Hydrogen Bonds Dictate the Coordination Geometry of Copper: Characterization of a Square‐Planar Copper(I) Complex

6,6′′‐Bis(2,4,6‐trimethylanilido)terpyridine (H2TpyNMes) was prepared as a rigid, tridentate pincer ligand containing pendent anilines as hydrogen bond donor groups in the secondary coordination sphere. The coordination geometry of (H2TpyNMes)copper(I)‐halide (Cl, Br and I) complexes is dictated by the strength of the NH–halide hydrogen bond. The CuICl and CuIICl complexes are nearly isostructural, the former presenting a highly unusual square‐planar geometry about CuI. The geometric constraints provided by secondary interactions are reminiscent of blue copper proteins where a constrained geometry, or entatic state, allows for extremely rapid CuI/CuII electron‐transfer self‐exchange rates. Cu(H2TpyNMes)Cl shows similar fast electron transfer (≈105 m−1 s−1) which is the same order of magnitude as biological systems.Entatic state: Hydrogen bonds constrain the geometry of CuI and CuII complexes. A highly unusual square‐planar geometry about CuI (see structure) is shown to be nearly isostructural to the CuII core. The minimal reorganization energy between redox states allows for extremely rapid CuI/CuII electron‐transfer self‐exchange rates.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134494/1/anie201511527_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134494/2/anie201511527-sup-0001-misc_information.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134494/3/anie201511527.pd

The SQM/COSMO filter: reliable native pose identification based on the quantum-mechanical description of protein–ligand interactions and implicit COSMO solvation

Current virtual screening tools are fast, but reliable scoring is elusive. Here, we present the "SQM/COSMO filter", a novel scoring function featuring a quantitative semiempirical quantum mechanical (SQM) description of all types of noncovalent interactions coupled with implicit COSMO solvation. We show unequivocally that it outperforms eight widely used scoring functions. The accuracy and chemical generality of the SQM/COSMO filter make it a perfect tool for late stages of virtual screening

An Exploration of the Ozone Dimer Potential Energy Surface

The (O3)2 dimer potential energy surface is thoroughly explored at the ab initio CCSD(T) computational level. Five minima are characterized with binding energies between 0.35 and 2.24 kcal/mol. The most stable may be characterized as slipped parallel, with the two O3 monomers situated in parallel planes. Partitioning of the interaction energy points to dispersion and exchange as the prime contributors to the stability, with varying contributions from electrostatic energy, which is repulsive in one case. Atoms in Molecules analysis of the wavefunction presents specific O⋯O bonding interactions, whose number is related to the overall stability of each dimer. All internal vibrational frequencies are shifted to the red by dimerization, particularly the antisymmetric stretching mode whose shift is as high as 111 cm−1. In addition to the five minima, 11 higher-order stationary points are identified

Photoionization of the fullerene ion C60+

Photoionization cross section of the fullerene ion C60+ has been calculated within a single-electron approximation and also by using a consistent many-body theory accounting for many-electron correlations.Comment: 8 pages, 3 figure

Ab-initio study of model guanine assemblies: The role of pi-pi coupling and band transport

Several assemblies of guanine molecules are investigated by means of first-principle calculations. Such structures include stacked and hydrogen-bonded dimers, as well as vertical columns and planar ribbons, respectively, obtained by periodically replicating the dimers. Our results are in good agreement with experimental data for isolated molecules, isolated dimers, and periodic ribbons. For stacked dimers and columns, the stability is affected by the relative charge distribution of the pi orbitals in adjacent guanine molecules. pi-pi coupling in some stacked columns induces dispersive energy bands, while no dispersion is identified in the planar ribbons along the connections of hydrogen bonds. The implications for different materials comprised of guanine aggregates are discussed. The bandstructure of dispersive configurations may justify a contribution of band transport (Bloch type) in the conduction mechanism of deoxyguanosine fibres, while in DNA-like configurations band transport should be negligible.Comment: 21 pages, 6 figures, 3 tables, to be published in Phys. Rev.