New Insights into Re₃(μ-Cl)₃Cl₆ Aromaticity. Evidence of σ- and π-Diatropicity

Abstract

We have theoretically evaluated the behavior of the Re3(μ-Cl)3Cl6 cluster under magnetic perturbation, and it clearly shows that the magnetic response within the Re3(μ-Cl)3 plane is highly diatropic in nature. An analysis of both the magnetically induced current density (MICD) and induced magnetic field (B(ind)) allows us to classify this cluster as doubly σ- and also π-aromatic on the magnetic criterion. These findings contradict the classical Re-Re double bond representation and favor a chemical bonding pattern that involves delocalized bonds.

Aromaticity in heterocyclic analogues of benzene: Dissected NICS and current density analysis

“…The topology of tridimensional chemical shielding isosurfaces are expected to be highly influenced by both the presence of functional groups (with multiple bonds) and the ring current effect of arenes, on the anisotropy of the chemical shielding . Our group and others have found analogous pictures, about anisotropy effects, via the analysis of the induced magnetic field (B ind z ), which is equivalent to NICS zz , on clusters and molecules . Figure depicts the selected planes (perpendicular to the molecular plane) containing isolines of the π‐electron contribution to NICS zz , for the set of studied molecules.…”

“…NICS values were computed employing the gauge‐including atomic orbital (GIAO) method and were dissected into their core, valence, σ, and π contributions using the natural chemical shielding analysis implemented in the NBO 6.0 program . Plots of NICS were generated using the VisIt 2.10.0 program and our own codes …”

“…[45,46] Plots of NICS were generated using the VisIt 2.10.0 program [47] and our own codes. [33,40,48] The magnetically induced current densities and the RCS have been obtained using the Dirac-Coulomb Hamiltonian implemented by Bast et al [49] in the DIRAC program package. [50] The small component basis set has been generated using unrestricted kinetic balance, which provides a flexible basis set for magnetic properties.…”

Which NICS method is most consistent with ring current analysis? Assessment in simple monocycles

“…22,34,38,60,65,66 Fig. 3 depicts selected planes (perpendicular to the molecular plane) containing isolines of the s-and the p-electron contribution to NICS zz , for the set of studied molecules.…”

Advances in bonding and properties of inorganic systems from relativistic calculations in Latin America

“…The anions are also aromatic but, conversely, spin‐orbit effects increase the aromaticity due to the fact that the 5d 5/2 spinors are now being populated and are more expanded than the scalar 5d orbital . This has been recently corroborated by Vasquez‐Espinal from both the magnetically induced current density (MICD) and induced magnetic field ( B ind ) calculations, showing the doubly σ‐ and also π‐aromatic character. Similarly, in 2010, spin‐orbit effects on aromaticity were explored for a series of Pd 3 and Pd 4 ‐based clusters …”