Synthesis of [Cu2(Me2[9]aneN2S)2(OH)2](PF6)2, a Hydroxo-Bridged Copper(II) Complex of N,N′-Dimethyl-1-thia-4,7-diazacyclononane (Me2[9]aneN2S). X-Ray Structural Analysis, Magnetic Susceptibility, E.P.R. and Visible Spectroscopy

1999 ◽  
Vol 52 (9) ◽  
pp. 861 ◽  
Author(s):  
Vincent A. Grillo ◽  
Trevor W. Hambley ◽  
Lawrence R. Gahan ◽  
Graeme R. Hanson ◽  
Robert Stranger ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Charge Transfer Band ◽  
Hydroxo Complex ◽  
Ferromagnetic Coupling ◽  
Visible Spectroscopy ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
Susceptibility Study ◽  
Fitting Parameters

The bis(µ-hydroxo) complex [Cu 2 (Me 2 [9]aneN 2 S) 2 (OH) 2 ] (PF 6 ) 2 (Me 2 [9]aneN 2 S = N,N′-dimethyl-1-thia-4,7- diazacyclononane) results after reaction of [Cu(Me 2 [9]aneN 2 S)(MeCN)] (PF 6 ) with dioxygen at −78°C in acetonitrile. The complex has been characterized by X-ray crystallography: orthorhombic, space group Pnma, with a 18.710(3), b 16.758(2), c 9.593(2) Å, and Z = 4. The structure refined to a final R value of 0.051. The complex contains two copper(II) ions bridged by two hydroxo groups with Cu···Cu 2.866(1) Å. The solid-state magnetic susceptibility study reveals ferromagnetic coupling, the fitting parameters being J = +46±5 cm −1 , g = 2.01±0.01 and ? = −0.58±0.03 K. The frozen-solution e.p.r. spectrum in dimethyl sulfoxide is characteristic of a monomeric copper(II) ion (g ‖ 2.300, g ⊥ 2.063; A ‖156.2 × 10 −4 cm −1 , A ⊥ 9.0 × 10 −4 cm −1 ) with an N 2 O 2 donor set. Thioether coordination to the copper(II) in solution is supported by the presence of an intense absorption assigned to a σ(S)→Cu II LMCT transition at c. 34000 cm −1 . The single-crystal spectrum of [Cu 2 (Me 2 [9]aneN 2 S) 2 (OH) 2 ] (PF 6 ) 2 (273 K) reveals d→d transitions at 14500 and 18300 cm −1 and a weak π(S)→Cu II charge-transfer band at approximately 25000 cm −1.

Structural and vibrational studies of 1,1,3,3-tetracyanopropane and 2,2,4,4,6-pentacyanocyclohexenamine

1987 ◽  
Vol 65 (2) ◽  
pp. 261-270 ◽  
Author(s):  
R. A. Bell ◽  
B. E. Brown ◽  
M. Duarte ◽  
H. E. Howard-Lock ◽  
C. J. L. Lock
Keyword(s):  
Unit Cell ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
New Methods ◽  
Cell Dimensions ◽  
Cell Data ◽  
Unit Cell Data ◽  
Monoclinic Cell ◽  
C Nmr

1,1,3,3-Tetracyanopropane, 1, was prepared in low yields by a literature method with 2,2,4,4,6-pentacyanocyclohexenamine, 2, as a major by-product. The products were examined by X-ray crystallography. 1 has an orthorhombic space group, Pbcn (No. 60) with cell dimensions, a = 7.158(2), b = 10.510(3), c = 9.733(2) Å and has four formula units in the unit cell. 2 has a monoclinic cell, P21/c (No. 14) with cell dimensions a = 14.368(3), b = 6.626(1), c = 12.300(2) Å, β = 115.60(1)° and has 4 formula units in the unit cell. Data were collected with use of MoKα radiation and a Nicolet P3 diffractometer. The crystal structures were determined by standard methods and refined to Rw = 0.037 (1) and Rw = 0.040 (2) on the basis of 782 and 2108 unique reflections. Bond lengths and angles in the two compounds are normal. 2 has what has been considered to be the less likely tautomeric structure. Both compounds were examined by 1H, 13C nmr, vibrational spectroscopy, and mass spectroscopy. For 2 there was no evidence of the alternative tautomeric structure. New methods were developed for the preparation of both compounds and the mechanism of the original reaction rationalized.

Crystal Structure, Spectroscopic and Redox Properties of Copper(II) Bis{2-[(2,6-dimethylphenyl)iminomethyl-3-methoxyphenolate]}

2007 ◽  
Vol 62 (9) ◽  
pp. 1133-1138 ◽  
Author(s):  
Veli T. Kasumov ◽  
Ibrahim Uçar ◽  
Ahmet Bulut ◽  
Fevzi Kösal
Keyword(s):  
Crystal Structure ◽  
Title Complex ◽  
Redox Properties ◽  
Orthorhombic Space Group ◽  
Long Distance ◽  
X Ray ◽  
X Ray Crystallography ◽  
Square Planar ◽  
Planar Molecules ◽  
Exchange Interaction Parameter

The coordination chemistry of N-(2,6-di-methylphenyl)-2-hydroxy-3-methoxybenzaldimine (1) with Cu(II) has been investigated by X-ray crystallography, electronic and EPR spectroscopies, as well as by electro- and magnetochemistry. The title complex 2 crystallizes in the orthorhombic space group P212121 (a = 8.1538, b = 17.7466, c =19.8507 Å). The mononuclear square-planar molecules 2 featuring trans-N2O2 coordination are connected via weak intermolecular C-H· · ·π interactions into infinite chains parallel to the a axis. Although the intermolecular Cu· · ·Cu separations within individual chains and between chains are very long (8.154 and 9.726 Å ), the exchange interaction parameter G = 2.03 < 4, estimated from solid state EPR spectra, suggests the existence of long-distance superexchange pathways between adjacent Cu(II) centers. The electronic and electrochemical features of the compound are also discussed.

Etude de l'effet des cations alcalins sur la structure du succinate de cuivre

1974 ◽  
Vol 52 (3) ◽  
pp. 418-425 ◽  
Author(s):  
P. Sharrock ◽  
T. Theophanides
Keyword(s):  
Magnetic Susceptibility ◽  
General Formula ◽  
Visible Spectroscopy ◽  
X Ray ◽  
Complex Salts

New complex-salts of copper of the general formula M2Cu(succinate)2.xH2O, where M = Li, Na, K, and NH4; 0 ≤ x ≤ 51/2 were synthesized. The complexes were studied by infrared and visible spectroscopy, thermogravimetry, X-ray powder patterns, and magnetic susceptibility measurements.

The FeOXTiO2 system. An X-Ray diffraction, thermogravimetric and magnetic susceptibility study

1989 ◽  
Vol 21 (1) ◽  
pp. 93-106 ◽  
Author(s):  
D. Gazzoli ◽  
G. Minelli ◽  
M. Valigi
Keyword(s):  
Magnetic Susceptibility ◽  
X Ray Diffraction ◽  
X Ray ◽  
Susceptibility Study ◽  
Magnetic Susceptibility Study

Article

1998 ◽  
Vol 76 (3) ◽  
pp. 307-312
Author(s):  
A Wallace Cordes ◽  
Robert C Haddon ◽  
Robin G Hicks ◽  
Richard T Oakley ◽  
Kristen E Vajda
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Magnetic Susceptibility ◽  
Electronic Structure ◽  
Charge Transfer ◽  
Electronic Structures ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Diamagnetic State

Electroreduction of the 2,5-thiophene-bridged bis(1,2,3,5-diselenadiazolylium) salt [T-2,5-Se][SbF6]2 in acetonitrile, at a Pt wire and in the presence of iodine, affords a highly conductive ( sigma = 102 S cm-1 at 293 K) 1:1 charge-transfer (CT) salt [T-2,5-Se][I], the crystal structure of which has been determined by single-crystal X-ray diffraction. The crystals belong to the orthorhombic space group Fm2m, a = 3.544(2), b = 10.9808(16), c = 31.464(5) Å , V = 1224.5(7) Å 3. The structure consists of perfectly superimposed pi -stacks of molecular units bridged by columns of disordered iodines. This packing motif is similar to that of the related 1,3-benzene-bridged derivative [1,3-Se][I], but the lateral intermolecular Se···Se interactions linking adjacent pi -stacks are considerably shorter, indicative of a more isotropic electronic structure for [T-2,5-Se][I]. Magnetic susceptibility measurements on [T-2,5-Se][I] nonetheless indicate a phase transition to a diamagnetic state near 200 K, behaviour similar to that observed for [1,3-Se][I]. The electronic structures and transport properties of the two compounds are discussed in the light of extended Hückel band-structure calculations.Key words: diselenadiazolyl, diradical, charge-transfer salt, magnetic susceptibility, crystal structure.

The metal-mediated conversion of octachlorocycloheptatriene into dodecachloroheptafulvalene: a synthetic, structural, and EHMO study

1996 ◽  
Vol 74 (11) ◽  
pp. 2258-2267 ◽  
Author(s):  
James A. Dunn ◽  
Hari K. Gupta ◽  
Alex D. Bain ◽  
Michael J. McGlinchey
Keyword(s):  
High Temperature ◽  
Molecular Orbital Calculations ◽  
Orthorhombic Space Group ◽  
Carbene Complexes ◽  
X Ray ◽  
X Ray Crystallography ◽  
Anti Conformation ◽  
Reaction Proceeds ◽  
Type C ◽  
Organometallic Precursors

Octachlorocycloheptatriene, C7Cl8, 3, reacts with a variety of organometallic precursors, e.g., Fe2(CO)9, Co2(CO)8, [(C5H5)Fe(CO)2]−, to give dodecachloroheptafulvalene, C14C12,12, in yields ranging from 54 to 68%. There is no evidence to support the intermediacy of carbene complexes of the type C7Cl6=MLn, and it is suggested that the reaction proceeds by the dechlorination of C7Cl8 to give hexachlorotropylidene, which dimerizes to the observed product. Extended Hückel molecular orbital calculations are used to show that the chlorinated carbene, C7Cl6, should be more stable than the corresponding parent system, C7Cl6. The EHMO calculations also reveal that planar heptafulvalenes are electronically disfavored and should exist preferentially in the S-anti conformation, as is the case for C14H12. The molecule C14Cl12,12, is shown by X-ray crystallography to be formed only as the syn conformer, which isomerizes to the anti structure only at high temperature. The conformations of the two seven-membered rings in 12 closely resemble that found in octachlorocycloheptatriene itself. C7Cl8, 3, crystallizes in the orthorhombic space group Pnma with a = 7.140(1) Å, b = 13.329(3) Å, c = 12.595(3) Å, and V = 1198.7(4) Å3 for Z = 4.3 adopts a severely bent boat structure in which the planes C(1)-C(7)-C(6) and C(2)-C(3)-C(4)-C(5) make angles of 51.8° and 32.4°, respectively, with the C(1)-C(2)-C(5)-C(6) plane. Key words: octachlorocycloheptatriene, heptafulvalenes, metal-mediated dimerization.

scholarly journals Hydrolysis of Scandium Alkyl Derivatives Supported by a Pentadentate Diborate Ligand: Interconversion of Hydroxo and Oxo Complexes

2019 ◽  
Author(s):  
Daniel W. Beh ◽  
Warren Piers ◽  
Laurent Maron ◽  
Yan Yang ◽  
Benjamin S. Gelfand ◽  
...  
Keyword(s):  
Solid State ◽  
Hydroxo Complex ◽  
Ambient Atmosphere ◽  
X Ray ◽  
X Ray Crystallography ◽  
Hydrolysis Products ◽  
Alkyl Derivatives ◽  
Rapid Formation ◽  
Hydrolysis Of ◽  
Pentadentate Ligand

Uncontrolled reaction of water with scandium alkyls (compounds <b>1-R</b>) supported by a dianionic, pentadentate ligand leads to rapid formation of an oxo-bridged dimer (<b>2</b>). Solid state samples can be exposed to ambient atmosphere to generate samples enriched in the bridging dihydroxo dimer <b>3</b>, which slowly converts to the m-oxo species with elimination of water. DFT computations show that <b>3</b> is actually more thermodynamically stable than <b>2</b>, but the reactivity of <b>3</b> with the water eliminated leads to its decomposition to <b>2</b> and several hydrolysis products. Some of these products were characterized by X-ray crystallography, specifically a hexameric scandium dihydroxo cluster (<b>4</b>) in which the pentadentate ligand has partially demetallated. Attempts to synthesize hydroxo complex <b>3</b> by protonation of <b>2</b> also lead to hydrolysis products.

Influence of fluorine substitution on the molecular conformation of 3′-deoxy-3′-fluoro-5-methyluridine

2020 ◽  
Vol 76 (4) ◽  
pp. 346-352
Author(s):  
Manisha N. Aher ◽  
Namrata D. Erande ◽  
Vaijayanti A. Kumar ◽  
Moneesha Fernandes ◽  
Rajesh G. Gonnade
Keyword(s):  
Molecular Conformation ◽  
Asymmetric Unit ◽  
Screw Axis ◽  
Orthorhombic Space Group ◽  
Fluorine Substitution ◽  
X Ray ◽  
X Ray Crystallography ◽  
Conformational Properties ◽  
Independent Molecules ◽  
Phase Angles

Fluorine substitutions on the furanose ring of nucleosides are known to strongly influence the conformational properties of oligonucleotides. In order to assess the effect of fluorine on the conformation of 3′-deoxy-3′-fluoro-5-methyluridine (RTF), C10H13FN2O5, we studied its stereochemistry in the crystalline state using X-ray crystallography. The compound crystallizes in the chiral orthorhombic space group P212121 and contains two symmetry-independent molecules (A and B) in the asymmetric unit. The furanose ring in molecules A and B adopts conformations between envelope (2E, 2′-endo, P = 162°) and twisted (2T3, 2′-endo and 3′exo, P = 180°), with pseudorotation phase angles (P) of 164.3 and 170.2°, respectively. The maximum puckering amplitudes, νmax, for molecules A and B are 38.8 and 36.1°, respectively. In contrast, for 5-methyluridine (RTOH), the value of P is 21.2°, which is between the 3E (3′-endo, P = 18.0°) and 3T4 (3′-endo and 4′-exo, P = 36°) conformations. The value of νmax for RTOH is 41.29°. Molecules A and B of RTF generate respective helical assemblies across the crystallographic 21-screw axis through classical N—H...O aand O—H...O hydrogen bonds supplemented by C—H...O contacts. Adjacent parallel helices of both molecules are linked to each other via O—H...O and O...π interactions.

The reaction of chloro(triphenylphosphine)gold(I) with 1-methylthymine

1987 ◽  
Vol 65 (7) ◽  
pp. 1568-1575 ◽  
Author(s):  
R. Faggiani ◽  
H. E. Howard-Lock ◽  
C. J. L. Lock ◽  
M. A. Turner
Keyword(s):  
Aqueous Methanol ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Cell Dimensions ◽  
Cell Data ◽  
Unit Cell Data ◽  
Related Compounds ◽  
C Nmr

1-Methylthyminato-N3-triphenylphosphinegold(I) was prepared by reacting chloro(triphenylphosphine)gold(I) with 1-methylthymine in aqueous methanol at pH 11. The product was examined by X-ray crystallography and was found to have the orthorhombic space group C2221 (no. 20) with cell dimensions a = 12.760(7) Å, b = 11.530(2) Å, c = 31.893(5) Å, and eight formula units in the unit cell. Data were collected with use of MoKα radiation and a Syntex P21, diffractometer. The crystal structure was determined by standard methods and refined to R = 0.112 and Rw = 0.076 on the basis of 4760 unique reflections. Bond lengths and bond angles are normal. Packing in the crystal lattice is dominated by the triphenylphosphine rings which arrange roughly as blades of a propellor and are the source of the crystal's chirality. The title and related compounds were also examined by 1H nmr, 13C nmr, and vibrational spectroscopy.

Thiophenophane metal complexes IV. Effects from ligand changes outside the coordination sphere

1996 ◽  
Vol 74 (11) ◽  
pp. 2340-2348 ◽  
Author(s):  
C. Robert Lucas ◽  
Shuang Liu
Keyword(s):  
Magnetic Susceptibility ◽  
Variable Temperature ◽  
Cyclic Voltammograms ◽  
Ferromagnetic Coupling ◽  
X Ray ◽  
H Nmr ◽  
Variable Temperature Magnetic Susceptibility ◽  
Structural Differences ◽  
Coordination Spheres ◽  
Temperature Responses

Preparation of two thiophenophane polythioether macrocycles and 11 of their complexes of Cu(I), Cu(II), Ag(I), and Pd(II) is described. The single crystal X-ray structure of [(CuBr)2(L1)x is reported: space group Pcma, a = 8.7120(6), b = 10.7791(5), c = 12.0929(5) Å, Z = 2, Rf = 0.052, Rw = 0.036 for 521 reflections. Variable-temperature magnetic susceptibility measurements for [(CuCl2)2(L1)] and [(CuCl2)2(L2)] reveal weak antiferromagnetic and weak ferromagnetic coupling, respectively. Cyclic voltammograms of these compounds display two unequal waves in acetonitrile solvent but only one in nitromethane or dimethyl sulfoxide. 1H NMR spectra of {[(η-C3H5)Pd]2(L1)}{PF6}2 and {[(η-C3H5)Pd]2(L2)}{PF6}2 in various solvents show different temperature responses. These magnetic, electrochemical, and NMR effects are discussed in the light of structural differences at sites in the two ligands that are outside the coordination spheres. Key words: magnetic susceptibility, copper, thioether, electrochemistry.

Sign in / Sign up

Export Citation Format

Share Document