Structures, stabilities and aromatic properties of endohedrally transition metal doped boron clusters M@B, M = Sc and Ti: a theoretical study.

A genetic search algorithm in conjunction with density functional theory calculations was used to determine the lowest-energy minima of the pure B22 cluster and thereby to evaluate the capacity of its isomers to form endohedrally doped cages with two transition metal atoms M (M = Sc and Ti). An important charge transfer from metal atoms M to the boron cage takes place, stabilizing the endohedral compounds, as predicted with the genetic algorithm implemented. High-level coupled-cluster theory CCSD(T) calculations were carried out to confirm that the structures found are the lowest-energy isomers.

Erratum: Del Castillo, R.M., et al. Electronic Peculiarities of a Self-Assembled ML Nanoball (M = Pd, Cr, or Mo). 2019, , 771.

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Molecular knot with nine crossings: Structure and electronic properties from density functional theory computation.

The electronic structure of a molecule with nine-crossing composite knots 9 link denoted by the Alexander-Briggs notation (complex-1) are studied by means of theoretical methods (DFT). The most interesting feature of this kind of molecules is their capability to capture anion spices inside the cage. Stability and chemical reactivity were evaluated taking advantage of the criteria chemical hardness and chemical potential.

Electronic Peculiarities of a Self-Assembled ML Nanoball (M = Pd, Cr, or Mo).

We use molecular mechanics and DFT calculations to analyze the particular electronic behavior of a giant nanoball. This nanoball is a self-assembled ML nanoball; with M equal to Pd; Cr; and Mo. These systems present an extraordinarily large cavity; similar to biological giant hollow structures.

CCl, a planar aromatic fullerene. Computational study of C-NMR chemical shift anisotropy patterns and aromatic properties.

The isolated-pentagon-rule (IPR) is a prime determinant of fullerene stabilization accounting for the difficult isolation of hollow C (n < 60) species. In this connection, the isolation and structural characterization of D-CCl as an IPR-violating fullerene are of interest owing to the study of factors providing further stability. Herein, we use DFT calculations to explore its aromatic behavior.

Symmetric nested complexes of fullerenes.

Large fullerenes such as C180 and C116 can be used as hosts for other molecules of the same family. Based on this idea, two complexes were designed, one in which C180 accepts a C60 molecule as a guest and the other in which C20 was placed inside C116. The behavior of these new assemblies was closer to that of a large endohedral complex rather than onion-like.

Hybridization vs. bond stretching isomerism in Ru(II) cyclometalated complexes of 2-phenylpyridine.

The phenomenon of formation of two isomers, yellow and orange, of the cyclometalated Ru(II) complex, [Ru(o-C₆H₄-py)(MeCN)₄]⁺, was investigated by EELS spectroscopy and theoretical calculations. Both forms show very similar structures and spectroscopic properties, but slight differences in X-ray data and absorption between them were noted. No double minimum on the potential energy surface was found and thus these two forms cannot be considered as bond stretching isomers.

Oligomerization of 3,5-dimethyl benzyl alcohol promoted by clay: experimental and theoretical study.

Linear oligomerization of 3,5-dimethyl benzyl alcohol is induced by a montmorillonite clay (Tonsil Optimum Extra), producing 1,3,5,7-tetramethyl-9,10-dihydro-anthracene, which, by loss of protons results in the product 1,3,5,7-tetramethylanthracene. It was also found that the compounds 4-(3´,5´-dimethylbenzyl)-1,3,5,7-tetramethyl-9,10-dihydroanthracece and 4-(3´,5´-dimethylbenzyl)-1,3,5,7-tetra-methylanthracene were formed from 1,3,5,7-tetramethyl-9,10-dihydroanthracene. 1,3,5,7-Tetramethylanthryl radical cation was formed from 1,3,5,7-tetramethyl-9,10-dihydroanthracene; it was characterized by Electronic Paramagnetic Resonance (EPR).

Aromaticity in cyanuric acid.

This study analyzes the aromatic nature of cyanuric acid (hexahydrotriazine) and some of its derivatives, in terms of aromatic stabilization energy (ASE) and electronic behavior. The simplest molecule (C(3)N(3)O(3)H(3)) is the most aromatic item out of the entire set, but some of the others also display aromatic character. The structure of all the rings is analyzed considering their molecular orbitals as well as studying the inductive effect.

Theoretical study on the series of [Au(3)Cl (3)M (2)] complexes, with M = Li, Na, K, Rb, Cs.

The prediction of the series of complexes [Au(3)Cl(3)M(2)] with M = Li, Na, K, Rb and Cs, has been achieved at the ab initio level of theory. All geometries were fully optimized at the MP2 level of theory; the central Au(3) cluster is capped by chlorine atoms and the alkaline metals lie above and below the plane of the central ring; aurophilic interactions were found on the metal cluster, and also a strong aromatic character coming from the delocalized d-electrons of the Au atoms according to nuclear independent chemical shift calculations. On the other hand, the chemical hardness parameter was used to test the stability of the series of complexes, and the Fukui indexes of electrophilic and nucleophilic attack were employed to explore possible sites where chemical reactivity may play a role.

Electronic analysis of vanadium and iron complexes containing distorted aromatic rings.

Aromatic rings can suffer severe distortions upon substituting transition metal centers with certain kinds of organometallic compounds. This property is very interesting because aromaticity can remain despite the deformation. Theoretical calculations at the density functional theory level were carried out on two such structures containing vanadium and iron centres [(C5H5-V-H)(2)C6H6 and (CpFe)(2)C6(CH3)(6)] in order to analyze the nature of the bonds as well as the magnitude of the prevalent aromaticity and how this depends on the electronic characteristics around each metal atom.