Controlling the unpaired electron by electrostatic attraction in the solid state

2021 ◽  
Author(s):  
Haiyan Cui ◽  
Liting Wang ◽  
Huapeng Ruan ◽  
Min Liu ◽  
Zhongtao Feng ◽  
...  
Keyword(s):  
Solid State ◽  
Unpaired Electron ◽  
Electrostatic Attraction ◽  
Electron Reduction ◽  
Large Spin

One-electron reduction of 2,7-tBu2-pyrene-4,5,9,10-tetraone (1) with potassium afforded two monoradicals 1K(cryp) and 1K(18c6), a radical tetramer [1K(15c5)]4 and a radical polymer (1K)2n. From 1K(cryp) and 1K(18c6), we demonstrated large spin...

scholarly journals Aerobically Stable and Substitutionally Labile α-Diimine Rhenium Dicarbonyl Complexes

2021 ◽  
Author(s):  
Kevin Schindler ◽  
Aurélien Crochet ◽  
Fabio Zobi
Keyword(s):  
Solid State ◽  
High Yield ◽  
Distorted Octahedral Geometry ◽  
The Core ◽  
Axial Ligands ◽  
Distorted Octahedral ◽  
Synthetic Routes ◽  
Monodentate Ligands ◽  
Electron Reduction ◽  
The One

New synthetic routes to aerobically stable and substitutionally labile a-diimine rhenium(I) dicarbonyl complexes are described. The molecules are prepared in high yield from the <i>cis-cis-trans-</i>[Re(CO)<sub>2</sub>(<i><sup>t</sup></i>Bu<sub>2</sub>bpy)Br<sub>2</sub>]<sup>-</sup> anion (<b>2</b>, where<b> </b><i><sup>t</sup></i>Bu<sub>2</sub>bpy is 4,4'-di-<i>tert</i>-butyl-2,2'-bipyridine), which can be isolated from the one electron reduction of the corresponding 17-electron complex (<b>1</b>). Compound <b>2 </b>is stable in the solid state, but in solution it is oxidized by molecular oxygen back to <b>1</b>. Replacement of a single bromide of <b>2</b> by s-donor monodentate ligands (Ls) yields stable neutral 18-electron <i>cis-cis-trans-</i>[Re(CO)<sub>2</sub>(<i><sup>t</sup></i>Bu<sub>2</sub>bpy)Br(L)] species. In coordinating solvents like methanol the halide is replaced giving the corresponding solvated cations. [Re(CO)<sub>2</sub>(<i><sup>t</sup></i>Bu<sub>2</sub>bpy)Br(L)] species can be further reacted with Ls to prepare stable <i>cis-cis-trans-</i>[Re(CO)<sub>2</sub>(<i><sup>t</sup></i>Bu<sub>2</sub>bpy)(L)<sub>2</sub>]<sup>+</sup> complexes in good yield. Ligand substitution of Re(I) complexes proceeds via pentacoordinate intermediates capable of Berry pseudorotation. In addition to the <i>cis-cis-trans-</i>complexes, <i>cis-cis-cis-</i> (all cis) enantiomers are also formed. In particular, <i>cis-cis-trans-</i>[Re(CO)<sub>2</sub>(<i><sup>t</sup></i>Bu<sub>2</sub>bpy)(L)<sub>2</sub>]<sup>+</sup> complexes establish an equilibrium with all cis enantiomers in solution. The solid state crystal structure of nearly all molecules presented could be elucidated. The molecules adopt a slightly distorted octahedral geometry. In comparison to similar <i>fac</i>-[Re(CO)<sub>3</sub>]<sup>+</sup>complexes, Re(I) diacarbonyl species are characterized by a bend (ca. 7°) of the axial ligands towards the a-diimine unit. [Re(CO)<sub>2</sub>(<i><sup>t</sup></i>Bu<sub>2</sub>bpy)Br<sub>2</sub>]<sup>-</sup> and [Re(CO)<sub>2</sub>(<i><sup>t</sup></i>Bu<sub>2</sub>bpy)Br(L)] complexes may be considered as synthons for the preparation of a variety of new stable diamagnetic dicarbonyl rhenium <i>cis-</i>[Re(CO)<sub>2</sub>]<sup>+</sup> complexes, offering a convenient entry in the chemistry of the core.

Electrocatalytic Activities of Trirutiles Based on MTaO6 (M=Co, Ni, Mg) for Oxygen Reduction Reaction

2009 ◽  
Vol 421-422 ◽  
pp. 459-462
Author(s):  
Takayuki Konishi ◽  
Hideki Kawai ◽  
Morihiro Saito ◽  
Jun Kuwano ◽  
Hidenobu Shiroishi
Keyword(s):  
Solid State ◽  
Acid Solution ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Reduction Reaction ◽  
Disk Electrode ◽  
Conventional Solid State Reaction ◽  
Rotating Ring Disk Electrode ◽  
Current Densities ◽  
Electron Reduction

The trirutile oxides MTa2O6 (M=Co,Ni,Mg) [MTs] and the substitution products M1-xNxTa2-yLyO6 (N=Mn, L=Sn,Ti,Zr) [M1-xNxTa2-yLy] were prepared by a conventional solid-state reaction. The oxygen reduction reaction (ORR) activities were evaluated with the onset potentials (Eon) of the ORR currents, the disk current densities (iD) and the efficiencies (Eff4) of 4-electron reduction, measured by a rotating ring-disk electrode (RRDE) technique. All the samples showed ORR activities and the Eon values were around +0.8 V vs. RHE in 0.1 M KOH. The CoTa2O6 electrocatalyst showed the best ORR property of the MTs samples: its Eff4 value was as high as ~80%. With substitution of Ti or Sn, the ORR activities of MgTa1.9T0.1O6, CoTa1.8Sn0.2O6 and NiTa1.9Ti0.1O6 were improved in alkaline solution, compared with those of MTa2O6. In acid solution, the same substitution of Ti and Sn resulted in improvement of Eff4, but no significant improvements of Eon and iD.

scholarly journals Redetermination of the crystal structure of tetralithium octafluoridozirconate(IV), Li4ZrF8, from single-crystal X-ray data

2019 ◽  
Vol 75 (2) ◽  
pp. 139-141 ◽  
Author(s):  
Alexander T. Chemey ◽  
Thomas E. Albrecht-Schmitt
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Single Crystal ◽  
Electrostatic Attraction ◽  
Structure Model ◽  
Crystal Data ◽  
Lithium Ions ◽  
X Ray ◽  
Structure Report

Presented herein is the crystal-structure redetermination of Li4ZrF8 from single-crystal X-ray data. Alkali zirconium fluorides are important in nuclear-relevant technologies, and zirconium is commonly employed as an analogue for tetravalent f-block elements. The previous structure report of this species is based on powder X-ray data [Dugat et al. (1995). J. Solid State Chem. 120, 187–196] but there has never been a refined structure model from single-crystal data. The octafluoridozirconate moieties are held together by electrostatic attraction to lithium ions without sharing of fluoride sites between zirconium(IV) ions.

Air-Tight Three-Electrode Design of Coaxial Electrochemical-EPR Cell for Redox Studies at Low Temperatures

2001 ◽  
Vol 66 (1) ◽  
pp. 52-66 ◽  
Author(s):  
František Hartl ◽  
Ronald P. Groenestein ◽  
Taasje Mahabiersing
Keyword(s):  
Unpaired Electron ◽  
Low Temperatures ◽  
Radical Anion ◽  
Reference Electrode ◽  
Octahedral Complex ◽  
Electrode Design ◽  
Epr Spectrum ◽  
Weak Point ◽  
Electron Reduction ◽  
Elegant Solution

The weak point of the original Allendoerfer electrochemical-EPR cell has been the reference electrode, placed outside the space-limited electrolysis cavity or not used at all in experiments at low temperatures. We present here an elegant solution to this problem, based on a modified air-tight design of an Allendoerfer cell equipped with a silver-wire pseudoreference electrode. The cell performance is demonstrated on one-electron electrochemical oxidation of heterocyclic 3,6-diphenyl-1,2-dithiine and one-electron reduction of 6-methyl-6-phenylfulvene and the pseudo-octahedral complex fac-[Re(benzyl)(CO)3(dmb)] (dmb = 4,4'-dimethyl-2,2'-bipyridine). In the latter case, the EPR spectrum of the radical anion [Re(benzyl)(CO)3(dmb)]•- points to predominant localization of the unpaired electron on the dmb ligand, in agreement with UV-VIS and IR spectroelectrochemical data.

Syntheses and properties of Di(cyclopentadienyl)titanium(III)chloride

1965 ◽  
Vol 18 (1) ◽  
pp. 9 ◽  
Author(s):  
AF Reid ◽  
PC Wailes
Keyword(s):  
Solid State ◽  
Unpaired Electron ◽  
Titanium Tetrachloride ◽  
Magnetic Measurements ◽  
Titanium Atom ◽  
High Yield ◽  
Titanium Trichloride ◽  
Moderate Yield

Di(cyclopentadienyl)titanium(III) chloride has been prepared in high yield by addition of tetrahydrofuran to dry mixtures of titanium trichloride and di(cyclopentadienyl)magnesium in stoicheiometric or excess amounts. Reaction of titanium tetrachloride with excess di(cyclopentadienyl)magnesium also yielded (C5H5)2TiCl in moderate yield. Some properties of the compound are given, including solid state and aqueous spectra. Magnetic measurements show the compound to have one unpaired electron per titanium atom.

scholarly journals Aerobically Stable and Substitutionally Labile α-Diimine Rhenium Dicarbonyl Complexes

2021 ◽  
Author(s):  
Kevin Schindler ◽  
Aurélien Crochet ◽  
Fabio Zobi
Keyword(s):  
Solid State ◽  
High Yield ◽  
Distorted Octahedral Geometry ◽  
The Core ◽  
Axial Ligands ◽  
Distorted Octahedral ◽  
Synthetic Routes ◽  
Monodentate Ligands ◽  
Electron Reduction ◽  
The One

New synthetic routes to aerobically stable and substitutionally labile a-diimine rhenium(I) dicarbonyl complexes are described. The molecules are prepared in high yield from the <i>cis-cis-trans-</i>[Re(CO)<sub>2</sub>(<i><sup>t</sup></i>Bu<sub>2</sub>bpy)Br<sub>2</sub>]<sup>-</sup> anion (<b>2</b>, where<b> </b><i><sup>t</sup></i>Bu<sub>2</sub>bpy is 4,4'-di-<i>tert</i>-butyl-2,2'-bipyridine), which can be isolated from the one electron reduction of the corresponding 17-electron complex (<b>1</b>). Compound <b>2 </b>is stable in the solid state, but in solution it is oxidized by molecular oxygen back to <b>1</b>. Replacement of a single bromide of <b>2</b> by s-donor monodentate ligands (Ls) yields stable neutral 18-electron <i>cis-cis-trans-</i>[Re(CO)<sub>2</sub>(<i><sup>t</sup></i>Bu<sub>2</sub>bpy)Br(L)] species. In coordinating solvents like methanol the halide is replaced giving the corresponding solvated cations. [Re(CO)<sub>2</sub>(<i><sup>t</sup></i>Bu<sub>2</sub>bpy)Br(L)] species can be further reacted with Ls to prepare stable <i>cis-cis-trans-</i>[Re(CO)<sub>2</sub>(<i><sup>t</sup></i>Bu<sub>2</sub>bpy)(L)<sub>2</sub>]<sup>+</sup> complexes in good yield. Ligand substitution of Re(I) complexes proceeds via pentacoordinate intermediates capable of Berry pseudorotation. In addition to the <i>cis-cis-trans-</i>complexes, <i>cis-cis-cis-</i> (all cis) enantiomers are also formed. In particular, <i>cis-cis-trans-</i>[Re(CO)<sub>2</sub>(<i><sup>t</sup></i>Bu<sub>2</sub>bpy)(L)<sub>2</sub>]<sup>+</sup> complexes establish an equilibrium with all cis enantiomers in solution. The solid state crystal structure of nearly all molecules presented could be elucidated. The molecules adopt a slightly distorted octahedral geometry. In comparison to similar <i>fac</i>-[Re(CO)<sub>3</sub>]<sup>+</sup>complexes, Re(I) diacarbonyl species are characterized by a bend (ca. 7°) of the axial ligands towards the a-diimine unit. [Re(CO)<sub>2</sub>(<i><sup>t</sup></i>Bu<sub>2</sub>bpy)Br<sub>2</sub>]<sup>-</sup> and [Re(CO)<sub>2</sub>(<i><sup>t</sup></i>Bu<sub>2</sub>bpy)Br(L)] complexes may be considered as synthons for the preparation of a variety of new stable diamagnetic dicarbonyl rhenium <i>cis-</i>[Re(CO)<sub>2</sub>]<sup>+</sup> complexes, offering a convenient entry in the chemistry of the core.

scholarly journals First Study on Nihonium (Nh, Element 113) Chemistry at TASCA

2021 ◽  
Vol 9 ◽  
Author(s):  
A. Yakushev ◽  
L. Lens ◽  
Ch. E. Düllmann ◽  
M. Block ◽  
H. Brand ◽  
...  
Keyword(s):  
Gas Phase ◽  
Unpaired Electron ◽  
Chemical Reactivity ◽  
Spin Orbit ◽  
Orbit Splitting ◽  
Spin Orbit Splitting ◽  
Theoretical Predictions ◽  
High Volatility ◽  
Chemical Studies ◽  
Large Spin

Nihonium (Nh, element 113) and flerovium (Fl, element 114) are the first superheavy elements in which the 7p shell is occupied. High volatility and inertness were predicted for Fl due to the strong relativistic stabilization of the closed 7p1/2 sub-shell, which originates from a large spin-orbit splitting between the 7p1/2 and 7p3/2 orbitals. One unpaired electron in the outermost 7p1/2 sub-shell in Nh is expected to give rise to a higher chemical reactivity. Theoretical predictions of Nh reactivity are discussed, along with results of the first experimental attempts to study Nh chemistry in the gas phase. The experimental observations verify a higher chemical reactivity of Nh atoms compared to its neighbor Fl and call for the development of advanced setups. First tests of a newly developed detection device miniCOMPACT with highly reactive Fr isotopes assure that effective chemical studies of Nh are within reach.

Preparation of Thin Cadmium Telluride Samples for Electron Microscope Studies

1974 ◽  
Vol 32 ◽  
pp. 548-549
Author(s):  
T. J. Magee ◽  
J. Peng ◽  
J. Bean
Keyword(s):  
Electron Microscope ◽  
Sulfuric Acid ◽  
Solid State ◽  
Sample Preparation ◽  
Cadmium Telluride ◽  
Potassium Dichromate ◽  
Optical Components ◽  
The Past ◽  
Solid State Devices

Cadmium telluride has become increasingly important in a number of technological applications, particularly in the area of laser-optical components and solid state devices, Microstructural characterizations of the material have in the past been somewhat limited because of the lack of suitable sample preparation and thinning techniques. Utilizing a modified jet thinning apparatus and a potassium dichromate-sulfuric acid thinning solution, a procedure has now been developed for obtaining thin contamination-free samples for TEM examination.

The Collagenic Molecular Structural Unit of Solid State Complexes

1971 ◽  
Vol 29 ◽  
pp. 478-479
Author(s):  
Kenneth M. Richter ◽  
John A. Schilling
Keyword(s):  
Molecular Weight ◽  
Solid State ◽  
Structural Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Naoh Treatment

The structural unit of solid state collagen complexes has been reported by Porter and Vanamee via EM and by Cowan, North and Randall via x-ray diffraction to be an ellipsoidal unit of 210-270 A. length by 50-100 A. diameter. It subsequently was independently demonstrated by us in dog tendon, dermis, and induced complexes. Its detailed morphologic, dimensional and molecular weight (MW) aspects have now been determined. It is pear-shaped in long profile with m diameters of 57 and 108 A. and m length of 263 A. (Fig. 1, tendon, KMnO4 fixation, Na-tungstate; Fig. 2a, schematic of unit in long, C, and x-sectional profiles of its thin, xB, and bulbous, xA portions; Fig. 2b, tendon essentially unmodified by ether and 0.4 N NaOH treatment, Na-tungstate). The unit consists of a uniquely coild cable, c, of ṁ 22.9 A. diameter and length of 2580-3316 A. The cable consists of three 2nd-strands, s, each of m 10.6 A.

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