Bite Distance Research Articles

The Crystal and Molecular Structure of Bis[1,2-Bis(Diphenylphosphino)Ethane] Dichlororuthenium(II)

Abstract The title compound, trans -[Ru(dppe)2Cl2], has I symmetry such that the chloride atoms are exactly trans. The coordination geometry is distorted octahedral owing, in part, to the restricted bite distance of the chelating dppe ligands. Important interatomic parameters are Ru-Cl 2.436(1), Ru-P(l), 2.389(1) Ru-P(2) 2.369(1) A and P(I)-Ru-P(2) 82.1(1)°. The compound crystallizes as a dichloromethane solvate in the monoclinic space group C2/c with unit cell dimensions a = 27.995(3), b = 13.85(1), c = 13.265(3) Å, β = 105.38(2)° and Z = 4. The structure was refined by a full-matrix least-squares procedure to final R = 0.038 for 3522 reflections with I ≥2.5σ(I).

ChemInform Abstract: Nickel‐Thiolate Chemistry Based on Chelating Ligands: Controlling the Course of Self‐Assembly Reactions via Ligand Bite Distances. Synthesis, Structures, and Properties of the Homoleptic Complexes (Ni3(SCH2C6H4CH2S)4)2‐, (Ni3(SCH2CH2S)4)2‐, and (Ni6(SCH2CH2CH2S)7)2‐.

AbstractThe reaction systems of NiCl2 and appropriate dithiolates in MeOH or acetone afford the title complexes (I) to (III).

N,N-Bis(2-hydroxyethyl)dithiocarbamato-S,S']dichlorogold(III)

[Au(C5H10NO2S2)Cl2], Mr = 448.1, space group P212121 (No. 19), a = 7.446 (2), b = 11.434 (4), c = 13.110 (3) A, V = 1116.2 (5) A3, Z = 4, Dm = 2.74 (5), Dx = 2.67 g cm 3, graphite-monochromatized Mo Ka radiation, lambda = 0.71069 A, mu = 144.0 cm-1, F(000) = 832.2, T = 298 K, R = 0.0432, wR = 0.0397 for 1974 unique reflections and 118 parameters. The gold atom is in a roughly squareplanar environment, distorted as a result of the small bite distance of the chelating dithiocarbamate ligand. Molecules pack in the crystal lattice such that there are linear...S...Au...S... chains parallel to the a axis.

Nickel-thiolate chemistry based on chelating ligands: controlling the course of self-assembly reactions via ligand bite distances. Synthesis, structures, and properties of the homoleptic complexes [Ni3(SCH2C6H4CH2S)4]2-, [Ni3(SCH2CH2S)4]2-, and [Ni6(SCH2CH2CH2S)7]2-

Preparation et etude radiocristallographique des complexes du nickel. Determination du groupe d'espace, affinement des parametres structuraux et structures moleculaires decrivant les differents isomeres

The crystal and molecular structure of [bis(diphenylphosphino)ethane]tricarbonyliron(0)

[Bis(diphenylphosphino)ethane]tricarbonyliron(0), Fe9(CO) 3-(Ph 2PCH 2CH 2-PPh 2), has been prepared by reducing FeCl 2 with metallic manganese under an atmosphere of CO in the presence of the diphosphine at room temperature in THF. The results of an X-ray diffraction study (room temperature, Mo- K α) are: P2 1/ n, a 12.260(6), b 15.890(7), c 14.227(6) Å, β 110.57(3)°, Z = 4, D c 1.378, D m 1.40 Mg m −3, R f ( 2957 413 ) = 0.0393. The iron is pentacoordinate, with a geometry intermediate between trigonal bipyramidal, with a phosphorus and a carbonyl apical, and square pyramidal with a carbonyl alpical. No significant differerences are observed between the FeP distances (av.2.224(2) Å) or between the FeCO distances (av. 1.770(5) Å). Comparison with the analogous bis(diphenylphosphino)methane derivative shows that the main differences in the coordination polyhedra arise from the difference in the P⋯P bite distance, which is 2.981(2) Å in the ethane derivative but only 2.650(3) Å in the methane derivative. The five-membered FePCCP chelate ring shows an unsymmetrical conformation, with one carbon atom tending to lie in the PFeP plane, the corresponding torsion about the FeP bond being almost zero (1.3(2)°). This kind of conformation is common for bis(diphenylphosphino)ethane chelating rings, suggesting a limited flexibility of that ring. The orientations of the phenyl groups are somewhat different from those in the corresponding bis(diphenylphosphino)methane complex.

The crystal and molecular structures of tris( O-ethylxanthato)-gallium(III) and indium(III)

The crystal structures of the title compounds, Ga(S 2COEt) 3 ( 1) and In(S 2COEt) 3 ( 2) have been determined by three dimensional X-ray diffraction methods. Both compounds crystallize in the trigonal space group R 3 - with Z = 6. Cell dimensions for ( 1) are a hex 15.065(1) and c hex 13.421(1) Å and for ( 2) 15.319(3) and 13.522(4) Å. Final R. and R w values 0.044 and 0.049 for ( 1) and 0.040 and 0.037 for ( 2) for 668 and 1153 statistically significant reflections respectively. The complexes are isostructural. The metal centres are in a distorted octahedral environment, the distortion arising from the restricted bite distance of the xanthate ligands. For each compound, each xanthate moiety chelates the metal atom with similar M-S bonds.

A structural study of metal binding of gem-diphosphonates, bone growth regulators

The crystal structures of sodium dichloromethylenediphosphonate tetrahydrate and calcium dichloromethylenediphosphonate pentahydrate, determined from single crystal X-ray diffractometer data, are compared with those of other bone growth regulators ( gem-diphosphonates and pyrophosphates). Na 2CCl 2(PO 3H) 2·4H 2O crystallizes triclinic (P 1 with Z = 2 formula units in a cell of constants: a = 11.27(2), b = 9.18(2), c = 5.91(1) Å, α = 88.57(2)°, β = 92.69(2)°, γ = 90.58(2)°; final R = 0.0359 and R w = 0.0453. The two crystallographically independent sodium ions both show octahedral coordination, but, while one of them is coordinated by two couples of oxygens from two chelating diphosphonate anions plus a chlorine atom and a water molecule, the other is surrounded by three oxygen atoms from three different diphosphonate anions and three water molecules. Two couples of these octahedra, sharing edges, form tetrameric clusters joined together by diphosphonate bridges. CaCCl 2(PO 3H) 2·5H 2O crystallizes orthorhombic ( Pnma) with unit cell dimensions: a = 10.278(2), b = 10.872(2), c = 11.899(2) Å, Z = 4; final R = 0.0389 and R w = 0.0449. Calcium is heptacoordinated by two oxygen atoms from a diphosphonate anion acting as a bidentate chelating agent, and five water molecules. The coordination polyhedron can be described as a distorted monocapped trigonal prism. Chlorine is not involved in coordination to the metal. In both compounds the diphosphonate anion interacts with the cation through deprotonated oxygen atoms and assumes a nearly eclipsed conformation which gives a O⋯O bite distance as short as 3.06–3.27 Å which seems particularly suitable for a bidentate chelation to calcium and is characteristic of this class of calcium phosphate metabolism regulators.

Effect of interligand repulsion of the molecular structures of bis-(dithiocarbamato) metal(II) complexes

A survey of the structural data on M(R 2 dtc) 2 , where R 2 dtc − is R 2 NCS 2 − and M II  Fe, Ni, Cu, Se, Te, Zn, Cd, Hg and Pb, has revealed that the ligand is essentially uncharged upon coordination to the metal ion and consequently should be considered as stereochemically rigid. A correlation between b (normalized bite distance) and r M (ionic radios of M) has been found and explained in terms of constant ∡SCS and variable r M . Both R(MS) and ∡SMS in this model are defined by the approach of M to the rigid CS 2 group. The interligand repulsion was found to depend heavily on the ligand's bite angle. The distortion of the molecular structures of M(R 2 dtc) 2 in the crystal state from the regular pseudotetrahedral or planar arrangements was explained as a means of reducing the interligand repulsion energy when an additional (intermolecular) contact is formed in the crystal due to crystal packing requirements.