Preparation, X-ray structure, and dynamic solution behaviour of N,N',N''-tris(2,6-diisopropylphenyl)- guanidine, and its reaction with molybdenum carbonyl

2000 ◽  
Vol 78 (12) ◽  
pp. 1613-1619 ◽  
Author(s):  
Robyn E Boeré ◽  
René T Boeré ◽  
Jason Masuda ◽  
Gotthelf Wolmershäuser
Keyword(s):  
Crystal Structure ◽  
Central Atom ◽  
X Ray ◽  
Triclinic System ◽  
Dynamic Solution ◽  
Free Energy Of Activation ◽  
Molybdenum Carbonyl ◽  
Vt Nmr ◽  
Solution Behaviour ◽  
Two Barriers

The reaction of N,N'-bis(2,6-diisopropylphenyl)carbodiimide with lithium 2,6-diisopropylanilide, quenching with water and recrystallization from heptane produces the symmetric guanidine [DipNH]2C=NDip which crystallizes in the triclinic system, space group P[Formula: see text], a = 10.6513(11), b = 10.8997(11), c = 16.2961(17) Å, α = 80.524(12), β = 78.921(13), γ = 70.060(12)°, V = 1735.2(3) Å3, Z = 2. The molecule crystallizes with three perpendicular 2,6-diisopropylphenyl groups, which surround and shield the central CN3 unit, and provide (almost) three-fold symmetry around the central atom. Its dynamic solution behaviour has been studied by VT NMR between -90 and +180°C, and is consistent with three distinct barriers to N-CAr rotation. Preliminary estimates of the Gibbs free energy of activation for the lower two barriers are 56 ± 2 and 73 ± 2 kJ mol–1. Reaction of the title compound with Mo(CO)6 in refluxing n-heptane produces [DipNH]2C=NDip·Mo(CO)3, a complex in which Mo(CO)3 is η6-coordinated to one of the diisopropylphenyl rings.Key words: crystal structure, diisopropylaniline, guanidine, bulky ligands.

The crystal structure of ethyl-Z-3-amino-2-benzoyl-2-butenoate and measurement of the barrier to E,Z-isomerization

1980 ◽  
Vol 58 (17) ◽  
pp. 1821-1828 ◽  
Author(s):  
Gary D. Fallon ◽  
Bryan M. Gatehouse ◽  
Allan Pring ◽  
Ian D. Rae ◽  
Josephine A. Weigold
Keyword(s):  
Crystal Structure ◽  
Nuclear Magnetic Resonance ◽  
Hydrogen Bond ◽  
Free Energy ◽  
Magnetic Resonance ◽  
Energy Of Activation ◽  
X Ray ◽  
X Ray Crystallography ◽  
Free Energy Of Activation ◽  
Nuclear Magnetic

Ethyl-3-amino-2-benzoyl-2-butenoate crystallizes from pentane as either the E (mp 82–84 °C) or the Z-isomer (mp 95.5–96.5 °C). The E isomer is less stable, and changes spontaneously into the Z, which bas been identified by X-ray crystallography. The structure is characterised by an N–H/ester CO hydrogen bond and a very long C2—C3 bond (1.39 Å). Nuclear magnetic resonance methods have been used to measure the rate of [Formula: see text] isomerization at several temperatures, leading to the estimate that the free energy of activation at 268 K is 56 ± 8 kJ.

Preparation, properties, and X-ray crystal structure of a 1:1 complex of tetrathiafulvalene and p-dinitrobenzene

1982 ◽  
Vol 60 (16) ◽  
pp. 2057-2061 ◽  
Author(s):  
Martin R. Bryce ◽  
Anthony S. Secco ◽  
James Trotter ◽  
Larry Weiler
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
Direct Methods ◽  
X Ray Diffraction ◽  
Crystalline Complex ◽  
X Ray ◽  
Triclinic System ◽  
Donor Acceptor ◽  
Bulk Magnetic Susceptibility ◽  
R Value

A crystalline complex of tetrathiafulvalene and p-dinitrobenzene has been prepared and characterised by esr and ir spectroscopy, bulk magnetic susceptibility, dc conductivity, and an X-ray diffraction analysis. It is a neutral 1:1 complex which is an insulator at room temperature, σRT = 2.5 × 10−7 ohm−7 cm−1. The complex crystallizes in the triclinic system, space group [Formula: see text] with cell constants a = 6.915(1), b = 7.615(1), c = 8.149(1) Å, α = 79.39(1), β = 69.55(1), γ = 70.81(1)°, Z = 1. Data were collected on an Enraf-Nonius CAD-4 diffractometer. The structure was solved by direct methods and refined to an R-value of 0.028 for 1222 observed reflections. The structure consists of molecules stacked in an alternating donor–acceptor fashion along the c-axis. Mixed sheets parallel to [Formula: see text] are comprised of tetrathiafulvalene and p-dinitrobenzene molecules arranged end-on in the [021] direction.

Synthesis and solution behaviour of stable mono-, di- and trinuclear Pd(II) complexes of 2,5-pyridinedihydroxamic acid: X-ray crystal structure of a novel Pd(II) hydroxamato complex

2012 ◽  
Vol 380 ◽  
pp. 291-300 ◽  
Author(s):  
Darren M. Griffith ◽  
Linda Bíró ◽  
James A. Platts ◽  
Helge Müller-Bunz ◽  
Etelka Farkas ◽  
...  
Keyword(s):  
Crystal Structure ◽  
X Ray ◽  
Solution Behaviour ◽  
Stable Mono

X-ray crystal structure and hydrocarbon solution behaviour of tetrameric 2,2-Bis(methoxymethyl)-1-propyllithium

1990 ◽  
Vol 31 (18) ◽  
pp. 2641-2642 ◽  
Author(s):  
W. Moene ◽  
M. Schakel ◽  
G.J.M. Hoogland ◽  
F.J.J. de Kanter ◽  
G.W. Klumpp ◽  
...  
Keyword(s):  
Crystal Structure ◽  
X Ray ◽  
Solution Behaviour ◽  
Hydrocarbon Solution

The crystal and molecular structure of copper(II) bis-(ethylenediamine)nitrate selenocyanate

1982 ◽  
Vol 47 (2) ◽  
pp. 409-420 ◽  
Author(s):  
Viktor Vrábel ◽  
Ján Garaj
Keyword(s):  
Crystal Structure ◽  
Least Squares Method ◽  
Crystal And Molecular Structure ◽  
Central Atom ◽  
Covalent Bond ◽  
Axial Direction ◽  
Analysis Method ◽  
Monoclinic System ◽  
X Ray ◽  
Intermolecular Contacts

The crystal structure of [Cuen2(NO3)]SeCN was solved by the single-crystal X-ray structural analysis method. The compound crystallizes in the monoclinic system with space group Pc. The unit cell has dimensions: a = 0.9254(3), b = 1.4018(3), c = 0.9722(5) nm, β = 99.20(3)°. The structure was refined by the least squares method to a final value of R = 6.8% for 1965 observed reflections. The crystal structure consits of polymeric cation chain [Cuen2(NO3)]+ and of free uncoordinated SeCN- anions. The nitrate ion NO-3 forms a bridging unit between two [Cuen3]2+ cations. The coordination polyhedron around the Cu(II) atom is a deformed octahedron, formed of two ethylendiamine molecules and two oxygen atoms of the NO-3 ions, bonded to divalent copper in the axial direction along the long coordinates. The crystal structure contains selenocyanate which is not bonded through a covalent bond to the central atom, but there are intermolecular contacts with its immediate surroundings.

scholarly journals Synthesis, Crystal Structure, and Electrical Properties of a New Molybdylarsenate LiNa5K3Mo11As3O45

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Hamadi Hamza ◽  
Mohamed Faouzi Zid ◽  
Ahmed Driss
Keyword(s):  
Crystal Structure ◽  
Electrical Conductivity ◽  
Solid State ◽  
Inorganic Compound ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
One Dimensional ◽  
X Ray ◽  
Triclinic System ◽  
State Method

LiNa5K3Mo11As3O45 is a new inorganic compound. It was synthesized by a solid state method. The crystal structure has been studied by single crystal X-ray analysis. The R-values reached 2.8%. The title compound crystallizes in the triclinic system, space group P-1, with a = 10.550 (2) Å, b = 11.723 (2) Å, c = 17.469 (3) Å, α = 102.35 (3)°, β = 87.61 (2)°, and γ = 111.03 (3)°. The anionic unit [Mo11As3O45]9− is formed by nine MoO6 octahedra, two MoO5 trigonal bipyramids, and three AsO4 tetrahedra. The association of [Mo11As3O45]9− units, running along [010], leads to a one-dimensional framework. Li, K, and Na are located in the space surrounding the anionic ribbons. This material was characterized by SEM microscopy, IR spectroscopy, and powder X-ray diffraction. The electrical conductivity was investigated from 528 K to 673 K by impedance complex followed by DSC spectroscopy.

Molecular conformation of di-o-anisylcarbinol: an X-ray diffraction study

1983 ◽  
Vol 61 (9) ◽  
pp. 2001-2005 ◽  
Author(s):  
C. Faerman ◽  
H. Negri ◽  
G. Punte ◽  
A. A. Vitale ◽  
N. S. Nudelman
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Diffraction Study ◽  
Molecular Conformation ◽  
Direct Methods ◽  
X Ray Diffraction ◽  
X Ray ◽  
Triclinic System ◽  
Phenyl Rings ◽  
R Factors

Di-o-anisylcarbinol crystallizes in the triclinic system, space group [Formula: see text] with a = 7.50 (4), b = 10.89 (4), c = 7.98 (3) Å, α = 101.9 (1), β = 94.1 (1), γ = 94.6 (1)°, Z = 2, V = 633.11 Å3, Dc = 1.28 mg m−3, Dm = 1.26 (1) mg m−3, CuKα radiation, λ = 1.54178 Å, μ(CuKα) = 0.633 mm−1, F(000) = 260. The structure has been determined by direct methods using single crystal X-ray data and refined by least-squares to the final R factors R = 5.89% and Rw = 5.35%. The molecule has a twist-skewed conformation with the phenyl rings on nearly orthogonal planes. The crystal structure shows a hydrogen-bonded dimer and a peculiar arrangement of the methoxy and phenyl groups.

Synthese und Strukturuntersuchung von Polyhalogeniden im System Iod/Brom / Syntheses and Structure Analyses of Polyhalides in the System Iodine/Bromine

1985 ◽  
Vol 40 (1) ◽  
pp. 45-52 ◽  
Author(s):  
Axel Parlow ◽  
Hans Hartl
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Central Atom ◽  
X Ray ◽  
Bromide Anion

Several polyhalide anions containing iodine and bromine have been synthesized with 2,2′- bipyridylium (BPH+) as the cation. The crystal structures of three compounds have been investigated by X-ray crystal structure analyses. BPH+(H3O)+(IBr2)2- (P1̄, a = 780.0(3), b = 815.4(3), c = 1547.9(6) pm, α = 75.59(7), β = 82.28(8), γ = 88.15(8)°, R = 6.5%) contains two independent, nearly linear, asymmetric IBr2- groups. In BPH+I2Br3- (P21/c, a = 1269.1(6), b = 673.0(4), c = 2047.4(8) pm, β = 112.39(9)°, R = 6.3%), the anion is V-shaped like other pentahalide anions. It can be characterized as consisting of two IBr molecules linked to a bromide anion with the longer I-Br bonds at the central atom. The polyhalide anions in [xxx] (P21/m, a = 435.1(2), b = 1710.6(7), c = 1349.0(6) pm, β = 97.56(9)°, R = 15.5%) form infinite zigzag layers. They are built up by IBr2- anions which are connected by iodine molecules. The cations are enclosed in columnar cavities within these layers

Sign in / Sign up

Export Citation Format

Share Document