scholarly journals The B2 Structural Motif as a Tool for Modulating Ring Currents in Monocyclic Li Clusters

Chemistry ◽  
2021 ◽  
Vol 3 (3) ◽  
pp. 1063-1073
Author(s):  
Slađana Đorđević ◽  
Slavko Radenković

Magnetically induced current densities, calculated at the M06-2X/def2-TZVP level using the diamagnetic-zero version of the continuous transformation of origin of current density (CTOCD-DZ) method, were employed to study the aromaticity in Li3B2− and Li4B2. It was found that the Li3/Li4 rings in Li3B2− and Li4B2 remarkably resemble the monocyclic Li3+ and Li42+ clusters. Unlike the parent Li3+ and Li42+ systems that sustain negligibly weak global current density circulation, the Li3B2− and Li4B2 clusters exhibit a strong diatropic current density. The present work demonstrates how structural modifications introduced by the B2 unit can be used for modulating the current density in cyclic Li-based clusters.

Author(s):  
Rashid R. Valiev ◽  
Theo Kurtén ◽  
Lenara Valiulina ◽  
Sergey Yu. Ketkov ◽  
Victor Cherepanov ◽  
...  

The magnetically induced current-density susceptibility tensor (CDT) of the lowest singlet and triplet states of the metallocenothiaporphyrins, where the metal is V, Cr, Mn, Fe, Co, Ni, Mo, Tc, Ru,...


2019 ◽  
Vol 21 (13) ◽  
pp. 7105-7114 ◽  
Author(s):  
Slađana Đorđević ◽  
Slavko Radenković

Magnetically induced current densities reveal the double aromatic character of the examined Be–B clusters.


2016 ◽  
Vol 18 (23) ◽  
pp. 15934-15942 ◽  
Author(s):  
Dage Sundholm ◽  
Raphael J. F. Berger ◽  
Heike Fliegl

The aromatic pathway of molecules with annelated aromatic and antiaromatic rings has been studied by calculating magnetically induced current densities.


2017 ◽  
Vol 19 (10) ◽  
pp. 7124-7131 ◽  
Author(s):  
Markus Rauhalahti ◽  
Stefan Taubert ◽  
Dage Sundholm ◽  
Vincent Liégeois

Magnetically induced current density of C6I62+ using GIMIC method and effective core potentials.


Author(s):  
Markus Rauhalahti ◽  
D Sundholm ◽  
Mikael P. Johansson

The magnetically induced current density of an intriguing naphthalene-fused heteroporphyrin have been studied, using the quantum-chemical, gauge-including magnetically induced currents (GIMIC) method. The ring-current strengths and current-density pathways for the...


2016 ◽  
Vol 18 (17) ◽  
pp. 11932-11941 ◽  
Author(s):  
Isaac Benkyi ◽  
Heike Fliegl ◽  
Rashid R. Valiev ◽  
Dage Sundholm

The aromatic pathways of carbaporphyrins and carbachlorins that are based on magnetically induced current density DFT-GIMIC calculations are presented and discussed.


Chemistry ◽  
2021 ◽  
Vol 3 (4) ◽  
pp. 1381-1391
Author(s):  
Mesías Orozco-Ic ◽  
Gabriel Merino

The aromaticity of [n]starphenes (n = 1, 4, 7, 10, 13, 16), as well as starphene-based [19]dendriphene, is addressed by calculating the magnetically induced current density and the induced magnetic field, using the pseudo-π model. When an external magnetic field is applied, these systems create diatropic currents that split into a global peripheral current surrounding the starphene skeleton and several local currents in the acene-based arms, resulting in large shielding cones above the arms. In particular, the arm currents are smaller than their linear analogs, and in general, the strengths of the ring currents tend to weaken as the starphene get larger.


2007 ◽  
Vol 79 (6) ◽  
pp. 969-979 ◽  
Author(s):  
Patrick W. Fowler ◽  
Mark Lillington ◽  
Leif P. Olson

The magnetic criterion of aromaticity is based on the ability of a cyclic system to support a ring current. If the ring current has the diatropic sense, the system is aromatic; if the sense is paratropic, the system is antiaromatic. Attribution of aromaticity ab initio therefore reduces to the calculation and visualization of induced current density. This can be achieved at modest computational cost within the ipsocentric approach, where current density at any point in space is calculated with that point as origin of vector potential. This choice leads to accurate maps of current density and a uniquely simple interpretation in terms of nonredundant orbital contributions governed by translational and rotational selection rules. For example, four-electron diatropicity and two-electron paratropicity are predicted for delocalized forms of [4n+2]- and [4n]-annulenes, respectively. A new application to homoaromatic systems is described. Two model tris-homoaromatics, both neutral molecules, are shown to exhibit a through-space, highest occupied molecular orbital (HOMO)-dominated, four-electron ring current, in a direct analogy with the conventional "aromatic" benzene π-current.


Author(s):  
I-Fei Tsu ◽  
D.L. Kaiser ◽  
S.E. Babcock

A current theme in the study of the critical current density behavior of YBa2Cu3O7-δ (YBCO) grain boundaries is that their electromagnetic properties are heterogeneous on various length scales ranging from 10s of microns to ˜ 1 Å. Recently, combined electromagnetic and TEM studies on four flux-grown bicrystals have demonstrated a direct correlation between the length scale of the boundaries’ saw-tooth facet configurations and the apparent length scale of the electrical heterogeneity. In that work, enhanced critical current densities are observed at applied fields where the facet period is commensurate with the spacing of the Abrikosov flux vortices which must be pinned if higher critical current density values are recorded. To understand the microstructural origin of the flux pinning, the grain boundary topography and grain boundary dislocation (GBD) network structure of [001] tilt YBCO bicrystals were studied by TEM and HRTEM.


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