Structures from Powders: Polynuclear Hg(II) Complexes Containing the Flexible Bisimidazolylmethane Ligand

Abstract

Several polynuclear Hg(II) complexes containing the flexible ditopic bisimidazolylmethane ligand (C(7)H(8)N(4), bim) have been prepared by reaction of equimolar quantities of mercury salts (acetate, cyanide, thiocyanate, chloride, and iodide) in EtOH or acetonitrile solution. Their crystal and molecular structures were retrieved from laboratory powder diffraction data, and their thermal properties were fully characterized, including the determination of the thermal expansion coefficients and the related strain tensor using thermodiffractometric methods. [Hg(bim)(CH(3)COO)(2)](2) consists of cyclic dimers with chelating acetates, while the [Hg(bim)X(2)](n) species (X = Cl, CN, SCN, and I) are one-dimensional polymers, with dangling X groups. A further complex of nominal Hg(2)(bim)Cl(2) formulation was also prepared, but the complexity and nonideality of its powder diffraction traces prevented the determination of its main structural features.

The structures of three Hg2X4L2macrocycles {X= Cl, Br and I, andL= 1,2-bis[4-(pyridin-3-yl)phenoxy]ethane} assembled from ether-bridged dipyridyl ligands

“…The Hg II centre lies in a highly distorted tetrahedral coordination environment defined by two N-atom donors from two pyridine rings and two coordinated X À anions (X = Cl, Br and I). The corresponding metal-ligand interatomic bond lengths and angles exhibit some differences in (I), (II) and (III) (Tables 1-3), but are comparable to the values of reported related Hg II complexes (Masciocchi et al, 2009). The diameters of the cavities in the middle of the macrocycles are 3.269 (7), 3.811 (7) and 2.770 (6) Å for the Cl, Br and I derivatives, respectively.…”

Structural and Thermodiffractometric Analysis of Coordination Polymers. Part II:1 Zinc and Cadmium Derivatives of the Bim ligand [Bim = Bis(1-imidazolyl)methane]

“…Whether this is a systematic or occasional stereochemical preference cannot be determined on the basis of our data alone, thus requiring a deeper structural and computational study and variation of the metals and overall stoichiometry and crystal packings. Work can be anticipated in the direction of understanding these aspects and has recently been communicated . To this goal, other derivatives with different counterions (iodides, nitrates, fluoroborates/phosphates, etc.)…”

Synthesis and Coordination Chemistry of Two N2-Donor Chelating Di(indazolyl)methane Ligands: Structural Characterization and Comparison of Their Metal Chelation Aptitudes

“…Our group have contributed in this field by reporting the bis(1,2,4-triazol-1-yl)alkane ligand CH 2 tz 2 , capable to coordinate to silver salts through the exodentate nitrogen atoms at the 4-positions of the triazole rings and yield bi- and three-dimensional polymers . We have also reported a bis(imidazol-1-yl)methane ligand able to afford novel polynuclear species based on Sn, Zn, Cd, and Hg …”