistry of Methylmercury(II) with Flexible Tripod Ligands Containing Pyridyl and N-Methylimidazolyl Groups, Including the Crystal Structure of [Bis(N-methylimidazol-2-y1)(pyridin-2-yl)methanol-N,N',N']methylmercury(II) Nitrate, [MeHg(py(N-MeIm)2COH)]N03

The ligand is present as a tridentate, based on one strong Hg-N(1') (N-MeIm) bond, 2.12 (1) A, and two weak Hg...N interactions of 2.58 (1) A (N-MeIm) and 2.89 (1) A (py). As expected for the presence of weak Hg...N interactions, the C(1)-Hg-N(1') angle is not far removed from linearity, 170.5(7)O, with the Hg...N interactions opposite this angle. Although the weak interactions are well short of van der Waals contact (ca. 3.23 A), they are clearly weak since the mercury atom lies 1.589 A above the mean plane of the N-MeIm ring and 0.456 A above the mean plane of the pyridine ring, compared with 0.304 A for the strongly bound N-MeIm ring. Although the hydroxyl hydrogen could not be confidently located, a close contact is observed to the nitrate ion, 0-(H)...O(1) being 2.71 (1) A; no other 0...O distances <3.2 A were observed.