Cationic Clusters Research Articles

Reactions of Photoionization-Induced CO-H2O Cluster: Direct Ab Initio Molecular Dynamics Study.

The hydrocarboxyl radical (HOCO) is an important species in combustion and astrochemistry because it is easily converted to CO2 after hydrogen reduction. In this study, the formation mechanism of the HOCO radical in a CO–H2O system was investigated by direct ab initio molecular dynamics calculations. Two reactions were examined for HOCO formation. First, the reaction dynamics of the CO–H2O cluster cation, following the ionization of the neutral parent cluster CO(H2O)n (n = 1–4), were investigated. Second, the bimolecular collision reaction between CO and (H2O)n+ was studied. In the ionization of the CO(H2O)n clusters (n = 3 and 4), proton transfer, expressed as CO(H2O)n+ → CO–(OH)H3O+(H2O)n–2, occurred within the (H2O)n+ cluster cation, and the HOCO radical was yielded as a product upon addition of CO and OH. This reaction proceeds under zero-point energy. Also, this radical was effectively formed from the collision reaction of CO with water cluster cation (H2O)n+, expressed as CO + OH(H3O+)(H2O)n–2 → HOCO–H3O+ + (H2O)n–2. If the intermolecular vibrational stretching mode is excited in the CO(H2O)n cluster (vibrational stretching between CO and the water cluster), the HOCO radical was detected after ionization when n = 2. The reaction mechanism was discussed based on the theoretical results.

The Coordination Chemistry and Clustering of Subvalent Ga+ and In+ upon Addition of σ‐Donor Ligands

AbstractThis review addresses the coordination chemistry (mainly) enabled by using the univalent [M(fluoroarene)2–3]+[Al(ORF)4]−‐salts (M=Ga, In; RF=C(CF3)3) as robust starting materials. In the course of this work, it became clear that the orbital energy of the ns2 (n=4, 5) lone pair in such [:M(L)n]+ cations reacts drastically depending on the quality of the ligand employed. Activation of the lone pair with strong σ‐donor ligands might be used for bond activation and oxidative addition reactions. Yet, unexpectedly, using sterically undemanding and electron rich ligands with limited π‐accepting properties, aggregation to highly charged and rather unusual univalent cluster cations [Mn(L)m]°+ (n=2…5, m=4…6, o=3…5) was observed. An overview and rationalization of these findings is presented here.

Electronic Structure and Electron Delocalization in Bare and Dressed Boron Pentamer Clusters.

The electronic structures of the lowest energy spin-states of the cationic, neutral and anionic bare boron pentamer clusters have been investigated by means of high level multiconfigurational type calculations, in view of the large static and dynamical electron correlation effects for these species. We found that resembles a singlet spin-state perfect pentagon, which bears no intra-annular chemical bonding interactions, as shown by our analysis of the electron delocalization carried out in terms of the normalized Giambiagi ring-current index, and the total and adjacent atom-pair delocalization indices. However, its lowest-energy triplet and quintet spin-state isomers have C2v symmetry, with large intra-annular chemical bonding interactions. This geometrical feature extends to both the neutral and the anionic species. Namely, the lowest-energy isomers of boron pentamer neutral and anionic clusters have peripheral and intra-annular sizable bonding interactions reflected in the delocalization of both π- and σ-type valence natural orbitals over the whole molecular plane, which impart large structural stability. In accordance to our calculations, the lowest energy triplet spin-state isomer of the anionic boron pentamer cluster has C2 symmetry, and consequently, it should show optical activity. Finally, we have studied the change of the geometrical structure of the boron pentamer clusters from planar to compact three-dimensional structures caused by the bonding of ligands to the boron atoms. Our explicit all-electron calculations have been rationalized in terms of the shell-closure of the delocalized valence orbitals of the clusters as predicted by the jellium model extended to nonspherical confinement potentials, circumscribing the role of the ligand to modulate the total number of valence electrons assigned to the core cluster.

Mechanism and kinetics of catalytic oxidation of CO to CO2 over Ptn+and MPtn-1+, (M=Sn, Rh &Ru; n=3, 4) clusters

Abstract Quantum chemical studies show the elementary effects of doping in the oxidation reaction of CO over Ptn+ and MPtn-1+ (M=Sn, Rh & Ru; n=3, 4) clusters. We have utilized MN12-SX screened-exchange (SX) hybrid functional in conjunction with def2TZVPP basis set to obtain electronic structures and thermochemical properties of all species involved in the reaction. It is found that the co-adsorptions of CO and O2 on pure Pt3+ and Pt4+ clusters are less exothermic, while doped SnPt2+ and SnPt3+ clusters show the most exothermic behavior. Bader charge analysis reveals the most significant dopant-host charge transfer on SnPt2+ and SnPt3+ clusters in the course of CO oxidation. Furthermore, the kinetics of the CO oxidation reaction is evaluated using transition state theory. The results show that the value of the rate constant is the highest for Sn doped Pt clusters in the first oxidation of CO to CO2 molecule than the other clusters. We have found that among the Sn, Rh and Ru doped cationic Pt clusters for CO conversion, Sn acts as a suitable alloy on Pt catalyst for building future catalytic converters and fuel cell electrode materials.

Boosting CO2 Electroreduction via the Synergistic Effect of Tuning Cationic Clusters and Visible‐Light Irradiation

Introducing an external light field can increase the intrinsic activity and energy efficiency for electrochemical CO2 reduction. Herein, a synergistic strategy that introduces photosensitive components and visible light into a stable system is reported to improve the performance for CO2 reduction. The catalytic kinetics studies indicate that the synergistic effect of implantation of cationic Ti and additional light driving is the primary responsibility for accelerating the first electron transfer to form a *COO- intermediate. This leads to a satisfactory CO2 -to-CO conversion for Zr/Ti-NB-Co in terms of high selectivity (Faradaic efficiency of 93.6% at -0.7V), remarkable catalytic activity (production rate up to 546mmol g-1 h-1 at -1.1V), excellent long-term stability (without performance decay over 11 h), and large turnover frequency of 1028 h-1 at -1.1V under visible light. These results imply that the photodriven Ti-based porphyrin catalyst not only can deliver more electrons, but also can act as a photoswitch to adjust the electron transfer pathway.

Synthesis, crystal structure and photocurrent response property of a copper(II)-organic supramolecular coordination compound based on [Cu4(phen)4(OH)4(H2O)2]4+ cations and [Cu(EDTA)]2− anions

A hydrogen-bonded hexanuclear cluster-based supramolecular coordination compound {[Cu4(phen)4(OH)4(H2O)2][Cu(EDTA)]2·14H2O}n (1) (phen = 1, 10-phenanthroline, EDTA4- = full deprotonated ethylenediamine tetraacetic acid) has been isolated through the self-assembly of aromatic diimine ligand phen and sexadentate ligand EDTA4- with acetate copper(II). The [Cu4(phen)4(OH)4(H2O)2][Cu(EDTA)]2·14H2O unit contains a centrally chair-like stepped hydroxy-bridged tetranuclear [Cu4(phen)4(OH)4(H2O)2]4+ cationic cluster, two opposite EDTA4- chelated mononuclear [Cu(EDTA)]2- coordination anions, and fourteen free water molecules. The discrete [Cu4(phen)4(OH)4(H2O)2][Cu(EDTA)]2·14H2O unit is extended to a 3D supramolecular structure {[Cu4(phen)4(OH)4(H2O)2][Cu(EDTA)]2·14H2O}n (1) by van der Waals interactions and hydrogen bonds. The structure of 1 has been defined by single crystal X-ray diffractometer (SCXRD), and well-characterized by a series of technologies, such as infrared spectroscopy, thermogravimetric analysis, and UV–Vis absorption spectroscopy and diffuse reflectance spectroscopy. In addition, the photocurrent response, electrochemistry and luminescence properties have also been investigated.

Vacuum Ultraviolet Photoionization Induced Proton Migration and Formation of a New C-N Bond in Pyridine Clusters Revealed by Infrared Spectroscopy and Mass Spectrometry.

The structures and reactions of pyridine (Pyd) cluster cations in a supersonic molecular beam generated upon photoionization at 9.2-9.4 eV were investigated by infrared (IR) action spectroscopy. The mass spectrum showed prominent peaks of (Pyd)m+ and H+(Pyd)m, m = 1-5. In the pyridine/pyridine-d5 mixture, the mass pattern indicated that H+ and D+ migrated during the formation and dissociation of the cluster cations. The IR photodissociation spectra of both (Pyd)2+ and H+(Pyd)2 revealed a N-H stretching band near 3400 cm-1, indicating that their structures are 1-(2-pyridyl)pyridin-1-ium and pyridinium-pyridine, respectively. Observation of the former product implies that the reaction proceeds via an α-distonic cation intermediate, while the latter product is formed via proton migration. The IR spectra of (Pyd)m+ and H+(Pyd)m, m ≥ 3, suggested that these clusters consist of a covalently bound (Pyd)2+ or H+(Pyd)2 core, respectively, with additional pyridines attached to them via hydrogen bonds and/or weak dispersive interactions.

Elucidating the Autoinhibitory Domain and IRBIT‐Binding Motifs of the Electrogenic Na/HCO 3 Transporter NBCe1‐B

NBCe1 is widely expressed throughout the body, playing crucial roles in transepithelial HCO3− transport (e.g., pancreatic ducts) and regulation of intracellular pH (e.g., central nervous system [CNS]). Of the five known variants, NBCe1-A is expressed mainly in proximal tubules, B is ubiquitous, C is in the CNS, and D and E are in reproductive organs. The extreme NH2-terminus (Nt) is a major determinant of transport activity, with the unique initial 41 amino acids (aa) of A (and perhaps D) containing an autostimulatory domain, and the unique initial 85 aa of B and C (and perhaps E) containing an autoinhibitory domain (AID). The cytosolic protein IRBIT [inositol trisphosphate (IP3)-receptor binding protein released with IP3] binds somewhere within the initial 85-aa of NBCe1-B (and perhaps C & E), largely nullifying the AID. In an earlier study of residues 28–62, inclusive, of NBCe1-B (e1B), we found that a 9-residue cationic cluster (40–48) is an essential component of the AID. In the present study, we: (a) determine the extent to which the remainder of the initial 85-aa of e1B (i.e., residues 2–27 & 63–85) contribute to the AID, (b) extend our analysis of the cationic cluster, and (c) elucidate the structural components of the IRBIT-binding site within the initial 85-aa of e1B. Our main experimental tool is the Xenopus oocyte, in which we express one of dozens of e1B constructs ± a highly active IRBIT construct (super-IRBIT [sIRBIT]) that lacks the PP1 binding site. We assess e1B functional activity by two-electrode voltage-clamping, and determine plasma-membrane expression of e1B and high-affinity sIRBIT binding to e1B by extracellular surface biotinylation, followed by NeutrAvidin pull-down of plasma-membrane proteins, and western blotting. We find that sIRBIT copurifies with biotinylated e1B, but only when the e1B AID is intact (i.e., e1B activity is low in the absence of sIRBIT). For example, sIRBIT does not copurify with the e1B-D940-48, which lacks the cationic cluster. We find that residues 63–85 are not necessary for either the AID or sIRBIT binding. We next used alanine scanning to explore residues 2–27. We find that a His-His motif (residues 26–27) is not essential for the AID, but is required both for stimulation of e1B activity by sIRBIT and for sIRBIT copurification with e1B. Thus, replacing HH with AA or DD produces an e1B construct with high e1B surface abundance, but low baseline activity, no stimulation by sIRBIT, and little sIRBIT copurification. Replacing HH with RR restores robust stimulation of e1B activity by sIRBIT, even though e1B surface abundance is markedly reduced. Regarding the cationic cluster, we replace the WT cation cluster—mostly made of arginine (R) residues—with increasing numbers (N) of lysine residues (KN) or histidine residues (HN). We observe that (1) the KN and HN constructs also produce autoinhibition, (2) sIRBIT relieves the autoinhibition, (3) sIRBIT co-purifies with the KN and HN constructs, and (4) the amount of co-purified sIRBIT gradually increases with increasing N for both KN and HN constructs, as is the case with RN constructs. Thus, a cluster of positive charge—contributed by RN, KN, or HN—is essential both for autoinhibition and sIRBIT binding.

Pseudo-Zwitterions Self-Assembled From Polycation and Anion-Clusters Showing Exceptional Water-Cleanable Anti-Crude Oil Adhesion Property

It is of great importance and practical value to develop a facile and operable surface treatment method of materials with excellent anti-pollution and anti-adhesion property, but still a huge challenge. In this work, a series of pseudo-zwitterions are prepared from electrostatic assembly of cationic polyethyleneimine and anionic phosphonic clusters. These pseudo-zwitterionic assemblies provide a strong hydration through electrostatic interaction with water and in turn create a barrier against oil foulants, leading to a nearly zero crude oil adhesion force. The pseudo-zwitterions decorated surfaces exhibit exceptional water-cleanable oil repellent property, even when they are completely dried and without pre-hydration before fouled by crude oil. While using these pseudo-zwitterions modified polymeric membranes for separating surfactant stabilized oil-in-water emulsion, less than 10% decline of permeating flux is observed throughout a 2 h continuous separation experiment, showing excellent emulsion separation ability and anti-pollution performance for high viscous oil.

Proton Transfer in Nitromethane-Ammonia Clusters under VUV Single-Photon Ionization Explored by Infrared Spectroscopy and Theoretical Calculations.

It is known that the acidity and reactivity of the CH bond can be enhanced after ionization. Also, this property plays a pivotal role in proton transfer reaction and in the formation of new molecules. Herein, infrared spectroscopy and high-precision quantum chemical calculations are used to study the neutral and cationic clusters of nitromethane-ammonia (CH3NO2-NH3). It is found that in the neutral cluster, CH3NO2 and NH3 are mainly bonded by three intermolecular hydrogen bonds, in which electrostatic contribution plays a major role. After vacuum ultraviolet (VUV) single-photon ionization of CH3NO2-NH3, the positive charge redistributes from the ionized nitrogen atom of NH3 to the CH3NO2 molecule immediately. Then, the proton of CH3NO2 transfers to NH3 to form a proton-transferred type structure CH2NO2-NH4+, without any effective energy barrier, due to the positive hyperconjugation of cationic nitromethane. A closed loop of positive charge transfer takes place in the CH3NO2-NH3 cluster after VUV ionization. The present work demonstrates that both the proton transfer reaction and charge transfer process have occurred in the ionized CH3NO2-NH3 cluster. Moreover, it is found that the proton transfer reaction is a result of the highly acidic CH bond caused by hyperconjugation between the σ (CH) bond and π orbital.

A comparative study on the reactivity of cationic niobium clusters with nitrogen and oxygen

We have prepared well-resolved Nbn+ (n = 1–10) clusters and report here an in-depth study on the essentially different reactivity with N2 and O2, by utilizing a multiple-ion laminar flow tube reactor in tandem with a customized triple quadrupole mass spectrometer (MIFT-TQMS). As results, the Nbn+ clusters are found to readily react with N2 and form adsorption products NbnN2m+; in contrast, the reactions with O2 give rise to NbnO1−4+products, and the odd-oxygen products indicate O-O bond dissociation, as well as increased mass abundance of NbO+ pertaining to oxygen-etching reactions. We illustrate how N2 prefers a physical adsorption on Nbn+clusters with an end-on orientation for all the products, and allow for size-selective Nbn+clusters to act as electron donor or acceptor in forming NbnN2m+. In contrast to these nitrides, the dioxides NbnO2+display much larger binding energies, with O2 always as an electron acceptor, corresponding to superoxide or peroxide states in the initial reactions. Density-of-states and orbital analyses show that the interactions between Nbn+ and O2 are dominated by strong π-backdonation indicative of incidental electron transfer; whereas weak π-backdonation and simultaneous σ donation interactions exist in NbnN2+. Further, reaction dynamics analysis illustrates the different interactions for N2 and O2 in approaching the Nbn+ clusters, showing the energy diagrams for N2 adsorption and O-O bond dissociation in producing odd-oxygen products. Fragment analyses with orbital correlation and donor-acceptor charge transfer are also performed, giving rise to full insights into the reactivities and interactions of such transition metal clusters with typical diatomic molecules.

IR Spectroscopic Characterization of H2 Adsorption on Cationic Cun+ (n = 4-7) Clusters.

IR spectra of cationic copper clusters Cun+ (n = 4–7) complexed with hydrogen molecules are recorded via IR multiple-photon dissociation (IRMPD) spectroscopy. To this end, the copper clusters are generated via laser ablation and reacted with H2 and D2 in a flow-tube-type reaction channel. The complexes formed are irradiated using IR light provided by the free-electron laser for intracavity experiments (FELICE). The spectra are interpreted by making use of isotope-induced shifts of the vibrational bands and by comparing them to density functional theory calculated spectra for candidate structures. The structural candidates have been obtained from global sampling with the minima hopping method, and spectra are calculated at the semilocal (PBE) and hybrid (PBE0) functional level. The highest-quality spectra have been recorded for [5Cu, 2H/2D]+, and we find that the semilocal functional provides better agreement for the lowest-energy isomers. The interaction of hydrogen with the copper clusters strongly depends on their size. Binding energies are largest for Cu5+, which goes hand in hand with the observed predominantly dissociative adsorption. Due to smaller binding energies for dissociated H2 and D2 for Cu4+, also a significant amount of molecular adsorption is observed as to be expected according to the Evans–Polanyi principle. This is confirmed by transition-state calculations for Cu4+ and Cu5+, which show that hydrogen dissociation is not hindered by an endothermic reaction barrier for Cu5+ and by a slightly endothermic barrier for Cu4+. For Cu6+ and Cu7+, it was difficult to draw clear conclusions because the IR spectra could not be unambiguously assigned to structures.

On the structure of the lowest spin states of [formula omitted]. Hybrid DFT vs. benchmark CASSCF-CASPT2 studies

The three lowest spin states (S = 0,1,2) of Li13+ are investigated using density functional theory (DFT) and benchmark CASSCF and CASPT2 with a couple of Dunning's cc-pVnZ basis sets. Full CASSCF(12,12)/cc-pVDZ geometry optimizations were done using optimized PBE0 structures. Since 12 electrons in 12 active orbitals span the complete active valence space, the present CASPT2/cc-pVTZ results provide benchmarks for this cationic cluster. The CASPT2(12,12)/cc-pVTZ lowest energy structures are a centered-squared antiprism singlet (S = 0) and a quintet (S = 2) icosahedron lying 3.4 kcal/mol above the former. The lowest triplet lies 5.6 kcal/mol above the singlet ground state and all the spin states have a rather strong multireference character. The dynamical behavior of this floppy cluster actually precludes the identification of a dominant structure for Li13+. Prediction of molecular properties is found to be very sensitive both to the electronic correlation treatment and the basis set used.

Nonuniform Proton Transfer and Strong Hydrogen Bonding within Cation, Anion, and Neutral Clusters of Ammonia and Hydrogen Fluoride.

Structural studies of ammonium halide nanoparticles can help to reveal fundamental information about the detailed nature of intermolecular forces. This study focuses on small ammonium fluoride clusters, which exhibit complex behavior in comparison to other ammonium halide clusters due to the weak acidity and strong hydrogen-bonding ability of HF. Calculations of optimized structures and binding energies are presented for cation, anion, and neutral clusters using MP2, CCSD(T), FNO-CCSD(T), ωB97M-V, and MN15 methods. The extent to which proton transfer occurs between two given cluster components was quantified using a dimensionless proton-transfer parameter (ξPT), leading to a classification of different types of hydrogen bonds within the clusters. Whereas the neutral clusters exhibit a complex transition from ordinary hydrogen bonding to a combination of shared-proton hydrogen bonds and complete proton transfers, the anion and cation systems exhibit a rapid transition toward complete proton transfer from HF to NH3, with incomplete proton transfer observed only in the smallest anion and cation clusters. Ionic interaction energies of these clusters were also computed and found to exhibit trends which can be interpreted by the size-dependent behavior of ξPT. This work extends our understanding of the size-dependent trends in intermolecular forces which govern the formation of anhydrous ammonium halide clusters as well as the relationship between strong hydrogen bonding and proton transfer.

Characterization of atmospheric-pressure spark generated atomic silver and gold clusters by time-of-flight mass spectrometry

The potential of using atmospheric-pressure spark ablation for production of atomic clusters has been shown in the recent past. In this study we used this method to produce atomic clusters in Argon and investigated their chemical composition with an atmospheric pressure interface time-of-flight mass spectrometer (APi-TOF-MS). Both anionic and cationic silver and gold clusters were generated and characterised. The carrier gas was used directly from the gas cylinder without the application of any additional gas purification. As a result, the carrier gas stream contained trace impurities of N2, O2, and H2O, as well as radicals such as O, OH, and H and their ionized forms resulting from the plasma created by the sparks. The experimental results show that different reactivities towards oxygen and water traces can be observed depending on the number of metal atoms in the clusters, their polarity, as well as their compositions; e.g., Aun− shows less reactive behaviour towards oxygen and hydrogen compared to Agn−. The results also show that certain cluster types can be generated at large enough quantities by atmospheric-pressure spark ablation, which considering the low installation and operating cost of the technique can pave the way towards its exploitation for numerous technological applications.

Experimental and emulational study on the role of ion in coal adsorbing kerosene: Water–kerosene interface and catenoid characteristics

Understanding the effect of ions on the interfacial tension (IFT) between kerosene and water is a prerequisite to predicting kerosene–mineral adsorption. Using a high-speed motion acquisition system, we investigated the height evolution of the catenoid with different IFTs. As the IFT increased, the height of catenoid first increased slowly and then increased sharply. The catenoid height of the oil–water interface was larger than was that of the water–gas, whereas the IFT was the opposite, indicating that height was related not only to the IFT, but also to the viscosity of the phases when the ring diameter was constant. The cation valence had a significant influence on the IFT. Interaction between the cation and water molecules led to the generation of cationic clusters. The literature indicates that the higher the valence of ion the easier it would be to form a cationic cluster, resulting in decreasing of the IFT. Our results matched these findings. At low ionic concentration, the IFT increased as the ion concentration increased. At high ionic concentration, the IFT decreased with increasing concentration because of the ionic pairs. The results of molecular dynamics simulation showed that the water molecules only moved toward kerosene molecules without ions. The hydrophilic groups in kerosene molecules spontaneously arranged toward the water–oil interface, whereas the hydrophobic groups stayed away from this interface. The water molecules burst into the kerosene phase in the presence of ions. The number of water molecule entering the kerosene phase increased with increasing ion concentrations. Our results can provide valuable insight into the development of technology for surfactant adsorption and mineral flotation.

Iranian Qara Qat fruit (redcurrant) in Arasbaran forests as the resource of anthocyanin pigments in formation of [ACN-Mg2+/Al3+/Ga3+/ Sn2+/Cr3+/Fe3+] chelation clusters

Clusters of metallic cations (Mg2+, Al3+, Ga3+, Sn2+, Cr3+ and Fe3+) jointed to anthocyanins in water media were studied for unraveling the color shifting of different complexes of these structures in the low ranges of pH. Anthocyanin jointed to metallic cation progresses the color expression range of anthocyanin in more different range of pH. In this verdict, it has been studied the metallic cations diffusing of deprotonating for the anthocyanin (B)-ring of cyanidin (Cy), delphinidin (Dp) and petunidin (Pt) in two media of gas and water, transforming flavylium cations to the blue quinonoidal bases at lower range of pH applying the infrared method by approaching Beer Lambert law for getting the physico-chemical parameters of frequency, intensity, and absorbance of the compounds, respectively. In previous investigation, it has been indicated that the important factor for enhancing the absorbance in a positive non-linear fashion due to deviating from the Beer Lambert law is the self-association of anthocyanins of cyanidin, delphinidin and petunidin of anthocyanin structures. The difference of heat of formation (∆HR) among clusters of metallic cations jointed to anthocyanins has been illustrated toward the double bonds and carbonyl groups by the chelation of (B)-ring for cyanidin, delphinidin and petunidin anthocyanins in two media of gas and water that explains the stability and color of [anthocyanin-metallic cations] cluster chelation of cyanidin (Cy), delphinidin (Dp) and petunidin (Pt) colorful pigments in a weak acidic medium. By this work we exhibited that the color of the anthocyanin chelates is an important factor for estimating the efficiency of these types of food colorants.

Study of the Reactions of Fullerene С60 with the Palladium-Containing Clusters of Molybdenum {Mo3PdS4} by Spectroscopic and Calculation Methods

The fabrication of hybrid materials combining the physicochemical properties of various classes is a complicated but promising trend for the development of the modern science. The formation of new hybrid cluster cations [Mo3Pd(C60)S4Cl3(R2Bipy)3]+ and [{Mo3PdS4Cl3(R2Bipy)3}2(C60)]2+ (Bipy is 2,2-bipyridine) containing fullerene C60 coordinated to the palladium atom by the reaction of [Mo3S4Cl3(R2Bipy)3]PF6 with Pd2(Dba)3 (Dba is dibenzylideneacetone) and C60 is shown by a complex of physicochemical methods. The reaction products are studied by IR and NMR (1H, 31Р, and C–H correlations) spectroscopy and mass spectrometry. The quantum-chemical calculations are performed by the DFT method for the correct interpretation of the spectroscopic data and elucidation of the electronic structures of the fullerene-containing compounds.

Ab initio Monte Carlo simulations of structure and electronic properties of copper-tin clusters

This study investigated the structural and electronic properties of (CuSn)n clusters with n = 1–6 using ab initio Monte Carlo Simulations and density functional theory calculations. Monte Carlo simulations were performed using a large number of initial structures of neutral, cationic, and anionic copper-tin clusters. Their stable structures were determined using B3LYP/def2-TZVP model chemistry and the most stable structures of neutral, cationic, and anionic copper-tin clusters were established. The values of bond angles and bond lengths, atomization energies, second differences of the energies, HOMO-LUMO gaps, Mulliken population analysis, adiabatic ionization potentials, and adiabatic electronic affinities were determined as a function of n.

A Synthetic Approach to Trinuclear Cluster with [Co3(μ3‐O)(μ‐OH)] Core: A Comparative Study on Cluster having [Co3(μ3‐O)(μ‐OH)] and [Co4(μ3‐O)4] Core

AbstractA synthetic approach to synthesize the cationic trinuclear cluster with [Co3(μ3‐O)(μ‐OH)] core has been reported. A comparative study with the closely relevant polynuclear cluster containing [Co4(μ3‐O)4] active core has also been carried out along with a plausible pathway for these two clusters. The minor spectroscopic and electrochemical changes observed for the cores are quite significant to distinguish them. The rigidity of the core can be well characterized by the solvent interaction. The involvement of the hydroxo group in the electrochemical process may help these clusters to be used for catalytic processes, although these [Co3(μ3‐O)(μ‐OH)] cationic clusters are thermally less stable than [Co4(μ3‐O)4] cuboidal clusters.