On the interaction of copper with tris(hydroxymethyl)aminomethane

1987 ◽  
Vol 65 (4) ◽  
pp. 821-826 ◽  
Author(s):  
M. F. Colombo ◽  
L. Austrilino ◽  
O. R. Nascimento ◽  
E. E. Castellano ◽  
M. Tabak
Keyword(s):  
Room Temperature ◽  
Copper Complexes ◽  
Spectroscopic Techniques ◽  
Fold Axis ◽  
X Ray ◽  
Nitrogen Ligands ◽  
Superhyperfine Structure ◽  
Pyramid Structure ◽  
Cell Dimensions ◽  
Ray Methods

The interaction of copper with tris(hydroxymethyl)aminomethane (TRIS) has been studied by optical and esr spectroscopic techniques. In solution, three different copper complexes are obtained as a function of pH. At pH 10 the room temperature esr parameters are g0 = 2.135, A0 = 82 G and nitrogen superhyperfine structure AN = 9.5 G, characteristic of two nitrogen ligands; at pH 6.5, g0 = 2.147, A0 = 65 G and at pH 5.0, g0 = 2.180, A0 = 44 G. The high pH complex was crystallized and its molecular structure determined by X-ray methods. Space group and cell dimensions are C2/c, a = 12.955(2) Å, b = 10.793(1) Å, c = 10.091(2) Å, β = 116.62(1)°, V = 1261.4(6) Å3, Z = 4, Dc = 1.694 g cm−3, R = 0.034 for938 reflections with I > 3σ(I). The Cu2+ ion is located on the two-fold axis and coordinated to the oxygen and nitrogen atoms of two TRIS moieties; these ligand atoms form the rectangular base of a pyramid structure in which oxygen from a water molecule acts as the fifth ligand.

Rotational Polymorphism of Methyl-Substituted Ammonium Perchlorates

1965 ◽  
Vol 9 ◽  
pp. 170-189 ◽  
Author(s):  
M. Stammler ◽  
R. Bruenner ◽  
W. Schmidt ◽  
D. Orcutt
Keyword(s):  
Phase Transition ◽  
Ammonium Perchlorate ◽  
Room Temperature ◽  
Decomposition Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Analysis Techniques ◽  
Cell Dimensions ◽  
Thermal Analysis Techniques ◽  
Space Requirements

AbstractThe thermal transformations which take place in solid methyl-substituted ammonium perchlorates have been studied using high-temperature X-ray diffraction and differential thermal analysis techniques. In the temperature range from 20°C to their decomposition temperature (above 300°C), ammonium perchlorate and tetramethyl ammonium perchlorate undergo only one enantiomorphic phase transition, namely at 240 and 340°C (with decomposition), respectively. This I—II transition is ascribed to the beginning of the free rotation of the ClO4− ions. The rotation of the cations, however, begins below room temperature. If the symmetry of the cation is lowered by having both methyl groups and hydrogens arranged around the nitrogen (as in monomethyl, dimethyl, and trimethyl ammonium perchlorates), there is an additional enantiomorphic phase transition. This I—II transformation is ascribed to the rotation of the cations which have, in the partially substituted ions, two sets of non-equivalent symmetry axes (different moments of inertia). The temperatures of transformation are discussed in terms of the space requirements for rotation. Symmetries and cell dimensions of some modifications were determined.

Synthesis, Crystal Structure and Magnetic Properties of a Copper(II) p-Formylbenzoate Complex

2012 ◽  
Vol 67 (11) ◽  
pp. 1185-1190 ◽  
Author(s):  
Jin-Li Qi ◽  
Wei Xu ◽  
Yue-Qing Zheng
Keyword(s):  
Room Temperature ◽  
Magnetic Measurements ◽  
X Ray Diffraction ◽  
Complex Molecules ◽  
Triclinic Space Group ◽  
X Ray ◽  
Cell Dimensions ◽  
Ferromagnetic Interactions ◽  
Aqueous Conditions ◽  
Discrete Complex

A new Cu(II) complex was prepared at room temperature from the reaction of p-formylbenzoic acid, phenanthroline, CuCl2⋅2H2O, and NaOH under ethanolic aqueous conditions. The complex has been characterized by X-ray diffraction, IR spectroscopy, TG-DTA analyses, and magnetic measurements. Single-crystal X-ray diffraction analysis indicated that the complex crystallizes in the triclinic space group P1̄ with the cell dimensions a=7.875(2), b=10.724(2), c=15.317(3) Å , α =102.65(3), β =93.71(3), γ =107:64(3)°. The Cu atoms are in the environment of distorted CuN2O3 tetragonal pyramids. These discrete complex molecules are packed through intermolecular π...π-stacking interactions and C-H...O hydrogen bonds forming a supramolecular structure. The title complex obeys the Curie-Weiss law with a Curie constant C=0:53 cm3 K mol-1 and a Weiss constant θ = -0:27 K. The shape of the xmT curve is characteristic of weak ferromagnetic interactions between the Cu(II) centers from 300 to 7 K, while there are weak antiferromagnetic interactions below 7 K.

Order-disorder transformations in graphite nitrates

1966 ◽  
Vol 291 (1426) ◽  
pp. 324-339 ◽  
Keyword(s):  
Room Temperature ◽  
Molecular Packing ◽  
Three Dimensions ◽  
Numerical Sequence ◽  
X Ray ◽  
Graphite Nitrate ◽  
Group 2 ◽  
Product Sequence ◽  
Ray Methods ◽  
Crystal Compound

Using synthetic near-ideal graphite obtained by hot-pressing and annealing pyrolytic material, we have prepared graphite nitrates from the first to the fourth sequence, under controlled conditions. For the first sequence compound, present determinations on form I (room temperature) agree with previous publications and confirm the stacking sequence A | A | A | A . Form I sequences 2, 3 and 4 show well defined stacking of the graphite networks, characterized by X-ray methods as follows: sequence network stacking* system unit cell (Å) space group 2 A | AB | BC | CA | A rhombohedral a H = 2⋅46 R 3 ¯ m c H = 33⋅45 3 A | ABA | ACA | A orthorhombic a = 2⋅46 Cmc 2 1 b = 4⋅26 c = 28⋅96 4 A | ABAB | BCBC | CACA | A rhombohedral a H = 2⋅46 R 3 ¯ m c H = 53⋅5 * The vertical lines imply layers of intercalate. In all these compounds, the stacking sequences found can be generated from the stacking in normal graphite, ABAB , if the change AB → A | A on entry of successive intercalate layers involves the movement of a boundary dislocation through the structure. Since it is observed that the end-product (sequence N ) under any given conditions is formed by way of a systematic numerical succession of higher sequence compounds ( N +2, N +1) as intermediates, this fundamental stacking change must reverse so that AB ⇌ A | A . When any of these sequences of graphite nitrate are cooled through a λ transformation around —20°C, increased ordering appears in the low temperature structures (form II). Each intercalate layer now exhibits two-dimensional long range order. In addition, successive intercalated layers within any crystallite are stacked in a non-random way, which in the case of the first sequence compound implies a structure that is periodic in three dimensions. Within any intercalated layer in form I, the molecular packing resembles that in liquids. In a given crystal compound the numerical sequence of such layers is regular, and successive intercalate layers occur after N carbon hexagon planes. In form II, molecular packing in the intercalated layers is crystalline. Some correlation also appears between the occupied sites in different filled layers. Implications of this order-disorder transformation are briefly discussed.

scholarly journals Bi- and trinuclear copper(I) complexes of 1,2,3-triazole-tethered NHC ligands: synthesis, structure, and catalytic properties

2016 ◽  
Vol 12 ◽  
pp. 863-873 ◽  
Author(s):  
Shaojin Gu ◽  
Jiehao Du ◽  
Jingjing Huang ◽  
Huan Xia ◽  
Ling Yang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Copper Complexes ◽  
Catalytic Properties ◽  
Polynuclear Complexes ◽  
Carbene Ligands ◽  
Efficient Catalyst ◽  
X Ray ◽  
X Ray Crystallography ◽  
Air Atmosphere ◽  
Highly Active

A series of copper complexes (3–6) stabilized by 1,2,3-triazole-tethered N-heterocyclic carbene ligands have been prepared via simple reaction of imidazolium salts with copper powder in good yields. The structures of bi- and trinuclear copper complexes were fully characterized by NMR, elemental analysis (EA), and X-ray crystallography. In particular, [Cu2(L2)2](PF6)2 (3) and [Cu2(L3)2](PF6)2 (4) were dinuclear copper complexes. Complexes [Cu3(L4)2](PF6)3 (5) and [Cu3(L5)2](PF6)3 (6) consist of a triangular Cu3 core. These structures vary depending on the imidazolium backbone and N substituents. The copper–NHC complexes tested are highly active for the Cu-catalyzed azide–alkyne cycloaddition (CuAAC) reaction in an air atmosphere at room temperature in a CH3CN solution. Complex 4 is the most efficient catalyst among these polynuclear complexes in an air atmosphere at room temperature.

Neue Arsenide mit ThCr2Si2- oder einer damit verwandten Struktur: Die Verbindungen ARh2As2 (A: Eu, Sr, Ba) und BaZn2As2 / New Arsenides with ThCr2Si2-type or Related Structures: The Compounds ARh2As2 (A: Eu, Sr, Ba) and BaZn2As2

2007 ◽  
Vol 62 (2) ◽  
pp. 155-161 ◽  
Author(s):  
Andrea Hellmann ◽  
Anke Löhken ◽  
Andreas Wurth ◽  
Albrecht Mewis
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Two Phase ◽  
Atomic Size ◽  
X Ray ◽  
Β Phase ◽  
Vertex Sharing ◽  
3D Network ◽  
Ray Methods ◽  
High Temperature Modification

Four new arsenides of rhodium and zinc were prepared by heating mixtures of the elements at high temperatures (1000 - 1200 °C) and investigated by single crystal X-ray methods. EuRh2As2 (a = 4.067(1), c = 11.319(2) Å ) and BaRh2As2 (a = 4.053(1), c = 12.770(3) Å ) crystallize with the well-known ThCr2Si2-type (I4/mmm; Z = 2). Due to the rigid layers of RhAs4 tetrahedra, and to the atomic size of europium and barium, the As-As distances between the layers with values of 2.97 and 3.66 Å, respectively, are very long. SrRh2As2 is polymorphic and undergoes two phase transitions at about 190 and 282 °C. Main features of the three crystal structures are also layers of RhAs4 tetrahedra. At room temperature α-SrRh2As2 (a = 5.676(1), b = 6.178(2), c = 11.052(2) Å ) probably crystallizes with the BaNi2Si2-type (Cmcm; Z = 4), whereas β -SrRh2As2 (a = 5.760(3), b = 6.067(4), c = 11.264(5) A° , Fmmm, Z = 4) forms a new orthorhombically distorted variant of the ThCr2Si2-type. Single crystals grown in a flux of lead and quenched at high temperature show that the γ -phase (a = 4.112(1), c = 11.431(6) Å ) crystallizes with the ThCr2Si2-type. The same is true for the high temperature modification of BaZn2As2 (β -phase; a = 4.120(1), c = 13.578(1) Å ), whereas the already known α-BaZn2As2 forms the α-BaCu2S2-type (Pnma; Z = 4) consisting of a 3D-network of edge- and vertex-sharing ZnAs4 tetrahedra with Ba atoms in the voids of this network.

X-ray study of the α–β transformation of berlinite (AlPO4)

1976 ◽  
Vol 54 (6) ◽  
pp. 638-647 ◽  
Author(s):  
H. N. Ng ◽  
C. Calvo
Keyword(s):  
Room Temperature ◽  
Translational Motion ◽  
Fold Axis ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Atomic Displacements ◽  
Β Phase ◽  
Four Corners ◽  
Dauphiné Twinning

The α–β transformation of berlinite (AlPO4) at 586 °C was studied by X-ray diffraction. Atomic displacements were obtained from results of least-squares refinement of data taken between room temperature and 600 °C using reflections whose intensity is unaffected by Dauphiné twinning. The results suggest a rotational motion of the PO4 and AlO4 tetrahedra around the two-fold axis together with a translational motion along the same axis as the transition is approached from below. The vibrational amplitudes of the atoms increase with temperature and have exceeded half of the separation between Dauphiné twin-related configurations at 500 °C. The final β-phase configuration is not achieved by this twinning due to the mismatch of the two configurational potential minima in the a direction. Analysis of the intensity vs. temperature data favours a single minimum model for the β phase configuration over an order–disorder model. The β-AlPO4 structure consists of alternate PO4 and AlO4 tetrahedra sharing all four corners with P—O and Al—O distances 1.505 and 1.694 Å respectively. The results are correlated with those obtained from temperature dependent studies by Raman scattering and by EPR on Fe3+-doped AlPO4.

Die Kristallstruktur von PPh4[MoOCl4(OCHNMe2)] / The Crystal Structure of PPh4[MoOCl4(OCHNMe2)]

1986 ◽  
Vol 41 (4) ◽  
pp. 523-526 ◽  
Author(s):  
Dieter Fenske ◽  
Kay Jansen ◽  
Kurt Dehnicke
Keyword(s):  
Crystal Structure ◽  
Carbon Tetrachloride ◽  
Octahedral Geometry ◽  
Distorted Octahedral Geometry ◽  
Dimethyl Formamide ◽  
Structural Investigations ◽  
X Ray ◽  
Distorted Octahedral ◽  
Cell Dimensions ◽  
Ray Methods

Green crystals of the title compound are formed in the reaction of (PPh4)2 [Mo2(O2C -Ph)4Cl2] ·2 CH2Cl2 with dimethyl formamide/carbon tetrachloride in the presence of water. According to the structural investigations by X-ray methods PPh4[MoCl4(O CHNMe2)] crystallizes orthorhombically in the space group C2221 with four formula units per unit cell (3132 observed, independent reflexions, R - 0.068). The cell dimensions are a = 792.1 pm, b = 1656.8 pm, c = 2211.3 pm. The structure consists of PPh4⊕ cations and anions [MoOCl4(OCHNMe2)]⊖, in which the coordination sphere of the molybdenum atom is of distorted octahedral geometry. The ligands are four equatorial chlorine atoms, one terminal O atom (Mo = O 165 pm) and the O atom of the dimethyl formamide molecule (MoO 232 pm). The IR spectrum is reported

Synthese, Kristallstruktur und Eigenschaften von Tetraaminophosphoniumchlorid [P(NH2)4]Cl / Synthesis, Crystal Structure, and Properties of Tetraaminophosphonium Chloride [P(NH2)4]Cl

1996 ◽  
Vol 51 (1) ◽  
pp. 127-132 ◽  
Author(s):  
Stefan Horstmann ◽  
Wolfgang Schnick
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
Phosphorus Pentachloride ◽  
Mean Value ◽  
Acetonitrile Solution ◽  
Anomeric Effect ◽  
Electron Pairs ◽  
X Ray ◽  
Hydrogen Bonding Interactions ◽  
Ray Methods

Abstract [P(NH2)4]Cl has been prepared by ammonolysis of phosphorus pentachloride in liquid ammonia. The product was purified by reacting the byproduct, ammonium chloride, with diethylamine and removing the diethylamine hydrochloride. Suitable single crystals were obtained from an acetonitrile solution in a temperature gradient between 60 °C and room temperature. The crystal structure of [P(NH2)4]Cl has been determined by single crystal X-ray methods (Pbcn, a = 470.8(2), b = 1622.3(3), c = 756.3(2) pm, Z = 4). In the solid, [P(NH2)4]+ and Cl- ions are found, resembling a TlI-analogous structure. The N-H···Cl distances indicate N-H···Cl hydrogen bonding interactions. The distortion of the P-N sceleton of the cation and the very short P-NH2 distances (mean value: 161.2 pm) have been confirmed by ab initio calculations, which show a generalized anomeric effect of the electron pairs at nitrogen and pπdπ bonding.

Synthese, Kristallstruktur und Eigenschaften von 1,1,3,3,3-Pentaamino-1-oxo- 1λ5 ,3λ5-diphosphaz-2-en, (NH2)2(O)P-N=P(NH2)3 / Synthesis, Crystal Structure, and Properties of 1,1,3,3,3-Pentaamino-1-oxo-1λ5, 3λ5-diphosphaz-2-ene, (NH2)2(O)P-N=P(NH2)3

1996 ◽  
Vol 51 (8) ◽  
pp. 1079-1083 ◽  
Author(s):  
N. Stock ◽  
W. Schnick
Keyword(s):  
Crystal Structure ◽  
Thermal Properties ◽  
Room Temperature ◽  
Three Dimensional ◽  
Intermolecular Hydrogen Bonding ◽  
Structure And Properties ◽  
X Ray ◽  
Hydrogen Bonding Interactions ◽  
Dimensional Network ◽  
Ray Methods

Coarse crystalline (NH2)2(O)P-N=P(NH2)3 is obtained from a NH3 saturated CH2Cl2 suspension of (NH2)2(O)P-N=P(NH2)3 NH4Cl at room temperature. (NH2)2(O)P-N=P(NH2)3·NH4Cl is synthesized by slow addition of Cl2(O)P-N=PCl3 to a solution of NH3 in CH2Cl2 at -78 °C. Excess NH4Cl is removed by treatment with HNEt2 followed by extraction with CH2Cl2. The crystal structure of (NH2)2(O)P-N=P(NH2)3 has been determined by single crystal X-ray methods (P21/c; a = 1462.8(3), b = 944.8(2), c = 1026.9(2) pm, β = 110.69(3)°; Z = 8). In the unit cell there are two crystallographically unique molecules. They form a three dimensional network by intermolecular hydrogen bonding interactions (N-H···N ≥ 313 pm. N-H···O ≥ 293 pm). The investigation of the thermal properties shows decomposition with evolution of NH3 above 80 °C.

Synthese und Kristallstruktur von [(Cl3Si)2N]2TiCl2 -ein perchloriertes N-Silyl-titanamid /Synthesis and Crystal Structure of [(Cl3Si)2N]2TiCl2 -a Fully Chlorinated N-Silyl Titanium Amide

1997 ◽  
Vol 52 (7) ◽  
pp. 819-822 ◽  
Author(s):  
Bernd Schwarze ◽  
Wolfgang Milius ◽  
Wolfgang Schnick
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Room Temperature ◽  
Titanium Atom ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Ray Methods ◽  
Cl Atoms

Abstract The chlorinated titanium amides [(Cl3Si)2N]2TiCl2 (1) and (Cl3Si)2NTiCl3 have been syn­thesized selectively from hexachlorodisilazane lithium and TiCl4. The crystal structure of 1 was determined by single crystal X-ray methods at room temperature (P212121, a = 1232.4(2), b = 1265.5(2), c -1469.1(2) pm, Z = 4). The central titanium atom of 1 is bound to two nitrogen atoms and two Cl atoms and is weakly coordinated further by two Cl atoms of the trichlorosilyl groups.

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