Michael J. Albright

Studies on main group metal-transition-metal bonded compounds.6. The structure of η5C5H5(CO)3MoHgCl

The crystal structure of η 5 -C 5 H 5 (CO) 3 MoHgCl has been determined from single crystal X-ray data collected by counter methods. The compound crystallizes in space group P42 1 c with 8 molecules per unit cell and lattice constants of a  12.014(4), c  15.322(7). Full-matrix least squares refinement gave discrepancy factors R 1  0.058 and R 2  0.062 for 854 data with 1 3σ (1). The critical bond lengths and angles are MoHg  2.673(3)A, HgCl  2.437(8)A, and MoHgCl  160.0(2)°. Crystals of η 5 C 5 H 5 (CO) 3 WHgBr were shown to be isomorphous with lattice constants of a  12.068(4)A and c  15.643(7)A.

Metal-silicon bonded compounds XVII. A 199Hg Ft NMR study of some silylmercury derivatives and selected organomercury compounds☆

Abstract The 199Hg NMR spectra were determined for a series of silylmercury derivatives of the form Hg(SiRR′R″)2 by Fourier transform techniques. A linear correlation between the chemical shift, δ(199Hg), and the sum of the orbital electronegativities on silicon is reported for symmetric species. The chemical shifts are also linearly dependent on the lowest energy UV absorption maximum for these derivatives. These observations are discussed in terms of the current theories dealing with chemical shifts of heavy nuclei. The 199Hg-29Si coupling constants have been tabulated with evindence presented indicating that these are dominated by the Fermi contact interaction. It has been found that these are dependent on the same energy terms as observed for the chemical shift. Limited studies are reported on solvent, concentration, and temperature dependence of the δ(199Hg) for these derivatives.

Intramolecular metal—double bond interactions : VIII. A 13C NMR investigation of metal—alkene compounds

Abstract A 13 C NMR investigation of terminally substituted normal butenes, pentenes, and hexenes is reported. These studies include data on one, two, and three bond 13 C— 199 Hg coupling constants as well as on changes in the chemical shifts of all carbons as a function of the electronegativity of the substituent. Attempts to correlate the chemical shifts of the olefinic carbons with metal—double bond interactions were inconclusive; however, large effects were observed on the chemical shifts of the olefinic carbon atoms when dipentenylzinc was complexed with 2,2′-bipyridyl. These shifts are attributed to the large anisotropic magnetic field associated with the aromatic rings and the proximity of the olefinic carbon atoms to these rings.

Studies on main group metal-transition-metal bonded compounds 7. A 199Hg NMR study of home group of some group VI trasition-metal mercury compounds

Abstract A 199Hg Fourier Tranformation NMR study has been carried out on Hg[M(CO)3C5H5]2 (M = Cr, Mo, W), [C5H5(CO)3M]HgCl, and [C5H5(CO)3W]HgX (X = Cl, Br, I, SCN). The 199Hg chemical shifts are −80, +115 and −348 ppm respectively for the symmetrical compounds, −542, −617, and −997 ppm for the chloride and −1200, −1529 and −924 ppm for the Br, I, SCN-tungsten derivatives respectively. The 199Hg chemical shifts for several other mercury derivatives are reported for comparison. All chemical shifts are relative to 90% HgMe2/10% internal lock C6F6 with positive values indicating decreasing shielding. The J199Hg-183W values are 151, 706, 690, 630 and 684 Hz for the symmetrical compound and the Cl, Br, I and SCN derivatives respectively. The factors which may influence these parameters are discussed briefley.

Metal-silicon bonded compounds : X. The molecular structures of 2,2,4,4,6,6,8,8-octamethyl-2,4,6,8-tetrasila-1,5-mercuracyclooctane and bis(triphenylsilyl) mercury

Abstract The crystal and molecular structure determinations of 2,2,4,4,6,6,8,8-octamethyl-2,4,6,8-tetrasila-1,5-mercuracyclooctane. Hg 2 Si 4 C 10 H 28 (I) and of bis-(triphenylsilyl)mercury, (Ph 3 Si) 2 Hg (II), are reported. The structures have been determined from single-crystal X-ray data collected by counter methods. Both molecules crystalize in the space group P 1 with one centrosymmetric molecule per unit cell. Each structure contains linear SiHgSi groups, with mercury-silicon distances of 2.490(4) A in I and 2.503(4) A II. In compound I the SiHgSi groups are linked by methylene bridges which form an eight member ring in the chair conformation. The cell dimensions for compound I are a 6.277(2), b 8.408(2), c 9.274(4) A, α 92.75(3), β 94.79(3) and γ 100.14(2)° with R 1 0.062 for 1809 observed reflections. The cell dimensions for compound II are a 9.999(4), b 11.727(8), c 7.654(5) A, α 99.87(5), β 115.35(4) and γ 98.41(4)°, with R 1 0.081 for 2394 observed reflections.