TY - JOUR
T1 - Probing the aromaticity of the (HtAc)3( 2-H)6, (HtTh)3(2-H) 6 and (HtPa)3(2-H)6 clusters
AU - Ramrez-Tagle, Rodrigo
AU - Alvarado-Soto, Leonor
AU - Arratia-Perez, Ramiro
AU - Bast, Radovan
AU - Alvarez-Thon, Luis
N1 - Funding Information:
This research used resources of the National Energy Research Scientific Computing Center, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The authors are grateful for the financial support of the Grants: FONDECYT 3100048, 1110758, and 11100446, UNAB-DI-17-11/R, UNAB-DI-06-10/R, and NUCLEUS MILLENNIUM No. P07-006-F. R.B. kindly acknowledges grant FONDECYT 11100446 which funded his visit to the Universidad Andres Bello.
PY - 2011/9/14
Y1 - 2011/9/14
N2 - In this study we report about the aromaticity of the prototypical (H tAc)3(2-H)6, (HtTh) 3(2-H)6, and (HtPa) 3(2-H)6 clusters via two magnetic criteria: nucleus-independent chemical shifts (NICS) and the magnetically induced current density. All-electron density functional theory calculations were carried out using the two-component zeroth-order regular approach and the four-component Dirac-Coulomb Hamiltonian, including scalar and spin-orbit relativistic effects. Four-component current density maps and the integration of induced ring-current susceptibilities clearly show that the clusters (HtAc) 3(2-H)6 and (HtTh)3( 2-H)6 are non-aromatic whereas (HtPa) 3(2-H)6 is anti-aromatic. However, for the thorium cluster we find a discrepancy between the current density plots and the classification through the NICS index. Our results also demonstrate the increasing influence of f orbitals, on bonding and magnetic properties, with increasing atomic number in these clusters. We think that the enhanced electron mobility in (HtPa)3(2-H)6 is due the significant 5f character of its valence shell. Also the participation of f orbitals in bonding is the reason why the protactinium cluster has the shortest bond lengths of the three clusters. This study provides another example showing that the magnetically induced current density approach can give more reliable results than the NICS index.
AB - In this study we report about the aromaticity of the prototypical (H tAc)3(2-H)6, (HtTh) 3(2-H)6, and (HtPa) 3(2-H)6 clusters via two magnetic criteria: nucleus-independent chemical shifts (NICS) and the magnetically induced current density. All-electron density functional theory calculations were carried out using the two-component zeroth-order regular approach and the four-component Dirac-Coulomb Hamiltonian, including scalar and spin-orbit relativistic effects. Four-component current density maps and the integration of induced ring-current susceptibilities clearly show that the clusters (HtAc) 3(2-H)6 and (HtTh)3( 2-H)6 are non-aromatic whereas (HtPa) 3(2-H)6 is anti-aromatic. However, for the thorium cluster we find a discrepancy between the current density plots and the classification through the NICS index. Our results also demonstrate the increasing influence of f orbitals, on bonding and magnetic properties, with increasing atomic number in these clusters. We think that the enhanced electron mobility in (HtPa)3(2-H)6 is due the significant 5f character of its valence shell. Also the participation of f orbitals in bonding is the reason why the protactinium cluster has the shortest bond lengths of the three clusters. This study provides another example showing that the magnetically induced current density approach can give more reliable results than the NICS index.
UR - http://www.scopus.com/inward/record.url?scp=80052920396&partnerID=8YFLogxK
U2 - 10.1063/1.3632056
DO - 10.1063/1.3632056
M3 - Article
C2 - 21932909
AN - SCOPUS:80052920396
SN - 0021-9606
VL - 135
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
IS - 10
M1 - 104506
ER -