4 research outputs found
Revisiting the Chemistry of the Actinocenes [(η<sup>8</sup>‑C<sub>8</sub>H<sub>8</sub>)<sub>2</sub>An] (An = U, Th) with Neutral Lewis Bases. Access to the Bent Sandwich Complexes [(η<sup>8</sup>‑C<sub>8</sub>H<sub>8</sub>)<sub>2</sub>An(L)] with Thorium (L = py, 4,4′-bipy, <i>t</i>BuNC, R<sub>4</sub>phen)
In stark contrast to uranocene, (Cot)<sub>2</sub>Th reacts with
neutral mono- or bidentate Lewis bases to give the bent sandwich complexes
(Cot)<sub>2</sub>Th(L) (L = py, 4,4′-bipy, <i>t</i>BuNC, phen, Me<sub>4</sub>phen). DFT calculations in the gas phase
show that, for both U and Th, formation of the bent compound (Cot)<sub>2</sub>An(L) should be facile, the linear and bent forms being close
in energy
Revisiting the Chemistry of the Actinocenes [(η<sup>8</sup>‑C<sub>8</sub>H<sub>8</sub>)<sub>2</sub>An] (An = U, Th) with Neutral Lewis Bases. Access to the Bent Sandwich Complexes [(η<sup>8</sup>‑C<sub>8</sub>H<sub>8</sub>)<sub>2</sub>An(L)] with Thorium (L = py, 4,4′-bipy, <i>t</i>BuNC, R<sub>4</sub>phen)
In stark contrast to uranocene, (Cot)<sub>2</sub>Th reacts with
neutral mono- or bidentate Lewis bases to give the bent sandwich complexes
(Cot)<sub>2</sub>Th(L) (L = py, 4,4′-bipy, <i>t</i>BuNC, phen, Me<sub>4</sub>phen). DFT calculations in the gas phase
show that, for both U and Th, formation of the bent compound (Cot)<sub>2</sub>An(L) should be facile, the linear and bent forms being close
in energy
Finite Temperature Infrared Spectra from Polarizable Molecular Dynamics Simulations
Infrared spectra of biomolecules
are obtained from molecular dynamics
simulations at finite temperature using the AMOEBA force field. Diverse
examples are presented such as <i>N</i>-methylacetamide
and its derivatives and a helical peptide. The computed spectra from
polarizable molecular dynamics are compared in each case to experimental
ones at various temperatures. The role of high-level electrostatic
treatment and explicit polarization, including parameters improvements,
is highlighted for obtaining spectral sensitivity to the environment
including hydrogen bonds and water molecules and a better understanding
of the observed experimental bands
Ab Initio Extension of the AMOEBA Polarizable Force Field to Fe<sup>2+</sup>
We extend the AMOEBA polarizable
molecular mechanics force field
to the Fe<sup>2+</sup> cation in its singlet, triplet, and quintet
spin states. Required parameters are obtained either directly from
first principles calculations or optimized so as to reproduce corresponding
interaction energy components in a hexaaquo environment derived from
quantum mechanical energy decomposition analyses. We assess the importance
of the damping of point-dipole polarization at short distance as well
as the influence of charge-transfer for metal-water interactions in
hydrated Fe<sup>2+</sup>; this analysis informs the selection of model
systems employed for parametrization. We validate our final Fe<sup>2+</sup> model through comparison of molecular dynamics (MD) simulations
to available experimental data for aqueous ferrous ion in its quintet
electronic ground state