Reply to the 'Comment on "Designing potentially singlet fission materials with an anti-Kasha behaviour"' by K. Jindal, A. Majumdar and R. Ramakrishnan, , 2025, , DOI: 10.1039/D4CP02863E.

In this reply to the preceding paper by K. Jindal, A. Majumdar, and R.

Correction: Designing potentially singlet fission materials with an anti-Kasha behaviour.

Correction for 'Designing potentially singlet fission materials with an anti-Kasha behaviour' by Ricardo Pino-Rios , , 2024, , 15386-15392, https://doi.org/10.1039/D4CP01284D.

Exploring the potential energy surface of BH: an exception of the Wade-Mingos rules.

An analysis of the potential energy surface of BH which, according to Wade-Mingos rules should have a tetrahedral structure, is presented. Our results indicate that the global minimum has a planar diamond-like boron skeleton and that the nearest local minimum lies 7.8 kcal mol above it.

Is azulene's local aromaticity and relative stability driven by the Glidewell-Lloyd rule?

The local aromaticity of azulene has been studied to understand their electronic properties. For this purpose, we have used the magnetic criterion through magnetically induced current density maps, ring current strengths, NICS(1), and the bifurcation value of three-dimensional surfaces of NICS. On the other hand, the delocalization criterion was used by calculating the MCI and ELF.

Anti-electrostatic cation⋯π-hole and cation⋯lp-hole interactions are stabilized collective interactions.

Collective interactions are a novel type of bond between metals and AX fragments with an electropositive central atom, A, and electronegative X substituents. Here, using electrostatic potential maps and state-of-the-art bonding analysis tools we have shown that collective interactions are anti-electrostatic cation⋯π-Hole or cation⋯lp-Hole interactions.

On the aromaticity and stability of benzynes in the ground and lowest-lying triplet excited states.

In this work, we have revisited the aromaticity of benzyne isomers at the unrestricted density functional theory level (UDFT) using the energetic, magnetic, and delocalization criteria. In addition, this last criterion has also been analyzed employing complete active space (CASSCF) calculations. The results show conservation of aromaticity in these monocycles.

Exploration of the potential energy surface in mixed Zintl clusters applying an automatic Johnson polyhedra generator: the case of EM (E = Si, Ge, Sn; M = Sb, Bi).

A new algorithm called Automatic Johnson Cluster Generator (AJCG) is presented, which, as its name indicates, allows the definition of the desired Johnson polyhedron to subsequently carry out all the possible permutations between the atoms that form this polyhedron. This new algorithm allows the exhaustive study of the structures' potential energy surface (PES). In addition, the AJCG algorithm is helpful for the study of three-dimensional compounds such as boranes or Zintl clusters and their structural derivatives with two or more different atoms.

On the Importance of Noncovalent Interactions in the Stabilization of Nonconventional Compounds Using Bulky Groups.

In this article, we studied the capability of bulky groups to contribute to the stabilization of a given compound in addition to the well-known steric effect related to substituents due to their composition (alkyl chains and aromatic groups, among others). For this purpose, the recently synthesized 1-bora-3-boratabenzene anion which contains large substituents was analyzed by means of the independent gradient model (IGM), natural population analysis (NPA) at the TPSS/def2-TZVP level, force field-based energy decomposition analysis (EDA-FF) applying the universal force field (UFF), and molecular dynamics calculations under the GFN2-xTB approach. The results indicate that the bulky groups should not only be considered for their steric effects but also for their ability to stabilize a system that could be very reactive.

Electronic Transmutation Concept: Is the Inverse Process Possible? An Evaluation of Main Group Compounds.

The electronic transmutation (ET) concept states that when an element with atomic number gains an electron, it transmutes into a + 1 element, leading to species that possess similar chemical bonding patterns and geometric structures regarding the original ( + 1) element. In this work, the opposite concept, that is, the inverse ET, is assessed. For this purpose, several main group compounds have been analyzed in terms of the adaptive natural density partitioning.

Evaluation of Slight Changes in Aromaticity through Electronic and Density Functional Reactivity Theory-Based Descriptors.

Aromaticity is a useful tool to rationalize the structure, stability, and reactivity in several compounds. Although aromaticity is not directly an observable, it is well accepted that electronic delocalization around the molecular ring is a key stabilizing feature of aromatic compounds. This contribution presents a systematic evaluation of the capability of delocalization and reactivity criteria to describe aromaticity in a set of fluorinated benzenes.

The hidden aromaticity in borazine.

The aromaticity of borazine (BNH), also known as the inorganic benzene, is a controversial issue since this compound has several characteristics that could qualify it as an aromatic compound. However, recent studies using magnetic criteria indicate that this compound should be considered as a non-aromatic system. This assignment is mainly due to diatropic currents in the nitrogen atoms without observation of ring currents.

Kick-Fukui: A Fukui Function-Guided Method for Molecular Structure Prediction.

Here, we introduce a hybrid method, named Kick-Fukui, to explore the potential energy surface (PES) of clusters and molecules using the Coulombic integral between the Fukui functions in the first screening of the best individuals. In the process, small stable molecules or clusters whose combination has the stoichiometry of the explored species are used as assembly units. First, a small set of candidates has been selected from a large and stochastically generated (Kick) population according to the maximum value of the Coulombic integral between the Fukui functions of both fragments.

Acenes and phenacenes in their lowest-lying triplet states. Does kinked remain more stable than straight?

The larger stability of phenacenes compared to their acene isomers in their ground states is attributed to the larger aromaticity of the former. To our knowledge the relative stability of acenes and phenacenes in their lowest-lying triplet states (T1) has not been discussed yet. Using unrestricted density functional theory calculations, our results show that for the smallest members of the series, acenes in their T1 states are more stable than the corresponding phenacenes.

Aromatic ouroboroi: heterocycles involving a σ-donor-acceptor bond and 4n + 2 π-electrons.

The aromaticity and dynamics of a set of recently proposed neutral 5- and 6-membered heterocycles that are closed by dative (donor-acceptor) or multi-center σ bonds, and have resonance forms with a Hückel number of π-electrons, are examined. The donors and acceptors in the rings include N, O, and F, and B, Be, and Mg, respectively. The planar geometry of the rings, coupled with evidence from different measures of aromaticity, namely the NICSzz, and NICSπzz components of the conventional nucleus independent chemical shifts (NICS), and ring current strengths (RCS), indicate non-trivial degrees of aromaticity in certain cases, including the cyclic C3B2OH6 and C3BOH5 isomers, both with three bonds to the O site in the ring.

Embedding a Planar Hypercoordinate Carbon Atom into a [4n+2] π-System.

Through delicate tuning of the electronic structure, we report herein a rational design of seventeen new putative global minimum energy structures containing a planar tetra- or pentacoordinate carbon atom embedded in an aromatic hydrocarbon. These structures are the result of replacing three consecutive hydrogen atoms of an aromatic hydrocarbon by less electronegative groups, forming a multicenter σ-bond with the planar hypercoordinate carbon atom and participating in the π-electron delocalization. This strategy that maximizes both mechanical and electronic effects through aromatic architectures can be extended to several molecular combinations to achieve new and diverse compounds containing planar hypercoordinate carbon centers.

Exploring the Potential Energy Surface of Trimetallic Deltahedral Zintl Ions: Lowest-Energy [SnGeBi] and [(SnGeBi)] Structures.

The synthesis and structural characterization of the dimer [(SnGeBi)] raise the possibility of obtaining a broad variety of analogous compounds with different Sn/Ge/Bi proportions. Several combinations of nine atoms have been detected by electrospray mass spectrometry as potential assembly units. However, [(SnGeBi)] remains as the unique experimentally characterized species in this series.

AUTOMATON: A Program That Combines a Probabilistic Cellular Automata and a Genetic Algorithm for Global Minimum Search of Clusters and Molecules.

A novel program for the search of global minimum structures of atomic clusters and molecules in the gas phase, AUTOMATON, is introduced in this work. This program involves the following: first, the generation of an initial population, using a simplified probabilistic cellular automaton method, which allows easy control of the adequate distribution of atoms in space; second, the fittest individuals are selected to evolve, through genetic operations (mating and mutations), until the best candidate for a global minimum surfaces. In addition, we propose a simple way to build the descendant structures by establishing a ranking of genes to be inherited.

Which NICS method is most consistent with ring current analysis? Assessment in simple monocycles.

The aromaticity of benzene, Al cluster, cyclopropane, borazine and planar cyclooctatetraene (COT) was analyzed according to different strategies based on nucleus-independent chemical shift (NICS) computations. The analysis of NICS-components evolution along the main molecular axis seems to be the most adequate and simplest strategy to predict the aromatic or antiaromatic character of the studied systems. Moreover, the analysis of the σ- and π-electron contributions to the out-of-plane component of NICS (NICS ) leads to the same qualitative and quantitative conclusions previously obtained by the analysis of the magnetically induced ring current densities.