Theoretical Rationalization Research Articles

Iron(iii) bis(pyrazol-1-yl)acetate based decanuclear metallacycles: synthesis, structure, magnetic properties and DFT calculations.

The synthesis, structural aspects, magnetic interpretation and theoretical rationalizations for a new member of the ferric wheel family, a decanuclear iron(iii) complex with the formula [Fe10(bdtbpza)10(μ2-OCH3)20] (1), featuring the N,N,O tridentate bis(3,5-di-tert-butylpyrazol-1-yl)acetate ligand, are reported. The influence of the steric effect on both the core geometry and coordination mode is observed. Temperature dependent (2.0-300 K range) magnetic susceptibility studies carried out on complexes 1 established unequivocally antiferromagnetic (AF) interactions between high-spin iron(iii) centers (S = 5/2), leading to a ground state S = 0. The mechanism of AF intramolecular coupling was proved using a broken-symmetry approach within the density functional method at the B3LYP/def2-TZVP(-f)/def2-SVP level of theory.

Theoretical rationalisation for the mechanism of N-heterocyclic carbene-halide reductive elimination at Cu(III), Ag(III) and Au(III).

Reductive elimination of imidazolium salts from Cu(III) is extremely sensitive to the anionic ligand (X or Y) type on Cu (e.g.ΔG(‡) ranges from 4.7 kcal mol(-1) to 31.8 kcal mol(-1), from chloride to benzyl). Weakly σ-donating ligands dramatically accelerate reductive elimination. Comparison with Ag/Au shows that the HOMO energy, strength of M-NHC and M-Y bonds and inherent stability of M(III) with respect to M(I) are critical to governing reaction feasibility.

Specific Reagent for Cr(III): Imaging Cellular Uptake of Cr(III) in Hct116 Cells and Theoretical Rationalization.

A new rhodamine-based reagent (L1), trapped inside the micellar structure of biologically benign Triton-X 100, could be used for specific recognition of Cr(III) in aqueous buffer medium having physiological pH. This visible light excitable reagent on selective binding to Cr(III) resulted in a strong fluorescence turn-on response with a maximum at ∼583 nm and tail of that luminescence band extended until 650 nm, an optical response that is desired for avoiding the cellular autofluorescence. Interference studies confirm that other metal ions do not interfere with the detection process of Cr(III) in aqueous buffer medium having pH 7.2. To examine the nature of binding of Cr(III) to L1, various spectroscopic studies are performed with the model reagent L2, which tend to support Cr(III)-η(2)-olefin π-interactions involving two olefin bonds in molecular probe L1. Computational studies are also performed with another model reagent LM to examine the possibility of such Cr(III)-η(2)-olefin π-interactions. Presumably, polar functional groups of the model reagent LM upon coordination to the Cr(III) center effectively reduce the formal charge on the metal ion and this is further substantiated by results of the theoretical studies. This assembly is found to be cell membrane permeable and shows insignificant toxicity toward live colon cancer cells (Hct116). Confocal laser scanning microscopic studies further revealed that the reagent L1 could be used as an imaging reagent for detection of cellular uptake of Cr(III) in pure aqueous buffer medium by Hct116 cells. Examples of a specific reagent for paramagnetic Cr(III) with luminescence ON response are scanty in the contemporary literature. This ligand design helped us in achieving the turn on response by utilizing the conversion from spirolactam to an acyclic xanthene form on coordination to Cr(III).

Coupling of Caged Molecule Dynamics to JG β-Relaxation III: van der Waals Glasses.

In the first two papers separately on the polyalcohols and amorphous polymers of this series, we demonstrated that the fast dynamics observed in the glassy state at high frequencies above circa 1 GHz is the caged dynamics. We showed generally the intensity of the fast caged dynamics changes temperature dependence at a temperature THF nearly coincident with the secondary glass transition temperature Tgβ lower than the nominal glass transition temperature Tgα. The phenomenon is remarkable, since THF is determined from measurements of fast caged dynamics at short time scales typically in the ns to ps range, while Tgβ characterizes the secondary glass transition at which the Johari-Goldstein (JG) β-relaxation time τJG reaches a long time of ∼10(3) s, determined directly either by positronium annihilation lifetime spectroscopy, calorimetry, or low frequency dielectric and mechanical relaxation spectroscopy. The existence of the secondary glass transition originates from the dependence of τJG on density, previously proven by experiments performed at elevated pressure. The fact that THF ≈ Tgβ reflects the density dependence of the caged dynamics and coupling to the JG β-relaxation. The generality of the phenomenon and its theoretical rationalization implies the same should be observable in other classes of glass-formers. In this paper, III, we consider two archetypal small molecular van der Waals glass-formers, ortho-terphenyl and toluene. The experimental data show the same phenomenon. The present paper extends the generality of the phenomenon and explanation from the polyalcohols, a pharmaceutical, and many polymers to the small molecular van der Waals glass-formers.

Propaganda, ideology, and democracy: A review of Jason Stanley, How Propaganda Works

Propaganda, ideology, and democracy: A review of Jason Stanley, <i>How Propaganda Works</i>

Theoretical Rationalization of the Emission Properties of Prototypical Cu(I)-Phenanthroline Complexes.

The excited state properties of transition metal complexes have become a central focus of research owing to a wide range of possible applications that seek to exploit their luminescence properties. Herein, we use density functional theory (DFT), time-dependent DFT (TDDFT), classical and quantum mechanics/molecular mechanics (QM/MM) molecular dynamics (MD) simulations to provide a full understanding on the role of the geometric and electronic structure, spin-orbit coupling, singlet-triplet gap and the solvent environment on the emission properties of nine prototypical copper(I)-phenanthroline complexes. Our calculations reveal clear trends in the electronic properties that are strongly correlated to the luminescence properties, allowing us to rationalize the role of specific structural modifications. The MD simulations show, in agreement with recent experimental observations, that the lifetime shortening of the excited triplet state in donor solvents (acetonitrile) is not due to the formation of an exciplex. Instead, the solute-solvent interaction is transient and arises from solvent structures that are similar to the ones already present in the ground state. These results based on a subset of the prototypical mononuclear Cu(I) complexes shed general insight into these complexes that may be exploited for development of mononuclear Cu(I) complexes for applications as, for example, emitters in third generation OLEDs.

Regional Practice of Developing Road Safety Behavior Competency in Future Specialists

Road safety – is one of the principal needs of the person, and to ensure it, the person must view himself as a subject thereof. Thus every person needs to have a developed ability to distinguish and prevent threats, and ensure personal safety when on the road. Training future specialists, capable of teaching road safety behavior to various age-groups of population is becoming one of the most important objectives of professional pedagogy. So the scientific novelty of the article is in: theoretical rationalization of the road safety behavior competence development process in the future specialists that reflects cognitive, disposition and asseptive personality characteristics; a designed model of regional system for ensuring road safety behavior based on participation, continuity, clustering, productivity, personification, prevention principles that covers all social and age-groups of population and directed at establishing a unified regional road safety behavior information and technology environment. Materials of the research can be used for improving educational courses for training future specialists in the field of

When is rational to order a diagnostic test, or prescribe treatment: the threshold model as an explanation of practice variation.

The threshold model represents an important advance in the field of medical decision-making. It is a linchpin between evidence (which exists on the continuum of credibility) and decision-making (which is a categorical exercise - we decide to act or not act). The threshold concept is closely related to the question of rational decision-making. When should the physician act, that is order a diagnostic test, or prescribe treatment? The threshold model embodies the decision theoretic rationality that says the most rational decision is to prescribe treatment when the expected treatment benefit outweighs its expected harms. However, the well-documented large variation in the way physicians order diagnostic tests or decide to administer treatments is consistent with a notion that physicians' individual action thresholds vary. We present a narrative review summarizing the existing literature on physicians' use of a threshold strategy for decision-making. We found that the observed variation in decision action thresholds is partially due to the way people integrate benefits and harms. That is, explanation of variation in clinical practice can be reduced to a consideration of thresholds. Limited evidence suggests that non-expected utility threshold (non-EUT) models, such as regret-based and dual-processing models, may explain current medical practice better. However, inclusion of costs and recognition of risk attitudes towards uncertain treatment effects and comorbidities may improve the explanatory and predictive value of the EUT-based threshold models. The decision when to act is closely related to the question of rational choice. We conclude that the medical community has not yet fully defined criteria for rational clinical decision-making. The traditional notion of rationality rooted in EUT may need to be supplemented by reflective rationality, which strives to integrate all aspects of medical practice - medical, humanistic and socio-economic - within a coherent reasoning system.

Absorbate-induced piezochromism in a porous molecular crystal.

Atmospherically stable porous frameworks and materials are interesting for heterogeneous solid–gas applications. One motivation is the direct and selective uptake of pollutant/hazardous gases, where the material produces a measurable response in the presence of the analyte. In this report, we present a combined experimental and theoretical rationalization for the piezochromic response of a robust and porous molecular crystal built from an extensively fluorinated trispyrazole. The electronic response of the material is directly determined by analyte uptake, which provokes a subtle lattice contraction and an observable bathochromic shift in the optical absorption onset. Selectivity for fluorinated absorbates is demonstrated, and toluene is also found to crystallize within the pore. Furthermore, we demonstrate the application of electronic structure calculations to predict a physicochemical response, providing the foundations for the design of electronically tunable porous solids with the chemical properties required for development of novel gas-uptake media.

Fully conjugated push-pull dendrons with high dipole moments in excited state; synthesis and theoretical rationalization

Novel fully conjugated push–pull dendrons were synthesized by a divergent approach to evaluate the performance of non-conventional architectures like dendritic one in charge separation processes associated with photovoltaic events. The dipole moments in excited state were estimated by the solvatochromic method, to be related to the charge separation efficiency. A 1:2 ratio of donor–acceptor groups (methoxy and nitro groups respectively) promotes the largest dipole moment in both ground and excited state (up to 17 D), due to the efficient electron density transfer over the entire molecule, through the π-electron system. The synthesized dendrons induce charge transfer on excitation as follows from UV–vis absorption–emission analysis and theoretical calculations. Copyright © 2015 John Wiley & Sons, Ltd.

A ligand field theory-based methodology for the characterization of the Eu2+ [Xe]4f65d1 excited states in solid state compounds

The theoretical rationalization of the open-shell 4f and 5d configuration of Eu2+ is by far not trivial because it involves a non-standard version of ligand field theory, based on a two-shell Hamiltonian. Here we present our methodology based on ligand field theory, taking the system CsCaBr3:Eu2+ as a case study with an octahedral coordination sphere of Eu2+. The ligand field, interelectronic and spin-orbit coupling parameters are deduced from experimental data. The assignment of the transitions to the corresponding irreducible representations of the double group was performed together with the intensity modelling resulting in an excellent match to the experimental spectra.

Active site engineering in UiO-66 type metal–organic frameworks by intentional creation of defects: a theoretical rationalization

The catalytic activity of the Zr-benzenedicarboxylate (Zr-BDC) UiO-66 increases by using synthesis modulators as trifluoroacetate (TFA) or hydrochloric acid (HCl), which can be removed post-synthetically.

Theoretical rationalization of the singlet-triplet gap in OLEDs materials: impact of charge-transfer character.

New materials for OLED applications with low singlet-triplet energy splitting have been recently synthesized in order to allow for the conversion of triplet into singlet excitons (emitting light) via a Thermally Activated Delayed Fluorescence (TADF) process, which involves excited-states with a non-negligible amount of Charge-Transfer (CT). The accurate modeling of these states with Time-Dependent Density Functional Theory (TD-DFT), the most used method so far because of the favorable trade-off between accuracy and computational cost, is however particularly challenging. We carefully address this issue here by considering materials with small (high) singlet-triplet gap acting as emitter (host) in OLEDs and by comparing the accuracy of TD-DFT and the corresponding Tamm-Dancoff Approximation (TDA), which is found to greatly reduce error bars with respect to experiments thanks to better estimates for the lowest singlet-triplet transition. Finally, we quantitatively correlate the singlet-triplet splitting values with the extent of CT, using for it a simple metric extracted from calculations with double-hybrid functionals, that might be applied in further molecular engineering studies.

The Narrative of Ricoeur’s Time and Narrative

This paper tackles two problems. The first is impossibility of direct application of ideas in Paul Ricoeur's book Time Narrative (hereafter referred to as TN or cited by volume page number) to literary studies. Ricoeur's work cannot be used for literary purposes without rethinking it. However, I limit myself in pointing out necessity of this task without undertaking it. (1) The second problem--which is central for this paper--focuses on some peculiarities of of TN. My main point is that, by means of attenuating its end, making its beginning ambiguous, expanding its middle, TN resists systematic tendencies of hermeneutic type of philosophizing thus, in postmodern era, evades pitfalls of constituting consciousness which masters all meaning. In formulating this problem, I take over try to elaborate in narratological direction Ricoeur's rethinking of Hegel's Reason in History. Ricoeur's critique of Hegel, as we will see, sets possibility for such development ajar without, however, exploring it. What intertwines two problems of essay is fact that they both arise from literary reading of philosophical work that, among many other things, deals with literary issues. TIME AND NARRATIVE AND LITERARY SCHOLARSHIP The first question that literary scholar faces while reading TN is asymmetrical meaning of seemingly symmetrical title of book. The conjunction and in Time Narrative (in original, Temps et recit) does not entwine together two equal notions such as (temps) narrative (recit) but rather suggests direction from which Ricoeur enters his project. In this methodological sense, and (et) stands for logical connector that means therefore: time, therefore In order to explain this formula is necessary to clarify two major sets of notions in book their relation. The first conceptual field in TN tackles issue of threefold mimesis, whereas second deals with relation between time narrative. 1. 1. The threefold mimesis--[mimesis.sub.1], [mimesis.sub.2], [mimesis.sub.3]--is universalization of Aristotle's mimesis in Poetics. It is notion that is applicable not solely to tragic plots, as in Aristotle, but to whole province especially to its two major branches comprising primary interest of Ricoeur: fictional historical narrative. Two basic notions are equivalent in terms of in Aristotle--mimesis or representation of action muthos or organization of events (1: 37). Muthos mimesis are operations, not structures, bear mark of production dynamism. In production of plots activity is primal with regard to any static structures (1: 33). Aristotle's poetics is art of composing plots. The operative dynamic character of Aristotle's mimesis is springboard for Ricoeur's reading of Poetics, opens possibility of elaborating on threefold mimesis as phenomenological version of what Poetics contains as seed. What is driving force of this elaboration? Explicitly, Poetics is work only about art of composition. Implicitly also refers to what precedes what follows act of emplotment. The former is realm of practical as opposed to theoretical rationalization. The latter is field where world of work world of receiver overlap start interacting. The threefold mimesis consists, first, of [mimesis.sub.1] or prefiguration; this is world of action. Following Heidegger, Ricoeur's main idea is that living practice precedes narratives: the 'happens to' someone before anyone tells it (1: 75). Ricoeur writes about existential analysis of human beings as 'entangled in stories' (1: 75) invents set of synonyms such as a prenarrative quality of experience, (as yet) untold stories, a potential story, an untold story (1: 74). …

Synthesis of 4,4-diphenyl-3,4-dihydro-2H-1,4-thiasiline

4,4-Diphenyl-3,4-dihydro-2H-1,4-thiasiline (3) was synthesized starting from diphenyl(divinyl)silane by a sequence of reactions including free-radical thiylation with thioacetic acid, reduction of thioacetate to thiol, heterocyclization of the latter, oxidation and the Pummerer rearrangement of the cyclic sulfoxide to the unsaturated cyclic organosilicon sulfide. Although compound 3 is hydrolytically more stable than its Si-dimethylated analogue, both compounds are hydrolyzed to the corresponding siloxanes with the cleavage of the Si‒ Csp2 rather than the Si‒ Csp3 bond. A theoretical rationalization for this is given.

Hydrogen Bonding Interaction between Active Methylene Hydrogen Atoms and an Anion as a Binding Motif for Anion Recognition: Experimental Studies and Theoretical Rationalization

Two new reagents, having similar spatial arrangements for hydrogen atoms of the active methylene functionalities, were synthesized and interactions of such reagents with different anionic analytes were studied using electronic spectroscopy as well as by using (1)H and (31)P NMR spectroscopic methods. Experimental studies revealed that these two reagents showed preference for binding to F(-) and OAc(-). Detailed theoretical studies along with the above-mentioned spectroscopic studies were carried out to understand the contribution of the positively charged phosphonium ion, along with methylene functionality, in achieving the observed preference of these two receptors for binding to F(-) and OAc(-). Observed differences in the binding affinities of these two reagents toward fluoride and acetate ions also reflected the role of acidity of such methylene hydrogen atoms in controlling the efficiencies of the hydrogen bonding in anion-Hmethylene interactions. Hydrogen bonding interactions at lower concentrations of these two anionic analytes and deprotonation equilibrium at higher concentration were observed with associated electronic spectral changes as well as visually detectable change in solution color, an observation that is generally common for other strong hydrogen bond donor functionalities like urea and thiourea. DFT calculations performed with the M06/6-31+G**//M05-2X/6-31G* level of theory showed that F(-) binds more strongly than OAc(-) with the reagent molecules. The deprotonation of methylene hydrogen atom of receptors with F(-) ion was observed computationally. The metal complex as reagent showed even stronger binding energies with these analytes, which corroborated the experimental results.

Diphosphonylation of Aromatic Diazaheterocycles and Theoretical Rationalization of Product Yields

Diphosphonylation of Aromatic Diazaheterocycles and Theoretical Rationalization of Product Yields

Virtual Logos – An Inclusive(ly) Political Alternative

Abstract The study raises the problem of rendering logos secondary in our virtual times. This statement is described by the investigation of the consequence that virtual logos recalibrates the relation logos-mentality-knowledge through conceptual digressions and translations, as well as through re-description. Within this context, the working hypothesis of the paper is that virtual logos bears the hallmarks of a cultural and political de-legitimating model. The purpose of this study is to verify the hypothesis reinterpreting the classical distinctions (such as practical rationality vs. theoretical rationality, understanding vs. explanation) and then validating the identified referential instances or manifestations of logos on the political sphere. The paper accepts the status of language as an institutional mode and code, gliding on various formulae for the logos user (of a postmodern nature). The methods, the findings and the results of the study describe a puzzle, a table of relating to different manners of conceptualization, a portrait of the appeal of virtual logos to the exteriorization of the stakes of narrative knowledge. In this approach, the authors are aware of the double legitimating of science, where technology becomes a contending factor in relation to knowledge, maintaining the subordination in front of virtual power. As a piece in this puzzle, the authors also use the technique of interconnections, capitalizing on Lyotard's affirmation that the new technologies are vulnerable to piracy. This effect of novelty can be also found in the reactions of the third German political force – the Pirate Party – with effect in the legitimacy of protection for on-line software (protecting and maybe stimulating citizens’ participation), reaction to the prospect of mere minimal democracy, symptom of the current post-industrial democracy. The conclusions and recommendations of the paper indicate, first, the virtual as a diminished model of politics, even more deprived of authenticity and maybe even more cynical. Second, at the same time, the paper shall emphasize that in this Age of Less (impoverished and codified communication, highly codified human relations, less human interaction), the realm of the virtual remains, nevertheless, both culturally and politically, a hope for increased citizen participation, as an alternative to the predicable failure of the technocrats and as counterweight to the disappointment with representative democracy.

Bulgakovʼs The Master and Margarita and the Illusions of Kantʼs Speculative Reason

Philosophical concepts are traditionally used to explain and analyse literary texts. This article tries to investigate the opposite dependency. Namely, how literary texts and characters could illustrate certain philosophical concepts while re-interpreting, extending and changing their original meaning. In Kantʼs context speculative (theoretical) rationality operates within strict limits: the visible tangible nature. Speculative reason may dream of overstepping the borders of nature and reaching for the invisible realm of ideas. However, for Kant, such tendencies lead to illusions and distortion of the proper working of human rationality. The extremes of speculative reason, i.e. this reasonʼs hubris, and its dreams, which are unlikely to be realized, have their illustration in the strange supernatural reality described in Bulgakovʼs novel. This article interprets Satanʼs actions in Moscow as a direct depiction of what Kant considered to be impossible: the unity of sensible nature and ideas under the rule of speculative reason.

Risk Assessment of Relay Protection Setting Value in Power Plant

Power plant relay protection setting value of the hidden harm causes of relay protection device is not correct, safe and stable operation of the power plant. In this paper, from the angle of the safe operation of power plant, the hidden danger to plant with the protection setting is studied and then the risk evaluation method of power plant relay protection setting values of hidden trouble is proposed. From the power plant relay protection setting value considering two aspects of probability and consequences of potential outbreak of different values, value potential risk is considered, and of a certain power plant in Hubei was made the risk assessment and analysis, in order to verify the theoretical rationality and accuracy.