scholarly journals 4,5-Diazafluorene and 9,9’-Dimethyl-4,5-Diazafluorene as Ligands Supporting Redox-Active Mn and Ru Complexes

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3189
Author(s):  
Wade C. Henke ◽  
Julie A. Hopkins ◽  
Micah L. Anderson ◽  
Jonah P. Stiel ◽  
Victor W. Day ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Visible Region ◽  
Structural Data ◽  
Spectroscopic Properties ◽  
X Ray Diffraction ◽  
Absorption Data ◽  
Redox Active ◽  
Ligand Charge Transfer ◽  
Ru Complexes ◽  
Active Nature

4,5-diazafluorene (daf) and 9,9’-dimethyl-4,5-diazafluorene (Me2daf) are structurally similar to the important ligand 2,2’-bipyridine (bpy), but significantly less is known about the redox and spectroscopic properties of metal complexes containing Me2daf as a ligand than those containing bpy. New complexes Mn(CO)3Br(daf) (2), Mn(CO)3Br(Me2daf) (3), and [Ru(Me2daf)3](PF6)2 (5) have been prepared and fully characterized to understand the influence of the Me2daf framework on their chemical and electrochemical properties. Structural data for 2, 3, and 5 from single-crystal X-ray diffraction analysis reveal a distinctive widening of the daf and Me2daf chelate angles in comparison to the analogous Mn(CO)3(bpy)Br (1) and [Ru(bpy)3]2+ (4) complexes. Electronic absorption data for these complexes confirm the electronic similarity of daf, Me2daf, and bpy, as spectra are dominated in each case by metal-to-ligand charge transfer bands in the visible region. However, the electrochemical properties of 2, 3, and 5 reveal that the redox-active Me2daf framework in 3 and 5 undergoes reduction at a slightly more negative potential than that of bpy in 1 and 4. Taken together, the results indicate that Me2daf could be useful for preparation of a variety of new redox-active compounds, as it retains the useful redox-active nature of bpy but lacks the acidic, benzylic C–H bonds that can induce secondary reactivity in complexes bearing daf.

scholarly journals A novel redox-active calix[4]arene-tetrathiafulvalene dyad

2011 ◽  
Vol 9 (6) ◽  
pp. 1102-1108 ◽  
Author(s):  
Bang-Tun Zhao ◽  
Xiao-Min Zhu ◽  
Qi-Ming Peng ◽  
Zhen-Ning Yan ◽  
Franck Derf ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Diffraction Analysis ◽  
Electrochemical Properties ◽  
Absorption Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Redox Active ◽  
Cesium Fluoride

AbstractA novel redox-active calix[4]arene-TTF 5 was prepared by the reaction of p-tert-butylcalix[4]arene 4 with the tosylated TTF 3 in the presence of cesium fluoride. The structure of the dyad 5 was identified by X-ray diffraction analysis, and the preliminary electrochemical properties of 5 were investigated by cyclic voltammetry (CV), for which two reversible one-electron waves were observed. Moreover, the UV-vis absorption spectra studies show that the dyad 5 undergoes progressive oxidation at the TTF moiety in presence of increasing amounts of Cu2+ or Hg2+.

scholarly journals Spectroscopic properties of lithium borate glass containing Sm3+ and Nd3+ ions

2020 ◽  
Vol 9 (3) ◽  
pp. 211
Author(s):  
I. Kashif ◽  
A. Ratep ◽  
S. Ahmed
Keyword(s):  
Borate Glass ◽  
Visible Region ◽  
Amorphous State ◽  
Spectroscopic Properties ◽  
Structural Vibration ◽  
Luminescence Spectra ◽  
Lithium Borate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lithium Borate Glass

<p><span>Lithium borate glass samples mixed with a different concentration of Sm<sup>3</sup>+ and Nd<sup>3+</sup> ions organized by quenching technique. Structural, vibration groups and spectral properties of glass samples investigated using X-ray diffraction, FTIR, UV/Vis/NIR and photoluminescence spectroscopy. The X-ray confirmed the lithium borate glass samples containing Sm<sup>3+</sup> and Nd<sup>3+</sup> ions in the amorphous state. Luminescence spectra of glass samples excited at 400 nm recorded, here three luminescence bands observed in Visible region, which due to spectra materials (Sm3+, Nd3+). These indicate that these glass samples responsible orange emission and used in the improvement of materials for LED, and optical devices. The functional vibration groups of the glass matrix studied using FTIR spectroscopy.</span></p>

Growth and characterizations of L-methioninium picrate single crystal for nonlinear optical applications

2016 ◽  
Vol 25 (04) ◽  
pp. 1650052 ◽  
Author(s):  
A. Alexandar ◽  
P. Surendran ◽  
S. Sakthy Priya ◽  
A. Lakshmanan ◽  
P. Rameshkumar
Keyword(s):  
Single Crystal ◽  
Nonlinear Optical ◽  
Visible Region ◽  
Spectroscopic Properties ◽  
Optical Microscope ◽  
Solution Technique ◽  
X Ray Diffraction ◽  
Diamond Pyramid ◽  
Optical Applications ◽  
Nonlinear Optical Applications

An organic nonlinear optical (NLO) single crystal of L-methioninium picrate (LMP) has been grown by slow evaporation solution technique (SEST) at a constant temperature of [Formula: see text]C. Formation of nucleation and growth kinetics of the crystal were observed using an optical microscope for different durations and it was found that the shape of nucleation is similar to the grown large size single crystals of the same material. The characterization techniques such as powder X-ray diffraction (PXRD) analysis, UV–Vis NIR, Vickers microhardness, piezoelectric d[Formula: see text] coefficient, photoconductivity and etching studies have been performed. The crystal system and lattice parameters of the grown crystal were determined by PXRD analysis. The spectroscopic properties of the synthesized compound were confirmed by Fourier transform infrared (FTIR) analysis. The UV–Vis NIR analysis was performed on the grown single crystal to find the optical absorption in the entire visible region. Attempts have been made to investigate the mechanical properties of LMP crystal using Vickers diamond pyramid indenter. In addition piezoelectric, photoconductivity and etching studies were carried out to study the d[Formula: see text] coefficient, photoconducting nature and surface properties respectively.

Tubulin structure at intermediate resolution

1995 ◽  
Vol 53 ◽  
pp. 852-853
Author(s):  
K. H. Downing ◽  
S. G. Wolf ◽  
E. Nogales
Keyword(s):  
High Resolution ◽  
Structural Data ◽  
Therapeutic Drug ◽  
Zinc Ions ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Negative Stain ◽  
Functional Mechanisms ◽  
Tubulin Structure

Microtubules are involved in a host of critical cell activities, many of which involve transport of organelles through the cell. Different sets of microtubules appear to form during the cell cycle for different functions. Knowledge of the structure of tubulin will be necessary in order to understand the various functional mechanisms of microtubule assemble, disassembly, and interaction with other molecules, but tubulin has so far resisted crystallization for x-ray diffraction studies. Fortuitously, in the presence of zinc ions, tubulin also forms two-dimensional, crystalline sheets that are ideally suited for study by electron microscopy. We have refined procedures for forming the sheets and preparing them for EM, and have been able to obtain high-resolution structural data that sheds light on the formation and stabilization of microtubules, and even the interaction with a therapeutic drug.Tubulin sheets had been extensively studied in negative stain, demonstrating that the same protofilament structure was formed in the sheets and microtubules. For high resolution studies, we have found that the sheets embedded in either glucose or tannin diffract to around 3 Å.

Effect of trytophan as dopant on potassium acid phthalate single crystals

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Single Crystals ◽  
Room Temperature ◽  
Visible Region ◽  
X Ray Diffraction ◽  
X Ray ◽  
Slow Evaporation Technique ◽  
Absorption Studies ◽  
Evaporation Technique ◽  
Potassium Acid Phthalate ◽  
Acid Phthalate

Optically transparent single crystals of potassium acid phthalate (KAP, 0.5 g) 0.05 g and 0.1 g (1 and 2 mol %) trytophan were grown in aqueous solution by slow evaporation technique at room temperature. Single crystal X- ray diffraction analysis confirmed the changes in the lattice parameters of the doped crystals. The presence of functional groups in the crystal lattice has been determined qualitatively by FTIR analysis. Optical absorption studies revealed that the doped crystals possess very low absorption in the entire visible region. The dielectric constant has been studied as a function of frequency for the doped crystals. The thermal stability was evaluated by TG-DSC analysis.

scholarly journals Synthesis and Electrochemical Properties of TiNb2O7 and Ti2Nb10O29 Anodes under Various Annealing Atmospheres

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 983
Author(s):  
Touraj Adhami ◽  
Reza Ebrahimi-Kahrizsangi ◽  
Hamid Reza Bakhsheshi-Rad ◽  
Somayeh Majidi ◽  
Milad Ghorbanzadeh ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Annealing Treatment ◽  
Lithium Ion ◽  
Argon Atmosphere ◽  
Oxygen Atmosphere ◽  
Annealing Atmosphere ◽  
Electrochemical Characteristics ◽  
X Ray Diffraction ◽  
Lower Capacity ◽  
Discharge Capacities

In this study, two compounds of TiNb2O7 and Ti2Nb10O29 were successfully synthesized by mechanochemical method and post-annealing as an anode material for lithium-ion batteries. The effect of annealing atmosphere on the morphology, particle size, and electrochemical characteristics of two compounds was investigated. For these purposes, the reactive materials were milled under an argon atmosphere with a certain mole ratio. Subsequently, each sample was subjected to annealing treatment in two different atmospheres, namely argon and oxygen. Phase and morphology identifications were carried out by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) to identify the phases and evaluate the morphology of the synthesized samples. The charging and discharging tests were conducted using a battery-analyzing device to evaluate the electrochemical properties of the fabricated anodes. Annealing in different atmospheres resulted in variable discharge capacities so that the two compounds of TiNb2O7 and Ti2Nb10O29 annealed under the argon atmosphere showed a capacity of 60 and 66 mAh/g after 179 cycles, respectively, which had a lower capacity than their counterpart under the oxygen atmosphere. The final capacity of the annealed samples in the oxygen atmosphere is 72 and 74 mAh/g, respectively.

Compressibility of β-As4S4: an in situ high-pressure single-crystal X-ray study

2012 ◽  
Vol 76 (4) ◽  
pp. 963-973 ◽  
Author(s):  
G. O. Lepore ◽  
T. Boffa Ballaran ◽  
F. Nestola ◽  
L. Bindi ◽  
D. Pasqual ◽  
...  
Keyword(s):  
Pressure Range ◽  
Substantial Reduction ◽  
Structural Data ◽  
Unit Cell ◽  
Van Der Waals Interactions ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Intermolecular Distances

AbstractAmbient temperature X-ray diffraction data were collected at different pressures from two crystals of β-As4S4, which were made by heating realgar under vacuum at 295ºC for 24 h. These data were used to calculate the unit-cell parameters at pressures up to 6.86 GPa. Above 2.86 GPa, it was only possible to make an approximate measurement of the unit-cell parameters. As expected for a crystal structure that contains molecular units held together by weak van der Waals interactions, β-As4S4 has an exceptionally high compressibility. The compressibility data were fitted to a third-order Birch–Murnaghan equation of state with a resulting volume V0 = 808.2(2) Å3, bulk modulus K0 = 10.9(2) GPa and K' = 8.9(3). These values are extremely close to those reported for the low-temperature polymorph of As4S4, realgar, which contains the same As4S4 cage-molecule. Structural analysis showed that the unit-cell contraction is due mainly to the reduction in intermolecular distances, which causes a substantial reduction in the unit-cell volume (∼21% at 6.86 GPa). The cage-like As4S4 molecules are only slightly affected. No phase transitions occur in the pressure range investigated.Micro-Raman spectra, collected across the entire pressure range, show that the peaks associated with As–As stretching have the greatest pressure dependence; the S–As–S bending frequency and the As–S stretching have a much weaker dependence or no variation at all as the pressure increases; this is in excellent agreement with the structural data.

scholarly journals Enhanced Photocatalytic Activity of Cu2O Cabbage/RGO Nanocomposites under Visible Light Irradiation

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1712
Author(s):  
Appusamy Muthukrishnaraj ◽  
Salma Ahmed Al-Zahrani ◽  
Ahmed Al Otaibi ◽  
Semmedu Selvaraj Kalaivani ◽  
Ayyar Manikandan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermo Gravimetric Analysis ◽  
Visible Region ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dye Pollutants ◽  
Transmission Electron

Towards the utilization of Cu2O nanomaterial for the degradation of industrial dye pollutants such as methylene blue and methyl orange, the graphene-incorporated Cu2O nanocomposites (GCC) were developed via a precipitation method. Using Hummers method, the grapheme oxide (GO) was initially synthesized. The varying weight percentages (1–4 wt %) of GO was incorporated along with the precipitation of Cu2O catalyst. Various characterization techniques such as Fourier-transform infra-red (FT-IR), X-ray diffraction (XRD), UV–visible diffused reflectance (UV-DRS), Raman spectroscopy, thermo gravimetric analysis (TGA), energy-dispersive X-ray analysis (EDX), and electro chemical impedance (EIS) were followed for characterization. The cabbage-like morphology of the developed Cu2O and its composites were ascertained from field-emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HR-TEM). In addition, the growth mechanism was also proposed. The results infer that 2 wt % GO-incorporated Cu2O composites shows the highest value of degradation efficiency (97.9% and 96.1%) for MB and MO at 160 and 220 min, respectively. Further, its catalytic performance over visible region (red shift) was also enhanced to an appreciable extent, when compared with that of other samples.

Magnetism and structure of a novel trinuclear cluster compound of divalent copper

1969 ◽  
Vol 22 (12) ◽  
pp. 2527 ◽  
Author(s):  
R Beckett ◽  
R Colton ◽  
BF Hoskins ◽  
RL Martin ◽  
DG Vince
Keyword(s):  
Structural Data ◽  
Hydroxyl Group ◽  
Cluster Compound ◽  
X Ray Diffraction ◽  
Trinuclear Cluster ◽  
Metal Atoms ◽  
Doublet Ground State ◽  
Molecular Orbital Analysis ◽  
Orbital Analysis ◽  
Unusual Type

The magnetic properties of a series of salts of the type [Cu3L3OH]2+ (where HL is pyridine-2-aldehyde oxime and L is the deprotonated ligand) have been examined. All of the compounds showed a magnetic moment of 1.00 B.M. per copper atom over a wide temperature range which suggests that the cation contains a trinuclear cluster of interacting copper atoms. The crystal structure of Cu3L3OH(SO4),xH2O has been determined by single- crystal X-ray diffraction techniques and confirms that the complex does indeed contain an unusual type of trinuclear cluster of metal atoms. The three copper atoms form an equilateral triangle and the sulphato group exhibits a highly novel ?tripod? bridging function to the Cu3 triangle. On the other side of the triangle, the hydroxyl group also bridges to all the metal atoms. A qualitative molecular orbital analysis not only suggests that the hydroxyl group is involved in four-centre bonding with the Cu3 triads, but also highlights its role in reducing the spin of the trimer so that only a doublet ground state is populated between 80-300�K. However, the alternative super-exchange mechanism cannot be ruled out by the magnetic and structural data.

Probing Structure Modification of Palladium Nanomaterials during Chemical Synthesis by using In Situ X-ray Diffraction: Electrochemical Properties

2015 ◽  
Vol 2 (4) ◽  
pp. 592-599 ◽  
Author(s):  
Yaovi Holade ◽  
Teko W. Napporn ◽  
Claudia Morais ◽  
Karine Servat ◽  
K. Boniface Kokoh
Keyword(s):  
Chemical Synthesis ◽  
Electrochemical Properties ◽  
Structure Modification ◽  
X Ray Diffraction ◽  
X Ray
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