A structural, solvent exchange and spin equilibrium study of (N,N-dimethylformamide)(R,S,R,S)-(1,4,8,11-tetramethyl-l,4,8,11- tetraazacyclotetradecane)nickel(II)

1984 ◽  
Vol 37 (4) ◽  
pp. 713 ◽  
Author(s):  
SF Lincoln ◽  
TW Hambley ◽  
DL Pisaniello ◽  
JH Coates
Keyword(s):  
Molecular Structure ◽  
Solid State ◽  
Least Squares ◽  
Methyl Groups ◽  
Solvent Exchange ◽  
X Ray Diffraction ◽  
X Ray ◽  
Equilibrium Study ◽  
Trigonal Bipyramidal ◽  
Spin Species

The molecular structure of R,S,R,S-[Ni {(-N(Me)(CH2)2N(Me)(CH2)3-)2} (OCHNMe2)](SO3CF3)2 has been determined in the solid state by X-ray diffraction methods. The geometry about nickel(11) is midway between square based pyramidal and trigonal bipyramidal with OCHNMe2 occupying the axial or an equatorial site in these geometries respectively. The nickel(II) is displaced 0.29 � from the least-squares tetraaza plane on the same side as the four methyl groups and OCHNMe2. In OCHNMe2 solution the formation of this five-coordinate high-spin species by coordination of OCHNMe2 by its four-coordinate low-spin precursor is characterized by K(298.2 K) = 10 � 2, ∆H = -12.8 � 2.7 kJ mol-1 and ∆S = -24.1 � 9.O JK-l mol-1 as determined by spectrophotometry. 1H (300 MHz) n.m.r. studies show that kwx(298.2 K) = (1.6 � 0.2) × 107 s-1, ∆H‡ = 27.8 � 0.4 kJ mol-1 and ∆S‡ = -13.O � 2.0 JK-1 mol-1 characterize the exchange of OCHNMe2 on R,S,R,S-[Ni {(-N(Me)(CH2)2N(Me)(CH2)3-)2 }(OCHNMe2)]2+.

A structural and carbon-nitrogen bond rotation study of N,N,N',N',2,2-hexamethylpropanediamide

1983 ◽  
Vol 36 (9) ◽  
pp. 1865 ◽  
Author(s):  
SF Lincoln ◽  
AM Hounslow ◽  
NJ Maeji ◽  
TW Hambley ◽  
MR Snow ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Solid State ◽  
Kinetic Parameters ◽  
Methyl Groups ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Rotation ◽  
Nitrogen Bonds ◽  
Rotation Study ◽  
Nitrogen Bond

The molecular structure of N,N,N',N',2,2-hexamethylpropanediamide has been determined in the solid state by X-ray diffraction methods. The structure of Me2NCOCMe2CONMe2 may be broadly described as two planar Me2NCO entities intersecting at the tetrahedral -CMe2- site. The angle between the normals to the two Me2NCO planes is 104.6�, and the two oxygen atoms are disposed outwards from the molecule and away from each other. Proton (270-MHz) n.m.r. studies yield k(320 K) 32.0 � 3.2 s-1, ΔH‡ 69.5 � 0.4 kJ mol-1 and ΔS‡ 0.6 � 1.1 J K-1 mol-1 for rotation of the N-methyl groups about the carbon-nitrogen bonds in CD3NO2 solution. Similar magnitudes for the kinetic parameters characterizing this process are obtained in CDCl3, and CD3CN solutions.

Crystal and molecular structure of diorganoammonium oxalatotrimethylstannate, [R2NH2][Me3Sn(C2O4)] (R=i-Bu, cyclohexyl)

2011 ◽  
Vol 34 (5-6) ◽  
pp. 127-130 ◽  
Author(s):  
Yaya Sow ◽  
Libasse Diop ◽  
Kieran C. Molloy ◽  
Gabrielle Kociok-Köhn
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonds ◽  
Diffraction Study ◽  
Crystal And Molecular Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Trans Complex ◽  
A Chain ◽  
Distorted Trigonal Bipyramidal

Abstract The title compounds [R2NH2][C2O4SnMe3](R=i-Bu, Cy), in which tin atoms adopt a distorted trigonal bipyramidal configuration, have been prepared and submitted to an X-ray diffraction study. These compounds have been obtained from the reaction of (Cy2NH2)2C2O4·H2O or (i-Bu2NH2)2C2O4 with SnMe3Cl. In both [R2NH2][C2O4SnMe3] compounds, the trans complex has an almost regular trigonal bipyramidal geometry around the tin atom. The SnMe3 residues are connected as a chain with bridging oxalate anions in a trans-SnC3O2 framework, the oxygen atoms being in axial positions. The cations connect linear adjacent chains through NH…O hydrogen bonds giving layered structures.

Reactions of (η5-C9H7)Rh(η2-C2H4)2 with quinones: molecular structure of [(η5-C9H7)Rh(2,3,5,6-C6O2(CH3)4)]

1999 ◽  
Vol 77 (2) ◽  
pp. 199-204
Author(s):  
Stephen A Westcott ◽  
Nicholas J Taylor ◽  
Todd B Marder
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Ground State ◽  
Slip Parameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
A Value ◽  
Hinge Angle

Reactions of (η5-C9H7)Rh(η2-C2H4)2 (1) with quinones were investigated. Substitution of the labile ethylene ligands was observed upon addition of either duroquinone (2,3,5,6-tetramethyl-1,4-benzoquinone) or 1,4-benzoquinone to complex 1. The molecular structure of neutral (η5-C9H7)Rh(2,3,5,6-C6O2(CH3)4) (3), determined by X-ray diffraction, shows that the duroquinone ligand lies in a plane nearly parallel to the indenyl group. The carbonyl moieties of duroquinone lie in a plane incorporating Rh, C2, and the midpoint between C3a and C7a of the indenyl ring. The slip parameter (Δ= d(average Rh-C3a,7a) -d(average Rh-C1,3)) was calculated to be 0.112(2) Å; whereas a value of ca. 0.05 Å had been obtained previously from film data. Values for the hinge angle (HA = angle between normals to the least-squares planes defined by C1, C2, C3 and C1, C7a, C3a, C3) and fold angle (FA = angle between normals to the least-squares planes defined by C1, C2, C3 and C3a, C4, C5, C7, C7a) are 7.2° and 4.0°, respectively.Key words: indenyl, rhodium, quinones, ring-slippage, ground-state distortion.

The Molecular Geometry of Diastereoisomeric Bis[α-(9-anthryl)ethyl] Ethers

1985 ◽  
Vol 38 (9) ◽  
pp. 1417 ◽  
Author(s):  
H Becker ◽  
VA Patrick ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Least Squares ◽  
Dihedral Angle ◽  
Molecular Geometry ◽  
Dihedral Angles ◽  
Methyl Groups ◽  
X Ray Diffraction ◽  
X Ray ◽  
Meso Form ◽  
Aromatic Systems

The crystal structures of racemic bis [α-(9-anthryl)] ether and its meso form have been determined by single-crystal X-ray diffraction methods at 295 K, being refined by least squares to residuals of 0.053 and 0.041 for 1868 and 3568 independent 'observed' reflections respectively. Crystals of the racemate are orthorhombic, Pcab, a 23.07(1), b 19.85(2), c 10.241(8) Ǻ, Z 8. Crystals of the meso form are triclinic, Pī , a 19.032(12), b 14.207(11), c 9.451(8) Ǻ, α 79.46(6), β 89.68(6), γ 68.97(5)°, Z 4. In the racemate , the dihedral angle between the methyl groups along the ether bonds is 12°, and the short axes of the anthracene moieties lie at an angle of about 120°. In the meso compound, for the two molecules the dihedral angles between the methyl groups along the ether bonds are 90 and 93°, the angle between the two anthracene moieties is 90°, and the interplanar angles between the partly overlapping aromatic systems are 46 and 43°.

The crystal structure of dibutyl-bis(pentamethylenedithiocarbamato)tin(IV)

1986 ◽  
Vol 51 (11) ◽  
pp. 2521-2527 ◽  
Author(s):  
Jan Lokaj ◽  
Eleonóra Kellö ◽  
Viktor Kettmann ◽  
Viktor Vrábel ◽  
Vladimír Rattay
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Least Squares ◽  
Coordination Polyhedron ◽  
Crystal And Molecular Structure ◽  
Distorted Octahedron ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray

The crystal and molecular structure of SnBu2(pmdtc)2 has been solved by X-ray diffraction methods and refined by a block-diagonal least-squares procedure to R = 0.083 for 895 observed reflections. Monoclinic, space group C2, a = 19.893(6), b = 7.773(8), c = 12.947(8) . 10-10 m, β = 129.07(5)°, Z = 2, C20H38N2S4Sn. Measured and calculated densities are Dm = 1.38(2), Dc = 1.36 Mg m-3. Sn atom, placed on the twofold axes, is coordinated with four S atoms in the distances Sn-S 2.966(6) and 2.476(3) . 10-10 m. Coordination polyhedron is a strongly distorted octahedron. Ligand S2CN is planar.

scholarly journals The reaction of 3,5-diphenyl-1,2-dithiolium-4-olate with aniline: the crystal structure of 1-phenylimino-2-phenylamino-3-phenylindene

1987 ◽  
Vol 65 (12) ◽  
pp. 2830-2833 ◽  
Author(s):  
David M. McKinnon ◽  
Peter D. Clark ◽  
Robert O. Martin ◽  
Louis T. J. Delbaere ◽  
J. Wilson Quail
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Direct Methods ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

3,5-Diphenyl-1,2-dithiolium-4-olate (1) reacts with aniline to form 1-phenylimino-2-phenylamino-3-phenylindene (3a). Under suitable conditions, 6-phenylbenzo[b]indeno[1,2-e]-1,2-thiazine is also formed. These structures are confirmed by alternative syntheses. The molecular structure of 3a has been determined by single crystal X-ray diffraction. Compound 3a crystallizes in the monoclinic space group C2/c with unit cell dimensions a = 20.777(3) Å, b = 6.130(3) Å, c = 31.327(3) Å, 3 = 99.59(1)°, and Z = 8. The structure was solved by direct methods and refined by least squares to a final R = 0.055. The molecular structure of 3a shows the three phenyl containing substituents to have the planes of their ring systems tilted between 40° and 60° from the plane of the indene system due to steric repulsions.

Crystal and Molecular Structure of Dithiocyanato(triphenylarsine)mercury(II)

1975 ◽  
Vol 53 (22) ◽  
pp. 3383-3387 ◽  
Author(s):  
Joseph Hubert ◽  
André L. Beauchamp ◽  
Roland Rivest
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Coordination Number ◽  
Diffraction Data ◽  
Crystal And Molecular Structure ◽  
Heavy Atom ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heavy Atom Method

The crystal and molecular structure of dithiocyanato(triphenylarsine)mercury(II) has been determined from X-ray diffraction data. The crystals are monoclinic, space group P21/c, with a = 10.290(7), b = 21.199(23), c = 10.719(7) Å, β = 112.00(2)°, and Z = 4. The structure has been solved by the heavy-atom method and refined by block-diagonal least-squares calculations. The agreement factor R obtained for 2607 'observed' reflections is 0.030. The crystal consists of single molecules. The 'characteristic' coordination number of mercury is three, with two sulfur and one arsenic atoms at the apexes of a triangle. The nitrogen atoms of the thiocyanate groups are at 2.67 and 2.74 Å from the adjoining mercury atoms and therefore link the different molecules together.

Molecular structure in the solid state (X-Ray diffraction) and in solution (1H and 13C NMR) of nifurtimox and two pyrazol-1-Yl analogs

2010 ◽  
Vol 97 (11-12) ◽  
pp. 1055-1066 ◽  
Author(s):  
Ma de la Concepción Foces-Foces ◽  
Félix Hernández Cano ◽  
Rosa Ma Claramunt ◽  
Alain Fruchier ◽  
José Elguero
Keyword(s):  
Molecular Structure ◽  
Solid State ◽  
13C Nmr ◽  
X Ray Diffraction ◽  
1H And 13C Nmr ◽  
X Ray

An Intermediate in the Conversion of an Acetylene to a Vinyl Derivative: The Crystal and Molecular Structure of trans-Chloromethylbis(trimethylarsine)-platinum(II) Hexafluorobut-2-yne

1972 ◽  
Vol 50 (14) ◽  
pp. 2276-2284 ◽  
Author(s):  
Brian W. Davies ◽  
Richard J. Puddephatt ◽  
Nicholas C. Payne
Keyword(s):  
Molecular Structure ◽  
Bond Length ◽  
Crystal And Molecular Structure ◽  
Three Dimensional ◽  
Free Ligand ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Monodentate Ligand ◽  
X Ray ◽  
Trigonal Bipyramidal

The crystal and molecular structure of trans-chloromethylbis(trimethylarsine)platinum(II) hexafluorobut-2-yne has been determined from three dimensional X-ray diffraction data recorded by diffractometric methods. The structure has been refined by full-matrix least-squares methods on F using 1156 reflections to an agreement factor R = 0.077. The crystals are monoclinic, space group [Formula: see text] with a = 6.803(8), b = 14.93(2), c = 20.20(2) Å, β = 104.9(1)°, and Z = 4. The coordination of the platinum atom is trigonal bipyramidal, with the acetylene considered a monodentate ligand, and the two trimethylarsine ligands occupying the equatorial plane. The chlorine atom and the methyl ligand occupy the apical positions, with Pt—Cl and Pt—C distances of 2.47(1) Å and 2.10(4) Å, respectively. The long Pt—Cl bond length indicates the strong trans-influence of the methyl ligand. The observed C—C bond length of 1.32(4) Å in the acetylene ligand is lengthened from the value of 1.22(9) Å measured in the free ligand. The geometry of the coordinated ligand is discussed in terms of the bonding scheme proposed by Greaves etal.

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