Rational synthesis of unidimensional mixed valence solids. Structural, spectral, and electrical studies of charge distribution and transport in partially oxidized nickel and palladium bisdiphenylglyoximates

1979 ◽  
Vol 101 (11) ◽  
pp. 2921-2936 ◽  
Author(s):  
Martin Cowie ◽  
Alain Gleizes ◽  
Gregory W. Grynkewich ◽  
Davida Webster Kalina ◽  
Malcolm S. McClure ◽  
...  
Keyword(s):  
Charge Distribution ◽  
Mixed Valence ◽  
Electrical Studies

Charge distribution in mixed-valence trimer

1994 ◽  
Vol 89 (11) ◽  
pp. 941-944 ◽  
Author(s):  
S. Matsuzaki ◽  
V.M. Yartsev
Keyword(s):  
Charge Distribution ◽  
Mixed Valence

scholarly journals Photoswitchable stable charge-distributed states in a new cobalt complex exhibiting photo-induced valence tautomerism

2015 ◽  
Vol 185 ◽  
pp. 347-359 ◽  
Author(s):  
Michael Slota ◽  
Marian Blankenhorn ◽  
Eric Heintze ◽  
Minh Vu ◽  
Ralph Hübner ◽  
...  
Keyword(s):  
Charge Distribution ◽  
Cobalt Complex ◽  
Mixed Valence ◽  
Magnetic Behavior ◽  
Inert Atmosphere ◽  
Molecular Structures ◽  
Paramagnetic Resonance ◽  
Valence Tautomerism ◽  
X Band ◽  
Huge Impact

We report the synthesis and magnetic and photomagnetic behaviour of a novel valence tautomeric cobalt complex, [Co(3,5-dbbq)2(μ-bpym)] (1) (3,5-dbbq = 3,5-di-tert-butyl-1,2-benzoquinone and μ-bpym = 2,2′-bipyrimidine). The synthesis is performed by reacting Co2(CO)8 and μ-bpym in the presence of the ligand 3,5-dbbq in a mixed solvent under inert atmosphere. The magnetic behavior clearly shows the presence of electron transfer from the catecholate ligand to the cobalt center, producing valence tautomers of [CoII(SQ)2] with a transition temperature (T1/2) of 215 K. Photomagnetic studies, performed via both SQUID magnetometry and X-band electron paramagnetic resonance, show the clear presence of photoinduced valence tautomerism, at temperatures considerably higher than previous systems. A metastable charge distribution is observed, strengthening previous investigations on the character of mixed valence ligands. Entropy-driven valence tautomeric interconversion is observed, and drives the transition to the most stable charge distribution. The complex has the ability to coordinate and can be used as a photoswitchable building block, with the photomagnetic characterisation evidencing a metastable state lifetime of the photo-induced valence tautomeric process of ca. 2.9 × 104 s below 20 K. The observed yields are higher than ones in similar systems, showing that tiny changes in the molecular structures may have a huge impact.

Charge distribution as a tool to investigate structural details. III. Extension to description in terms of anion-centred polyhedra

2015 ◽  
Vol 71 (1) ◽  
pp. 34-47 ◽  
Author(s):  
Jean-Guillaume Eon ◽  
Massimo Nespolo
Keyword(s):  
Charge Distribution ◽  
Mixed Valence ◽  
Theoretical Description ◽  
Oxidation Number ◽  
Acta Cryst ◽  
Coordination Polyhedra ◽  
Structural Details ◽  
Mixed Valence Compounds ◽  
Experimental Geometry ◽  
Insight Into

The charge distribution (CHARDI) method is a self-consistent generalization of Pauling's concept of bond strength which does not make use of empirical parameters but exploits the experimental geometry of the coordination polyhedra building a crystal structure. In the two previous articles of this series [Nespoloet al.(1999).Acta Cryst.B55, 902–916; Nespoloet al.(2001).Acta Cryst.B57, 652–664], we have presented the features and advantages of this approach and its extension to distorted and heterovalent polyhedra and to hydrogen bonds. In this third article we generalize CHARDI to structures based on anion-centred polyhedra, which have drawn attention in recent years, and we show that computations based on both descriptions can be useful to obtain a deeper insight into the structural details, in particular for mixed-valence compounds where CHARDI is able to give precise indications on the statistical distribution of atoms with different oxidation number. A graph-theoretical description of the structures rationalizes and gives further support to the conclusions obtainedviathe CHARDI approach.

scholarly journals Sr5Os3O13: a mixed valence osmium(v,vi) layered perovskite variant exhibiting temperature dependent charge distribution

2018 ◽  
Vol 47 (17) ◽  
pp. 5968-5976 ◽  
Author(s):  
Shrikant A. Mohitkar ◽  
Jürgen Nuss ◽  
Henning A. Höppe ◽  
Claudia Felser ◽  
Martin Jansen
Keyword(s):  
Charge Distribution ◽  
Perovskite Structure ◽  
Mixed Valence ◽  
Charge Ordering ◽  
Layered Perovskite ◽  
Temperature Dependent

New mixed-valent Sr5Os3O13 represents a particular cutout of the perovskite structure and features continuous charge ordering with temperature.

Study of charge transfer in FeTi

1983 ◽  
Vol 41 ◽  
pp. 296-297
Author(s):  
J. Taft∅
Keyword(s):  
Charge Transfer ◽  
Charge Distribution ◽  
Electron Scattering ◽  
Periodic System ◽  
Electron Distribution ◽  
Scattering Amplitude ◽  
Transition Elements ◽  
Hartree Fock ◽  
Cscl Structure ◽  
The Right

It is well known that for reflections corresponding to large interplanar spacings (i.e., sin θ/λ small), the electron scattering amplitude, f, is sensitive to the ionicity and to the charge distribution around the atoms. We have used this in order to obtain information about the charge distribution in FeTi, which is a candidate for storage of hydrogen. Our goal is to study the changes in electron distribution in the presence of hydrogen, and also the ionicity of hydrogen in metals, but so far our study has been limited to pure FeTi. FeTi has the CsCl structure and thus Fe and Ti scatter with a phase difference of π into the 100-ref lections. Because Fe (Z = 26) is higher in the periodic system than Ti (Z = 22), an immediate “guess” would be that Fe has a larger scattering amplitude than Ti. However, relativistic Hartree-Fock calculations show that the opposite is the case for the 100-reflection. An explanation for this may be sought in the stronger localization of the d-electrons of the first row transition elements when moving to the right in the periodic table. The tabulated difference between fTi (100) and ffe (100) is small, however, and based on the values of the scattering amplitude for isolated atoms, the kinematical intensity of the 100-reflection is only 5.10-4 of the intensity of the 200-reflection.

Heisenberg and double exchange in iron mixed valence [Fe6S6]+ supercluster

1997 ◽  
Vol 90 (3) ◽  
pp. 445-463 ◽  
Author(s):  
M. CZERWINSKI ◽  
J. DĄBROWSKI
Keyword(s):  
Mixed Valence ◽  
Double Exchange
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