A crystallographic and spectroscopic study of mercury(II) dithiocarbamate

1981 ◽  
Vol 59 (18) ◽  
pp. 2746-2749 ◽  
Author(s):  
Chung Chieh ◽  
Sing Kwen Cheung
Keyword(s):  
Mass Spectrum ◽  
Spectroscopic Study ◽  
Least Squares ◽  
Least Squares Method ◽  
Two Dimensional ◽  
Polymeric Compound ◽  
Full Matrix ◽  
Space Group ◽  
Polymeric Networks ◽  
Ir Bands

Ammonium dithiocarbamate, H2NCS2NH4, decomposes easily but the anion forms a stable mercury(II) complex, the crystals of which are orthorhombic with a = 7.851(3), b = 17.565(7), c = 12.051(3) Å, and space group Pbca. The structure was solved by the Patterson method and refined by the full-matrix least-squares method to an R of 0.038 for 781 reflections. The structure consists of layers of two-dimensional polymeric networks. The dimeric subunits in the layer containing two each of mutually connected Hg atoms and dithiocarbamates are further linked by other bridging dithiocarbamates forming a sheet-like structure. Each Hg atom bonds to four S atoms from four separate dithiocarbamates with Hg—S distances of 2.499(4), 2.508(4), 2.533(4), and 2.629(4) Å. The ir bands observed were: ν(NH2), 3320, 3220, 3125; δ(NH2), 1600; ν(C—N), 1395; ρr(NH2), 1172; and v(C—S), 840 cm−1. The mass spectrum of this polymeric compound gave peaks corresponding to Hg, S2, CNH2, HNCS, S, CS2, S5, S4, S3, and S8 in the order of their intensities.

Verfeinerung der Kristallstruktur eines basaltischen Magnesio-Hastingsites

1981 ◽  
Vol 156 (3-4) ◽  
Author(s):  
E. M. Walitzi ◽  
F. Walter
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Least Squares Method ◽  
Three Dimensional ◽  
Full Matrix ◽  
Space Group ◽  
X Ray

AbstractThe crystal structure of the basaltic clino-amphibole magnesio-hastingsite was refined from three-dimensional photographic X-ray data by a full matrix least-squares method in the space group

Structural studies and redox reactivity of platinum complexes of 14-membered tetraaza macrocyclic ligands

1997 ◽  
Vol 75 (10) ◽  
pp. 1363-1374 ◽  
Author(s):  
S. Chandrasekhar ◽  
W.L. Waltz ◽  
J.W. Quail ◽  
L. Prasad
Keyword(s):  
Cyclic Voltammetry ◽  
Least Squares ◽  
Mass Spectroscopy ◽  
Least Squares Method ◽  
Direct Methods ◽  
Complex Ions ◽  
Orthorhombic Space Group ◽  
Full Matrix ◽  
Space Group ◽  
Electrospray Mass Spectroscopy

Pt(II) monomeric complexes of N-containing macrocycles have been synthesized and characterized in solution by 1H NMR, 13C NMR, and electrospray mass spectroscopy (ESMS) and in the solid state by X-ray crystallography. Crystals of [Pt(cyclam)](ClO4)2 (cyclam = 1,4,8,11-tetraazacyclotetradecane) are orthorhombic, space group P21cn, a = 9.596 (3), b = 14.595 (21), c = 24.8782 (20) Å, Z = 8. The structure was solved by direct methods and was refined by the full-matrix least-squares method to R = 0.073 and Rw = 0.093 for 2976 reflections with I ≥ 2.5σ(I). Crystals of [Pt(N-methylcyclam)]-(ClO4)2•CH3CN (N-methylcyclam = 1,4,8,11 tetramethyl-1,4,8,11-tetraazacyclotetradecane = NMe4cyclam = tmc) are orthorhombic, space group Pmcn, a = 9.574 (8), b = 14.116 (5), c = 17.5456 (15) Å, Z = 4. The structure was solved by direct methods and was refined by the full-matrix least-squares method to R = 0.067 and Rw = 0.091 for 2216 reflections with I ≥ 2.5σ(I). Cyclic voltammetry and EPR spectroscopy have been used to study the redox reactivity of the Pt(II)and Pt(IV) complex ions. The solution chemistry of Pt(IV) complexes based on cyclam and N-methylcyclam was investigated by electrospray mass spectrometry. Electrospray mass spectral evidence has been obtained for the formation of [Pt(III)(cyclam)Cl2]+ and [Pt(III)(N-methylcyclam)Cl2]+ ions. Keywords: Pt macrocycles, crystallography, electrospray mass spectroscopy, cyclic voltammetry, Pt(III) complex ions, tetraaza macrocycles.

A Polymeric Silver Lutidine Tetrafluoroborate Compound, [Ag( lut )2(µ4-BF4)]N, With Weak μ4-Tetrafluoroborate Coordination to Silver

1987 ◽  
Vol 40 (4) ◽  
pp. 761 ◽  
Author(s):  
E Horn ◽  
MR Snow ◽  
ERT Tiekink
Keyword(s):  
Least Squares ◽  
Silver Atom ◽  
Polymeric Compound ◽  
Dichloromethane Solution ◽  
Full Matrix ◽  
Polymeric Structure ◽  
Space Group

Silver tetrafluoroborate reacts with 2,6-lutidine ( lut ), in dichloromethane solution, to form the polymeric compound [Ag( lut )2(�4-BF4)]n. The polymeric structure is comprised of [Ag( lut )2]+ units each of which is connected by two bidentate links to two [�4-BF4]-anions. The compound crystallizes in the tetragonal space group I41/acd with a 15 .O69(4) and c l4.391(3) �. A full-matrix least-squares refinement on 271 reflections, with I ≥ 2.5σ(I), converged with final R 0.027 and Rw 0.025. The complex exhibits an unusual splitting of the BF4 v3 mode into six peaks which has been interpreted as three doublets arising from coupling between the BF4- anions attached to the same silver atom.

Crystal Structures of K2MgCl4 and Cs2MgCl4

1975 ◽  
Vol 53 (1) ◽  
pp. 114-118 ◽  
Author(s):  
Cyril S. Gibbons ◽  
Vincent C. Reinsborough ◽  
W. Alexander Whitla
Keyword(s):  
Least Squares ◽  
Supporting Evidence ◽  
Two Dimensional ◽  
Alkali Chloride ◽  
Full Matrix ◽  
Space Group ◽  
X Ray ◽  
Chloride Melts ◽  
Group I ◽  
Complex Ion

Supporting evidence for complex ion formation in MgCl2 alkali chloride melts was sought from a single crystal X-ray analysis of the title compounds. Crystals of K2MgCl4 are tetragonal, a = 4.94, c = 15.58 Å, Z = 2, space group I 4/mmm. The compound is isostructural with K2NiF4, and was determined with MoK α diffractometer data and refined by full-matrix least-squares to R = 0.046 for 180 reflections.Crystals of Cs2MgCl4 are orthorhombic, a = 9.777, b = 7.514, c = 13.234 Å,Z = 4, space group Pnma. The compound is isostructural with β-K2SO4, and was determined with MoKα diffractometer data and refined by full-matrix least-squares to R = 0.074 for 1084 reflections. The K2MgCl4 structure contains an infinite two-dimensional array of MgCl6 octahedra sharing edges. The Cs2MgCl4 structure contains discrete MgCl42− anions which likely continue to exist in the melt close to the melting point.

The stuctural nature of a Bender's salt: an X-ray study of potassium O-methyl monothiocarbonate

1975 ◽  
Vol 28 (6) ◽  
pp. 1195 ◽  
Author(s):  
BF Hoskins ◽  
CN Murphy
Keyword(s):  
Single Crystal ◽  
Least Squares ◽  
Least Squares Method ◽  
Potassium Ions ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
Space Group ◽  
X Ray ◽  
Bond Lengths

The structure of the Bender's salt, potassium O-methyl monothiocarbonate (C2H3O2S-K+), has been determined by single crystal X- ray diffraction methods. The crystals are monoclinic of space group P21/c with a 6.7295(5), b 6.9438(5), c 11.1520(10) Ǻ, β 110.93(2)� and Z 4. The structure was solved using a direct phasing programme in conjunction with the Patterson synthesis and refined by a full-matrix least-squares method to R 0.041 for the 788 independent statistically significant reflections collected by counter methods. The crystals are composed of potassium ions and O-methyl monothiocarbonate anions. Each anion is essentially planar with bond lengths and angles having values very similar to those of related systems.

Studies in aryltin chemistry. Part 6. Crystal and molecular structures of tetra(p-methylsulphonylphenyl)tin(IV) and tetra(p-methylsulphinylphenyl)tin(IV) monohydrate

1990 ◽  
Vol 68 (8) ◽  
pp. 1277-1282 ◽  
Author(s):  
Ivor Wharf ◽  
Michel G. Simard ◽  
Henry Lamparski
Keyword(s):  
Least Squares ◽  
Crystal Structures ◽  
Direct Method ◽  
Molecular Structures ◽  
Water Molecules ◽  
Monoclinic Space Group ◽  
Molecular Symmetry ◽  
Asymmetric Unit ◽  
Full Matrix ◽  
Space Group

Tetrakis(p-methylsulphonylphenyl)tin(IV) and tetrakis(p-methylsulphinylphenyl)tin(IV) n-hydrate have been prepared and their spectra (ir 1350–400 cm−1; nmr, 1H, 13C, 119Sn) and X-ray crystal structures are reported. The first compound is monoclinic, space group C2/c, Z = 4, with a = 21.589(6), b = 6.207(3), c = 22.861(11) Å, β = 93.80(3)° (22 °C); the structure was solved by the direct method and refined by full-matrix least squares calculations to R = 0.043 for 2755 observed reflections. It has 2 molecular symmetry with the methyl group and one oxygen atom completely disordered in both CH3S(O2) groups in the asymmetric unit. The second compound is tetragonal, space group P42/n, Z = 2, with a = b = 15.408(6), c = 6.379(2) Å (−100 °C); the structure was solved by the Patterson method and refined by full-matrix least squares calculations to R = 0.060 for 1209 observed reflections. It has [Formula: see text] molecular symmetry with the whole asymmetric unit disordered. Water molecules occupy positions on parallel 42 axes but molecular packing requirements prevent all sites having 100% occupancy giving n ~ 1 for the hydrate. Keywords: Tetra-aryltins, crystal structures, sulphone, sulphoxide, hydrogen-bonding.

A modified tangent-gas approximation for two-dimensional steady flow

1958 ◽  
Vol 4 (6) ◽  
pp. 600-606 ◽  
Author(s):  
G. Power ◽  
P. Smith
Keyword(s):  
Least Squares ◽  
Steady Flow ◽  
Variational Approach ◽  
Least Squares Method ◽  
Two Dimensional ◽  
Subsonic Flows ◽  
Von Karman ◽  
Straight Line ◽  
Volume Relationship ◽  
Pressure Volume Relationship

A set of two-dimensional subsonic flows past certain cylinders is obtained using hodograph methods, in which the true pressure-volume relationship is replaced by various straight-line approximations. It is found that the approximation obtained by a least-squares method possibly gives best results. Comparison is made with values obtained by using the von Kármán-Tsien approximation and also with results obtained by the variational approach of Lush & Cherry (1956).

Structure of the Tris(diallyldithiocarbamate)cobalt(III) Complex

1992 ◽  
Vol 57 (2) ◽  
pp. 332-338 ◽  
Author(s):  
Eleonóra Kellö ◽  
Jan Lokaj ◽  
Viktor Vrábel
Keyword(s):  
Least Squares ◽  
Metal Atom ◽  
Least Squares Method ◽  
Heavy Atom ◽  
Distorted Octahedron ◽  
Monoclinic System ◽  
Space Group ◽  
Twofold Axis ◽  
Diagonal Approximation ◽  
Heavy Atom Method

The structure of [Co{S2CN(CH2-CH=CH2)2}3] was determined by the heavy atom method, all nonhydrogen atoms being refined by anisotropic diagonal approximation using the least squares method to the value of R= 0.067 for 1 024 reflections with I ≥ 1.96σ(I). The substance is isostructural with [Fe{S2CN(CH2-CH=CH2)2}3], crystallizes in the monoclinic system, space group C2/c, lattice parameters a = 1.8763(9), b = 1.0209(5), c = 1.5402(7) nm, β = 106.18(4)°, Z = 4. Cobalt is coordinated by 3 dithiocarbamate ligands in the bidentate way, the average Co-S lenght is 0.2267(2) nm. The metal atom and two ligand atoms are located on the twofold axis. The CoS6 polyhedron is a trigonally distorted octahedron.

Structural studies of organoboron compounds. XX.(Salicylaldoximato-O,N)diphenylboron

1984 ◽  
Vol 62 (7) ◽  
pp. 1363-1368 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Hydrogen Bonds ◽  
Least Squares ◽  
Chelate Ring ◽  
Direct Methods ◽  
Structural Studies ◽  
Organoboron Compounds ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
Phenolic Oxygen

Crystals of (salicylaldoximato-O,N)diphenylboron are triclinic, a = 10.125(2), b = 10.797(1), c = 14.760(2) Å, α = 89.05(1), β = 86.98(1), γ = 83.18(1)°, Z = 4, space group [Formula: see text]. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.040 and Rw = 0.048 for4145 reflections with I ≥ 3σ(I). The structure consists of two crystallographically independent, but essentially identical, molecules linked by strong [Formula: see text] hydrogen bonds to form continuous spirals along the a axis. The Ph2B moiety is chelated by the phenolic oxygen and oxime nitrogen atoms of the ligand resulting in the formation of a non-planar six-membered chelate ring. Important libration-corrected mean bond lengths are O—B = 1.516(1), N—B = 1.609(2), and C—B = 1.613(2) Å.

Coordinated fluoride in rhenium(I) carbonyl complexes

1984 ◽  
Vol 37 (1) ◽  
pp. 35 ◽  
Author(s):  
E Horn ◽  
MR Snow
Keyword(s):  
Hydrogen Bonding ◽  
Least Squares ◽  
Mass Spectra ◽  
Structural Data ◽  
Monoclinic Space Group ◽  
Carbonyl Complexes ◽  
Full Matrix ◽  
Space Group ◽  
Corrected Data ◽  
R Value

Bromide abstraction from the complexes Re(CO)3L2Br (where L = SbPh3 and L2 = bpy, dpe, tmen)* by AgF2H gives the corresponding fluoro compounds Re(CO)3L2F. Mass spectra and structural data show that the fluoride in these complexes is coordinated to the metal. The structures of Re(CO)3(tmen)F and [Re(CO)3(tmen)F]2H.HOBF3 are reported here. Crystals of Re(CO)3(tmen)F are monoclinic, space group P21/c, with a 8.202(2), b 13.115(9), c 12.048(4) � and β 102 24(3)�. A full-matrix least-squares refinement by using the absorption corrected data gave a conventional R value of 0.041. [Re(CO)3(tmen)F]2H.HOBF3 also crystallizes in the space group P21/c. The lattice parameters are: a 17.495(2), b 10.772(2), c 15.447(1) � and β ( 101.409(8)�. The final R value of a blocked least-squares calculation converged at 0.061. In these two complexes the simple Re-F distance is 2.040(4) �, in Re(CO)3(tmen)F. The Re-F distance is increased to 2.236(10)�, as a result of hydrogen bonding between the fluoride and HOBF3 in the latter compound.

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