Binuclear copper(II) complexes of the tetradentate ligand 1,4-di(2′-pyridyl)aminophthalazine: some novel five-coordinate derivatives

1969 ◽  
Vol 47 (22) ◽  
pp. 4141-4152 ◽  
Author(s):  
L. K. Thompson ◽  
V. T. Chacko ◽  
J. A. Elvidge ◽  
A. B. P. Lever ◽  
R. V. Parish
Keyword(s):  
Room Temperature ◽  
Principal Series ◽  
Magnetic Data ◽  
Binuclear Copper ◽  
Neutral Form ◽  
Deprotonated Form ◽  
Copper Salts ◽  
X Ray ◽  
Anionic Ligand ◽  
Aromatic Carboxylate

Reaction of the title ligand (L) with copper salts leads to the formation of three principal series of compounds, LCu2X3(OH)•H2O (X = Cl, Br), LCu2(RCO2)3, and LCu2(RCO2)4, where RCO2 represents various aliphatic and aromatic carboxylate species. Magnetic data, electronic spectroscopic data both at room temperature and at −196 °C, infrared spectra, and microanalytical data are correlated to reveal that these complexes contain a binuclear copper-copper system in which the copper atoms are 5-coordinate and square pyramidal. Brief details are presented of an X-ray structural analysis of the chloride complex confirming the structure proposed.The ligand forms complexes both in its neutral form and in an anionic deprotonated form. The ultraviolet spectra of the complexes distinguish these modes of bonding. The electronic spectra are discussed in terms of the 5-coordinate square pyramidal copper chromophore deemed to be present. In the complex L2Cu, the copper atom has a trigonally distorted 6-coordinate environment with tridentate anionic ligand.

scholarly journals Dioxidovanadium(V) complexes with pyridoxalaminoguanidine: Synthesis, spectral and structural characterization

2013 ◽  
Vol 78 (8) ◽  
pp. 1161-1170 ◽  
Author(s):  
Mirjana Lalovic ◽  
Vukadin Leovac ◽  
Ljiljana Vojinovic-Jesic ◽  
Marko Rodic ◽  
Ljiljana Jovanovic ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Oxygen Atom ◽  
Structural Characterization ◽  
Ammoniacal Solution ◽  
Neutral Form ◽  
Deprotonated Form ◽  
Spontaneous Transformation ◽  
X Ray ◽  
X Ray Crystallography

Three square-pyramidal complexes of dioxidovanadium(V) with pyridoxalaminoguanidine (PLAG), of the formulas NH4[VO2(PLAG?2H)]?H2O (1), VO2(PLAG?H) (2) and K[VO2(PLAG?2H)]?H2O (3) have been synthesized and characterized by IR and UV-Vis spectral analysis and in case of 1 and 3 by X-ray crystallography as well. The reaction of aqueous ammoniacal solution of NH4VO3 and PLAG resulted in formation of 1, which in MeOH undergoes spontaneous transformation into 2, which, in turn, in the reaction with KOH transforms into 3. In these complexes PLAG is coordinated in a common tridentate ONN mode, via phenoxide oxygen atom and nitrogen atoms of azomethine and imino groups of the aminoguanidine fragment. In all previously characterized complexes PLAG was coordinated in neutral form. However, here we have proven that this ligand can be coordinated in both mono- (2) and doubly deprotonated form (1 and 3) as well. [Projekat Ministarstva nauke Republike Srbije, br. 172014].

Investigation of magnetic properties in Mn incorporated InSb, InP, and GaAs, synthesized through controlled-ambient annealing

2004 ◽  
Vol 825 ◽  
Author(s):  
Joel Hollingsworth ◽  
Prabhakar Bandaru
Keyword(s):  
Data Storage ◽  
Room Temperature ◽  
Magnetic Semiconductors ◽  
Magnetic Data ◽  
X Ray Diffraction ◽  
Electronic Information ◽  
Furnace Annealing ◽  
New Approach ◽  
X Ray ◽  
Curie Temperatures

AbstractMagnetic semiconductors are of interest for emerging spintronic applications, such as the integration of electronic information processing with magnetic data storage. We report on a new approach - furnace annealing under controlled ambients – aimed at increasing Mn incorporation and synthesizing new magnetic semiconductors with Tc greater than/around room temperature. These annealing treatments are hypothesized to reduce the effect of Mn interstitials. We have obtained preliminary SQUID magnetometry results which indicate ferromagnetic Curie temperatures of around 130 K in (In,Mn) Sb and 60 K in (In, Mn)P. X-ray diffraction was used to characterize phase homogeneity.

Transition Metal Complexes of Oxamide Oxime, 1. Synthesis and X-Ray Crystal Structure of Tris(oxamide oxime-N1,N1′)cobalt(III) Triiodide [Co(H2oxao)3]I3

1993 ◽  
Vol 48 (12) ◽  
pp. 1719-1722 ◽  
Author(s):  
Michel Mégnamisi-Bélombé ◽  
Irene Jokwi ◽  
Emmanuel Ngameni ◽  
Robert Roux ◽  
Bernhard Nuber
Keyword(s):  
Crystal Structure ◽  
Transition Metal Complexes ◽  
Room Temperature ◽  
Magnetic Data ◽  
Formula Unit ◽  
X Ray Diffraction ◽  
Specific Difference ◽  
Full Matrix ◽  
X Ray ◽  
Trigonal Structure

Tris(oxamide oxime-N1,N1′)cobalt(III) triiodide, [Co(H2oxao)3]I3, has been synthesized, and its structure determined by single crystal X-ray diffraction at room temperature. The trigonal structure (rhombohedral space group R 3̄ c) was refined by full matrix least-squares to a final R (Rw) of 4.1 (3.5)% for 51 parameters and 911 observed independent reflections. The structure consists exclusively of quasi-octahedral chiral cobaloxime cations, [Co(H2oxao)3]3+, and iodide anions. This structure is isotypic to that of the homologous Ni-based salt analyzed previously in which, as a matter of specific difference, one H2O molecule of crystallization per formula unit is present. Moreover, whereas nickel in the latter salt was identified as NiII on the basis of magnetic data, preliminary voltammetric data clearly reveals Com in the present salt.

Binuclear Copper(II) Complexes of Some Tetradentate Pyridyl Phthalazine Ligands. Structure, Electrochemistry and Magnetism - Crystal-Structure of Aqua-µ-[1,4-Di-(4',6'-Dimethylpyridin-2'-Ylamino)-Phthalazine-N1',µ-N2 ,µ-N3,N1'']-µ-Hydroxo-Dinitratodicopper(II) Nitrate

1986 ◽  
Vol 39 (7) ◽  
pp. 1007 ◽  
Author(s):  
SK Mandal ◽  
TC Woon ◽  
LK Thompson ◽  
MJ Newlands ◽  
EJ Gabe
Keyword(s):  
Variable Temperature ◽  
Magnetic Moments ◽  
Magnetic Data ◽  
Redox Potentials ◽  
Binuclear Copper ◽  
Triclinic Space Group ◽  
X Ray ◽  
One Step ◽  
Strong Exchange ◽  
Very High

The molecular structure of aqua-μ-[1,4-di(4′,6′-dimethylpyridin-2′- ylamino )phthalazine-N1′,μ-N2,μ-N3,N1′]-μ- hydroxo-dinitratodicopper (II) nitrate has been determined by single-crystal X-ray diffractometry . The compound is triclinic, space group Pī , with two molecules in the unit cell of dimensions a 7.8064(11), b 12.9137(14), c 14.8564(14), α 69.857(8), β 80.074(10), γ 83.659(11). The structure was refined by least-squares to a residual of 0.057 for 2806 reflections. The binuclear centre in the complex involves a five-coordinate and a tetragonally distorted six-coordinate copper atom, each with a coordinated, bidentate nitrate, a copper-copper separation of 3.156 Ǻ and a Cu-O(H)-Cu bridge angle of 113.7°. This complex, and other related systems, exhibit low room-temperature magnetic moments (< 1.2 BM), suggesting antiferromagnetically coupled binuclear copper centres , and in the case of the complex [Cu2( paps )(OH)Cl3].3H2O variable- temperature magnetic data indicate moderately strong exchange with -2J = 432 cm-1. Very high redox potentials are observed for these complexes [0.00-0.83 V (v. s.c.e .)] involving two-electron transfer in one step or two separate steps.

Electron Microscopy of Human Gallstones

1971 ◽  
Vol 29 ◽  
pp. 296-297
Author(s):  
C. Wolpers ◽  
R. Blaschke
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Bile Pigment ◽  
X Ray Diffraction ◽  
Triclinic Crystal System ◽  
X Ray ◽  
Follow Up Study ◽  
Infra Red ◽  
Main Components

Scanning microscopy was used to study the surface of human gallstones and the surface of fractures. The specimens were obtained by operation, washed with water, dried at room temperature and shadowcasted with carbon and aluminum. Most of the specimens belong to patients from a series of X-ray follow-up study, examined during the last twenty years. So it was possible to evaluate approximately the age of these gallstones and to get information on the intensity of growing and solving.Cholesterol, a group of bile pigment substances and different salts of calcium, are the main components of human gallstones. By X-ray diffraction technique, infra-red spectroscopy and by chemical analysis it was demonstrated that all three components can be found in any gallstone. In the presence of water cholesterol crystallizes in pane-like plates of the triclinic crystal system.

Opening images of synaptic vesicles and calcium localization by means of microwave fixation method

1990 ◽  
Vol 48 (2) ◽  
pp. 182-183
Author(s):  
Vinci Mizuhira ◽  
Hiroshi Hasegawa
Keyword(s):  
Synaptic Vesicles ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Sampling Procedure ◽  
Fixation Method ◽  
Potassium Oxalate ◽  
X Ray ◽  
Cacodylate Buffer ◽  
Ultrathin Sections ◽  
Microwave Fixation

Microwave irradiation (MWI) was applied to 0.3 to 1 cm3 blocks of rat central nervous system at 2.45 GHz/500W for about 20 sec in a fixative, at room temperature. Fixative composed of 2% paraformaldehyde, 0.5% glutaraldehyde in 0.1 M cacodylate buffer at pH 7.4, also contained 2 mM of CaCl2 , 1 mM of MgCl2, and 0.1% of tannic acid for conventional observation; and fuether 30-90 mM of potassium oxalate containing fixative was applied for the detection of calcium ion localization in cells. Tissue blocks were left in the same fixative for 30 to 180 min after MWI at room temperature, then proceeded to the sampling procedure, after postfixed with osmium tetroxide, embedded in Epon. Ultrathin sections were double stained with an useal manner. Oxalate treated sections were devided in two, stained and unstained one. The later oxalate treated unstained sections were analyzed with electron probe X-ray microanalyzer, the EDAX-PU-9800, at 40 KV accelerating voltage for 100 to 200 sec with point or selected area analyzing methods.

Evidence for ordered Fe3Ni

1987 ◽  
Vol 45 ◽  
pp. 216-217
Author(s):  
K.B. Reuter ◽  
D.B. Williams ◽  
J.I. Goldstein
Keyword(s):  
Experimental Data ◽  
Martensitic Transformation ◽  
Electron Diffraction ◽  
Room Temperature ◽  
Direct Evidence ◽  
Transformation Product ◽  
Iron Meteorites ◽  
X Ray ◽  
Ni Content ◽  
Temperature Transformation

In the Fe-Ni system, although ordered FeNi and ordered Ni3Fe are experimentally well established, direct evidence for ordered Fe3Ni is unconvincing. Little experimental data for Fe3Ni exists because diffusion is sluggish at temperatures below 400°C and because alloys containing less than 29 wt% Ni undergo a martensitic transformation at room temperature. Fe-Ni phases in iron meteorites were examined in this study because iron meteorites have cooled at slow rates of about 10°C/106 years, allowing phase transformations below 400°C to occur. One low temperature transformation product, called clear taenite 2 (CT2), was of particular interest because it contains less than 30 wtZ Ni and is not martensitic. Because CT2 is only a few microns in size, the structure and Ni content were determined through electron diffraction and x-ray microanalysis. A Philips EM400T operated at 120 kV, equipped with a Tracor Northern 2000 multichannel analyzer, was used.

Electron Microscope study of commensurate-incommensurate phase transition in BaZnGeO4

1990 ◽  
Vol 48 (4) ◽  
pp. 172-173
Author(s):  
Naoki Yamamoto ◽  
Makoto Kikuchi ◽  
Tooru Atake ◽  
Akihiro Hamano ◽  
Yasutoshi Saito
Keyword(s):  
Phase Transition ◽  
Electron Microscope Study ◽  
Room Temperature ◽  
Hexagonal Lattice ◽  
Ferroelectric Materials ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Periodic Arrays ◽  
Modulation Wave Vector

BaZnGeO4 undergoes many phase transitions from I to V phase. The highest temperature phase I has a BaAl2O4 type structure with a hexagonal lattice. Recent X-ray diffraction study showed that the incommensurate (IC) lattice modulation appears along the c axis in the III and IV phases with a period of about 4c, and a commensurate (C) phase with a modulated period of 4c exists between the III and IV phases in the narrow temperature region (—58°C to —47°C on cooling), called the III' phase. The modulations in the IC phases are considered displacive type, but the detailed structures have not been studied. It is also not clear whether the modulation changes into periodic arrays of discommensurations (DC’s) near the III-III' and IV-V phase transition temperature as found in the ferroelectric materials such as Rb2ZnCl4.At room temperature (III phase) satellite reflections were seen around the fundamental reflections in a diffraction pattern (Fig.1) and they aligned along a certain direction deviated from the c* direction, which indicates that the modulation wave vector q tilts from the c* axis. The tilt angle is about 2 degree at room temperature and depends on temperature.

Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

2020 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Crystal Growth ◽  
Single Crystal ◽  
Room Temperature ◽  
Growth Technique ◽  
Salt Hydrate ◽  
X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

Sign in / Sign up

Export Citation Format

Share Document