S2 Configuration Research Articles

Synthesis of 4-Amino-N-[2 (diethylamino)Ethyl]Benzamide Tetraphenylborate Ion-Associate Complex: Characterization, Antibacterial and Computational Study.

The 4-amino-N-[2 (diethylamino) ethyl] benzamide (procainamide)-tetraphenylborate complex was synthesized by reacting sodium tetraphenyl borate with 4-amino-N-[2 (diethylamino) ethyl] benzamide, chloride salt, and procainamide in deionized water at room temperature through an ion-associate reaction (green chemistry) at room temperature, and characterized by several physicochemical methods. The formation of ion-associate complex between bio-active molecules and/or organic molecules is crucial to comprehending the relationships between bioactive molecules and receptor interactions. The solid complex was characterized by infrared spectra, NMR, elemental analysis, and mass spectrometry, indicating the formation of ion-associate or ion-pair complex. The complex under study was examined for antibacterial activity. The ground state electronic characteristics of the S1 and S2 complex configurations were computed using the density functional theory (DFT) approach, using B3LYP level 6-311 G(d,p) basis sets. R2 = 0.9765 and 0.9556, respectively, indicate a strong correlation between the observed and theoretical 1H-NMR, and the relative error of vibrational frequencies for both configurations was acceptable, as well. HOMO and LUMO frontier molecular orbitals and molecular electrostatics using the optimized were used to obtain a potential map of the chemical. The n → π* UV absorption peak of the UV cutoff edge was detected for both configurations of the complex. Spectroscopic methods were structures used to characterize the structure (FT-IR and 1HNMR). In the ground state, DFT/B3LYP/6-311G(d,p) basis sets were used to determine the electrical and geometric properties of the S1 and S2 configurations of the title complex. Comparing the observed and calculated values for the S1 and S2 forms, the HOMO-LUMO energy gap of compounds was 3182 and 3231 eV, respectively. The small energy gap between HOMO and LUMO indicated that the compound was stable. In addition, the MEP reveals that positive potential sites were around the PR molecule, whereas negative potential sites were surrounding the TPB site of atoms. The UV absorption of both arrangements is comparable to the experimental UV spectrum.

Diffuse Basis Functions for Relativistic s and d Block Gaussian Basis Sets

Diffuse s, p, and d functions have been optimized for use with previously reported relativistic basis sets for the s and d blocks of the periodic table. The functions were optimized on the 4:1 weighted average of the s2 and p2 configurations of the anion, with the d shell in the dn+1 configuration for the d blocks. Exponents were extrapolated for groups 2 and 12, which have unstable or weakly bound anions. The diffuse basis sets have been tested by application to calculations of electron affinities of the group 11 elements (Cu, Ag, and Au), double electron affinities of the group 11 monocations, and potential energy curves of Mg2 and Ca2 van der Waals dimers, as well as some response properties of the group 1 anions (Rb-, Cs-, and Fr-), the group 2 elements (Sr, Ba, and Ra), and RbLi, CsLi, and FrLi molecules.

Horizon acoustics of the GHS black hole and the spectrum of AdS2

We uncover a novel structure in Einstein-Maxwell-dilaton gravity: an AdS2 × S2 solution in string frame, which can be obtained by a near-horizon limit of the extreme GHS black hole with dilaton coupling λ ≠ 1. Unlike the Bertotti-Robinson spacetime, our solution has independent length scales for the AdS2 and S2, with ratio controlled by λ. We solve the perturbation problem for this solution, finding the independently propagating towers of states in terms of superpositions of gravitons, photons, and dilatons and their associated effective potentials. These potentials describe modes obeying conformal quantum mechanics, with couplings that we compute, and can be recast as giving the spectrum of the effective masses of the modes. By dictating the conformal weights of boundary operators, this spectrum provides crucial data for any future construction of a holographic dual to these AdS2 × S2 configurations.

Relationship between the Atomic Structure and Electrochemistry. 1. Electric Force, Standard Reduction Potential E°, and Standard Reaction Gibbs Free Energy ΔG°.

The relationship among the standard reaction Gibbs free energy ΔG°, the standard reduction potential E°, and the atomic structure parameters of radius, nuclear charge, and isoelectronic orbitals nl is accomplished through the attraction electric force Felec. In relationship with E°, it was necessary to define two new reference scales: E0° with a final state of E° in the element, which allowed to have a parabolic trend of ΔG° versus Felec, and E°,0 whose final state is the ion with a more negative charge (e.g., −1, –2, −3). The relationship with ΔG° is related to the concept of chemical stability, and the relationship with E°,0 is more related to the concept of electronegativity. In relationship with ΔG°, it was necessary to predict the values of possible new cations and noncommon cations in order to find a better trend of ΔG° versus Felec, whose stability is analyzed by Frost diagrams of the isoelectronic series. This dependence of ΔG° on Felec is split into two terms. The first term indicates the behavior of the minimum of ΔG° for each isoelectronic orbital nl, while the second term deals with the parabolic trend of this orbital. For the minima of the configuration np6, a hysteresis behavior of the minima of ΔG° is found: an exponential behavior from periods 1 and 2 and a sigmoidal behavior from periods 5 and 4 to interpolate period 3. It is also found that the proximity of unfilled np or (n + 1)s orbitals induces instability of the ion in configurations ns2/nd2/4f2 and nd10/nd8(n + 1)s2, respectively. On the contrary, the stability of the orbitals np6 does not depend on the neighboring empty (n + 1)s0 orbitals. Both phenomena can be explained by the stability of the configuration of noble gas np6 and the nd10(n + 1)s2 configuration. We have also found that it is possible to increase the reduction potential E°,0 (macroscopic electronegativity), although the electric force Felec decreases because the orbital overlap influences the electronegativity.

Optimized Enhancement Effect of Sulfur in Fe-N-S Codoped Carbon Nanosheets for Efficient Oxygen Reduction Reaction.

The study on the design and preparation of oxygen reduction reaction (ORR) electrocatalysts with high efficiency is currently attracting great concern. Among different types of catalysts, heteroatom-doped carbon-based catalysts have exhibited promising potential, and the exploration of optimized matching of the doping elements is crucial to the design and fabrication of this category of catalysts. Herein, by annealing commercially available and cost-effective precursors, Fe-N-S codoped graphene-like carbon nanosheet catalysts were prepared. The atomically dispersed Fe atoms coordinated with the N atoms to form FeN4 sites as proved by X-ray absorption spectroscopy. By facile modulation of the relative amount of the precursors, the contents of thiophene-S (Th-S) and Fe-N4 sites could be tuned and a series of catalysts with different Th-S/Fe ratios were prepared. The doped sulfur exhibited an enhancement effect on ORR performance, and strikingly, the enhancement efficiency could be optimized by fine modulation of the Th-S/Fe ratio in the catalysts. Furthermore, it was found that when the Th-S/Fe ratio reached an optimal value of 1.8, the ORR performance was significantly boosted, especially in acidic media. The experimental data were supported by density functional theory calculation results, which indicated that the ORR overpotential of the S2(FeN4) configuration model (corresponding to the Th-S/Fe ratio of 2) was lower than that of S3(FeN4) and S1(FeN4). The optimized catalyst (denoted as FeN/SNC-900-3) displayed highly efficient ORR activity in both alkaline and acidic media. In alkaline media, the half-wave potential was 49 mV more positive than that of the commercial Pt/C catalyst, and in acidic media, the half-wave potential was close to that of Pt/C. Moreover, the stability of FeN/SNC-900-3 was outstanding, and the relative current density showed only a slight decay in both alkaline and acidic media after 40,000 s. A primary Zn-air battery with FeN/SNC-900-3 as the cathode catalyst exhibited a high peak power density of up to 153 mW cm-2 and superior cycling stability over 200 cycles.

NACA 4412 Kanadı Üzerinde Bir Emme Kanalı Tasarlanmasının Aerodinamik Etkileri

In this study, a wing is designed by using NACA 4412 profile and computational numerical analysis is discussed with suction method. First of all, the 3D wing is designed with the SolidWorks and the numerical study of this designed wing is carried out using ANSYS Fluent, a famous CFD (i.e. Computational Fluid Dynamics) software. It is based upon finite volume method approach. Two different configurations are used for numerical study. The first of these configurations is the S1, which represents the initial state of the wing; S2 refers to the wing design with suction channel. The straight flight angle of attack of the wing is 6 degree and the flow separations over the wing, which occurred in 25% of the wing chord length, are calculated at this angle of attack by the numerical study. At this point of chord length, a venturi channel is formed which initial point is the upper surface of the wing and throughout the inner part and finally meets with air from the trailing edge. The main purpose of this channel is to decrease the force at the place where the flow begins to deteriorate during the flight and to increase the aerodynamic performance. In order to be able to examine the change in aerodynamic performance, the lift and drag coefficient values on the wing are obtained in 10 angles of attack (i.e. -6, -4, -2, 0, 2, 4, 6, 8, 10, 12) separately for both configurations. These coefficients obtained for S1 and S2 configurations are compared with each other. In this numerical study based on the comparison results, it is found that there is a significant increase in the performance of S2 configuration compared to the S1 configuration.

Asymmetric covalence bonding between In 5s and O 2p states in ferroelectric InFeO3

The structural evolution, electronic and magnetic properties of the high-pressure nonpolar orthorhombic phase (orthorhombic, space group Pnma) and the LiNbO3-type (rhombohedral, space group R3c) InFeO3 have been explored via first-principles calculations. Furthermore, the ferroelectric properties of the LiNbO3-type phase have been revisited thoroughly. First of all, the nonpolar orthorhombic phase crystallized within Pnma space group was theoretically recognized. Secondly, the results reasonably reproduced the pressure-induced R3c →Pnma structural phase transition, which is in fair agreement with the experimental observation that the LiNbO3-type phase can be achieved from the decompression of the high pressure perovskite phase. In addition, the electric polarization for the non-centrosymmetric LiNbO3-type within the G-type antiferromagnetic ground state is evaluated to be 86.5 μC/cm2 by means of the Berry phase formula. More interestingly, in conjunction with the geometric factor, an additional mechanism behind the ferroelectric displacement is clarified as the strong chemical bonding between the In 5s and O 2p orbitals, i.e., the hidden tendency to create space for the unoccupied antibonding states, independent of whether the cation is an s0 or s2 configuration, and is manifested in terms of the analysis of Born effective charges, potential energy surfaces, charge density isosurfaces.

Photoluminescence of monovalent indium centres in phosphate glass

Valence control of polyvalent cations is important for functionalization of various kinds of materials. Indium oxides have been used in various applications, such as indium tin oxide in transparent electrical conduction films. However, although metastable In+ (5 s2 configuration) species exhibit photoluminescence (PL), they have attracted little attention. Valence control of In+ cations in these materials will be important for further functionalization. Here, we describe In+ species using PL and X-ray absorption fine structure (XAFS) analysis. Three absorption bands in the UV region are attributed to the In+ centre: two weak forbidden bands (1S0 → 3P1, 1S0 → 3P2) and a strong allowed band (1S0 → 1P1). The strongest PL excitation band cannot be attributed to the conventional allowed transition to the singlet excited state. Emission decay of the order of microseconds suggests that radiative relaxation occurs from the triplet excitation state. The XAFS analysis suggests that these In+ species have shorter In–O distances with lower coordination numbers than in In2O3. These results clearly demonstrate that In+ exists in a metastable amorphous network, which is the origin of the observed luminescent properties.

Electron transfer pathways from the S2-states to the S3-states either after a Ca2 +/Sr2 + or a Cl−/I− exchange in Photosystem II from Thermosynechococcus elongatus

The site for water oxidation in Photosystem II (PSII) goes through five sequential oxidation states (S0 to S4) before O2 is evolved. It consists of a Mn4CaO5-cluster close to a redox-active tyrosine residue (YZ). Cl− is also required for enzyme activity. By using EPR spectroscopy it has been shown that both Ca2+/Sr2+ exchange and Cl−/I− exchange perturb the proportions of centers showing high (S=5/2) and low spin (S=1/2) forms of the S2-state. The S3-state was also found to be heterogeneous with: i) a S=3 form that is detectable by EPR and not sensitive to near-infrared light; and ii) a form that is not EPR visible but in which Mn photochemistry occurs resulting in the formation of a (S2YZ)′ split EPR signal upon near-infrared illumination. In Sr/Cl-PSII, the high spin (S=5/2) form of S2 shows a marked heterogeneity with a g=4.3 form generated at low temperature that converts to a relaxed form at g=4.9 at higher temperatures. The high spin g=4.9 form can then progress to the EPR detectable form of S3 at temperatures as low as 180K whereas the low spin (S=1/2) S2-state can only advance to the S3 state at temperatures≥235K. Both of the two S2 configurations and the two S3 configurations are each shown to be in equilibrium at ≥235K but not at 198K. Since both S2 configurations are formed at 198K, they likely arise from two specific populations of S1. The existence of heterogeneous populations in S1, S2 and S3 states may be related to the structural flexibility associated with the positioning of the oxygen O5 within the cluster highlighted in computational approaches and which has been linked to substrate exchange. These data are discussed in the context of recent in silico studies of the electron transfer pathways between the S2-state(s) and the S3-state(s).

A large and complex structural polymorphism at 16p12.1 underlies microdeletion disease risk

There is a complex relationship between the evolution of segmental duplications and rearrangements associated with human disease. We performed a detailed analysis of one region on chromosome 16p12.1 associated with neurocognitive disease and identified one of the largest structural inconsistencies with the human reference assembly. Various genomic analyses show that all examined humans are homozygously inverted relative to the reference genome for a 1.1-Mbp region on 16p12.1. We determined that this assembly discrepancy stems from two common structural configurations with worldwide frequencies of 17.6% (S1) and 82.4% (S2). This polymorphism arose from the rapid integration of segmental duplications, precipitating two local inversions within the human lineage over the last 10 million years. The two human haplotypes differ by 333 kbp of additional duplicated sequence present in S2 but not in S1. Importantly, we show that the S2 configuration harbors directly oriented duplications specifically predisposing this chromosome to disease rearrangement.

CLUSTER AND SHELL STRUCTURES IN THE FERMIONIC MOLECULAR DYNAMICS APPROACH

Nuclei in the p- and sd-shell are studied within the Fermionic Molecular Dynamics (FMD) model that uses Gaussian wave packets as single-particle states. Intrinsic many-body basis states are given by Slater determinants which have to be projected on parity, angular momentum and total linear momentum to restore the symmetries of the Hamiltonian. The flexibility of the Gaussian basis allows to economically describe states with shell structures as well as states featuring clustering or halos. The same effective interaction derived from the realistic Argonne V18 interaction in the Unitary Correlation Operator Method (UCOM) framework is used for all nuclei. We discuss the spectrum of 12 C with a special emphasis on the structure of the first excited 0+ state, the famous Hoyle state. In the FMD approach the Hoyle state is found to be dominated by dilute α-cluster configurations. Recent measurements of the charge radii of Neon isotopes show an intriguing behaviour. This can be explained in FMD calculations by a structure change from 17 Ne and 18 Ne which can be essentially considered as an 15 O or 16 O core plus two protons in s2 or d2 configurations, respectively. For the heavier isotopes we find that the admixture of 3 He and 4 He cluster configurations in the ground states leads to much larger charge radii than obtained in a mean-field calculation.

Photoluminescence in the UV–VIS region of polyvalent ions in glasses

Photoluminescence in the ultraviolet and visible region is a very sensitive analytical method and also an important optical property of glasses which depends strongly on active centers, surrounding host glass composition and their interactions. Fluoride, phosphate, and silicate glasses doped with active luminescent ions of different electronic configurations were investigated. Ions with s2 configuration, Sn2+, Pb2+, Sb3+, absorb strongly in the ultraviolet and yield broad emission bands in the ultraviolet and blue spectral area. Mn2+ ions (3d5) provide broad red emission in fluoride and phosphates due to octahedral coordination, and green emission in silicates by tetrahedral coordination, with long lifetime. Rare earth ions with 4fn configuration show a lot of sharp excitation and emission bands. Red emission is given by Sm3+ (4f5) and Eu3+ (4f6) ions in all glasses investigated. Yellow emission of Eu2+ (4f7) was detected in fluorides. Efficient green emission was obtained with Ho3+ (4f10) and Er3+ (4f11) especially in fluoride hosts.

The Role of the S1 State of Carotenoids in Photosynthetic Energy Transfer: The Light-Harvesting Complex II of Purple Bacteria

Using time-dependent density functional theory (TDDFT), we obtained the excitation energy transfer coupling (Coulombic coupling) between the S1 state of rhodopin glucoside (RG) and the Qy state of bacteriochlorophylls (BChl) in the light-harvesting complex II (LH2) of purple photosynthetic bacterium Rhodopseudomonas (Rps.) acidophila. Our results suggest that the small mixing of S2 character arising from symmetry-breaking of the carotenoid plays an important role in the Coulombic coupling. As a result the carotenoid (car) S1 couplings to chlorophylls are similar to a set of scaled down Car(S2)−BChl(Qy) couplings. We also report results for 6,10,15,19-tetramethyl-2-cis-4,6,8,10,12,14,16,18,20-all trans-22-cis-tetracosaundecaene, the polyene backbone of RG with six methyl groups attached, in two different structures: an optimized planar structure and the crystal structure of RG with hydrogen atoms replacing the two end groups, which is distorted from its planar structure. The mixing of S2 configuration is ...

Development of Photocatalyst Materials for Water Splitting with the Aim at Photon Energy Conversion.

A photocatalyst which has extensively been studied so far is TiO2 with a 3.0-3.2eV band gap. Well-known photocatalysts with visible-light response are only Pt/CdS and WO3. Thus, photocatalyst materials mainly employed have been so limited. In such a background, new photocatalysts with high activity have recently been developed. Alkali and alkaline earth tantalates have arisen as a new group of photocatalyst materials for water splitting into H2 and O2 under ultra-violet light irradiation. They showed the activities even without co-catalysts such as Pt, being different from titanate photocatalysts. When NiO co-catalysts were loaded on tantalate photocatalysts, except for LiTaO3, the photocatalytic activities were drastically increased. Among the tantalates, NiO/NaTaO3 showed the highest activity. Moreover, the activity of NiO/NaTaO3 was improved by La-doping. On the other hand, highly crystalline BiVO4 powders with scheelite (monoclinic) and zircon type (tetragonal) structure were selectively synthesized by an aqueous process. The BiVO4 powder with the scheelite structure showed a high photocatalytic activity for O2 evolution in the presence of sacrificial reagent (Ag+) under visible light irradiation (λ>420nm). The photocatalytic activity of the BiVO4 powder prepared by the aqueous process was much higher than that of BiVO4 prepared by a conventional solid state reaction. Zn0.957Cu0.043S (band gap: 2.5eV) and Zn0.999Ni0.001S (band gap: 2.3eV) photocatalysts showed high activities for H2 evolution from an aqueous K2SO3 and Na2S solution under visible light irradiation without co-catalysts such as Pt. ZnNb2O6, Bi2W2O9, Bi2WO6, and Bi3TiNbO9 consisting of ions with d10 and s2 configuration were also active for H2 or O2 evolution from aqueous solutions containing sacrificial reagents.

Sobre a aplicabilidade da termogravimetria para a estimativa de parâmetros termoquímicos de compostos de coordenação: os elementos lantanídicos

By using thermochemical data reported for a series of chelates of the type [Ln(thd)3], thd = 2, 2, 6, 6 ­ tetramethyl- 3,5-heptanedione and Ln = La, Pr, Nd, Sm, Gd, Tb, Ho, Er, Tm and Yb, empirical correlations were found involving thermochemical parameters (e.g. dissociation enthalpy) and the thermodynamic temperatures of the beginning of thermal degradation of the chelates, ti. It is shown that ti values are of capital importance in the study of this all class of coordination compounds. Among others, the empirical equation is obtained: r3+ = (-0,013.Z + 1,36)/0,005, that relates the lanthanide cation radius (pm) with the atomic number of the element. The remarkable fact is that this equation is achieved by using thermogravimetric and calorimetric parameters. Is also shown that ti values are related with the P(M) function values, which are very close related with the energy difference, DE, between the lowest electronic energy level of the fns2d1 configuration and the lowest energy level of the fn+1s2 configuration in the neutral gaseous atoms.

Effect of pacing site on ventricular fibrillation initiation by shocks during the vulnerable period.

The critical point hypothesis for the upper limit of vulnerability (ULV) states that the site of S1 pacing should not affect the ULV S2 shock strength for a single S2 shock electrode configuration but may affect the S1-S2 interval at which sub-ULV shocks induce ventricular fibrillation (VF). Furthermore, early post-S2 activations leading to VF should arise in areas with low potential gradients of similar magnitude, regardless of the S1 site. This hypothesis was tested in 10 pigs by determining ULVs for three S1 sites [left ventricular apex (LVA), LV base (LVB), and right ventricular outflow tract (RVOT)] with one S2 configuration (LVA patch to superior vena cava catheter). T-wave scanning was performed with biphasic S2 shocks incremented from 60 V in 40-V steps and stepped up or down in 20- and 10-V steps. Activations and S2 potential gradients were recorded at 528 epicardial sites. Although shocks just below the ULV induced VF significantly earlier in the T wave when the S1 site was the RVOT than when it was the LVA or LVB, ULVs were not significantly different for the three S1 pacing sites. Early post-S2 activations arose closer to the S2 electrode for weak S2s but moved to distant low potential gradient areas as the S2 strengthened. Just below the ULV, early post-S2 activations arose in the RVOT when the S1 site was the LVA or LVB but arose along the RV base when the S1 site was the RVOT. Early site potential gradients were not significantly different just below the ULV (LVA: 8.2 +/- 4.1 V/cm; LVB: 8.6 +/- 4. 9 V/cm; RVOT: 8.7 +/- 4.4 V/cm). At the ULV, early post-S2 activations arose from the same areas but did not induce VF. The results support the critical point hypothesis for the ULV. For this S2 configuration, no single point in the T wave could be used to determine the ULV for all S1 sites.

The missing fluorescence of s-trans butadiene

Geometry of the S0 and S1 states of s-trans butadiene is optimized and the corresponding force fields calculated using a multiconfiguration self-consistent field (MCSCF) method in the complete active space formulation. Three stable conformations of the S1(2Ag) state are shown to be nonplanar (S2, C2, and C1 symmetry), quasidegenerate and separated by a barrier along torsional coordinates of ca. 1600 cm−1. The planar C2h conformation forms a transition state between the S2 and C2 configurations. It is shown by model calculations that the out-of-plane deformation of the S1 state increases dramatically its rate of internal conversion to the ground state. Thus, although the energy gap for the transition is larger in butadiene than that in octatetraene, the internal conversion S1uS0 is estimated to be 3–5 orders of magnitude faster in butadiene. Fast internal conversion in this molecule explains its lack of fluorescence.

Use of the virial theorem in the calculation of wavefunctions for helium autoionising states

The virial theorem is used as a supplementary constraint, in conjunction with a normal variational principal, in order to obtain wavefunctions for the (2s2)1S, (2p2)1S, (2p2)1D, (2s, 2p)1P and (2s,2p)3P autoionising states of helium. Good energies are obtained, except for the 1D state. The angular-correlation properties of the wavefunctions are compared with those of Lipsky-Conneely type functions (1977) and the effect of the mixing of the s2 and p2 configurations in investigated for the 1S states. A comparison is made of the resonance widths calculated using various approximations for the degenerate continua and matrix elements of either the Hamiltonian H or the operator (PHQ+QHP). A compact and relatively simple expansion basis is used in order to simplify subsequent collision calculations. This does not allow mixing with higher autoionising states to be taken into account; this affects the correlation properties of the 1P and 3P states and the width of the (2p2)1S state.

Arene Complexes of Univalent Gallium, Indium, and Thallium

AbstractArene complexes of main‐group metals were, until recently, rare species—in contrast to the now classical, analogous complexes of transition metals. In systematic investigations, it has been possible to prepare and structurally characterize arene complexes of the univalent elements gallium, indium, and thallium, which directly follow the d‐block elements in the periodic table. This new type of compound is characterized by centric (η6) coordination of the metal to the arene; both mono‐ and bis(arene) complexes are known. The interaction can be explained by the perfect agreement between the HOMO/LUMO symmetry of the arene and of the low‐valent metal. The electronic states of the nd10(n + 1)s2 configuration, which are partially modified by relativistic effects, play a particularly important role. The relationship to the few known complexes of the neighboring elements (SnII, PbII) becomes plausible via the isoelectronic principle. The arene/GaI, InI, TlI systems are of potential significance as homogeneous reducing agents and as agents for the activation of aromatic compounds, the purification of metals, and the separation of metals from nonaqueous media.

Influence of crystal structure on the luminescence of ions with s2 configuration

It is shown that the Stokes shift and thermal quenching temperature of the luminescence of Pb 2+ and Bi 3+ depend strongly on the stiffness of the host lattice, as is to be expected from the configurational coordinate diagram.