Solution-state NMR and X-ray crystallography were used to investigate the complexation of HgCl2 by the potentially tetradentate ligand tris [(6-methyl-2-pyridyl)methyl]amine (TLA) in acetonitrile. A change in the ligand conformation as a function of the metal-to-ligand ratio could be indirectly monitored through large changes in (3)J((HHg)-H-1-Hg-199) to the methylene protons at -40 degrees C. The solution-state NMR were correlated with two solid-state structures. The five-coordinate complex [Hg(TLA)Cl-2] (I) crystallizes in the triclinic space group P (1) over bar with a = 8.663(3) Angstrom, b 11.539(4) Angstrom, c = 13.739(3) Angstrom, alpha 80.81(2)degrees, beta = 75.84(2)degrees, gamma 80.97(3)degrees, and Z = 2. The Hg-N-amine distance of 2.505(7) Angstrom for the tridentate ligand is the same as the average Hg-N-lutidyl distance of 2.50(3) Angstrom for the two bound lutidyl nitrogens. [Hg(TLA)Cl](2)(Hg2Cl6) (2) also crystallizes in P (1) over bar with a = 10.606(2) Angstrom, b = 15.104(3) Angstrom, c 17.785(4) Angstrom, alpha = 67.46(3)degrees, beta = 83.52(3)degrees, gamma = 80.29(3)degrees, and Z = 2. The ligand is tetradentate in the two crystallographically unique cations which are arranged in a dimer-like orientation. The average Hg-CI distance is 2.37 (1) Angstrom, and the average interionic Hg-Cl distance is 3.51(1) Angstrom. The Hg-N-lutidyl distances are of two types : two have an average distance of 2.36(3) Angstrom, nearly the same as the Hg-N-amine distance of 2.35(2) Angstrom. The remaining four N-lutidyl distances have an average distance of 2.56(5) Angstrom.