scholarly journals Tuning Electronic Structures of Covalent Co Porphyrin Polymers for Electrocatalytic CO 2 Reduction in Aqueous Solutions

CCS Chemistry ◽  
2022 ◽  
pp. 1-21
Author(s):  
Yabo Wang ◽  
Xue-Peng Zhang ◽  
Haitao Lei ◽  
Kai Guo ◽  
Gelun Xu ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Electronic Structures ◽  
Porphyrin Polymers

On the Structure of Lead(II) Complexes in Aqueous Solutions. I. Trinuclear Clusters

1995 ◽  
Vol 60 (4) ◽  
pp. 527-536 ◽  
Author(s):  
Martin Breza ◽  
Alena Manová
Keyword(s):  
Quantum Chemistry ◽  
Aqueous Solutions ◽  
Electronic Structures ◽  
Mndo Method ◽  
Model Systems ◽  
Trinuclear Clusters ◽  
The Stability ◽  
Semiempirical Mndo

Using semiempirical MNDO method of quantum chemistry the optimal geometries and corresponding electronic structures of [Pb3(OH)n]6-n model systems as well as of their hydrated [Pb3(OH)n(H2O)8-n]6-n analogues (n = 4, 5) are investigated. The most stable trinuclear lead(II) complexes present in aqueous solutions correspond to cyclo-(μ3-OH)(μ2-OH)3Pb32+, Pb(μ-OH)2Pb(μ-OH)2Pb2+, cyclo-(μ3-OH)2(μ2-OH)3Pb3+, Pb(OH)(μ-OH)2Pb(μ-OH)Pb(OH)+ and Pb(OH)(μ-OH)2Pb(μ-OH)2Pb+ systems. The key role of OH bridges (by vanishing direct Pb-Pb bonds) on the stability of individual isomers is discussed.

Electronic Structures of Crystalline and Aqueous Solutions of LiBr, NaBr, KBr, and KBrO3:  In Situ Br L-Edge Near-edge X-ray Absorption Fine Structure

2003 ◽  
Vol 107 (46) ◽  
pp. 12562-12565 ◽  
Author(s):  
Shuji Matsuo ◽  
Ponnusamy Nachimuthu ◽  
Dennis W. Lindle ◽  
Hisanobu Wakita ◽  
Rupert C. C. Perera
Keyword(s):  
Fine Structure ◽  
Aqueous Solutions ◽  
Electronic Structures ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption

On the Structure of Lead(II) Complexes in Aqueous Solutions. III. Hexanuclear Clusters

2002 ◽  
Vol 67 (2) ◽  
pp. 219-227 ◽  
Author(s):  
Martin Breza ◽  
Alena Manová
Keyword(s):  
Quantum Chemistry ◽  
Aqueous Solutions ◽  
Electronic Structures ◽  
Mndo Method ◽  
Experimental Techniques ◽  
Hexanuclear Clusters ◽  
Semiempirical Mndo

Optimum geometries based on experimental structures and corresponding electronic structures of [Pb6(μ3-OH)8]4+ and [Pb6O(μ3-OH)6]4+ clusters as well as of their hydrated [Pb6(μ3-OH)8(H2O)6]4+ and [Pb6O(μ3-OH)6(H2O)6]4+ analogues are investigated using the semiempirical MNDO method of quantum chemistry. Direct Pb-Pb and O-O bonds are vanishing in the systems under study. Small differences in interatomic Pb-Pb and Pb-O distances between these clusters indicate that they cannot be distinguished by recent experimental techniques in solution. Both the mentioned structures are stable and might coexist in solution.

Study of the Rheological Properties of Aqueous Solutions of Porphyrin Polymers

2017 ◽  
Vol 87 (12) ◽  
pp. 3097-3101
Author(s):  
E. V. Alopina ◽  
T. S. Usacheva ◽  
T. A. Ageeva ◽  
O. I. Koifman
Keyword(s):  
Aqueous Solutions ◽  
Rheological Properties ◽  
Porphyrin Polymers

On the Stability of Hydroxo-Dilead(II) Complex Cations

2003 ◽  
Vol 68 (12) ◽  
pp. 2377-2385 ◽  
Author(s):  
Martin Breza ◽  
Stanislav Biskupič
Keyword(s):  
Aqueous Solutions ◽  
Electronic Structures ◽  
Hartree Fock ◽  
The Stability ◽  
Total Charges

Using Hartree-Fock, B3LYP and MP2 treatments, the optimal geometries and corresponding electronic structures of various isomers of [Pb2(OH)n]q complex cations with total charges q = 4 - n, n = 1, 2, 3, are investigated. [Pb(μ-OH)Pb]3+ seems to be the most stable whereas [Pb(μ-OH)Pb(OH)]2+ and [Pb(μ-OH)Pb(OH)2]+ are unstable (because additional non-bridging hydroxyl weakens the neighboring Pb-Oμ and Oμ-Hμ bonds). Direct Pb-Pb and Oμ-Oμ interactions are weakly antibonding in all the systems under study. The clusters are held together exclusively by relatively weak Pb-O bonds. Non-measurable concentrations of [Pb(μ-OH)Pb]3+ in aqueous solutions might be explained by its reaction with OH- yielding preferably unstable [Pb(μ-OH)Pb(OH)]2+ species.

Electronic Structures of Formic Acid (HCOOH) and Formate (HCOO–) in Aqueous Solutions

2012 ◽  
Vol 3 (13) ◽  
pp. 1754-1759 ◽  
Author(s):  
Matthew A. Brown ◽  
Fernando Vila ◽  
Martin Sterrer ◽  
Stephan Thürmer ◽  
Bernd Winter ◽  
...  
Keyword(s):  
Formic Acid ◽  
Aqueous Solutions ◽  
Electronic Structures

Site-specific electronic structure of imidazole and imidazolium in aqueous solutions

2018 ◽  
Vol 20 (12) ◽  
pp. 8302-8310 ◽  
Author(s):  
F. Meyer ◽  
M. Blum ◽  
A. Benkert ◽  
D. Hauschild ◽  
Y. L. Jeyachandran ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Aqueous Solutions ◽  
Electronic Structures ◽  
Site Specific ◽  
X Ray

The electronic structures of aqueous imidazole and imidazolium solutions are studied in an atom- and site-specific fashion using soft X-ray spectroscopy.

Ultrathin frozen sections of yeast without aldehyde prefixation

1978 ◽  
Vol 36 (2) ◽  
pp. 58-59
Author(s):  
K. J. Böhm ◽  
a. E. Unger
Keyword(s):  
Aqueous Solutions ◽  
Biological Material ◽  
Yeast Cells ◽  
Frozen Sections ◽  
Good Preservation ◽  
Ultrathin Frozen Sections

During the last years it was shown that also by means of cryo-ultra-microtomy a good preservation of substructural details of biological material was possible. However the specimen generally was prefixed in these cases with aldehydes.Preparing ultrathin frozen sections of chemically non-prefixed material commonly was linked up to considerable technical and manual expense and the results were not always satisfying. Furthermore, it seems to be impossible to carry out cytochemical investigations by means of treating sections of unfixed biological material with aqueous solutions.We therefore tried to overcome these difficulties by preparing yeast cells (S. cerevisiae) in the following manner:

Imaging polymers, proteins and dna in aqueous solutions with the atomic force microscope

1989 ◽  
Vol 47 ◽  
pp. 32-33
Author(s):  
S.A.C. Gould ◽  
B. Drake ◽  
C.B. Prater ◽  
A.L. Weisenhorn ◽  
S.M. Lindsay ◽  
...  
Keyword(s):  
Amino Acids ◽  
Dna Sequencing ◽  
Aqueous Solutions ◽  
Atomic Force Microscope ◽  
Piezoelectric Crystal ◽  
Atomic Force ◽  
Structure Of Molecules ◽  
Optical Lever

The atomic force microscope (AFM) is an instrument that can be used to image many samples of interest in biology and medicine. Images of polymerized amino acids, polyalanine and polyphenylalanine demonstrate the potential of the AFM for revealing the structure of molecules. Images of the protein fibrinogen which agree with TEM images demonstrate that the AFM can provide topographical data on larger molecules. Finally, images of DNA suggest the AFM may soon provide an easier and faster technique for DNA sequencing.The AFM consists of a microfabricated SiO2 triangular shaped cantilever with a diamond tip affixed at the elbow to act as a probe. The sample is mounted on a electronically driven piezoelectric crystal. It is then placed in contact with the tip and scanned. The topography of the surface causes minute deflections in the 100 μm long cantilever which are detected using an optical lever.

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