Boron centres allow design, control and systematic tuning of neutral homoaromatics for functionalization purposes

Homoaromatic compounds are currently viewed more as an interesting novelty with little to no practical application. Based on calculations within density functional theory, we show that the unique charge redirection properties of tricoordinate boron, along with it being isolobal to a carbocation allow for a larger range of two‐electron donors to be utilized, leading to the rational design of homoaromatic compounds better suited to functionalization. Among others, these compounds show a strong dependency on the relative positioning of the hetero‐atoms within the ring system, a modulation control rendered possible by the insertion of the boron centres

Magnetic Antiaromaticity─Paratropicity─Does Not Necessarily Imply Instability

Magnetically induced ring currents are a conventional tool for the characterization of aromaticity. Dia- and paratropic currents are thought to be associated with stabilization (aromaticity) and destabilization (antiaromaticity), respectively. In the present work, I have questioned the validity of the paratropic currents as a measure of antiaromaticity among monocyclic hydrocarbons. I have shown that while reduced/oxidized radical ions of hydrocarbons sustain strong paratropic currents, they often gain extra stabilization via cyclic conjugation compared to their acyclic counterparts.National Science Centre,Poland 2020/39/B/ST4/02022 ; Poland’s High-Performance Computing Infrastructure PLGrid (HPC Centers: ACK Cyfronet AGH) grant no.PLG/2022/01605

1 H NMR is not a proof of hydrogen bonds in transition metal complexes

Ministry of Education, Youth and Sports of the Czech Republic Program NPU I [LO1504]; Czech Science FoundationGrant Agency of the Czech Republic [17-07091S]; CESNET [LM2015042]; CERIT Scientific Clouds [LM2015085

Path-dependency of energy decomposition analysis & the elusive nature of bonding

Here, we provide evidence of the path-dependency of the energy components of the energy decomposition analysis scheme, EDA, by studying a set of thirty-one closed-shell model systems with the D2h symmetry point group. For each system, we computed EDA components from nine different pathways and numerically showed that the relative magnitudes of the components differ substantially from one path to the other. Not surprisingly, yet unfortunately, the most significant variations in the relative magnitudes of the EDA components appear in the case of species with bonds within the grey zone of covalency and ionicity. We further discussed that the role of anions and their effect on arbitrary Pauli repulsion energy components affects the nature of bonding defined by EDA. The outcome variation by the selected partitioning scheme of EDA might bring arbitrariness when a careful comparison is overlooked

Metallaaromaticity - a protean world

The nature of magnetically induced current densities (MICD) of metallabenzenes and related compounds has been examined with relativistic DFT calculations to assess the magnetic aromaticity of the molecules. The origin of the total MICD has been analyzed in terms of individual molecular orbital (MO) contributions. Our study reveals that the s-framework of the molecules always makes a diamagnetic contribution to the MICD. On the other hand, p-MOs and Craig–Möbius type p-MOs, i.e., MOs in which the dxy/dxz orbitals of the metal centers change the phase of the wave function akin to a Möbius twist, may not make a diatropic contribution. We have identified metallabenzenes with multiple magnetic aromaticities. In the case of iridabenzenes, s-MICD has been found to decrease dramatically from Ir(III) to Ir(V) systems. Furthermore, a brief examination of some recently synthesized metallapolycycles has shown that the metal center in a given ring can strongly modulate the aromaticity of neighboring rings. Finally, the finding that relatively minor perturbations in the ligand environment of the metal can substantially influence the aromaticity of metallabenzenes and related molecules underscores the protean character of metallaaromaticity and the need for even wider-ranging investigations. Considering the conflicts between magnetic response and ground-state aromaticity criteria (energetic, structural, and electronic criteria), we propose that the term aromatic be used for labeling a molecule if and only if all criteria confirm aromaticity. In other words, neither magnetic nor ground-state criteria are necessary and sufficient conditions for labeling a molecule aromatic

Relativity or aromaticity? A first-principles perspective of chemical shifts in osmabenzene and osmapentalene derivatives

We have studied the magnetic response properties and aromaticity of osmium metallacycles by means of scalar-relativistic (1c) and fully relativistic (4c) density functional theory computations. For osmabenzene, whose aromatic character is controversial, a topological analysis of the current density has revealed the presence of a unique σ-type Craig-Möbius magnetic aromaticity. We show that the partially filled osmium valence shell induces a large paratropic current, which may interfere with certain methods commonly used to analyze aromaticity, in particular NICS. Further, we show that the extreme deshielding of the light atoms in the vicinity of the osmium atoms in osmapentalene derivatives is not a consequence of aromaticity but can be explained by paramagnetic couplings between σOs - C bonding orbitals and the π∗Os orbitals. We demonstrate that variations in the orientation of the induced magnetic currents through the molecule dictates the alternating signs of the spin-orbit contribution to the NMR chemical shift. This journal is © the Owner Societies.programme "Projects of Large Research, Development, and Innovations Infrastructures" [CESNET LM2015042]; Research Council of NorwayResearch Council of Norway [LM2015070]; Program I [LO1504]; programme "Projects of Large Research, Development, and Innovations Infrastructures" by CERIT Scientific Cloud [CERIT Scientific Cloud LM2015085]; programme "Projects of Large Research, Development, and Innovations Infrastructures" by IT4 Innovations National Supercomputing Center [LM2015070

A quest for ideal electric field-driven MX@C70 endohedral fullerene memristors: which MX fits the best?

Endohedral fullerenes with a dipolar molecule enclosed in the fullerene cage have great potential in molecular electronics, such as diodes, switches, or molecular memristors. Here, we study a series of model systems based on MX@D5h(1)-C70 (M = a metal or hydrogen, X = a halogen or a chalcogen) endohedral fullerenes to identify potential molecular memristors and to derive a general formula for rapid identification of potential memristors among analogous MX@Cn systems. To obtain sufficiently accurate results for switching barriers and encapsulation energies, we perform a benchmark of ten DFT functionals against ab initio SCS-MP2 and DLPNO-CCSD(T) methods at the complete basis set limit. The whole series is then investigated using the PBE0 functional which was found to be the most efficient vs. the ab initio methods. Nine of the 34 MX@C70 molecules studied are predicted to have suitable switching barriers to be considered as potential candidates for molecular switches and memristors. We have identified several structure–property relationships for the switching barrier and response of the systems to the electric field, in particular the dependence of the switching barrier on the available space for M–X switching and faster response of the system to the electric field with a larger dipole moment of MX and [email protected] Science Foundation (21-17806S); Ministry of Education, Youth and Sports of the Czech Republic project e-INFRA CZ project (ID: 90140); National Science Centre, Poland, 2020/39/B/ST4/0202

Reply to: on the existence of collective interactions reinforcing the metal-ligand bond in organometallic compounds

Ministry of Education, Youth and Sports of the Czech Republic [e-INFRA CZ LM2018140]; PLGrid (HPC Centers: ACK Cyfronet AGH) [PLG/2022/016057]; Spanish MICINN [PID2021-122763NB-I00]; National Science Centre, Poland [2020/39/B/ST4/02022]; Natural Sciences and Engineering Research Council of Canada (NSERC); Canada Research Chairs Progra

Collective interactions among organometallics are exotic bonds hidden on lab shelves

Natural Sciences and Engineering Research Council of Canada (NSERC); Canada Research Chairs Program; Ministry of Education, Youth and Sports of the Czech Republic [LM2018140]; Spanish MICINN [PGC2018-095953-B-I00]; National Science Centre, Poland [2020/39/B/ST4/02022

Reply to: An approach to the resolution of the dispute on collective atomic interactions

REPLYING TO P. Polestshuk Nature Communications https://doi.org/10.1038/s41467-024-54552-z (2024)FCT/DL57 researcher program for funding (https://doi.org/10.54499/DL57/2016/CP1479/CT0050); grants PTDC/QUI-QIN/0252/2021 (https://doi.org/10.54499/PTDC/QUI-QIN/0252/2021); research unit funding through UIDB/04046/2020 (https://doi.org/10.54499/UIDB/04046/2020) and UIDP/04046/2020 (https://doi.org/10.54499/UIDP/04046/2020); grant PID2021-122763NB-I00 funded by MICIU (https://doi.org/10.13039/501100011033); “ERDF A way of making Europe”; National Science Centre, Poland 2020/39/B/ST4/02022