Preparation of Mercury(II) Complexes of Tris[(2-pyridyl)methyl]amine and Characterization by X-ray Crystallography and NMR Spectroscopy

The complexation of Hg(II) by the tripodal ligand tris[(2-pyridyl)methyl]amine (TMPA) was investigated by solution state NMR and X-ray crystallography. Mercury coordination compounds exhibiting rarely observed room-temperature solution state NMR 1 H 199 Hg and 13 C 199 Hg satellites were characterized. Solvent, counterion, temperature, and concentration effects on solution state NMR properties were investigated. The solution state NMR were correlated with two solid state structures. The eight-coordinate complex [Hg(TMPA) 2 ](ClO 4 ) 2 ( 1 ) crystallizes in the monoclinic space group P 2 1 / n with a = 9.735(10) Å, b = 10.963(2) Å, c = 18.553(34) Å, β = 103.81(12)°, and Z = 2. The mercury is at the inversion center of a bicapped trigonal antiprism. The Hg−N amine distance is 2.560(3) Å, and the average Hg−N pyridyl distance is 2.58(2) Å. The five-coordinate complex [Hg(TMPA)Cl] 2 (HgCl 4 ) ( 2 ) crystallizes in the triclinic space group P 1̄ with a = 11.887(2) Å, b = 13.260(2) Å, c = 15.278(4) Å, α = 112.27(2)°, β = 109.39(2)°, γ = 90.670(10)°, and Z = 2. The two crystallographically unique cations are distorted trigonal bipyramids. The average Hg−Cl distance is 2.355(12) Å, the average Hg−N amine distance is 2.43(2) Å, and the average Hg−N pyridyl distance is 2.40(5) Å.