6-31G Level Research Articles

Application of density functional theory on the NO-char heterogeneous reduction mechanism in the presence of CO2

In order to obtain the mechanism of the effect of CO2 on the NO heterogeneous reduction, density functional theory (DFT) was adopted to investigate the interactions between char and NO with the participation of CO2. The armchair configuration composed with several aromatic ring clusters was selected as the carbonaceous surfaces. Geometric optimizations were carried out at the B3LYP-D3/6-31G(d) level. Energies of optimized geometries were calculated at the B3LYP-D3/def2-TZVP level. The results show that, the surface carbonyl groups produced by the adsorption of CO2 combine with the adsorbed NO to desorb CO2, thereby providing adjacent carbon active sites for subsequent NO adsorption and N2 desorption. Thermodynamic studies show that the exothermic heat of this reaction is 853.9 kJ/mol, and the highest energy barrier is 297.0 kJ/mol without the participation of CO2, but the exothermic heat of this reaction is 593.7 kJ/mol, and the highest energy barrier is 214.1 kJ/mol with the participation of CO2. Kinetic studies show that over the temperature range of 298.15–1800 K, the reaction rate constants of rate-limiting steps are calculated with conventional transition state theory. The rate constant with the participation of CO2 is higher than that without the participation of CO2. In summary, CO2 plays a promoting role in interacting with NO and char and reducing energy barrier to form N2 directly.

Role of pH in the stability of cytosine-cytosine mismatch and canonical AT and GC base pairs mediated with silver ion: a DFT study

Metallo-nucleic acids have been investigated for their applications in the field of nanodevices and genetic expansion. The cytosine-Ag+-cytosine mismatch base pair interactions and their stability in nucleic acids have attracted the attention of chemists. We report a systematic study of canonical, mismatch, Ag+ mediated system with CC, AT, and GC base pairs computationally. The stability of such mismatch base pairs is dependent on the pH range ~ 5 to 9 and the duplexes beyond this range are unstable. The DFT calculations performed with the model DNA duplexes comprising of such mismatch pairs reveal the stability trend while varying the pH conditions. The stability of canonical Watson–Crick ATGC base pairs was compared with the CCAT and CCGC mismatch base pairs and the calculated results at B3LYP-D3/6-31G(d) level of theory in the aqueous phase suggest that the base stacking and hydrogen bonding are well maintained in the former case, however, the larger perturbations in the geometry are observed with the mispair and relatively unstable. The calculated binding energy B3LYP-D3/6-31G(d) level of theory of ATGC is energetically more stable (~ 20 kcal/mol) than the mismatch base pairs. The Ag+ mediated mismatch base pairs i.e., C_CAT and C_CGC examined at the same level of theory suggest that the CC mismatch base pairs complexed with proper alignment to the Ag+ ion and the AT and GC bases maintained the hydrogen bonding interactions. The relative binding energies have been calculated with 6–311 + G(d,p) basis set using B3LYP-D3 and wb97xd DFT functionals in the study. The mismatched base pair duplex systems i.e., C_CAT and C_CGC are structurally similar to the canonical Watson–Crick base pairs and energetically stable by ~ 40 and ~ 50 kcal/mol compared to the canonical ATGC base pairs. The experimental report on the thermal transition profile in 5’-(A)10C(A)10–3’ and 5’ (T)10C(T)10–3’ duplexes showed remarkable stability and corroborate the calculated results (Ono et al. in Chem Commun 4825−4827, 2008). The stability of Ag+ mediated mismatch bases at the higher pH 9 was also examined and the nucleobases such as guanine and thymine would be deprotonated under this condition. The calculated results suggest that the CCA_T and CCG_C duplexes are largely distorted with the complexation of Ag+ with the AT and GC base pairs and would in turn denature the duplex. The AIM analysis performed at B3LYP-D3/6-31G(d) level of theory for all the studied Ag+ mediated complexes reveals that the Ag+ interaction with the corresponding nucleobases was electrostatic in nature. The role of pH in governing the stability of C–Ag+-C complex formation in mismatch base nucleic acids is crucial for their application of genetic expansion and nucleic acid-based nanodevices.Graphical abstract

Synthesis, characterization, antimicrobial, cytotoxic, DNA-interaction, molecular docking and DFT studies of novel di- and tri-organotin(IV) carboxylates using 3-(3-nitrophenyl)2-methylpropenoic acid

One diorganotin(IV) [n-Bu2SnL2] (1) and two triorganotin(IV) carboxylates [n-Bu3SnL] (2) and [Ph3SnL] (3) [L = 3-(3-nitrophenyl) 2-methylpropenoic acid] were synthesized and characterized by elemental analysis, FT-IR and NMR (1H, 13C) spectroscopies. The geometry of complexes and binding mode of ligand were worked out through FT-IR and NMR spectroscopies. The ligand coordinate with Sn via carboxylato oxygen in monodentate fashion leading to four coordinated geometries around Sn center. The effectiveness of complexes towards their antimicrobial and cytotoxic potential was evaluated and a significant extent of antimicrobial potential was observed with a few exceptions. Molecular docking studies were performed for these complexes to check their interaction with DNA. Results from this study revealed that these compounds can bind favorably with cisplatin binding site and targeting the major groove of DNA. The complex-DNA interaction study was also performed through UV-Vis spectroscopic technique and viscosity measurement, and the observed experimental results were well matched with theoretical results. Computational vibrational analysis, frontier molecular orbital (FMO), natural bond orbitals (NBOs), linear and non-linear optical (NLO) properties of ligand and complexes 1-3 were calculated by density functional theory (DFT) and time-dependent DFT (TDDFT) using CAM-B3LYP/6-31G (d,p) level of theory to evaluate spectroscopic, structural parameters and reactivity patterns.

Energetic azo compounds based on 2,2′, 4,4′, 6,6′- hexanitroazobenzene: Structures, detonation performance, and sensitivity

Density functional theory (DFT) has been applied to explore the general rules for structure design of azo compounds through energetic properties and stability. Structures of 2,2′, 4,4′, 6,6′- hexanitroazobenzene (HNAB) derivatives were designed and optimized using B3LYP /6-31G(d,p) level, and the heat of formation (ΔfH) were evaluated by constructing isodesmic reactions. Results reveal that the azo bridging (–NN–) is useful for increasing the heat of formation. Kamlet–Jacobs equations were employed to evaluate detonation performance, while the sensitivity was explored by correlating with the bond dissociation energy (BDE), electronic structural parameters (EHOMO, ELUMO, and ΔELUMO-HOMO), oxygen balance (OB), and charges on nitro group (QNO2). According to our calculations, some designed HNAB derivatives possess interesting properties, such as good detonation performance and high stability, even beyond RDX and HMX, revealing that the presence of azo bridging (–NN–) backbone together with the introduction of various energetic groups is a promising choice in the design of high energy density materials (HEDMs).

Computational Study of the Influence of the π-bridge Conjugation Order of Quinodimethane-based Derivatives for Dye Sensitized Solar Cells (DSSCs) Using Density Functional Theory (DFT)

Several series of quinodimethane-based derivatives with different conjugated π-bridge groups (phenyl ring, thiophenyl ring and benzothiadiazoyl ring) were investigated by different conjugation orders using density functional theory (DFT) at B3LYP /6-31g(d) level. Computational results show that, all three π-bridge groups obviously improve the optoelectronic properties of dyes compared with the reference, with more suitable energy levels and wider absorption bands. For the series of dyes with different numbers (n) of phenyl rings, larger order of π-bridge conjugation leads to a larger band gap from 2.501 eV to 2.547 eV, while the other series with thiophenyl rings has a wider absorption band and a red shift of the first absorption peak from 522.86 nm (2.371 eV) to 565.25 nm (2.193 eV) when the conjugation order increases. Benzothiadiazoyl ring was also studied as a part of π-bridge conjugation. The structure of donor - phenyl - benzothiadiazoyl -thiophenyl - anchor shows the lowest LUMO level (-2.929 eV) and a relatively high HOMO level (-5.049) among all the derivatives, but with a wide absorption band since it has two strong absorption peaks (489.24 nm and 400.41 nm with strengths of 0.7883 and 0.6625 respectively). Generally, dyes with thiophenyl rings shows more suitable optoelectronic properties for being candidate sensitizers for dye sensitized solar cells, and a combination of different aromatic rings as π-bridges is also a valuable way for designing new dye molecules in the future’s work.

Estimation of ground and excited-state dipole moments of three symmetric carbocyanine dyes via the analysis of luminescence properties

The solvatochromic effect of solvents on the absorption and fluorescence spectra of three carbocyanine dyes, namely 1,1′,3,3,3′,3′-hexamethylindocarbocyanine chloride (HIC); 1,1′,3,3,3′,3′-hexamethylindodicarbocyanine iodide (HIDC); and 3,3′-diethyloxadicarbocyanine iodide (DODC), have been investigated. The experimental ground and excited-state dipole moments of the dyes have been estimated via the well-known models by Lippert-Mataga, Bakhshiev, Kawski-Chamma-Viallet, and the Dimroth-Reichardt’s empirical model. The influence of the solvation effect on the luminescence quantum yields was also examined and a strong correlation between the luminescence quantum yield values and the solvent viscosity was established. The fluorescence signal enhancement sensitivities between dyes were compared based on the Förster-Hoffmann equation. DFT and TDDFT calculations at the CAM-B3LYP/6-31G(d,p) level of theory were performed for the analysis of the nature of the electron transitions in absorption and excitation processes. Six phases different in polarity were considered during these computations, namely the gas, toluene, chloroform, acetone, methanol, and water. Transition electron density plots, Mulliken atomic partial charges, and Mayer bond orders were used for the analysis of the redistribution of electron density upon excitation. The specific behavior of the dyes in the glycerol medium was interpreted via the analysis of non-covalent interactions between the dye and glycerol molecules in terms of the reduced density gradient method.

The electrosorption of 3-bromo-2-nitrothiophene on gold as studied with surface-enhanced Raman spectroscopy

The electrosorption of 3-bromo-2-nitrothiophene on a polycrystalline gold electrode has been studied with surface-enhanced Raman spectroscopy SERS. Results imply a tilted orientation of the 3-bromo-2-nitrothiophene molecule with a sulfur atom of the thiophene ring and oxygen atoms of the nitro group interacting directly with the gold surface. The UV-Vis spectrum of the 3-bromo-2-nitrothiophene is recorded and its results indicated that the SERS spectra were measured under off-resonance conditions. Cyclic voltammetry measurements of the 3-bromo-2-nitrothiophene were made and the oxidation and reduction potentials of the 3-bromo-2-nitrothiophene at the gold electrode have been reported. The experimental infrared and Raman data are supported by density functional theory (DFT) calculations of 3-bromo-2-nitrothiophene using the B3LYP level of theory and 6-31G (d) basis set. The vibrational frequencies of the molecule were computed using the optimized geometry obtained from the DFT calculations. The calculated spectra are very close to the recorded infrared and Raman of the solid 3-bromo-2-nitrothiophene. No imaginary frequencies are observed in the calculated spectra. Also, DFT calculations are performed to predict and investigate the adsorption behavior of 3-bromo-2-nitrothiophene on the Au surface. In this DFT calculations, the adsorbed 3-bromo-2-nitrothiophene on the gold electrode surfaces was modeled as the metal−molecule complex. Synopsis: Electrosorption of 3-bromo-2-nitrothiophene on a polycrystalline gold electrode was discussed. The adsorption orientation and adsorption sites of the 3-bromo-2-nitrothiophene molecule at the gold surface were reported. Electrochemical investigations show a reversible redox behavior in the anodic and cathodic scan direction. The computed frequencies of the 3-bromo-2-nitrothiophene molecule support the results obtained from the recorded IR and Raman spectra.

The influence of recombinant interferon on morphological and biochemical parameters of calves’ blood in early postnatal period

The main mortality of young cattle due to infectious diseases mostly occurs in the first two months of the life, which is resulted from the calves' immune system immaturity. In order to correct the immunological status, various immunomodulators are used, interferons in particular. The aim of the study was to assess the effect of recombinant bovine interferon-α2d on the biochemical and morphological parameters of the calves' blood in the early postnatal period. Two groups of young animals were formed. Calves from the 1st group (G1,n=10) was twice injected interferon intramuscularly with the interval between injections - 7 days (500 th. MU). The 2nd group was a control (G2, n=10), the injection of the immunostimulant was replaced with saline. Before the beginning (on the 7th day of life) and at the end of the experiment (on the 21st day of life), the blood was taken for the biochemical and morphological analysis. In G1 and G2, the concentration of unconjugated bilirubin at the beginning of the experiment was 2.2 ± 0.2 and 2.1 ± 0.3 mmol/L respectively, in the G1 interferon concentration decreased to 1.1 ± 0.1 mmol/L, which was 2 times less than in the G2 (P ≤ 0.01). The activity of alkaline phosphatase at the beginning of the study was 613.8 ± 54.2 in the G2 and 514.6 ± 22.4 units/L in the G1. By the 21st day of life, the level of it decreased by 16.2% (431, 1 ± 38.0 units/L) in the G1, and it was less by 31.3% (P ≤ 0.05) than the G2 (627.3 ± 77.6 units/ L). The ALT activity at the beginning of the experiment was 4.0 ± 0.8 unit/ L in the G2 and 6.1 ± 1.2 units/L in the G1. After two weeks in the G2 level of ALT increased to 6.0 ± 2.0 U / L, while in calves from the G1, on the contrary, it was decreased in 2.4 times (P≤0.05) - 2.5 ± 0.1 U / L. The AST activity in the intact group by the 21st day was 16.0 ± 8.0 units/ L, which was 8.4 times higher (P≤0.05) than in the G1 (1.9 ± 0.4). Under the influence of interferon, there was the increase in the average concentration of leukocytes (by 13.2%), as well as the decrease in the relative number of neutrophils by 36.8% (P≤0.05). The absolute number of agranulocytes increased by 37.7% (P≤0.05) compared to the control one (5.3 ± 0.5 * 109/ L) and it was 7.3 ± 0.7 * 109/ L. Thus, parenteral injection of recombinant bovine interferon-α2d to calves in the early postnatal period causes the decrease in transaminase activity and bilirubin concentration, as well as the increase in the number of cells responsible for the humoral immune response.

Atomically Precise Insights into Metal–Metal Bonds Using Comparable Endo-Units of Sc 2 and Sc 2 C 2

The precise identification of metal–metal bonds is critical to fully understanding the nature of metal–metal bonding but remains a fundamental challenge. Herein, we show the essence of Sc–Sc bonds ...

Heteroatom-bridged pillar[4]quinone: evolutionary active cathode material for lithium-ion battery using density functional theory

Quinone-based macrocyclic compounds have been proposed as promising electrode materials for rechargeable lithium-ion batteries (LIBs). To improve the electrochemical performance, in this paper, two heteroatom-bridged pillar[4]quinones (namely, oxa- and thia-pillar[4]quinones) are presented as active cathode materials for LIBs. The geometry structures, electronic structural properties, and electrochemical properties of these new species are calculated by Density Functional Theory (DFT) at the M06-2X/6-31G(d,p) level of theory. Two heteroatom-bridged pillar[4]quinones possess higher theoretical specific capacity (659 mA h g−1 and 582 mA h g−1 for oxa- and thia- pillar[4]quinones, respectively) than that of parental pillar[4]quinone (446 mA h g−1). The electrochemical performances of oxa- and thia-pillar[4]quinones are predicted theoretically to be superior to those of pillar[4]quinone as cathode material for LIBs. Compared with oxa-pillar[4]quinone, thia-pillar[4]quinone is predicted to be slightly more suitable as cathode electrode material. These results may provide fresh ideas and guidelines for enhancing the performance of quinones organic electrode materials for LIBs. Two heteroatom-bridged pillar[4]quinones, Oxapillar[4]quinone and Thiapillar[4]quinone, are proposed as the electrode active molecules. The lithium storage mechanisms and electrochemical properties are investigated by using DFT calculations. The results show that the heteroatom-bridged pillar[4]quinones are predicted theoretically to exihibit a better electrode material performance than the parent pillar[4]quinone.

Adsorption of melphalan anticancer drug on C24, B12N12, B12C6N6, B6C12N12 and B6C6N12 nanocages: A comparative DFT study

Anticancer drug delivery is becoming a central scientific defy since it allows locating drug release near the tumor cell and circumventing secondary side effects. Based on density functional theory (DFT) calculations, adsorption of most abundant melphalan anticancer drug specie at physiological pH on a series of small 24 atoms nanoclusters (C24, B12N12 and carbon doped boron nitride molecules: B12C6N6, B6C12N6 and B6C6N12), was carried out both in vacuum and solvent (water) environment conditions at B3LYP-D3(BJ)/6-31G(d,p) level of theory. The most stable chemisorption state for melphalan was through oxygen atom onto all nanocluster under study, in comparison with chlorine and nitrogen atoms and comparing both environments, the computed results indicate that the adsorption of melphalan in the solvent environment is in general more stable. According to our results, boron nitride and some of its mixed nanoclusters may serve as potential drug delivery nanovehicles for melphalan drug. The results from this work are expected to motivate further inquiries concerning these systems, using both theoretical and experimental approaches, in order to validate their versatility as nanovehicles.

Triphenylamine based donor-acceptor-donor type small molecules for organic solar cells

To ascertain geometry optimization, chemical reactivity, electronic absorption spectra, charge transport rate, transition density matrix (TDM), and density of states (DOS) properties, four novel Donor-Acceptor-Donor (D-A-D) type small molecules have been investigated through DFT and TD-SCF at selected hybrid CAM-B3LYP functional. Amongst all molecules,F2shows maximum λ value with chlorobenzene solvent (λmax = 526 nm) while F3 possess the lowest energy band gap (4.35 eV) and surpassed in exhibiting the best photovoltaic properties and conversion efficiency due to presence of strong electron-withdrawing acceptor moiety. Moreover, the results imply that the newly designed moieties (F1-F4) proved defter in executing low reorganization energies, low binding energies, higher dipole moment, and comparable frontier molecular orbitals regarding modelR. In conclusion designed molecule parameters were calculated using functional CAM-B3LYP/6-31G level of theory as a useful tactic in the quest for achieving good photovoltaic applications.

The mechanism of conversion of substituted glycals to chiral acenes via Diels-Alder reaction: a computational study.

Synthesis of linearly fused aromatic systems using a glycal-based diene with an aryne is a long-standing topic of interest in glycal chemistry. We have examined the mechanistic pathways for the transformation of substituted glycals to chiral fused aromatic cores via Diels-Alder (DA) reaction using the SMDACN-M06-2X/6-31G(d) level of theory. The DA reactions of E (1a) and Z (1a') forms of C-2 alkenyl glycal and an aryl glycal (1b) as a diene were examined with a benzyne intermediate generated as a dienophile. The computational results reveal that 1a and 1b can only be transformed into the fused aromatic cores by the base-catalyzed reaction because a [1,5] sigmatropic hydrogen shift is not feasible. The activation free energy barrier for the base-catalyzed proton abstraction process is 4.2 kcal mol-1 and there is almost no barrier for stereoisomeric 1a DA-complexes. The activation free energy barrier values for stereoisomeric 1b DA-complexes for the base-catalyzed proton abstraction process are 10.8 and 12.4 kcal mol-1. The appropriate orientation of glycal-ring-oxygen and hydrogen at the 5th position of Z (1a') forms of C-2 alkenyl glycal facilitates the [1,5] sigmatropic hydrogen shift; however, the base-catalyzed reaction is energetically more favored than the former case. The rate-determining step for 1a and 1a' is the ring-opening step (18.2 and 19.5 kcal mol-1 for the S-stereoisomer), whereas the DA adduct formation step is the rate-determining step for 1b (16.1 kcal mol-1 for the S-stereoisomer). The structural analysis reveals the formation of the preferred S-stereoisomer over the R-stereoisomer with the respective dienes.

Detailed kinetic modeling of nitroglycerin low-temperature decomposition

Nitroglycerin (NG) is mostly used as an ingredient in double-base propellant formulations. In this study, a first automatically generated detailed kinetic model of NG decomposition has been developed. The construction of this model was made possible by performing computations with the open source software package Reaction Mechanism Generator (RMG). To enable a faster convergence, significant intermediate species of NG decomposition and optimized operating conditions were indicated in the RMG input parameters. Thermochemical data related to the significant NG decomposition species were derived from ab initio calculations at the B3LYP 6-31G(d, p) level of theory. To validate the RMG-built mechanism, simulations were performed with CHEMKIN-Pro. Computed species profiles from simulations were compared with flash pyrolysis measurements from the literature. Sensitivity analysis were performed and the most important elementary reactions were identified. Some rate constants were slightly adjusted to improve the predictivity of the model. The model is able to predict the species concentration profile of the main pyrolysis products. Although experimental data are scares, this automated kinetic generation approach, applied to energetic materials, seems to be highly promising.

Understanding reactivity of a triazole derivative and its interaction with graphene and doped/undoped-coronene—a DFT study

In the present study, 4-[(E)-(2-chorobenzylidene)amino]-3-(2-chlorobenzyl)-1H-1,2,4-triazole-5(4H)-thione (CAC) was characterized by spectroscopic investigations. The complete vibrational assignments of frequencies based on PED analysis was determined by DFT through ωB97X-D method with the level of 6-31g(d) basis and compared with experimental values. Recently nanocluster based drug delivery systems have become the most skilful to study. Interaction mechanism of CAC over coronene (G), doped CAC-G-X (X = B/N/P) and with graphene were investigated. Variations in chemical descriptors are also noted to understand sensing property of CAC molecule-nanoclusters. The analysis of different properties demonstrates enhancement effect which makes it significant in detecting CAC in other products. Molecular electrostatic potential energy surface was employed to investigate the most reactive sites. Besides to gain better insight on structural features, HOMO-LUMO band gap energy and other chemical parameters was obtained. The anticancer activity of CAC against various inhibitors for different protein targets (4AT9, 6NE5, 5ZBQ, and 3A43) was studied using molecular docking. Communicated by Ramaswamy H. Sarma

Feasibility of Ca12O12 Nanocluster in Lithium and Sodium Atom/Ion Batteries: DFT Study

DFT calculations at the B3LYP-D3/6-31G (d) level of theory was employed to study the possibility of the Ca12O12 nanocluster in Li and Na atom/ion batteries. For this reason, the interaction of Ca12O12 nanocluster with Li/Na atoms and Li+/Na+ cations was calculated. Based on results the adsorption energies for two Li+/Na+ cations are considerably higher than their corresponding atomic species. Eg value of Ca12O12 nanocluster slightly increases in adsorption of Li/Na atomic forms while it was narrowed as consequence of the cationic forms adsorption. The values obtained for the cell voltage of Li/Ca12O12 and Na/Ca12O12 were 1.82 and 2.49 V respectively which show that Ca12O12 may be appropriate for application in both lithium and sodium ion-batteries. Moreover, the cell voltage of Na@Ca12O12 is considerably high which shows that this nanocluster is highly beneficial for storage performance ion batteries.

Theoretical study of structural effects on reactivity and stability of isomeric pyrano-, thiopyrano-, and selenopyranopyrroles

In this study, global and local DFT reactivity descriptors for isomeric pyrano-, thiopyrano- and selenopyranopyrroles have been calculated. The geometric optimization of the obtained structures was realized with the density functional theory (DFT, B3LYP) at the level of 6-31G(d) and show these isomers have planar configurations. The structural properties such as dipole moments, bond lengths and bond angles of these isomers were calculated. The heats of formation have also been calculated based on the optimized geometry. The energies of HOMO and LUMO molecular orbitals are used to determine several global descriptors as a measure of their electronic properties, relative stabilities and chemical reactivities. These include total energy (E), ionization potential (I), electron affinity (A), chemical hardness (η), chemical softness (S), electronic chemical potentials (μ) and electrophilicity (ω). Selenopyrano[2,3-c]pyrrole possesses the highest electrophilicity and minimum chemical hardness among the calculated isomeric structures. The largest calculated dipole moment belongs to pyrano[3,2-b]pyrrole, while thiopyrano[3,4-b]pyrrole has the lowest.

Theoretical Prediction on a Novel Reduction-Responsive Nanoring Having a Disulfide Group for Facile Encapsulation and Release of Fullerenes C60 and C70

In this work, a novel reduction-responsive disulfide bond-containing cycloparaphenylene nanoring molecule (DSCPP) with a pyriform shape has been designed. In addition, the interactions between the designed nanoring (host) and fullerenes C60 and C70 (guests) were investigated theoretically at the M06-2X/6-31G(d,p) and M06-L/MIDI! levels of theory. By analyzing geometric characteristics and host–guest binding energies, it is revealed that the designed DSCPP is an ideal host molecule of guests C60 and C70. DSCPP presents excellent elastic deformation during the encapsulation of C60 and C70. The high binding energies suggest that both DSCPP⊃C60 and DSCPP⊃C70 (∼92 and 118 kJ·mol–1 at the M06-2X/6-31G(d,p) level of theory) are stable host–guest complexes, and the guest C70 is more strongly encapsulated than C60 in the gas phase. The thermodynamic information indicates that the formation of the two host–guest complexes is thermodynamically spontaneous. In addition, the frontier molecular orbital (FMO) features and intermolecular weak interaction region between DSCPP and fullerenes gusts are discussed to further understand the structures and properties of the DSCPP⊃fullerene systems. Finally, the ring-opening mechanism of the DSCPP under reduction conditions is investigated.

Asymmetric Spirocyclization Enabled by Iridium and Brønsted Acid-Catalyzed Formal Reductive Cycloaddition

A catalytic, enantioselective spirocyclization of formanilides or formylindolines and enamides has been developed herein. The reaction proceeds through a sequential iridium-catalyzed hydrosilylatio...

TD-DFT, NBO, AIM, RDG and Thermodynamic Studies of Interactions of 5-Fluorouracil Drug with Pristine and P-doped Al12N12 Nanocage

In the present study, the capability of the pristine and P-doped Al12N12 nanocage to deliver and detect of 5-Fluorouracil (5-FU) anticancer drug are investigated using the density functional theory (DFT) at the cam-B3LYP/6-31G(d, P) level of theory. The adsorption energy, thermodynamic parameters, natural bond orbital (NBO), atom in molecule theory (AIM), quantum parameters, reduced density gradient (RDG) and UV-visible spectrum for all selected models are calculated and results are analyzed. The values of adsorption energy (Eads) and thermodynamic parameters (ΔG and ΔH) for 5-FU@Al12N12 and 5-FU@Al12N11P complexes are negative and obtained results reveal that all adsorption processes are spontaneous and suitable to make a delivery of drug. The ΔΔG(sol) values of the all studied systems in the presence of water and ethanol solvent are positive and this property is favourable to shooting drug in biological system. The AIM, RDG, NBO calculated results indicate that the interaction between 5-FU drug and Al12N12 nanocage is weak covalent or strong electrostatic type. The bandgap energy of the 5-FU/Al12N12 nanocage complex alters slightly from original values, and so the pristine and P doped Al12N12 nanocage is not an excellent candidate for making a sensitive sensor for the 5-FU drug.