Josep M. Oliva's research while affiliated with Institute of Physical Chemistry Rocasolano and other places

Publications (81)

Article
The electronic–structure properties of the low–lying electronic states and the absorption cross sections of mercury halides HgCl2, HgBr2, HgI2, HgBrCl, HgClI, and HgBrI have been determined within the UV–Vis spectrum range (170 nm ≤ λphoton ≤ 600 nm) by means of the complete–active–space self–consistent field/multi–state complete–active–space secon...
Article
B18H20(NC5H5)2 is a rare example of two conjoined boron hydride subclusters of nido and arachno geometrical character. At room temperature, solutions of B18H20(NC5H5)2 emit a 690 nm fluorescence. In the solid state, this emission is shifted to 620 nm and intensifies due to restriction of the rotation of the pyridine ligands. In addition, there is a...
Article
The electronic states of atmospheric relevant molecules IBr and HgBr2 are reported, within the UV-Vis spectrum range (170 nm <= lambda(photon) <= 600 nm) by means of the complete-active-space self-consistent field/multi-state complete-active-space second-order perturbation theory/spin-orbit restricted-active-space state-interaction (CASSCF/MS-CASPT...
Article
We report a study on the thermochemical properties of a wide variety of halogen-containing organic compounds with relevance on several atmospheric chemical processes, such as catalytic ozone destruction. In particular, we have computationally determined the standard molar enthalpies of formation, (g), and the carbon-halogen bond dissociation enthal...
Article
Full-text available
Carbon is the most versatile of chemical elements in combining with itself or other elements to form chains, rings, sheets, cages, and periodic 3D structures. One of the perspective trends for creating new molecules of nanotechnological interest deals with constructs which may be formed by chemically linking of cage molecules. The growing interest...
Chapter
This issue of Theoretical Chemistry Accounts collects a compilation of research works presented at the 9th edition of the Electronic Structure: Principles and Applications conference (ESPA-2014) held in Badajoz, Spain, on the July 2–4, 2014.
Article
The connection of 12 s = ½ closo-azadodecaborane radical units (NB11H11•), where a hydrogen atom is removed from the nitrogen atom, produces a supericosahedron [(NB11H6•)12](S), S being the total spin of the system. This work describes the study of the low-lying energy spin-projected states of this supericosahedron with two different geometrical ar...
Article
Full-text available
In a previous work, we reported the electronic structure of dimer diradicals composed of two S = ½ closo-carborane CB11H 12 · structural units (Theor. Chem. Acc. (2013) 132: 1329). That work has been extended here in order to describe a linear dimer, a linear and a cyclical trimer, and a tetrahedral structure of these units connected by means of a...
Chapter
In this Chapter we describe the electronic structure of ground states and excited states of the two isomers of octadecaborane (22), anti- and syn-B18H22, and the new derivative of anti-B18H22, the polyhedral substituted borane 4,4′-(HS)2-anti-B18H20. A theoretical interpretation is given on the fluorescence of the anti-B18H22 isomer, and the non-ra...
Article
Carborane clusters, as anthropogenic molecules, are not found in Nature. In this work we study, both experimentally and computationally, the gas-phase and liquid-phase acidity (pKa) of the carborane acid closo-1-COOH-1,7-C2B10H11. The experimental gas-phase acidity was determined with electrospray tandem mass spectrometry (ESI/MS), by using the Ext...
Article
This work studies the ability of the two-center local spin quantities, provided by the partitioning of the expectation value of the spin-squared operator corresponding to N-electron systems, for determining spin-exchange coupling constants within the Heisenberg spin Hamiltonian model. The spin-exchange parameters, which characterize this Hamiltonia...
Article
Carborane clusters are not found in Nature and are exclusively man-made. In this work we study, both experimentally and computationally, the gas-phase acidity (measured GA = 1325 kJ•mol-1, computed GA = 1321 kJ•mol-1) and liquid-phase acidity (measured pKa = 2.00, computed pKa = 1.88) of the carborane acid closo-1-COOH-1,7-C2B10H11. The experimenta...
Article
Known borane polyhedral cluster characteristics can be used for predicting new architectural constructs. We propose additional structures derived from B18H22 : three positional isomers different from the well-known anti-B18H22 and syn-B18H22 boranes. We have also derived two new cyclic structures based on the condensation of borane pentagonal pyram...
Article
4,4′-(HS)2-anti-B18H20 (I) is prepared by thiolation of anti-B18H22 (II) in presence of AlCl3 and S (sealed glass pressure vessel, 125 °C, 16 h) followed by benzene extraction of the obtained reaction products.
Article
The tuning of the photophysical properties of the highly fluorescent boron hydride cluster anti-B18H22 (1), by straightforward chemical substitution to produce 4,4'-(HS)2-anti-B18H20 (2), facilitates intersystem crossing from excited singlet states to a triplet manifold. This subsequently enhances O2((1)Δg) singlet oxygen production from a quantum...
Article
Electronic structure computations have been performed on diradical systems composed of two carborane radicals CB11H12· connected through acetylene, ethylene and ethane bridge units, leading, respectively, to a linear and two trans structures. Each cage possesses one unpaired electron and the total system can thus be coupled to a singlet or a triple...
Chapter
Boron chemistry does not have the parallel of carbon chemistry or organic chemistry. However, the peculiar electronic configuration of boron involves a rich variety of different interactions which emerge as a voyage between the world of organic, inorganic, and metal chemistry. In particular, we report on reaction mechanisms and properties of monome...
Article
We present an experimental and computational study of the oligomerization in icosahedral closo-(car)boranes Li-2[B12H12] (I) and Li[CB11H12] (II). The experiments were performed on a hybrid ESI-TQ-FT-ICR mass spectrometer equipped with a 7.0 T superconducting magnet. The computational study consisted of finding energy minimum structures for the mol...
Article
To date, crystal structures of the cyclic mercury complexes [μ-1,2-(C(2)B(10)H(10))(n)Hg(n)], with n = {3, 4}, have been found. However, the same structures substituting Hg by Au, which implies a charge z = {-3, -4} for n = {3, 4} respectively, have not been found. In this work, we present geometrical and electronic structure properties of the titl...
Article
Various sorts of isomer enumeration problems are addressed in the context of polycarboranes, with special illustrative focus on the case of dicarboranes, for which then various numerical results are given. A systematic and general Pólya-theoretic methodology is used to make the computations, including some new techniques being applicable to a wide...
Article
There is current interest, both for basic science and technological applications, in fluorocarbons such as CF4 and the related molecules. Here we first report a Hartree–Fock calculation of the ground-state electron density in the octahedral molecule SF6 using the experimentally determined bond length. From this density, the number of electrons lyin...
Article
In this paper we report the results obtained when calculating the electronic structure of the H4 molecular system within the framework of the G-particle-hole Hypervirial equation (GHV). This method determines directly the G-particle-hole matrix of the state considered without a previous knowledge of the wave-function. Our primary aim is to compare...
Article
The crystal structure of ScB12 suggests the possible existence of the closo B24H242− borane and derived exo and endohedral complexes. The extraction of the B24 ‘perfect’ truncated octahedron from the ScB12 crystal structure and the minimization of the energy by means of quantum-chemical computations leads to a snub cube structure. The two found sta...
Article
General formulae are introduced for counting the number of different isomers derived from linearly connecting n carboranes CB11H12q (s), with q and s representing charge and spin. Interconnections are via the C-atom or the B-atom para to the C-atom. The mathematical simplicity of the argument is emphasized, and the possibility of having different n...
Article
The photophysics of the two isomers of octadecaborane(22), anti- and syn-B(18)H(22), have been studied by UV-vis spectroscopic techniques and theoretical computational methods. In air-saturated hexane, anti-B(18)H(22) shows fluorescence with a high quantum yield, Φ(F) = 0.97, and singlet oxygen O(2)((1)Δ(g)) production (Φ(Δ) ∼ 0.008). Conversely, i...
Article
Photodissociation experiments have been performed for the parabanic acid (C3H2N2O3) molecule in vapor phase using time-of-flight mass spectrometry and synchrotron radiation in the VUV photon energy range. Electron ion coincidence (PEPICO) spectra and partial ion yields have been recorded as a function of the photon energy covering the 11–21 eV vale...
Article
The Hubbard model, which is widely used in physics but is mostly unfamiliar to chemists, provides an attractive yet simple model for chemistry beyond the self consistent field molecular orbital approximation. The Hubbard model adds an effective electron-electron repulsion when two electrons occupy the same atomic orbital to the familiar Hückel Hami...
Article
Composite many-electron systems are considered in terms of the wave-functions for the different component subsystems (e.g., atoms). In this weak-interaction limit, there may be degrees of freedom, which arise from that of the degeneracies of the wave-functions for each of the isolated subsystems, and which then are describable in terms of an effect...
Article
In the pursuit of detecting the first endohedral polyhedral borane complex, we report a quantum-chemical computational study of energy landscapes for diexo isomers derived from Li2B12H12 and the exo/endo isomer Li@{LiB12H12}. Geometries, electronic structure and energy barriers are computed for the interconversion between diexo isomers and the exo/...
Article
This paper uses DFT and G3(MP2) calculations to examine whether unbridged 10-membered rings can be made by (pi)6 + (pi)4 cycloadditions to (Z)- and (E)-hexatrienes, hexa-1,5-dien-3-ynes, (Z)-hexa-1,3-dien-5-ynes, hexa-1,2,3,5-tetraenes, and (Z)-hexa-3-ene-1,5-diynes. Cycloadditions to four 4pi reactants, buta-1,3-diene, butenyne, butatriene, and bu...
Article
We report on the electronic structure of the 12-vertex icosahedral clusters r-X(2)Z(10)H(12) and Z(12)H(12)(2-), where X = {C, Si} and Z = {B, Al}. The least stable cluster--with the lowest HOMO-LUMO gap (E(g))--corresponds to the ortho-X(2)Z(10)H(12) isomers for all values of X = {C, Si} and Z = {B, Al}. The well-known energetic order E(para) < E(...
Article
The structural characterization of an ortho-lithiated diphenylphosphinic amide is described for the first time. Multinuclear magnetic resonance ((1)H, (7)Li, (13)C, (31)P) studies as a function of temperature and concentration employing 1D and 2D methods showed that the anion exists as a mixture of one monomer and two diastereomeric dimers. In the...
Article
The electronic structure of a neutral, a radical anion, and a dianion carborane dimer connected via an acetylenic bridge unit (HB)11CCCC(BH)11 is analyzed by quantum chemical methods. Geometries, relative stabilities, and singlet–triplet gaps are determined in the neutral and dianion species for the lowest-lying singlet and triplet states and for t...
Article
A computational study on the stability of neutral, singly and doubly negatively charged aluminium clusters Alnz, with n = {13, 18, 23, 39, 55), and z = {0, -1, -2} is presented. Estimates of electron affinities (EA) were computed with (i) all-electron quantum-mechanical calculations with full geometry optimization on Alnz, with n = {13, 18, 23, 39,...
Article
The synthesis and X-ray analysis of complexes [(micro-1,12-C2B10H10){Au(PPh3)}2] and [(micro-1,2-C2B10H10){Au(PMe3)}2] have provided the experimental data needed to analyse two points. The first point is the use of these data to carry out a computational study with the aim of comparing the electronic structures and relative stabilities of the organ...
Article
The thermodynamic stability and properties of different phosphorus carbide phases are studied as a function of composition with first-principles periodic density-functional theory calculations. Calculations are reported for P(4)C(3), PC, and P(3)C(4) and a range of possible structures examined for each. For P(4)C(3), the favored structures are defe...
Article
Full-text available
The 12 cage-anchoring points of the very stable icosahedral ortho-, meta-, and para-carborane allow the design of multidimensional architectures provided new self-assembling routes are devised. We provide bases for constructing carborane molecular architectures through high-level quantum chemical computations. We consider ejection mechanisms for th...
Article
Full-text available
Quantum-mechanical electronic structure computations were employed to explore initial steps towards a comprehensive design of polycarborane architectures through assembly of molecular units. Aspects considered were (i) the striking modification of geometrical parameters through substitution, (ii) endohedral carboranes and proposed ejection mechanis...
Article
Structures, relative stabilities, singlet-triplet gaps, and the ground-state character of mono- and diradicals derived from the three icosahedral carborane cage isomers have been computed by unrestricted broken-symmetry DFT and by CASPT2 methods. Whereas the bond dissociation energies (BDE) leading to the carborane monoradicals are close to the ben...
Article
By means of quantum-mechanical calculations, we study the influence of the charge, spin, substituents, and atom encapsulation on the volume of the cages in icosahedral boranes and carboranes B 12H 122-, CB 11H 12-, o-C 2B 10H 12, m-C 2B 10H 12, p-C 2B 10H 12 and 1,2-disubstituted o-C 2B 10H 12. Monoradicals derived from hydrogen abstraction in o-C...
Article
The stability of endohedral carboranes X@{1,n-C2B10H12} (X = Li+, Be2+; n = 2, 7, 12) and X@{CB11H12-} (X = Li+, Be2+) is studied using electronic structure calculations with the B3LYP/6-311+G(d,p) model. Our calculations suggest that all endohedral compounds are local energy minima; for the exohedral complexes X···cage, the global energy minimum a...
Article
On the basis of high-level quantum chemical calculations, closed-cage carboranes are shown to be prospective nanoscale mass selective conveyors via a photochemical switch. A mechanism is evidenced in which stable carborane boxes with lithium as endohedral atom, Li@CB11H12, can be photoinduced to sequentially evolve opening the cage, releasing the i...
Article
The interaction of light with isolated and pairs of silver nanowires with ellipsoidal cross-sections is studied with the finite-difference time-domain (FDTD) method. A Drude model frequency-dependent dielectric constant, with parameters fit to empirical data, is employed. We determine the optical spectra, surface plasmon resonances and near-field p...
Article
Substituents bearing amino groups in positions 2, 4 and 6 of sym-triazines (1,3,5-triazines) share the planarity of the corresponding aromatic triazine moiety to different extent. In these systems, pi-electron delocalization also ranges over adjacent N atoms of amino groups. The origin of both chemical features is attributed to the stabilization of...
Article
This work introduces a calibrated B3LYP/6-31G(d) study on the electronic structure of singlet and triplet neutral species of 1,2-substituted icosahedral 1,2-R(2)-1,2-C(2)B(10)H(10) and octahedral 1,2-R(2)-1,2-C(2)B(4)H(4) molecules with R = {H, OH, SH, NH(2), PH(2), CH(3), SiH(3)} and their respective dianions formed by proton removal on each R gro...
Article
Neutral and especially dianionic 6- and 12-vertex closo ortho-carboranes (o-carboranes) 1,2-R2-1,2-C2BnHn (R = H, CH3, NH2, OH, F, SiH3, PH2, SH, Cl, as well as e-, CH2-, NH-, O-, SiH2-, PH-, and S- exhibit extremely large variations (over 1 A!) of the cage CC distances, from 1.626 to 2.638 A, at the B3LYP/6-31G//B3LYP/6-31G DFT level. These CC "bo...
Article
That methyl groups attached to carbon atoms are electron donors must not be generally assumed. In boron clusters, Me groups on boron are electron withdrawing. At the B3LYP/6-31G* level of theory, it has been proven that the Mulliken charge on each boron after substitution of -H by -Me increases by +0.18 unit. This leads to a high build-up of positi...
Article
An ab initio study on the electronic structure of the subnitrides NaBa{sub 3}N, Na{sub 5}Ba{sub 3}N, and Na{sub 16}Ba{sub 6}N is performed for the first time. The NaBa{sub 3}N and Na{sub 5}Ba{sub 3}N phases consist of infinite {sup 1}{sub {infinity}}[NBa{sub 6/2}] strands composed of face-sharing NBa{sub 6} octahedra surrounded by a 'sea' of sodium...
Article
We report a joint computational and luminescence study on the low-lying excited states of sym-triazines, namely, 1,3,5-triazine (1) and the ubiquitous herbicides atrazine [6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine (2)] and ametryn [6-methylthio-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine (3)]. Geometrical structures, energetics...
Article
Full-text available
Fourier-transform ion cyclotron resonance (FTICR) mass spectrometric studies have been performed on donor-acceptor and donor-bridge acceptor fullerene-based systems. Matrix-assisted laser desorption/ionization (MALDI) was used for ion production; both the positive and negative ion modes were utilized. In addition, collision-induced dissociation (CI...
Article
The usefulness of qualitative and quantitative theoretical approaches in solid state chemistry is discussed by considering three different types of problems: (a) the distribution of boron and carbon atoms in MB2C2 (M=Ca, La, etc.) phases, (b) the band structure and Fermi surface of low-dimensional transition metal oxides and bronzes, and (c) the co...
Article
The structure and stability of periodic solid phosphorus carbide phases P4C3+8n (n = 0–4) are studied at zero and high pressure using periodic density functional theory as implemented in the codes SIESTA and CASTEP. For each composition a range of structures is examined, including both defective diamond-like and graphitic-like structures. At zero p...
Article
First-principles periodic density-functional theory calculations suggest ternary fluorides LiMgF3, NaCaF3 and LiNiF3 should adopt the ferroelectric LiNbO3 structure at low temperatures; LiMgF3 and LiNiF3 are predicted to have negative enthalpies of formation from the binary fluorides.
Article
The interaction of light with nanometer scale diameter single and multiple silver nanowires, coated externally with a dielectric material, is studied with the finite-difference time-domain method. As would be expected, the surface plasmon polariton resonance positions for the single nanowires shift to the red as the thickness of the coating is incr...
Article
Full-text available
Cited By (since 1996): 11, Export Date: 2 May 2012, Source: Scopus
Article
The electronic structure of the recently reported ternary nitride Ca(2)GeN(2) has been studied by means of first-principles density functional calculations. The relatively short nonbonded Ge...Ge contacts along the direction approximately perpendicular to the plane of the bent GeN(2) units confer a large dispersion to the energy bands based on the...
Article
1,2-Cc-substituted o-carboranes, where Cc represents the cluster carbon atoms, display a range of experimental/computed Cc⋯Cc distances from 1.629/1.624 Å for the unsubstituted parent compound 1,2-C2B10H12 (1) to 1.798/1.818 Å for l,2-(SPh)2-l,2-C2B10H10 (5)1 or 1.858(5)/1.826(5) for l,2-μ-SCH2(CH2OCH2)2CH2S-1,2-C2B10H10 (7). Different Cc⋯Cc distan...
Article
In this paper, the chemistry of 3-X-1,2-closo-C(2)B(10)H(11) (X = halogen) derivatives is extended. Molecular orbital and (11)B and (13)C NMR calculations on these species are presented. A qualitative interpretation of the (11)B NMR spectra of closo o-carborane derivatives is also provided. The synthesis of 3-X-1-R-o-carborane (X = I, Br and R = Me...
Article
The basicity order in acetonitrile for a series of phosphines is: 1,5-diphosphabicyclo[3.3.3]undecane 1 (pK(a) for the protonated ion similar to 17.9) < 1,6-diphosphabicyclo[4.3.3]dodecane 2 (pK(a) similar to 22.5) < 1,6-diphosphabicyclo[4.4.3]tridecane 3 (pK(a) 27.8). The latter is therefore comparable to Schwesinger's P-1-t-Bu base but still sign...
Article
The electronic structure of monoclinic ${\mathrm{TeMo}}_{5}{\mathrm{O}}_{16},$ a molybdenum oxide recently reported and expected to be a new low-dimensional metal, has been studied by means of first principles density functional calculations. The study predicts that monoclinic ${\mathrm{TeMo}}_{5}{\mathrm{O}}_{16}$ should not be metallic (as previo...
Article
Experimental and computed 11B NMR signals are assigned for the first time in the yet X-ray unresolved 1,2-(SH)2-1,2-C2B10H10ortho-carborane (3). The B3LYP/6-31G∗/GIAO//B3LYP-6-31G∗ computed 11B NMR chemical shifts compare well with experiment with an error of 2–4 ppm. It is found that the computed C1–C2 distance in the carborane cage for 3 is 1.803...
Article
The electronic structure of the layered ternary nitrides CaMN2 (M= Ta, Nb) has been studied and the results are compared with those for the related LiMoN2 phase. It is shown that the former are two-dimensional metals, with a Fermi surface very similar to that of the 1T-TaX2 (X= S, Se) dichalcogenides, whereas the latter is a three-dimensional metal...
Article
Modern valence-bond theory, in its spin-coupled form, is used to study the electronic structure of the transition structures in the Cope rearrangement. It is found that the transition structure described by a “chair” geometry with a “6-in-6” CASSCF/6-31G* wave function is clearly aromatic while the CASSCF/6-31G*“boat” transition structure correspon...
Article
Generalized transition state theory calculations are performed on the dimerization of diaminocarbene [(H2N)2C:] (1) to tetrakis(amino)ethene [(H2N)2CC(NH2)2] (2). This process involves the formation of a double bond from two carbenes and therefore inclusion of correlation energy is vital. The density functionals BPW91, B3LYP and the QCISD(T)//MP2...
Article
Stable diaminocarbenes, including imidazol-2-ylidenes, undergo complexation with lithium, sodium and potassium species; the crystal structure of a complex of 1,3-diisopropyl-3,4,5,6-tetrahydropyrimid-2-ylidene 1 with KN(SiMe3)(2) is reported.
Article
The electronic structure of the benzene methylene isomers fulvene, dimethylenecyclobutene, and trimethylenecyclopropene is studied using spin-coupled theory. It is shown that the three isomers all possess three noninteracting π-bonds and very low resonance energies. This is to be contrasted with benzene, where the symmetric coupling of the π-electr...
Data
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...
Data
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...
Article
Spin-coupled theory is used to study the changes which occur in the electronic wave function as a system moves along the intrinsic reaction coordinate (IRC) for the case of conrotatory and disrotatory motion in the ground-state electrocyclic interconversion of cyclobutene to cis-butadiene. It is shown that the reaction is already well under way in...
Article
A new relation between the wave functions of the atomic states 2H and 2P arising from the configuration d3 and the wave functions of two molecular states arising from the configuration h3 in icosahedral symmetry molecules is presented. This relation gives an insight into the unknown origin of the non-relativistic Hartree-Fock degeneracy of the atom...
Article
The spin-coupled valence bond method is used to study the doublet valence excited states and the n=3 Rydberg excited states of the allyl radical below the first ionization potential 8.13 eV. The calculations included three pi electrons in the active space. Our results are close to those resulting from the most extensive MO-CI calculations reported...
Article
The structure and stability of periodic solid phosphorus carbide phases P4C38n (n 0-4) are studied at zero and high pressure using periodic density functional theory as implemented in the codes SIESTA and CASTEP. For each composition a range of structures is examined, including both defective diamond-like and graphitic-like structures. At zero pres...

Citations

... The statistical error (confidence intervals, CIs) associated to the MC sampling can be inferred either using directly the standard error (assuming asymptotic normality) 14,25 or using a re-sampling technique such as bootstrap. 26 As normality is not granted either on ΔE or on f (see Figure S1), it is statistically more robust to use a bootstrap re-sampling. ...
... 42,46−50 A similar interplay between emission properties and cluster− fluorophore orientation is also seen for boron hydride subclusters and pyridine ligands. 51 Among o-carborane−fluorophore adducts studied to date, the o-carborane−anthracene (o-CB−Ant) molecule and its derivatives have attracted significant attention for both theoretical and synthetic studies since the seminal works by Chujo and co-workers. 24,25 In solution, o-CB−Ant shows dual emissions with low quantum yields, where the high-energy S 1 → S 0 transition has a local excited (LE)-state character on anthracene, whereas the low-energy transition shows twisted ICT (TICT). ...
... Our understanding of the behavior of Hg in the atmosphere has advanced in several ways over the past few years. A growing body of computational research has determined likely mechanisms by which elemental Hg is oxidized and oxidized Hg is reduced (Dibble et al., 2012;Dibble and Schwid, 2016;Dibble, 2017a, 2017b;Lam et al., 2019;Saiz-Lopez et al., 2019;Saiz-Lopez et al., 2018;Sitkiewicz et al., 2016;Sitkiewicz et al., 2019), and this research is narrowing down the field of probable Hg compounds in the atmosphere. Current computational work predicts that atmospheric oxidized Hg will be dominated by HgBrOH and HgBr 2 (Saiz-Lopez et al., 2019). ...
... The only place where it decreased was at the suburban station (Casa de Campo), pointing to complicated changes in its regime. Previously, reductions in NO x resulted in increases in O 3 (Dávalos et al., 2017). In this case, if the changes in emissions were a lot higher and no effect was seen, which is because the VOCs are affecting the O 3 , as was found to occur by other authors (Ding et al., 2021;Lin et al., 2021). ...
... The control of electronic and magnetic properties of molecules is the tip of the iceberg within modern nanoscience and nanotechnology [1]. In the last two decades, we have been involved in the study of the electronic structure of polyhedral (metalla)heteroborane molecules in their ground and excited states [2], and also exploring how the properties of these-isolated or connected-systems change as function of charge and spin [3][4][5]. In 2006, we proposed a photochemical window mechanism by which a Li (+) ion could be inserted inside and ejected from an icosahedral CB 11 H 12 (−) cage [6]. ...