Structural Chemistry of the Platinum Group-Metals: MCl2(bpy) (M = Pd, Pt, bpy = 2,2′-Bipyridine)

1992 ◽  
Vol 45 (2) ◽  
pp. 417 ◽  
Author(s):  
AJ Canty ◽  
BW Skelton ◽  
PR Traill ◽  
AH White
Keyword(s):  
Least Squares ◽  
Structure Determination ◽  
Structural Chemistry ◽  
Platinum Group Metals ◽  
Full Matrix ◽  
X Ray ◽  
Planar Molecules ◽  
Platinum Group

A singlecrystal X-ray structure determination of (2,2′-bipyridine)dichloropalladium(II), iso- morphous with the 'yellow' form of the platinum(II) analogue, has been carried out. Crystals are orthorhombic, Pbca, a 18.144(5), b 15.952(5), c 7.494(2) A, Z 8, 1113 diffractometer reflections being refined by full matrix least squares to a residual of 0.052. The planar molecules of PdCl2(bpy) are stacked into columns along the c direction, at a separation of c/2, neighbouring molecules in the stacks being related by glide planes with Pd…Pd separations of 4.587(2) A.

Structural Chemistry of the Platinum Group Metals: the Palladacyclopentane Complex (Butane-1,4-diyl)(N,N,N',N'-tetramethylethylenediamine)palladium(II)

1994 ◽  
Vol 47 (11) ◽  
pp. 2119 ◽  
Author(s):  
AJ Canty ◽  
BW Skelton ◽  
PR Traill ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Structure Determination ◽  
Structural Chemistry ◽  
Platinum Group Metals ◽  
X Ray ◽  
Planar Complex ◽  
Square Planar ◽  
Platinum Group

A single-crystal X-ray structure determination of the reagent (butane-1,4-diyl)(N,N,N′,N′- tetramethylethylenediamine)palladium(II) has shown that crystals are orthorhombic, Pbca, a 15.832(3), b 14.128(9), c 11.451(3) Ǻ, Z 8. The square planar complex has puckered PdCH2CH2CH2CH2 and PdNMe2CH2CH2NMe2 rings in which the outer carbon atoms deviate by c. �0.35 Ǻ from the 'PdC2N2' mean plane.

Crystal Structure of N,N,N′,N′-Tetrakis-(trimethylsilyl)ethane-1,2-diamine

1985 ◽  
Vol 38 (11) ◽  
pp. 1729 ◽  
Author(s):  
LM Engelhardt ◽  
CL Raston ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Structure Determination ◽  
Title Compound ◽  
Full Matrix ◽  
X Ray ◽  
Methylene Groups

The title compound, [{(Me3Si)2NCH2}2], has been structurally characterized by a single-crystal X-ray structure determination at 130 K, being refined by full-matrix least-squares to a residual of 0.057 for 1244 'observed' reflections. Crystals are monoclinic, C2/c, a 21.00(2), b 9.089(8), c 11.744(9) Ǻ, β 92.31(7)°, Z 4. Molecules lie on inversion centres, but with some disorder of the methylene groups. Si -N are 1.735 Ǻ, and N-CH2 1.53(1) for the major fragment (70%). The nitrogen in the major fragment is approximately trigonal planar; Si -N- Si 124.6(3)°, Si -N-C 117.5(4), 115.5(4)°.

Complexes of the methyl tris(3,5-dimethylpyrazol-1-yl) gallate ligand, MeGa(N2C5H7)3−, and its hydroxy derivative, MeGa(N2C5H7)2(OH)−. Crystal and molecular structure of [MeGa(N2C5H7)2(OH)]Mo(CO)2(η3-C4H7)

1979 ◽  
Vol 57 (2) ◽  
pp. 139-146 ◽  
Author(s):  
Kenneth R. Breakell ◽  
Steven J. Rettig ◽  
Alan Storr ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Least Squares ◽  
Structure Determination ◽  
Carbonyl Compounds ◽  
Crystal And Molecular Structure ◽  
Hydroxy Derivative ◽  
Full Matrix ◽  
Sterically Demanding

The synthesis and coordinating properties of the tridentate tris-chelating ligand, methyl tris(3,5-dimethylpyrazol-1-yl)gallate, MeGa(N2C5H7)3−, are described. Carbonyl and nitrosyl carbonyl compounds of manganese, molybdenum, and tungsten incorporating this ligand are detailed. The ready conversion of the above ligand to the less sterically demanding tris-chelating 'hydroxy' ligand [MeGa(N2C5H7)2(OH)]− occurs in attempted syntheses of the 'η3-allyl' complexes, [MeGa(N2C5H7)3]M(CO)2'η3-allyl', (where M = Mo or W, 'η3-allyl' = η3-C3H5, η3-C4H7). The tridentate chelating nature of this 'hydroxy' ligand is conclusively demonstrated in the crystal structure determination of the complex, [MeGa(N2C5H7)2(OH)]-Mo(CO)2(η3-C4H7). Crystals of this complex are monoclinic, a = 14.020(4), b = 10.110(1), c = 15.493(7) Å, β = 111.58(3)°, Z = 4, space group P21/n. The structure was solved by Patterson and Fourier syntheses and was refined by full-matrix least-squares procedures to a final R of 0.40 and Rw of 0.043 for 3374 reflections with I ≥ 3.5σ(I).

Heterocyclic Compounds from Alloxan and Amines. XIV. Structure of Even-Electron Products Derived from Free-Radical Betaines

1979 ◽  
Vol 32 (9) ◽  
pp. 1943 ◽  
Author(s):  
JW Clark-Lewis ◽  
MR Taylor ◽  
J Westphalen
Keyword(s):  
Free Radical ◽  
Least Squares ◽  
Heterocyclic Compounds ◽  
Full Matrix ◽  
X Ray ◽  
Dimer Structure

X-ray crystallographic determination of structure has shown that the even-electron product obtained thermally from 5-(10-phenyl-5,10-dihydro-5-phenazinioyl)-1,3-dimethyl-4-barbiturate (1) (e.g. by heating in benzene) has the structure 1,3-dimethy1-5-(10-phenyl-2,10-dihydrophenazin-2-ylidene)- hexahydropyrimidine-2,4,6-trione (3) instead of the previously supposed dehydro dimer structure (2). Crystals of compound (3) are triclinic, Pī, a 11�014(3), b 9�343(3), c 10�927(3) �, α 110�47(4), β 64�99(4), γ 101�47(4)�, Z = 2. Full-matrix least-squares refinement gave R 0�09. The rearrangement that occurs in the conversion of the free-radical betaine (1) into the trione (3) is a novel type of N to p-aromatic rearrangement which presumably entails dissociation followed by recombination and oxidation.

1,2,3,4-Tetra-O-acetyl-β-D-arabinopyranose: A Neutron Refinement and Comparison with X-Ray Refinement

2002 ◽  
Vol 55 (2) ◽  
pp. 167 ◽  
Author(s):  
V. J. James ◽  
F. H. Moore ◽  
J. D. Stevens
Keyword(s):  
Neutron Diffraction ◽  
Least Squares ◽  
Diffraction Study ◽  
Neutron Diffraction Study ◽  
Precise Determination ◽  
Hydrogen Atoms ◽  
Full Matrix ◽  
X Ray ◽  
Motion Parameters

A neutron diffraction study of 1,2,3,4-tetra-O-acetyl-β-D-arabinopyranose, C13H18O9, has been carried out. Space group P21; Z 2; a 10.0779(5), b 9.0228(5), c 8.9659(5) �and β 101.965(5)°. Full-matrix least squares refinements varying anisotropic parameters for all atoms have led to a discrepancy value over all data of 0.058 and R w 0.054. This structure gives a precise determination of position and thermal motion parameters for all hydrogen atoms. The neutron diffraction results agree well with the X-ray results for non-hydrogen positional and thermal parameters.

Funktionelle Trimethylphosphanderivate, XXII [1] Struktur und Reaktivität von Lithium-tris(dimethylphosphino)methanid sowie Molekülstruktur von / Functional Trimethylphosphine Derivatives, X X II [1] Structure and Reactivity of Lithium-tris(dimethylphosphino)methanide and Molecular Structure of

1984 ◽  
Vol 39 (11) ◽  
pp. 1518-1528 ◽  
Author(s):  
Hans Heinz Karsc ◽  
Lothar Weber ◽  
Dietmar Wewers ◽  
Roland Boese ◽  
Gerhard Müller
Keyword(s):  
Least Squares ◽  
Structure Determination ◽  
Solvent Molecule ◽  
Pair Interaction ◽  
Major Product ◽  
Monoclinic Space Group ◽  
Reaction Conditions ◽  
Space Group ◽  
X Ray

Abstract The reaction of Lithium-tris(dimethylphosphino)methanide with methyl iodide is sensitive to the choice of the solvent and reaction conditions; in pentane at room temperature and in the presence of tetramethylethylenediamine, Me3P = C(PMe2)2 is the major product, whereas in tetrahydrofuran, (Me2P)3C -CH3 is formed predominantly. Under similar conditions, Lithium-bis- (dimethylphosphino)methanide reacts with Mel to give (Me2P)2C(CH3)H as the main product. An X-ray structure determination of the tetrahydrofuran solvate of LiC(PMe2)3 reveals this compound to be dimeric with one solvent molecule coordinating to Li. A pseudo tetrahedral coordination sphere around each Li atom is completed by two phosphino groups of one [C(PMe2)3]- anion and a contact ion pair interaction with the carbanionoid center of the second. The crystals are monoclinic, space group P21/n, with a = 928.5(2), b = 1250.8(3), c = 1407.9(3) pm, β = 100.07(1)°, V = 1609.9 • 106 pm3 Dc = 1.13 g/cm3 for Z - 4 at -40 °C. Full-matrix least-squares refinement of 249 parameters based on 2158 reflections converged at R = 0.029. The ligand properties of (Me2P)3CCH3 are tested in its reactions with (CO)4Cr(C7H8) and (CO)5Cr[CH2S(O)Me2] from which and may be isolated. The latter crystallizes in the monoclinic space group P21/c with a - 1218.5(3). b = 881.7(3), c = 1824.1(4) pm, β = 106.66(2)°, V = 1877.6(9) • 106 pm3, Dc = 1.37 g/cm3 for Z = 4. Least-squares refinement of 218 parameters on 1615 reflections produced R = 0.063. The structure determination confirms the molecule to contain a five-membered heterocycle in an approximate envelope conformation.

Isolation and Crystal Structure of Limonidilactone—a Labdane Diterpene From Vitex limonifolia

1995 ◽  
Vol 48 (1) ◽  
pp. 133 ◽  
Author(s):  
S Aphaijitt ◽  
K Nimgirawath ◽  
A Suksamrarn ◽  
U Tooptakong
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Structure Determination ◽  
Spectroscopic Methods ◽  
Full Matrix ◽  
X Ray ◽  
Labdane Diterpene ◽  
Least Squares Techniques

The structure of a new labdane diterpene, limonidilactone , from the leaves of Vitex limonifolia Wall. ( Verbenaceae ) has been established by spectroscopic methods and a single-crystal X-ray structure determination. Crystals are orthorhombic, P212121, a 19.373(10), b 10.871(7), c 8.207(3) Ǻ, Z 4. Diffractometer data were refined by full-matrix least-squares techniques to a residual of 0.043 for 1436 independent 'observed' reflections.

The Chemistry of Eremophila Spp. XXIX. The Absolute Configuration of (+)-Syringaresinol Dimethyl Ether

1987 ◽  
Vol 40 (11) ◽  
pp. 1913 ◽  
Author(s):  
IR Bytheway ◽  
EL Ghisalberti ◽  
S Gotsis ◽  
PR Jefferies ◽  
BW Skelton ◽  
...  
Keyword(s):  
Absolute Configuration ◽  
Structure Determination ◽  
Title Compound ◽  
Room Temperature ◽  
Orthorhombic Space Group ◽  
Full Matrix ◽  
X Ray ◽  
The Absolute ◽  
Dibromo Derivative

The absolute configuration of the title compound has been established from a single-crystal room temperature X-ray structure determination of its dibromo derivative, C24H28Br2O8. Crystals of the latter are orthorhombic, space group P21212, a l6.696(5), b l5.660(3), c 4.713(1) �, Z 2; 1452 independent 'observed' reflections yielded R 0.033 following full-matrix least-squares refinement. The molecule lies on a crystallographic 2 axis. The occurrence of lignans in Eremophila species is summarized.

scholarly journals Schaurteite, Ca3Ge(SO4)2(OH)6·3H2O

2013 ◽  
Vol 69 (2) ◽  
pp. i6-i6 ◽  
Author(s):  
Marcus J. Origlieri ◽  
Robert T. Downs
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Structure Determination ◽  
Site Symmetry ◽  
Asymmetric Unit ◽  
Natural Sample ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray

This report presents the first crystal structure determination of the mineral schaurteite, ideally Ca3Ge(SO4)2(OH)6·3H2O, tricalcium germanium bis(sulfate) hexahydroxide trihydrate. This single-crystal X-ray diffraction study investigated a natural sample from the type locality at Tsumeb, Namibia. Schaurteite is a member of the fleischerite group of minerals, which also includes fleischerite, despujolsite, and mallestigite. The structure of schaurteite consists of slabs of Ca(O,OH,H2O)8polyhedra (site symmetrymm2) interleaved with a mixed layer of Ge(OH)6octahedra (-3m.) and SO4tetrahedra (3m.). There are two H atoms in the asymmetric unit, both located by full-matrix refinement, and both forming O—H...O hydrogen bonds.

Synthesis, Properties and Crystal Structure Determination of a Perchloroheptafulvalene Isomer

1985 ◽  
Vol 38 (3) ◽  
pp. 383 ◽  
Author(s):  
HM Hugel ◽  
E Horn ◽  
MR Snow
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Structure Analysis ◽  
Lithium Chloride ◽  
Structure Determination ◽  
Full Matrix ◽  
Space Group ◽  
Synthesis Properties ◽  
R Value

Crystals of the syn-perchloroheptafulvalene isomer, C14Cl12, crystallize in the space group C2/c with a 12.376(6), b 10.980(4), c 15.242(4)Ǻ and β 100.54(3)°. The structure analysis of the isomer indicates molecular packing disorder into two orientations about the centre of symmetry. In the final full-matrix least-squares refinement the conventional R value converged at 0.042. Formation of the syn isomer is most likely to proceed through the perchloroheptatrienyl anion which can dimerize and form syn-perchloroheptafulvalene by cis elimination of lithium chloride.

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