We report the structure of a fungal enzyme that activates the amide bond, allowing nucleophilic chemistry.

Determining the absolute configuration of a molecule is possible by means of various chiroptical spectroscopic methods, one of them being vibrational Raman optical activity (VROA). By adopting a laser excitation wavelength in resonance with an electronic transition, the weak spectral signals can be selectively enhanced. We implement a Kohn-Sham methodology for the calculation of resonance and off-resonance VROA spectra to (S)-naproxen and (S)-ibuprofen and discuss their band patterns. The resonance enhancement of the VROA spectrum of (S)-naproxen at an incident wavelength of 514.5 nm caused by an absorption tail as well as the typical off-resonance behavior of the VROA spectrum of (S)-ibuprofen at the same incident wavelength can be well reproduced. VROA spectra are also predicted under full resonance conditions.

An activated fragment which is structurally unstable when considered isolated can be stabilized through binding to a suitable molecular environment; for instance, to a transition-metal fragment. The metal fragment may be designed in a shell-wise build-up of a surrounding molecular environment. However, adding more and more atoms in a consecutive fashion soon leads to a combinatorial explosion of structures, which is unfeasible to handle without automation. Here, we present a fully automated and parallelized framework that constructs such an embedding environment atom-wise. Molecular realizations of such an environment are constructed based on simple heuristic rules intended to screen a sufficiently large portion of the possible compound space and are then subsequently optimized by electronic structure methods. (Constrained-optimized) structures are then evaluated with respect to a scoring function, for which we choose here the concept of gradient-driven molecule construction. This concept searches for structure modifications that reduce the forces on all atoms. We develop and analyze our approach at the example of CO activation by reproducing a known compound and mapping out possible alternative structures and their effect on the stabilization of a (bent) CO ligand. For all generated structures, the nuclear gradient on the activated fragment and its coordination energy are evaluated to steer the design process. © 2017 Wiley Periodicals, Inc.

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