2,9-Bis(1,2,4-triazin-3-yl)-1,10-phenanthroline (BTPhen)-based ligands show great promise in the separation of trivalent lanthanides and actinides. Experimental studies have shown that americium forms stronger complexes with the BTPhen ligands than europium; most theoretical studies have so far failed to reproduce these results. In the current study, three different metal forms (the naked cation, its nitrate or perchlorate salts and tetraaqua solvated salts) were used to study different complexation reactions. It was shown that in the case of naked cations and salts, europium forms the most stable complex with the 2,9-bis(1,2-triazin-3-yl)-1,10-phenanthroline ligand in all of the reactions compared. However, europium is also more strongly interacting (compared to americium) with anions and water molecules in the tetraaquatrinitrato or tetraaquatriperchlorato complexes. That shifts the energies of reactions like Am(NO3)3·4H2O + [Eu(H2O)4BTPhen]3+ = [Am(H2O)4BTPhen]3+ + Eu(NO3)3·4H2O in favor of the americium being complexed with BTPhen and europium with anions and water. Therefore, the americium complexes with BTPhen become the more stable form, in an agreement with the experimental studies. Comparison of counterion influence (nitrate vs. perchlorate) indicates that bigger preference for americium over europium complexation corresponds to the nitrate complexes and stems mainly from the fact that in M(NO3)3(H2O)4 europium is stabilized more than in M(ClO4)3(H2O)4.

Computational study for three isomeric nitroanilines was carried out to find a nonempirical model to predict their relative ionization efficiencies compared to the corresponding experimental logIE values. The CBS-QB3 method was used for the gas-phase calculations of protonated nitroanilines, and the SCC-DFTB method for the calculations of spherical droplets, containing one protonated nitroaniline molecule, one hydronium cation, and 48 acetonitrile molecules, randomly generated by the PACKMOL program. The obtained results show that neither the gas-phase energy of protonated nitroaniline (or gas-phase basicity) nor the average energy of droplets can be used to predict the ionization efficiency ordering of those isomers. However, the difference of gas-phase and droplet energies gives a good correlation with logIE values and, thus, can be used for the prediction of relative ionization efficiencies.

Aza-peptides are peptidomimetics developed to avoid drawbacks connected with peptide instability in drugs. However, information concerning their bioactivity is quite limited due to the absence of efficient synthetic strategies to these compounds by SPPS (solid-phase peptide synthesis) method. Herein, we investigate, the effect of steric hindrance of various aza-amino acids (AzGly, AzAla, AzLeu, AzVal) on their reactivity with the N-terminus of amino acids in the synthesis of model aza-peptide H-AzAA-Ala-Phe-NH2 using BTC (Bis(trichloromethyl) carbonate) as an activator for aza-amino acid precursor. The results of kinetic measurements showed that this method could be used for aza-amino acid incorporation into peptide regardless of the structure of the preceding amino acid. However, for effective coupling of AzGly, DSC (N,N′-Disuccinimidyl carbonate) is the preferable activator.

2,9-bis(1,2,4-triazin-3-yl)-1,10-phenantroline (BTPhen) based ligands have shown great promise in separation of trivalent lanthanides and actinides. Although many experimental studies have shown that americium is forming stronger complexes with the BTPhen ligands than europium, most theoretical studies have thus far failed to reproduce these results. In the current study, two different metal forms (the naked cation and its tetraaquatrinitrato complex) were used to study five different complexation reactions. It was shown that in case of naked cations europium forms the most stable complex with the 2,9-bis(1,2-diazin-3-yl)-1,10-phenanthroline (BTPhen-CH) ligand in all of the compared reactions. In case of tetraaquatrinitrato complex it was shown that europium gets a higher stabilizing effect and thus americium complexes with BTPhen-CH become the more stable form, as can be seen in the experimental studies.

We report a mass spectrometry study of the interaction between three representative Au(I) catalysts containing the ligands L = JohnPhos (2-biphenylyl-[bis(2-methyl-2-propanyl)]phosphine), TPP (PPh3, triphenylphosphine), the N-heterocyclic carbene IPr (carbene form of 1,3-bis(2,6-diisopropylphenyl)-2,3-dihydro-1H-imidazole), and 27 organic molecules S (substrates) bearing organic functionalities often present in reactants (alkenes, alkynes, allenes, enol ethers, aldehydes, ketones, and epoxides). An experimental scale of gas-phase relative binding energy between three L(Au+) ions and the organic substrates was established by energy-resolved experiments of the 81 cationic two-coordinate gold adducts L(Au+)S using a quadrupole ion trap mass spectrometer. The experimental scale is expressed in units of normalized collision energy for 50% dissociation (NCE50) of the precursor ion. In parallel, the gas-phase bond dissociation energetics and the structure of adducts were probed by DFT calculations. The experimental affinity order of each substrate for the three cationic gold complexes L(Au+), IPr(Au+) > TPP(Au+) > JohnPhos (Au+) is well reproduced by the calculated bond dissociation energies E. At the computational level used in this study, the agreement between the calculated Delta E and the experimental NCE so values is limited to series of substrates with the same functionality, and reasonable correlations NCE50 vs Delta E are observed within series. The DFT-optimized structures are discussed and compared with available X-ray crystal structures. Although no general trend can be observed between bond lengths or their changes upon coordination with the L(Au+) cations and dissociation energies, a significant correlation between the Au-O distance (S = O-bases) and Delta E is observed.

Data on the gas-phase energetics of anion/cation interactions are relatively scarce. In this work, gas-phase alkali metal cation basicity (AMCB) scales were established for a series of 15 benzoate ions XC6H4COO- with Li+, Na+, K+, Rb+, and Cs+ on the basis of mass spectrometry experiments and high-level calculations. A wide range of electron-donating and electron-withdrawing substituents were included in the study. The thermochemical values were calculated by ab initio methodologies and extrapolated to the complete basis set limit. For each metal cation, the experimental relative cation basicity values of the anions were established quantitatively by applying the Cooks' kinetic method to the cation-bound heterodimers [(XC6H4COO-)M+(YC6H4COO-)]-, generated by electrospray ionization. The self-consistency of these AMCB scales was ascertained by multiple overlap of the individual relative basicities. In parallel, the proton gas-phase basicities (GBs) of the benzoate anions (gas-phase acidities of the respective benzoic acids) were calculated in order to compare the results of the theoretical method with known experimental GB values. The experimental and calculated GB values agree quite accurately (average absolute deviation = 3.2 kJ mol-1). The relative experimental AMCB scales and the absolute calculated AMCB scales are highly correlated, and the two sets agree by better than 4 kJ mol-1. It is also demonstrated that the five series of calculated AMCBs are highly correlated with the calculated GB.

A literature curated dataset containing 24 distinct metal oxide (MexOy) nanoparticles (NPs), including 15 physicochemical, structural and assay-related descriptors, was enriched with 62 atomistic computational descriptors and exploited to produce a robust and validated in silico model for prediction of NP cytotoxicity. The model can be used to predict the cytotoxicity (cell viability) of MexOy NPs based on the colorimetric lactate dehydrogenase (LDH) assay and the luminometric adenosine triphosphate (ATP) assay, both of which quantify irreversible cell membrane damage. Out of the 77 total descriptors used, 7 were identified as being significant for induction of cytotoxicity by MexOy NPs. These were NP core size, hydrodynamic size, assay type, exposure dose, the energy of the MexOy conduction band (EC), the coordination number of the metal atoms on the NP surface (Avg. C.N. Me atoms surface) and the average force vector surface normal component of all metal atoms (v⊥ Me atoms surface). The significance and effect of these descriptors is discussed to demonstrate their direct correlation with cytotoxicity. The produced model has been made publicly available by the Horizon 2020 (H2020) NanoSolveIT project and will be added to the project’s Integrated Approach to Testing and Assessment (IATA).

Criteria that have been used to describe alkene strain can be divided into energetic and geometrical criteria. An overview of strain criteria from both groups is given, and altogether, 16 different criteria have been calculated with the DFT M062X/TZVP method for several strained alkene series. Factor analysis was used to judge whether these strain criteria measure the same underlying phenomena. The factor analysis showed that for systematically substituted ethene derivatives (series A) all the studied criteria were describing the same thing. The factor analysis showed that for series B, where the double bonds geometry is fixed with a cyclic backbone, at least two different criteria (e.g. gas-phase basicity and hydrogenation reaction enthalpy) are needed to describe the overall strain. We propose that these two different expressions of strain describe strain related to reactivity and thermodynamics. Those two strains were well-correlated in the first series.

The complexation reactions between lanthanide 3(+) cations and 2,9-bis(1,2,4-triazin-3-yl) 1,10-phenanthroline and its derivatives were studied with density functional theory Perdew-Burke-Ernzerhof functionals. The complexes consisted of one lanthanide cation and two ligand molecules. Complexation reactions were found to be exothermic and spontaneous in the gas phase. Absolute values of complextion energy and enthalpy increase in the lanthanide series and follow linear trends of lanthanide atomic number. All the bond lengths decrease in the lanthanide series with increasing charge density.

Chiral cyclohexanohemicucurbit[n]urils (n = 6, 8) (cycHCs) are able to bind guests through multiple "outer surface interactions", which in the case of planar zinc porphyrins leads to induction of chirality. Crystal structures of complexes of complementary sized hosts revealed social self-sorting, while in the solution phase one cycHC can accommodate up to three porphyrin molecules with log K-total 9.

Bromine formation in the mixture of solid NaBr and KNO3 was observed and the process was studied in different acidified organic solvent–water mixtures by monitoring the bromination of acetanilide and other compounds, containing activated aromatic substituents. This assay is based on fast bromination reaction of these aromatic compounds, as differently from the assay of Br2, the brominated aromatics can be easily determined by conventional gas chromatography–mass spectrometry (GC–MS) methods. It was found that bromine was generated autocatalytically on the surface of salt crystals and the reaction was characterized by a lag period, the duration of which depended on reaction conditions, and importantly on the type of the organic solvent in the reaction mixture. As the bromine formation could be easily controlled by reaction conditions, it was suggested that the studied reaction might have practical applications as an environmentally friendly and economically feasible bromination method. It was also shown that the bromination of aromatics followed the mechanism of classical electrophilic aromatic substitution reaction.

In the search for novel tools to combat cancer, nanoparticles (NPs) have attracted a lot of attention. Recently, the controlled release of cancer-cell-killing metal ions from doped NPs has shown promise, but fine tuning of dissolution kinetics is required to ensure specificity and minimize undesirable toxic side-effects. Theoretical tools to help in reaching a proper understanding and finally be able to control the dissolution kinetics by NP design have not been available until now. Here, we present a novel set of true nanodescriptors to analyze the charge distribution, the effect of doping and surface coating of whole metal oxide NP structures. The polarizable model of oxygen atoms enables light to be shed on the charge distribution on the NP surface, allowing the in detail study of the factors influencing the release of metal ions from NPs. The descriptors and their capabilities are demonstrated on a Fe-doped ZnO nanoparticle system, a system with practical outlook and available experimental data.

We compared different computational methods (quantum chemical and DFT) for calculations of binding energies of 8- and 9-coordinated lanthanoid–aqua complexes. We used nine computational methods and compared the results with those obtained by the CCSD(T) method. All the nine methods provided relatively similar results and calculated energies correlated very well with the CCSD(T) obtained energies for complexes of this type. The comparison of basis sets revealed that combination of Dolg’s (5s5p4d)/[4s4p3d] + 2s1p1d basis set for lanthanoids and the cc-pvdz basis set for non-lanthanoids can be suggested as optimal for further studies of lanthanoids cation complexation.

We compared different computational methods (quantum chemical and DFT) for calculations of binding energies of 8- and 9-coordinated lanthanoid-aqua complexes. We used nine computational methods and compared the results with those obtained by the CCSD(T) method. All the nine methods provided relatively similar results and calculated energies correlated very well with the CCSD(T) obtained energies for complexes of this type. The comparison of basis sets revealed that combination of Dolg's (5s5p4d)/[4s4p3d] + 2s1p1d basis set for lanthanoids and the cc-pvdz basis set for non-lanthanoids can be suggested as optimal for further studies of lanthanoids cation complexation.

The applicability of 12 different quantum chemical calculation methods, including density functional theory (DFT) and ab initio methods, for describing strained alkenes and modeling their gas-phase basicities (GB), hydrogenation enthalpies, and double bond geometries was studied for a series of systematically defined compounds R1R2C=CR3R4. The calculated values were compared to experimental data that had been compiled from literature for several compounds within the series. The closest relationship between the computational results and experimental data occurred with the G2MP2 ab initio method. The best DFT method for GB values was M062X and for hydrogenation enthalpies PBEPBE. At the same time, the relative effects of compound structure variations on the calculated values were similar among all 12 of the calculation methods tested. The double bond length was relatively insensitive to the sizes of the R substituents in R1R2C=CR3R4, but the torsion angles changed significantly in response to structural changes to the compounds when none of the groups R1-R4 was hydrogen.

The development and implementation of safe-by-design strategies is key for the safe development of future generations of nanotechnology enabled products. The safety testing of the huge variety of nanomaterials that can be synthetized is unfeasible due to time and cost constraints. Computational modeling facilitates the implementation of alternative testing strategies in a time and cost effective way. The development of predictive nanotoxicology models requires the use of high quality experimental data on the structure, physicochemical properties and bioactivity of nanomaterials. The FP7 Project MODERN has developed and evaluated the main components of a computational framework for the evaluation of the environmental and health impacts of nanoparticles. This chapter describes each of the elements of the framework including aspects related to data generation, management and integration; development of nanodescriptors; establishment of nanostructure-activity relationships; identification of nanoparticle categories; hazard ranking and risk assessment.

Alkenes are organic compounds that have a carbon-carbon double bond functional group. Usually this functional group has planar structure that determines geometry of alkene molecules. However, if the double bond is situated at a bridgehead position, where the double bond carbon atoms belong to two different cycles, or if there are very bulky substituents at the double bond, the planar geometry of the double bond can be distorted. The strain effect, rising from this distortion, changes energy of the molecule and will also change its reactivity. It has been shown that strain effect may play a significant role in certain reactions [1-4].

Mechanism of an efficient and easily applicable catalytic system for the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction, consisting of phosphane-ligated Cu-I carboxylates and apolar/aprotic solvent was investigated by means of 1H NMR reaction monitoring techniques, isotope exchange studies, and DFT calculations (at the M06L/6-311++ G(d,p)//B97D/cc-pVDZ (SDD) level of theory). Kinetic analysis indicates 1st order kinetics with respect to [Azide] and nonlinear positive order in [Cu]. H/D scrambling between alkynes reveals a quickly reached equilibrium existing between Cu-I-carboxylates and Cu-I-acetylides and that proton transfer processes are mediated by acetate/acetic acid system. According to the computational results, the Cu-triazolide forms a dinuclear structure that equalizes the copper atoms in the catalytic complex.