Disappearance of Odd-Even Effects at the Substrate Interface of -Alkanes.

The physical and chemical properties of organic compounds having alkyl chains are frequently influenced by the parity of the chain length, which is known as the odd-even effect. Understanding the molecular origin of this phenomenon is particularly important for designing materials used in organic thin-film devices. In this work, we focus on thin films of -alkanes as the simplest model to study the odd-even effect at the substrate interface and analyze the aggregation structure using p-polarized multiple-angle incidence resolution spectrometry in combination with grazing incidence X-ray diffraction.

Reactivity and Product Selectivity of Fluoroalkyl Carbonates in Substitution Reactions with Primary Alcohols and Amines.

The present study reports a systematic investigation of the substitution reactions of a series of symmetric and unsymmetric fluoroalkyl carbonates with primary alcohols or amines. The reactivity of the haloalkyl carbonate depends mainly on the electrophilicity and steric crowdedness of the carbonyl group and the leaving ability of the haloalkyl alcohols. Diethyl carbonate as a reference substrate showed no reaction with the alcohol or amine.

Stereoisomer-dependent conversion of dinaphthothienothiophene precursor films.

Soluble precursor materials of organic semiconductors are employed for fabricating solution-processable thin film devices. While the so-called precursor approach has already been tried for various organic electronic devices such as transistors and solar cells, understanding of the conversion process in the film lags far behind. Here, we report that molecular aggregation of the precursor compound significantly influences the thermal conversion reaction in the film.

DFT Study of α-Keggin-type Iso-polyoxotungstate Anions [HWO] ( =1-4): Can [HWO] Exist?

The Keggin-type iso-polyoxotungstate (iso-POT) anions [HWO] 's, in which their central vacancies are occupied by protons, are attractive materials. It is of importance to reveal if the vacancies can be fully occupied by four protons. For further understanding the speciation of these iso-POT anions, relative stabilities and proton transfer reactions between H[HWO] and [HWO] were examined in detail by using the first-principles calculations (the nudged elastic band method, the synchronous transit-guided quasi-Newton method, the intrinsic reaction coordinate method, and frequency analysis calculations).

Spin-Crossover-Triggered Linkage Isomerization by the Pedal-like Motion of the Azobenzene Ligand in a Neutral Heteroleptic Iron(III) Complex.

The temperature dependence of magnetic susceptibility of [Fe(azp)(qsal-Me)]·0.5CHOH [Hqsal-Me = 5-methyl--(8-quinoyl)salicylaldimine, Hazp = 2,2'-azobisphenol] demonstrated that the spin-crossover (SCO) transition behavior changed from an abrupt transition to consecutive gradual conversions, and moreover, the initial abrupt transition was recovered, keeping the complex at room temperature. The variable-temperature crystal structures revealed that an SCO-triggered linkage isomerization of the azobenzene ligand from one orientation to two disordered orientations and the relaxation from the disordered orientations to the original orientation occurred.

A Theoretical Approach to the Fluorophilicity of Ions via the Gibbs Energy of Ion Transfer at the Fluorous Solvent/Water Interface.

The non-Bornian solvation model has been applied to a theoretical consideration of the Gibbs free energy for the transfer of fluorinated anions, non-fluorinated cations, and non-fluorinated anions at the 2H,3H-decafluoropentane (DFP)/water (W) and 1,2-dichloroethane (DCE)/W interfaces. According to our previous experimental results, the fluorinated anions are more stable in DFP than DCE, while the non-fluorinated cations and anions are less stable in DFP. To understand this characteristic feature of DFP, energy decomposition analyses have been performed for the hypothetical transfer of ions at the DFP/DCE interface.

Photo-on-Demand Base-Catalyzed Phosgenation Reactions with Chloroform: Synthesis of Arylcarbonate and Halocarbonate Esters.

Carbonate esters are utilized as solvents and reagents for C1 building blocks in organic synthesis. This study reports a novel photo-on-demand in situ synthesis of carbonate esters with CHCl solutions containing a mixture of an aromatic or haloalkyl alcohol having relatively high acidity, and an organic base. We found that the acid-base interaction of the alcohol and base in the CHCl solution plays a key role in enabling the photochemical reaction.

Photo-on-Demand Synthesis of Vilsmeier Reagents with Chloroform and Their Applications to One-Pot Organic Syntheses.

The Vilsmeier reagent (VR), first reported a century ago, is a versatile reagent in a variety of organic reactions. It is used extensively in formylation reactions. However, the synthesis of VR generally requires highly toxic and corrosive reagents such as POCl, SOCl, or COCl.

Computational Prediction of Adsorption Equilibrium for Nonionic Surfactants at the Oil/Water Interface.

The non-Bornian solvation model has been applied for predicting the adsorption equilibrium for nonionic surfactants at the oil (O)/water (W) interface. In the non-Bornian model, the small contribution from the long-range electrostatic interaction is ignored, and the solvation or resolvation energy is formulated based on the short-range solute molecule (or ion)-solvent interactions-cavity formation, Coulomb, polarization, charge transfer, etc. These interaction energies are given by zero, first, and second-order functions of the local electric field () on the molecular surface, which can be estimated by density functional theory calculation.

Alternative Face-on Thin Film Structure of Pentacene.

Pentacene attracts a great deal of attention as a basic material used in organic thin-film transistors for many years. Pentacene is known to form a highly ordered structure in a thin film, in which the molecular long axis aligns perpendicularly to the substrate surface, i.e.

Prediction of the Standard Gibbs Energy of Ion Transfer across the 1,2-Dichloroethane/Water Interface.

The standard Gibbs energy of ion transfer at the 1,2-dichloroethane/water interface (ΔG°) was determined for 26 organic cations and 24 anions by means of ion-transfer voltammetry with a micro oil/water interface. Based on the data sets, a theoretical analysis was performed with the non-Bornian solvation model, in which the solvation energy of an organic ion is evaluated from local electric fields on the surface of the ion. The semi-empirical equations thus obtained are available for relatively accurate prediction of ΔG° for organic ions.

An Acid-Responsive Single Trichromatic Luminescent Dye That Provides Pure White-Light Emission.

A novel acid-responsive single trichromatic luminescent dye capable of emitting pure white light (WL) is reported. A newly designed -phenylene-bridged bipyrrole bearing -alkylimino groups () specifically provides WL emission upon mixing with trifluoroacetic acid (TFA) in a CHCl solution. The emission originates from the trichromatic luminescent behavior of upon protonation of the imino groups.

Can Electron-Rich Oxygen (O) Withdraw Electrons from Metal Centers? A DFT Study on Oxoanion-Caged Polyoxometalates.

The answer to the question "Can electron-rich oxygen (O) withdraw electrons from metal centers?" is seemingly simple, but how the electron population on the M atom behaves when the O-M distance changes is a matter of controversy. A case study has been conducted for Keggin-type polyoxometalate (POM) complexes, and the first-principles electronic structure calculations were carried out not only for real POM species but also for "hypothetical" ones whose heteroatom was replaced with a point charge. From the results of natural population analysis, it was proven that even an electron-rich O, owing to its larger electronegativity as a neutral atom, withdraws electrons when electron redistribution occurs by the change of the bond length.

Comprehensive Understanding of Structure-Controlling Factors of a Zinc Tetraphenylporphyrin Thin Film Using pMAIRS and GIXD Techniques.

The performance of an organic electronic device is significantly influenced by the anisotropic molecular structure in the film, which has long been difficult to predict especially for a solution process. In the present study, a zinc tetraphenylporphyrin (ZnTPP) thin film prepared by a solution process was chosen to comprehensively explore the molecular-arrangement mechanism as a function of representative film-preparation parameters: solvent, film-preparation technique, and thermal annealing. The anisotropic structure was first analyzed by using a combination of infrared p-polarized multiple-angle incidence resolution spectrometry (pMAIRS) and grazing incidence X-ray diffraction (GIXD), which readily revealed the molecular orientation and crystal structure, respectively.

Prediction of the Standard Gibbs Energy of Transfer of Organic Ions Across the Interface between Two Immiscible Liquids.

The non-Bornian solvation model was applied for evaluation of the standard Gibbs energy (ΔGtr°,W→O) of transfer of organic ions from water (W) to organic solvent (O = nitrobenzene). The solvation energy of an ion in either W or O is basically formulated as the energy required for the formation of a nanosized ion–solvent interface around the ion; however, many organic ions with strongly charged groups (e.g.

Coextraction of water into nitrobenzene with organic ions.

Various organic anions (sulfonates (RSO3(-)), carboxylates (RCO2(-)), and phenolates (RO(-))) and ammonium cations (RNH3(+), R2NH2(+), and R3NH(+)) were distributed in the nitrobenzene (NB)-water system by using Crystal Violet and dipicrylaminate, respectively. The number of water molecules (n) being coextracted into NB with an ion was then determined by the Karl Fischer method. The n values determined and those reported previously showed the variation from 0.

How can multielectron transfer be realized? A case study with keggin-type polyoxometalates in acetonitrile.

Theoretical consideration and computational simulation have been performed on the voltammetric properties of Keggin polyoxometalates (POMs), and the conversion from successive one-electron transfer in unacidified media to four-electron transfer (through two-electron transfer) in acidified media has been discussed. Perfect simulation of the cyclic voltammograms of POMs could be achieved using the standard formal potentials and the protonation constants, systematically evaluated by the equations, in which “simple (intrinsic)” and “synergistic (extrinsic)” electron-withdrawing effects of the μ4-oxygen were taken into consideration. In the proposed model, the formal potential of the one-electron redox waves for the ith reduction step is presented by Ei°(z0, s) = Ei** + 0.

A route to a Keggin-type alpha-[(X(III)O4)Mo12O35(OH)]4- anion through an Anderson-type [X(III)(OH)6Mo6O18]3- anion: X = Ga.

From an aqueous Mo(VI)-Ga(III)-HCl system, a colourless complex was isolated as a K(+) salt, which consists of a hexaprotonated Anderson-type [Ga(OH)(6)Mo(6)O(18)](3-) anion. A yellow complex became kinetically stable by the presence of CH(3)CN at concentrations of 30-40% (v/v). The X-ray structural analysis revealed that the yellow (NPr(n)(4))(4)[(GaO(4))Mo(12)O(35)(OH)] crystal contains an alpha-Keggin structure and the oxygen atom at an edge-shared contact is protonated.

Effect of the central oxoanion size on the voltammetric properties of Keggin-type [XW(12)O(40)](n-) (n = 2-6) complexes.

An alpha-Keggin-type [ZnW(12)O(40)](6-) complex was prepared and structurally characterized. Unlike [XW(12)O(40)](n-) (n = 3-5) complexes that undergo one- and two-electron reductions in neutral and acidic media, respectively, [ZnW(12)O(40)](6-) showed a four-electron redox wave in acidified CH(3)CN. The present study demonstrated that the voltammetric properties of the Keggin anions were governed by the bond valence of the mu(4)-O-W bond as well as the ionic charge, and the four-electron behavior was ascribed to the increase of the bond valence (the decrease of the mu(4)-O-W distance), owing to the greater X-mu(4)-O distances.

An approach to the synthesis of polyoxometalate encapsulating different kinds of oxoanions as heteroions: bisphosphitopyrophosphatotriacontamolybdate [(HPO3)2(P2O7)Mo30O90]8-.

A yellow [(HPO(3))(2)(P(2)O(7))Mo(30)O(90)](8-) anion was prepared as a tetrapropylammonium (Pr(4)N(+)) salt from a 50 mM Mo(VI)-2 mM P(2)O(7)(4-)-4 mM HPO(3)(2-)-0.95 M HCl-60% (v/v) CH(3)CN system at ambient temperature. The (Pr(4)N)(8)[(HPO(3))(2)(P(2)O(7))Mo(30)O(90)] salt crystallized in the orthorhombic space group P(nma) (No.

Novel synthesis of benzalacetone analogues of naphth[a]azulenes by intramolecular tropylium ion-mediated furan ring-opening reaction and X-ray investigation of a naphth[1,2-a]azulene derivative.

[reaction: see text] Benzalacetone analogues of naphth[1,2-a]azulene (8), naphth[2,1-a]azulene (13), and naphth[2,3-a]azulene (18) were synthesized from 2-(5-methyl-2-furyl)-1-tropylionaphthalene (7), 1-(5-methyl-2-furyl)-2-tropylionaphthalene (12), and 2-(5-methy-2-furyl)-3-tropylionaphthalene (17), respectively. The synthetic method is based on furan ring-opening reaction by the intramolecular electrophilic attack of a tropylium ion. Single-crystal X-ray work on the naphth[1,2-a]azulene derivative (8) revealed that its tetracyclic system exhibited deformation from planarity similar to that of benzo[c]phenanthrene (tetrahelicene).