A Two-Dimensional Coordination Polymer Formed from Cobalt(II) and an Extended Dipyridyl Ligand

2020 ◽  
Vol 73 (6) ◽  
pp. 547 ◽  
Author(s):  
Hydar A. AL-Fayaad ◽  
Rashid G. Siddique ◽  
Kasun S. Athukorala Arachchige ◽  
Jack K. Clegg
Keyword(s):  
Coordination Polymer ◽  
Cell Volume ◽  
Crystal Structures ◽  
Unit Cell Volume ◽  
Suzuki Coupling ◽  
Unit Cell ◽  
Square Lattice ◽  
Two Dimensional ◽  
Cobalt Ions ◽  
One Dimensional

The synthesis of the extended dipyridyl ligand 4,4′-(2,5-dimethyl-1,4-phenylene)dipyridine (L) in an improved yield via the palladium catalysed Suzuki coupling of 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (1) and 1,4-dibromo-2,5-dimethylbenzene (2) is reported along with its use to form a two-dimensional coordination polymer [Co2L2(OAc)4(H2O)2]n. The coordination polymer consists of one-dimensional chains of octahedral cobalt ions bridged by acetate ligands which are connected to form two dimensional sheets with square lattice (sql) topology via the dipyridyl ligands (L). The structure contains small voids totalling ~6.6% of the unit cell volume. The crystal structures 1, L, L·2H2O, and L·2HNO3 are also reported.

Electron–phonon interaction in three-, two- and one-dimensional ternary mixed crystals

2016 ◽  
Vol 30 (15) ◽  
pp. 1650182
Author(s):  
Junhua Hou ◽  
Yunpeng Fan
Keyword(s):  
Cell Volume ◽  
Effective Mass ◽  
Unit Cell Volume ◽  
Three Dimensional ◽  
Unit Cell ◽  
Mixed Crystals ◽  
Phonon Interaction ◽  
One Dimensional ◽  
Electron Phonon Interaction ◽  
Self Trapping

The electron–phonon (e–p) interaction in three-dimensional (3D), two-dimensional (2D) and one-dimensional (1D) ternary mixed crystals is studied. The e–p interaction Hamiltonians including the unit cell volume variation in ternary mixed crystals are obtained by using the modified random-element-isodisplacement model and Born–Huang method. The polaronic self-trapping energy and renormalized effective mass of GaAs[Formula: see text]Sb[Formula: see text], GaP[Formula: see text]As[Formula: see text] and GaP[Formula: see text]Sb[Formula: see text] compounds are numerically calculated. It is confirmed theoretically that the nonlinear variation of the self-trapping energy and effective mass with the composition is essential and the unit cell volume effects cannot be neglected except the weak e–p coupling. The dimensional effect cannot also be ignored.

Electron–phonon interaction in quasi-1D ternary mixed crystals of polar semiconductors

2015 ◽  
Vol 29 (23) ◽  
pp. 1550130 ◽  
Author(s):  
Yunpeng Fan ◽  
Junhua Hou
Keyword(s):  
Cell Volume ◽  
Unit Cell Volume ◽  
Mixed Crystal ◽  
Random Element ◽  
Unit Cell ◽  
Mixed Crystals ◽  
Phonon Modes ◽  
Phonon Interaction ◽  
One Dimensional ◽  
Electron Phonon Interaction

The electron–optical-phonon interaction between an electron and two branches of LO-phonon modes in a quasi-one-dimensional ternary mixed crystal (TMC) of polar semiconductors is studied. The new electron–phonon interaction Hamiltonian including the unit-cell volume variation in TMCs is obtained by using the modified random element isodisplacement model and Born–Huang method. The energies of polaron are numerically calculated for several systems of III–V compounds. A group of III-nitride mixed crystals is also taken into numerical calculation in our theory. It is verified theoretically that the obvious nonlinearity of the polaronic energy and effective mass with the composition is essential and the unit-cell volume effects cannot be neglected except the very weak e–p coupling.

scholarly journals Synthesis, Characterization and Biological Studies of Ether–Based Ferrocenyl Amides and their Organic Analogues

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 480
Author(s):  
Sana Waseem Abbasi ◽  
Naveed Zafar Ali ◽  
Martin Etter ◽  
Muhammad Shabbir ◽  
Zareen Akhter ◽  
...  
Keyword(s):  
Single Crystal ◽  
Cell Volume ◽  
Crystal Structures ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
Spectral Studies ◽  
Scavenging Activity ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray

Ferrocenyl amides (FB1-FB13) and their organic analogues (BZ1-BZ13) were prepared by a low-temperature condensation method. Ferrocenyl amides were synthesised using 4-ferrocenylbenzoyl chloride and ether-based amines and diamines. Benzoyl chloride was used to synthesise organic analogues by reacting with various amines. The synthesised compounds were characterised by elemental, spectroscopic (FT-IR and NMR) and single crystal X-ray diffraction methods. Crystal structures of the representative organic analogues (BZ2 and BZ6) were solved by single crystal X-ray diffraction. BZ2 crystallises in the triclinic space group P 1 ¯ with a unit cell volume of V = 1056.6(3) Å3 and with two formula units per unit cell. Whereas BZ6 assembles in the orthorhombic space group Pbca with four formula units per unit cell and a unit cell volume of V = 1354.7(2) Å3. Spectral studies confirmed the presence of amide linkages in the synthesised compound with a strong N—H·····O=C hydrogen bonding network established between amide groups of neighbouring molecular scaffolds further stabilising the molecular stacking in accordance with the archetypal crystal structures. The bioactive nature of each compound was assessed by DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity, hydrogen peroxide scavenging activity and total antioxidant activity. Antidiabetic, anticholinesterase enzyme inhibition tests, as well as antibacterial activities, were performed showing significant biological activity for ferrocenyl amides as compared to their organic analogues.

DIFFERENCE OF VARIATION OF UNIT CELL VOLUME V AND Tc WITH OXYGEN CONTENT IN YBa2Cu3O7−x AND LaBa2Cu3O7+x

1988 ◽  
Vol 02 (03n04) ◽  
pp. 641-650
Author(s):  
G.C. CHE ◽  
S.S. XIE ◽  
J.K. LIANG ◽  
K.S. LI ◽  
D.N. ZHENG ◽  
...  
Keyword(s):  
Cell Volume ◽  
Oxygen Content ◽  
Unit Cell Volume ◽  
Lattice Parameter ◽  
Unit Cell ◽  
Dimensional Chain ◽  
One Dimensional ◽  
The One

In YBa 2 Cu 3 O 7−x, the more the oxygen content is the higher is the Tc, the smaller is the lattice parameter c and the unit cell volume V. But in LaBa 2 Cu 3 O 7+x the less the oxygen content is, the higher is the Tc, the larger are c and V. These may be due to oxygen content being less than 7.0 in YBa 2 Cu 3 O 7−x and more than 7.0 in LaBa 2 Cu 3 O 7+x. These results give some informations regarding superconducting mechanism and show that the one-dimensional chain plays an important role.

Design of Organic Superconductors Based on Bedt-TTF

1992 ◽  
Vol 247 ◽  
Author(s):  
Gunzi Saito ◽  
Tokutaro Komatsu ◽  
Toshikazu Nakamura ◽  
Hideki Yamochi
Keyword(s):  
Cell Volume ◽  
Structural Properties ◽  
Unit Cell Volume ◽  
Structural Characteristics ◽  
Three Dimensional ◽  
Organic Superconductors ◽  
Unit Cell ◽  
Two Dimensional ◽  
Effective Volume ◽  
Anion Layer

ABSTRACTA close examination of the relation between Tc and structural characteristics of BEDT-TTF superconductors has revealed that there is a good correlation between the effective volume (VeffαVc-Vanion and Tc but no such correlation between the unit cell volume (Vc) and Tc. In order to increase Veff, it is favorable to use big but thin anion which can form a thin two-dimensional anion layer. Three-dimensional donor interactions are critical to have sizable Tc. According to the designing, two new superconductors; K-(BEDT-TTF)2CuCN[N(CN)2] (Tc=11.2K) and K'-(BEDT-TTF)2Cu2(CN)3 (Tc=3.8K), are prepared and their physical and structural properties are described. Their Tc's are discussed in terms of veff.

scholarly journals Allanite at high temperature: effect of REE on the thermal behaviour of epidote-group minerals

2021 ◽  
Vol 48 (9) ◽  
Author(s):  
G. Diego Gatta ◽  
Francesco Pagliaro ◽  
Paolo Lotti ◽  
Alessandro Guastoni ◽  
Laura Cañadillas-Delgado ◽  
...  
Keyword(s):  
Cell Volume ◽  
Thermal Behaviour ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
Atomic Scale ◽  
Elastic Behaviour ◽  
Positive Trend ◽  
Cell Parameters ◽  
Thermal Anisotropy ◽  
Different Temperatures

AbstractThe thermal behaviour of a natural allanite-(Ce) has been investigated up to 1073 K (at room pressure) by means of in situ synchrotron powder X-ray diffraction and single-crystal neutron diffraction. Allanite preserves its crystallinity up to 1073 K. However, up to 700 K, the thermal behaviour along the three principal crystallographic axes, of the monoclinic β angle and of the unit-cell volume follow monotonically increasing trends, which are almost linear. At T > 700–800 K, a drastic change takes place: an inversion of the trend is observed along the a and b axes (more pronounced along b) and for the monoclinic β angle; in contrast, an anomalous increase of the expansion is observed along the c axis, which controls the positive trend experienced by the unit-cell volume at T > 700–800 K. Data collected back to room T, after the HT experiments, show unit-cell parameters significantly different with respect to those previously measured at 293 K: allanite responds with an ideal elastic behaviour up to 700 K, and at T > 700–800 K its behaviour deviates from the elasticity field. The thermo-elastic behaviour up to 700 K was modelled with a modified Holland–Powell EoS; for the unit-cell volume, we obtained the following parameters: VT0 = 467.33(6) Å3 and αT0(V) = 2.8(3) × 10–5 K−1. The thermal anisotropy, derived on the basis of the axial expansion along the three main crystallographic directions, is the following: αT0(a):αT0(b):αT0(c) = 1.08:1:1.36. The T-induced mechanisms, at the atomic scale, are described on the basis of the neutron structure refinements at different temperatures. Evidence of dehydroxylation effect at T ≥ 848 K are reported. A comparison between the thermal behaviour of allanite, epidote and clinozoisite is carried out.

scholarly journals Study of Structural, Magnetic, and Mossbauer Properties of Dy2Fe16Ga1−xNbx (0.0 ≤ x ≤ 1.0) Prepared via Arc Melting Process

2021 ◽  
Vol 7 (3) ◽  
pp. 42
Author(s):  
Jiba N. Dahal ◽  
Kalangala Sikkanther Syed Ali ◽  
Sanjay R. Mishra
Keyword(s):  
Isomer Shift ◽  
Cell Volume ◽  
Intermetallic Compounds ◽  
Unit Cell Volume ◽  
Rietveld Analysis ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Arc Melting ◽  
Nb Content

Intermetallic compounds of Dy2Fe16Ga1−xNbx (x = 0.0 to 1.00) were synthesized by arc melting. Samples were investigated for structural, magnetic, and hyperfine properties using X-ray diffraction, vibration sample magnetometer, and Mossbauer spectrometer, respectively. The Rietveld analysis of room temperature X-ray diffraction data shows that all the samples were crystallized in Th2Fe17 structure. The unit cell volume of alloys increased linearly with an increase in Nb content. The maximum Curie temperature Tc ~523 K for x = 0.6 sample is higher than Tc = 153 K of Dy2Fe17. The saturation magnetization decreased linearly with increasing Nb content from 61.57 emu/g for x = 0.0 to 42.46 emu/g for x = 1.0. The Mössbauer spectra and Rietveld analysis showed a small amount of DyFe3 and NbFe2 secondary phases at x = 1.0. The hyperfine field of Dy2Fe16Ga1−xNbx decreased while the isomer shift values increased with the Nb content. The observed increase in isomer shift may have resulted from the decrease in s electron density due to the unit cell volume expansion. The substantial increase in Tc of thus prepared intermetallic compounds is expected to have implications in magnets used for high-temperature applications.

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