Intrinsic Dynamic and Static Nature of Halogen Bonding in Neutral Polybromine Clusters, with the Structural Feature Elucidated by QTAIM Dual-Functional Analysis and MO Calculations

The intrinsic dynamic and static nature of noncovalent Br-∗-Br interactions in neutral polybromine clusters is elucidated for Br4–Br12, applying QTAIM dual-functional analysis (QTAIM-DFA). The asterisk (∗) emphasizes the existence of the bond critical point (BCP) on the interaction in question. Data from the fully optimized structures correspond to the static nature of the interactions. The intrinsic dynamic nature originates from those of the perturbed structures generated using the coordinates derived from the compliance constants for the interactions and the fully optimized structures. The noncovalent Br-∗-Br interactions in the L-shaped clusters of the Cs symmetry are predicted to have the typical hydrogen bond nature without covalency, although the first ones in the sequences have the vdW nature. The L-shaped clusters are stabilized by the n(Br)→σ*(Br–Br) interactions. The compliance constants for the corresponding noncovalent interactions are strongly correlated to the E(2) values based on NBO. Indeed, the MO energies seem not to contribute to stabilizing Br4 (C2h) and Br4 (D2d), but the core potentials stabilize them, relative to the case of 2Br2; this is possibly due to the reduced nuclear–electron distances, on average, for the dimers.

Intrinsic Dynamic and Static Nature of Halogen Bonding in Neutral Polybromine Clusters with the Structural Feature, Elucidated by QTAIM Dual Functional Analysis and MO Calculations

The intrinsic dynamic and static nature of the non-covalent Br-*-Br interactions in the neutral polybromine clusters is elucidated for Br4–Br12, applying QTAIM dual functional analysis (QTAIM-DFA). The asterisk (*) emphasizes the existence of the bond critical point (BCP) on the interaction in question. Data from the fully optimized structures correspond to the static nature of interactions. The intrinsic dynamic nature is originated from those of the perturbed structures generated using the coordinates derived from the compliance constants for the interactions and the fully optimized structures. The non-covalent Br-*-Br interactions in the L-shaped clusters of the Cs symmetry are predicted to have the typical hydrogen bond nature without covalency, although the first ones in the sequences have the vdW nature. The L-shaped clusters are stabilized by the n(Br)->σ*(Br–Br) interactions. The compliance constants for the corresponding non-covalent interactions are strongly correlated to the E(2) values based on NBO. Indeed, the MO energies seem not contribute to stabilize Br4 (C2h) and Br4 (D2d), but the core potentials stabilize them, relative to the case of 2Br2, maybe due to the reduced nuclear-electron distances in the average for the dimmers.

The nature of G⋯E–Y σ(3c–4e) in o-MenGCH2C6H4EY (MenG = Me2N and MeE; E = O, S, Se and Te; Y = F, Cl, Br, EMe and Me) with contributions from CT and compliance constants in noncovalent G⋯E interactions

The nature of E⋯E′ in 1-RECH2-2-R′E′C6H4 (E/E′ = O, S, Se and Te) is clarified with QTAIM approach and NBO analysis, after structural determinations.

Effective in silico prediction of new oxazolidinone antibiotics: force field simulations of the antibiotic–ribosome complex supervised by experiment and electronic structure methods

We propose several new and promising antibacterial agents for the treatment of serious Gram-positive infections. Our predictions rely on force field simulations, supervised by first principle calculations and available experimental data. Different force fields were tested in order to reproduce linezolid's conformational space in terms of a) the isolated and b) the ribosomal bound state. In a first step, an all-atom model of the bacterial ribosome consisting of nearly 1600 atoms was constructed and evaluated. The conformational space of 30 different ribosomal/oxazolidinone complexes was scanned by stochastic methods, followed by an evaluation of their enthalpic penalties or rewards and the mechanical strengths of the relevant hydrogen bonds (relaxed force constants; compliance constants). The protocol was able to reproduce the experimentally known enantioselectivity favoring the S-enantiomer. In a second step, the experimentally known MIC values of eight linezolid analogues were used in order to crosscheck the robustness of our model. In a final step, this benchmarking led to the prediction of several new and promising lead compounds. Synthesis and biological evaluation of the new compounds are on the way.

Molecular recognition of naphthalene diimide ligands by telomeric quadruplex-DNA: the importance of the protonation state and mediated hydrogen bonds

How important are mediated hydrogen bonds in terms of molecular recognition? Compliance Constants (relaxed force constants) give the answer.

III-defined concepts in chemistry: rigid force constants vs. compliance constants as bond strength descriptors for the triple bond in diboryne

In a recent publication in this journal, the interpretation of the Braunschweig's diboryne as a true triple bond is questioned.