Thermodynamics of the silver—silver thiocyanate electrode in urea—water mixtures

E.m.f. measurements on cells of the type Ag(s), AgCNS(s), KCNS(c)//KCl(c), AgCl(s), Ag(s) in four different composition of urea—water mixtures at seven different temperatures from 5 to 35°C have been made to determine the standard potentials of the silver—silver thiocyanate electrode in these media. These values have been used to evaluate the transfer thermodynamic quantities accompanying the transfer of 1 g ion of CNS^? ion from the standard state in water to the standard state in urea—water mixtures.     

2:1 cocrystals of homochiral and achiral amino acid zwitterions with Li+ salts: water-stable zeolitic and diamondoid metal-organic materials

Eight 2:1 cocrystals of amino acid zwitterions and Li(+) salts were crystallized from hot water to afford cationic networks based on tetrahedral lithium cations: square grids, an ABW topology net, and diamondoid nets.     

Photoisomerization and proton-coupled electron transfer (PCET) promoted water oxidation by mononuclear cyclometalated ruthenium catalysts

Photoisomeric transformations in ruthenium polypyridyl complexes have been rarely reported. Herein we report the geometrical transformation of cyclometalated trans-[Ru(tpy)(PAD)(OH(2))](+) ([1](+)) to the cis-[Ru(tpy)(PAD)(OH(2))](+) ([1a](+)) (tpy = 2,2';6',2"-terpyridine, PAD = 2-(pyrid-2'-yl)acridine) isomer upon irradiation of visible light (λ ≥420 nm). Due to a proton-induced tautomeric equilibrium between the Ru-C bond and Ru═C coordination, the π* energy levels of PADH are lower than those of tpy by 12.61 and 12.24 kcal mol(-1), respectively, in [1](+) and [1a](+). Isomers [1](+) and [1a](+) both act as catalytic oxygen-evolving complexes (OECs) chemically as well as electrochemically.     

Comparative Study of C(∧)N and N(∧)C Type Cyclometalated Ruthenium Complexes with a NAD(+)/NADH Function

Cyclometalated ruthenium complexes having C(∧)N and N(∧)C type coordinating ligands with NAD(+)/NADH function have been synthesized and characterized by spectroscopic methods. The variation of the coordinating position of σ-donating carbon atom leads to a drastic change in their properties. Both the complex Ru(phbn)(phen)(2)]PF(6) ([1]PF(6)) and [Ru(pad)(phen)(2)]PF(6) ([2]PF(6)) reduced to Ru(phbnHH)(phen)(2)]PF(6) ([1HH]PF(6)) and [Ru(padHH)(phen)(2)]PF(6) ([2HH]PF(6)) by chemical and electrochemical methods. Complex [1]PF(6) photochemically reduced to [1HH]PF(6) in the presence of the sacrificial agent triethylamine (TEA) upon irradiation of visible light (λ ≥ 420 nm), whereas photochemical reduction of [2]PF(6) was not successful. Both experimental results and theoretical calculations reveal that upon protonation the energy level of the π* orbital of either of the ligands phbn or pad is drastically stabilized compared to the nonprotonated forms. In the protonated complex [Ru(padH)(phen)(2)](PF(6))(2) {[2H](PF(6))(2)}, the Ru-C bond exists in a tautomeric equilibrium with Ru═C coordination and behaves as a remote N-heterocyclic carbene (rNHC) compex; on the contrary, this behavior could not be observed in protonated complex [Ru(phbnH)(phen)(2)](PF(6))(2) {[1H](PF(6))(2)}.     

Oscillation of neutral delay difference equations of second order with positive and negative coefficients

This paper is concerned with a class of neutral difference equations of second order with positive and negative coefficients of the forms

Directional compton profile studies of GaP

59.54 keV gamma ray Compton profiles (CP) of GaP along (100) and (1 1 1) directions are reported. The measured anisotropy has qualitatively similar features as given by the recent pseudopotential calculations for other III–V compound semiconductors. The average valence profile is found to be more peaked compared to that of the pure covalent semiconductors Si and Ge. This suggests that inonicity has the effect of making the valence-electron wave functions of compound semiconductors more diffused. Theoretical calculations on the directional Compton profiles of GaP will be of great use for an exact comparision with the present data, which will help in detailed understanding of the electronic structure of GaP.     

Pre-transitional effects in a nematic and a polymesomorphic liquid crystal

Measurements of ultrasonic velocity V, specific volume v and adiabatic compressibility K_ad are carried out in a monotropic nematic liquid crystal, p-anisal-p-phenetidine (pApP), and a polymesomorphic liquid crystal, p-n-decyloxybenzoyl-p-cresol (DBC) with nematic and smectic A phases. Temperature variation of the order parameter is estimated. The pre-transitional effects observed in v and K_ad are discussed on the basis of de Gennes' theory generalized by Bendler, and the critical exponents are estimated.     

Photoluminescence Quenching in Self‐Assembled CsPbBr3 Quantum Dots on Few‐Layer Black Phosphorus Sheets

An ordered self‐assembly of CsPbBr₃ quantum dots (QDs) was generated on the surface of few‐layer black phosphorus (FLBP). Strong quenching of the QD fluorescence was observed, and analyzed by time‐resolved photoluminescence (TR‐PL) studies, DFT calculations, and photoconductivity measurements. Charge transfer by type I band alignment is suggested to be the cause of the observed effects.