Structural and Electronic Properties of Bis[2-(pyrazin-2-ylamino)-4-(pyridin-2-yl)thiazolato]iron(II) and Its Solvated Derivatives

1994 ◽  
Vol 47 (5) ◽  
pp. 891 ◽  
Author(s):  
BJ Childs ◽  
DC Craig ◽  
KA Ross ◽  
ML Scudder ◽  
HA Goodwin
Keyword(s):  
Electronic Properties ◽  
Room Temperature ◽  
Singlet State ◽  
Methanol Solution ◽  
Monoclinic Space Group ◽  
Deprotonated Form ◽  
Complex Molecules ◽  
Quintet State ◽  
Structural And Electronic Properties ◽  
Continuous Temperature

The uncharged complex [Fe( pzapt )2] [ pzapt is the deprotonated form of 2-(pyrazin-2-ylamino)-4-(pyridin-2-yl) thiazole ] crystallizes with varying degrees of solvation , depending on the solvent. The electronic properties of the solvates differ. For all of them temperature dependence of the magnetic moment is observed, associated with a continuous temperature-induced singlet (1A1) ↔ quintet (5T2) transition. The transition is centred below room temperature for the benzene solvates but the unsolvated and chloroform solvate complexes exist predominantly in a singlet low-spin state. Overall the stabilization of the singlet state is greater in this system than in the previously studied [Fe( papt )2] [ paptH = 2-(pyridin-2-ylamino)-4-(pyridin-2-yl) thiazole ]. A spin equilibrium has been characterized for both [Fe( pzapt )2] and [Fe( papt )2] in methanol solution. The crystal structure of [Fe( pzapt )2].3/2C6H6 reveals Fe-N bond lengths consistent with both singlet and quintet state iron(II) being present. The benzene molecules are incorporated into the lattice as groups of three by occupying channels created by the packing of the complex molecules. Bis [2-(pyrazin-2-ylamino)-4-(pyridin-2-yl) thiazole ]iron(II) sesquibenzene solvate: monoclinic, space group P 21/c, a 14.894(7), b 12.601(2), c 16.777(8) Ǻ, β 94.57(2)°, Z 4.

Structural and Electronic Properties of the Iron(II) and Nickel(II) Bis(ligand) Complexes of 6-(5-Methyl-1,2,4-oxadiazol-3-yl)-2,2′-bipyridine— a Terpyridine-Based Tridentate

1999 ◽  
Vol 52 (7) ◽  
pp. 673 ◽  
Author(s):  
Bradley J. Childs ◽  
Marcia L. Scudder ◽  
Donald C. Craig ◽  
Harold A. Goodwin
Keyword(s):  
Electronic Properties ◽  
Spectroscopic Data ◽  
Room Temperature ◽  
Spin Transition ◽  
Iron Complex ◽  
Ligand Field ◽  
Monoclinic Space Group ◽  
Space Group ◽  
C 23 ◽  
Structural And Electronic Properties

Iron(II) and nickel(II) bis(ligand) complexes of 6-(5-methyl-1,2,4-oxadiazol-3-yl)-2,2′-bipyridine (L) are described. The ligand field in the iron complex is close to that at the singlet ( 1 A1) ? quintet ( 5 T2) crossover and magnetic and Mössbauer spectral evidence indicates that a spin transition occurs in salts of the iron complex but is centred above room temperature. The structures of [FeL2] [CF3SO3]2.CH3CN and [NiL2] [BF4]2.CH3CN were determined and both are very similar to the structures of the corresponding terpyridine complexes. Spectroscopic data indicate that for the iron complex π-interaction between the metal and the ligand is less than that in the terpyridine system. [FeL2] [CF3SO3]2.CH3CN is monoclinic, space group P 21/c; a 8 . 232(5), b 25 . 273(10), c 17 . 306(10) Å, β 92 . 37(3)°, Z 4; [NiL2] [BF4]2.CH3CN is monoclinic, space group P 21/c; a 8 . 136(2), b 17 . 558(2), c 23 . 783(7) Å, β 109 . 32(1)°, Z 4.

Electronic and Structural Properties of Iron(II) and Nickel(II) Cationic Complexes of 2-(Pyrazin-2-ylamino)-4-(pyridin-2-yl)thiazole

1997 ◽  
Vol 50 (2) ◽  
pp. 129 ◽  
Author(s):  
Bradley J. Childs ◽  
John M. Cadogan ◽  
Donald C. Craig ◽  
Marcia L. Scudder ◽  
Harold A. Goodwin
Keyword(s):  
Room Temperature ◽  
Singlet State ◽  
Monoclinic Space Group ◽  
Counter Anion ◽  
Triclinic Space Group ◽  
Space Group ◽  
A Value ◽  
Complex Salts ◽  
Electronic And Structural Properties ◽  
Continuous Temperature

Complex salts containing the [FeIIN6]2+ derivative of 2-(pyrazin-2-ylamino)-4-(pyridin-2-yl)thiazole (pzaptH) undergo continuous, temperature-induced singlet (1A1) quintet (5T2) transitions with the transition temperature being dependent on the nature of the counter anion and the presence of solvate water, the latter tending to stabilize the singlet state. A transition is also observed for the fluoroborate salt in methanol solution. The extent of stabilization of the singlet state for iron(II) in these complexes is somewhat greater than in those derived from the previously studied 2-(pyridin-2-ylamino)-4-(pyridin-2-yl)thiazole. The crystal structures of [Fe(pzaptH)2] [CF3SO3]2 and [Ni(pzaptH)2] [BF4]2.2H2O have been determined. The average Fe-N distance is 1·985 Å, a value consistent with the essentially low-spin nature of the complex at room temperature, and the average Ni-N distance is 2·089 Å. In both complexes the bridging >NH group is involved in hydrogen bonding to the anions and, in the nickel complex, also to the solvate water. The uncoordinated nitrogen of the pyrazine ring is not hydrogen-bonded. Bis[2-(pyrazin-2-ylamino)-4-(pyridin-2-yl)thiazole]iron(II) triflate: triclinic, space group P -1, a 8·794(5), b 11·082(6), c 17·49(1) Å, α 77·59(4), β 86·80(4), γ 84·21(4)°, Z 2. Bis[2-(pyrazin-2-ylamino)-4-(pyridin-2-yl)thiazole]nickel(II) tetrafluoroborate dihydrate: monoclinic, space group P 21/c, a 8·784(3), b 8·795(2), c 41·16(1) Å, β 94·58(2)°, Z 4.

Structural Characterization of Two Crystalline Forms of Bis[2-(1,5-dimethyltrazol-3-yl)-1,10-phenanthroline]-iron(II) Perchlorate—a Spin Crossover System

1996 ◽  
Vol 49 (4) ◽  
pp. 497 ◽  
Author(s):  
KH Sugiyarto ◽  
DC Craig ◽  
HA Goodwin
Keyword(s):  
Room Temperature ◽  
Singlet State ◽  
Crystal Packing ◽  
Bulk Sample ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Quintet State ◽  
Crystalline Forms

At room temperature bis [2-(1,5-dimethyltriazol-3-yl)-1,10-phenanthroline]iron(II) perchlorate has magnetic and Mossbauer spectral properties which indicate that it contains both singlet and quintet state iron(II) in a ratio of approximately 1:2. Two polymorphs were identified in a small batch of crystals grown from acetone/ethanol for crystal structure determination. In polymorph 1 the average iron-nitrogen distance (1.97 Ǻ) is close to the value usually obtained for purely singlet state iron(II) in an [FeN6]2+ system, whereas that for polymorph 2 (2.09 Ǻ) is consistent with the 1:2 ratio of singlet-to-quintet state species. The Mossbauer spectrum of the crystallographic sample is virtually identical to that of the bulk sample. There are small differences in the coordination sphere which could account for the different extent of stabilization of the singlet state in the two polymorphs. The crystal packing differs markedly for the two polymorphs but reveals no obvious rationalization for the spin-state differences. Bis [2-(1,5-dimethyltriazol-3-yl)-1,10-phenanthroline]iron(II) perchlorate , two-thirds water (polymorph 1): monoclinic, space group P 21/c, a 10.766(3), b 25.806(3), c 12.491(4) Ǻ, β 91.17(1)°, Z 4. Bis [2-(1,5-dimethyltriazol-3-yl)-1,10-phenanthroline]iron(II) perchlorate monohydrate (polymorph 2): orthorhombic, space group Pbca, a 16.687(4), b 12.272(2), c 34.305(8) Ǻ, Z 8.

STRUCTURAL AND ELECTRONIC PROPERTIES OF THE Li/Si(001) SURFACE

1996 ◽  
Vol 03 (03) ◽  
pp. 1487-1494
Author(s):  
J.W. CHUNG
Keyword(s):  
Electronic Properties ◽  
Binding Sites ◽  
Room Temperature ◽  
Structural Models ◽  
Metallic Phase ◽  
Surface Band ◽  
Ordered Structures ◽  
Initial Stage ◽  
Structural And Electronic Properties ◽  
Characteristic Features

Atomic arrangements and electronic properties of the Li-adsorbed Si(001) surface are briefly reviewed. Characteristic features of a series of ordered structures with increasing Li coverage at room temperature are described. Structural models invoking a dimer flipping mechanism are discussed for the first two ordered structures, (2×2)-Li and (2×1)-Li, which are proposed as reconstructions of the silicon substrate. It is shown that the metallic phase found at an initial stage of adsorption is a result of substrate metallization, which explains the presence of an intraband surface plasmon. The features of the surface band structures for the first two ordered structures are discussed in terms of variation of the binding sites with coverage. All the unique features of the Li/Si(001) surface essentially exhibit the size effects of Li.

Tunable electronic properties in the van der Waals heterostructure of germanene/germanane

2015 ◽  
Vol 17 (18) ◽  
pp. 12194-12198 ◽  
Author(s):  
Run-wu Zhang ◽  
Chang-wen Zhang ◽  
Wei-xiao Ji ◽  
Feng Li ◽  
Miao-juan Ren ◽  
...  
Keyword(s):  
Electric Field ◽  
Band Gap ◽  
Electronic Properties ◽  
External Electric Field ◽  
High Performance ◽  
Room Temperature ◽  
Van Der Waals ◽  
Van Der Waals Heterostructure ◽  
Structural And Electronic Properties

We investigate the structural and electronic properties of germanene/germanane heterostructures. The band gap in these heterostructures can be effectively modulated by the external electric field and strain. These results provide a route to design high-performance FETs operating at room temperature in nanodevices.

scholarly journals [Cr3O(CH3COO)6(H2O)3]NO3⋅HNO3⋅H2O, Triaqua-Hexakis(Μ- Acetato)-Μ3-Oxo-Trichromium(III) Nitrate Nitric Acid Solvate Monohydrate

2006 ◽  
Vol 1 (1) ◽  
pp. 88-96
Author(s):  
Marco Bettinelli ◽  
Adolfo Speghini ◽  
Gabriele Bocelli ◽  
Olesea Gherco ◽  
Valeriu Mereacre ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Room Temperature ◽  
Methanol Solution ◽  
Monoclinic Space Group ◽  
Free Molecule ◽  
Crystalline Compound ◽  
Acid Complex ◽  
Space Group

Reaction in methanol solution of the trinuclear ‘basic’ chromium(III) acetate with Pr(NO3)3⋅5H2O and further extraction by chloroform-acetone mixture led to the formation of novel unusual [Cr3O(CH3COO)6(H2O)3]NO3⋅HNO3⋅H2O (1) cluster with one “free” molecule of nitric acid. Complex 1 crystallizes in the monoclinic space group P21/c with, at room temperature, a = 13.624(2), b = 15.032(2), c = 15.180(2) Å, β = 112.98(3) °, Z = 4, and V = 2862.09 Å3. The obtained crystalline compound has been synthesized and characterized by IR and UV/Vis methods.

Towards an electronic grade nanoparticle-assembled silicon thin film by ballistic deposition at room temperature: the deposition method, and structural and electronic properties

2017 ◽  
Vol 5 (15) ◽  
pp. 3725-3735 ◽  
Author(s):  
Giorgio Nava ◽  
Francesco Fumagalli ◽  
Salvatore Gambino ◽  
Isabella Farella ◽  
Giorgio Dell'Erba ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electronic Properties ◽  
High Throughput ◽  
Room Temperature ◽  
Plasma Synthesis ◽  
Deposition Method ◽  
Silicon Thin Film ◽  
Silicon Thin Films ◽  
Structural And Electronic Properties

High-throughput plasma synthesis of highly crystalline nanoparticle-assembled silicon thin films.

Pressure Dependence of the Structural and Electronic Properties of Organic Superconductors

1989 ◽  
Vol 173 ◽  
Author(s):  
D. Chasseau ◽  
J. Gaultier ◽  
H. Houbib ◽  
M. Rahal ◽  
L. Ducasse ◽  
...  
Keyword(s):  
Bulk Modulus ◽  
Electronic Properties ◽  
Pressure Dependence ◽  
Pressure Range ◽  
Room Temperature ◽  
Organic Superconductors ◽  
Cell Parameters ◽  
Transfer Integrals ◽  
Structural And Electronic Properties ◽  
Experimental Pressure

ABSTRACTThe pressure dependence (≤12 × 102 MPa) of the cell parameters of (TMTSF)2 - C104 and κ - (BEDT-TTF)2 - Cu(NCS)2 has been measured at room temperature. The magnitudes of the principal compressibilities calculated and the bulk modulus (B) do not vary all over the experimental pressure range for (TMTSF)2 - C104, while ki decrease slightly for κ - (ET)2 - Cu(NCS)2 and its Dulk modulus strongly increases. The directions of the principal compressibilities strongly varywith pressure for the former salt; in the latter case, the projections of the directions of the smallest and of the largest principal compressibilities remain parallel and perpendicular to the long molecular axis respectively whereas the intermediate is along the monoclinic b axis.The crystal structures have been refined at 4 × 102 ,6 × 102 and 9.5 × 102 MPa (R = 0.05) for (TMTSF)2 - C104 and at 7 × 102 MPa (R = 0.095) for κ - (ET)2 - Cu(NCS)2. The transfer integrals have been calculated for the two compounds. In (TMTSF)2 - C104, both normal and transverse overlaps strongly increase with pressure; the dimerization is reduced under pressure and the two largest transverse interactions become identical. In κ - (ET)2 - Cu(NCS)2, the intra-dimer interaction strongly increases whereas the variations of the inter-dimer interactions may be very different.

First-Principles Study of Structural and Electronic Properties of MoS1.5Se0.5 Alloy

2019 ◽  
Vol 18 (03n04) ◽  
pp. 1940006
Author(s):  
J. Gusakova ◽  
B. K. Tay ◽  
V. Gusakov
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Room Temperature ◽  
Band Gaps ◽  
Monomolecular Layer ◽  
Optical Band Gaps ◽  
First Principles Study ◽  
Structural And Electronic Properties ◽  
Probable Distribution ◽  
Good Agreement

The effects of relative positions of Se atoms in a monomolecular layer of MoS[Formula: see text]Se[Formula: see text] have been studied. It is demonstrated that the distribution of Se atoms between top and bottom chalcogen planes is most energetically favorable. For a more probable distribution of Se atoms this monolayer alloy is a direct semiconductor with the fundamental bandgap of 2.35[Formula: see text]eV. We have also evaluated the optical band gaps of the alloy at 77[Formula: see text]K (1.86[Formula: see text]eV) and room temperature (1.80[Formula: see text]eV), which are in a good agreement with the experimentally measured bandgap of 1.79[Formula: see text]eV.

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