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Solution-state NMR and X-ray crystallography were used to investigate the complexation of Hg(II) by the tridentate ligand bis [(2-pyridyl)methyl]amine (BMPA). Mercury coordination compounds exhibiting rarely observed solutionstate NMR 1 H 199 Hg satellites were characterized. Temperature and concentration effects on solution-state NMR properties were investigated. The solution-state NMR were correlated with two solid-state structures. The distorted trigonal prismatic complex [Hg(BMPA) 2 ](ClO 4 ) 2 ‚0.5toluene (1) crystallizes in the triclinic space group P1 h with a ) 10.953(5) Å, b ) 12.812(5) Å, c ) 13.006(5) Å, R ) 67.50(3)°, β ) 82.74(3)°, γ ) 67.88(3)°, and Z ) 2. The Hg-N amine bonds are 2.404(4) and 2.350(4) Å and the Hg-N pyridyl bond lengths are similar, ranging from 2.352(4) to 2.557(5) Å. Solution NMR studies are consistent with rapid equilibrium between isomeric trigonal prismatic and facial octahedral forms of this complex. A twisting mechanism is proposed to mediate interconversion. The distorted square planar complex [Hg(BMPA)NCCH 3 ](ClO 4 ) 2 ( 7) crystallizes in the monoclinic space group P2 1 /c with a ) 12.987(2) Å, b ) 17.469(4) Å, c ) 8.886(2) Å, β ) 95.200(12)°, and Z ) 4. The Hg-N amine distance is 2.403 Å, the average Hg-N pyridyl distance is 2.23 Å, and the Hg-N nitrile distance is 2.229 Å. The BMPA ligand is bound to Hg(II) in a meridional fashion with a solvent molecule in the same plane and close associations to two axial perchlorates with Hg-O distances of 2.707(7) and 2.90(2) Å. Solution NMR studies support limited dynamics for a cation with similar interactions between BMPA and Hg(II).

Bright blue Cu(Dipica)(2)(BF(4))(2) crystallizes in the monoclinic space group P2(1)/n, with unit cell parameters a = 23.406(6) Å, b = 9.338(2) Å, c = 25.573(7) Å, beta = 95.39(2) degrees, and Z = 8. The structure was solved by conventional Patterson and Fourier methods. The R and R(w) values for 5282 observed reflections were 7.06% and 9.10% respectively. Two structurally different complex cations are present in the same unit cell, one hexacoordinate and the other pentacoordinate. In the hexacoordinate cation, the two tridentate bis(2'-picolyl)amine ligands are trans-facially coordinated with two pyridine nitrogens and the two secondary amine nitrogens situated on four positions in a plane [Cu-N(pyr) = 2.189(6), 2.146(6) Å; Cu-N(sat) = 2.207(6), 2.201(5) Å]. The remaining two pyridine nitrogens constitute the axis [Cu-N(pyr) = 2.035(5), 2.038(5) Å] in an equatorially expanded pseudooctahedral geometry. The pentacoordinate cation possesses a square-pyramidal configuration, the two secondary nitrogens being mutually cis, with one Dipica equatorially tridentate [Cu-N(pyr) = 2.044(5), 2.027(5) Å, Cu-N(sat) = 1.995(5) Å]. The other Dipica functions as a bidentate ligand, with one of the pyridine nitrogens occupying the equator [Cu-N(pyr) = 1.986(5) Å] and the aliphatic nitrogen defining the axial copper position [Cu-N(sat) = 2.344(5) Å]. Its second pyridine is uncoordinated but hydrogen-bonded to the coordinated NH of the other ligand. Solution properties offer no clear distinction between the two cation stereochemistries. The ternary chelates [Cu(Dipica)(Acac)]ClO(4) and [Cu(Dipica)(Bipy)](ClO(4))(2) are also described.

The reaction of K28Li5H7[P8W48O184].92H2O with early lanthanides under hydrothermal and conventional conditions yields novel structures of the molecular formula Ln4(H2O)28K6Li7[K subsetP8W48O184(H4W4O12)2Ln2(H2O)10] congruent with 57H2O, Ln = La (1), Ce (2, 2a), Pr (3), Nd (4), in which the central cavity of the precursor anion is occupied by lanthanide cations and H4W4O12 moieties. The new heteropolyanions were characterized by elemental analysis, infrared spectroscopy, 31P NMR, and X-ray crystallography. All of the crystals are monoclinic, space group C2/m, with lattice constants (A, Epsilon) a = 33.061(3), b = 30.986(3), c = 15.1649(13), beta = 103.607(2), (1); a = 33.0577(16), b = 31.0562(15), c = 15.2320(7), beta = 104.015(2), (2); a = 33.0577(16), b = 31.0562(15), c = 15.2320(7), beta = 104.015(2), (2a); a = 33.007(2), b = 31.060(2), c = 15.2129(10), beta = 104.0140(10), (3); a = 32.913(19), b = 31.155(18), c = 15.135(9), beta = 103.495(11), (4); and Z = 2.