Reversible phase transition of the 1:1 complex between 18-crown-6 and n-propylammonium triiodide

Solid-state structure of the crystalline 1:1 complex [C 3 H 10 N(18-crown-6)] + [I 3 ](1) between 18-crown-6 and n-propylammonium triiodide has been determined at 293 and 93 K,respectively,showing a change from monoclinic P2 1 /m to monoclinic P2 1 /a.Crystal structural analysis shows that in addition to van der Waals’ forces,conventional N-H···O hydrogen bonds are the key interactions.Measurements of unit cell parameters versus temperature show that the values of one of the three axes and the crystal volume change abruptly and remarkably at 220 K,indicating a first-order phase transition.The lack of the mirror plane in the low temperature structure is the most important differences between the two structural forms.Differential scanning calorimetry(DSC) measurement confirms that 1 undergoes a reversible phase transition at about 220 K with a thermal hysteresis of 3.5 K.The relatively large latent heat makes 1 a good candidate for phase change materials.The phase transition is accompanied by an anomaly of dielectric constant during heating and cooling process near the phase transition temperature.     

A thermal stable cathode buffer based on an inexpensive tetranuclear zinc(II) complex for organic photovoltaic devices

An inexpensive material,i.e.,tetranuclear zinc(Ⅱ) complex,(Zn4O(AID)6) [AID = 7-azaindolate],was utilized as a cathode buffer in organic photovoltaic(OPV) devices,leading to the improvement of device performance.Compared to OPV devices based on a conventional cathode buffer of TPBi(1,3,5-tris(2-N-phenylbenzimidazolyl)benzene),although the freshly prepared devices showed similar performance,when heated to a series of high temperatures under air,the short circuit current and the open circuit voltage of the Zn4O(AID)6 devices dropped more slowly,indicating the superiority of using Zn4O(AID)6 as a cathode buffer over TPBi in OPV devices.     

Role of cetyltrimethyl ammonium bromide, crystal violet and humic acid in the degradation of diclofenac under simulated sunlight irradiation

The photodegradation of diclofenac in the absence/presence of cetyltrimethyl ammonium bromide,crystal violet and humic acid under simulated sunlight has been studied.Under the study conditions,it is apparent that cetyltrimethyl ammonium bromide and crystal violet concentrations inhibit effects on the photodegradation of diclofenac.Humic acid has no distinct effect on the photodegradation of diclofenac.Crystal violet has an obvious antagonistic action for humic acid and a similar antagonistic action between cetyltrimethyl ammonium bromide and crystal violet.Cetyltrimethyl ammonium bromide and humic acid have synergistic effect.An antagonistic action is present between cetyltrimethyl ammonium bromide,crystal violet and humic acid.Moreover,a simple linear model which describes the obtained results is shown.     

Crystal formation and growth mechanism of inorganic nanomaterials in sonochemical syntheses

A clear understanding of the nucleation, growth, coarsening, and aggregation processes of nanomaterials is necessary to enable the preparation of highly controlled nanostructures. Among wet chemical synthetic methods, ultrasound-assisted preparation has become an important tool in material science. The formation and crystal growth mechanism under ultrasound is special compared with other wet chemical synthetic routes. In this review, we discussed the chemical and physical effect of ultrasound and summarized the ultrasonic effect on crystallization. The sonolysis of water and the cavitation-induced microjet impact and shockwave are the two key factors in the sonochemical formation of inorganic nanomaterials. The ultrasonic-assisted Ostwald ripening and oriented attachment processes have been reviewed for the possible crystal growth mechanisms in the fabrication of inorganic nanostructures.     

Chiral‐Substrate‐Assisted Stereoselective Epoxidation Catalyzed by H2O2‐Dependent Cytochrome P450SPα

The stereoselective epoxidation of styrene was catalyzed by H₂O₂‐dependent cytochrome P450_SPα in the presence of carboxylic acids as decoy molecules. The stereoselectivity of styrene oxide could be altered by the nature of the decoy molecules. In particular, the chirality at the α‐positions of the decoy molecules induced a clear difference in the chirality of the product: (R)‐ibuprofen enhanced the formation of (S)‐styrene oxide, whereas (S)‐ibuprofen preferentially afforded (R)‐styrene oxide. The crystal structure of an (R)‐ibuprofen‐bound cytochrome P450_SPα (resolution 1.9 Å) revealed that the carboxylate group of (R)‐ibuprofen served as an acid–base catalyst to initiate the epoxidation. A docking simulation of the binding of styrene in the active site of the (R)‐ibuprofen‐bound form suggested that the orientation of the vinyl group of styrene in the active site agreed with the formation of (S)‐styrene oxide.     

Molecular Spintronics Based on Single‐Molecule Magnets Composed of Multiple‐Decker Phthalocyaninato Terbium(III) Complex

Unlike electronics, which is based on the freedom of the charge of an electron whose memory is volatile, spintronics is based on the freedom of the charge, spin, and orbital of an electron whose memory is non‐volatile. Although in most GMR, TMR, and CMR systems, bulk or classical magnets that are composed of transition metals are used, this Focus Review considers the growing use of single‐molecule magnets (SMMs) that are composed of multinuclear metal complexes and nanosized magnets, which exhibit slow magnetic‐relaxation processes and quantum tunneling. Molecular spintronics, which combines spintronics and molecular electronics, is an emerging field of research. Using molecules is advantageous because their electronic and magnetic properties can be manipulated under specific conditions. Herein, recent developments in [LnPc]‐based multiple‐decker SMMs on surfaces for molecular spintronic devices are presented. First, we discuss the strategies for preparing single‐molecular‐memory devices by using SMMs. Next, we focus on the switching of the Kondo signal of [LnPc]‐based multiple‐decker SMMs that are adsorbed onto surfaces, their characterization by using STM and STS, and the relationship between the molecular structure, the electronic structure, and the Kondo resonance of [TbPc₂]. Finally, the field‐effect‐transistor (FET) properties of surface‐adsorbed [LnPc₂] and [Ln₂Pc₃] cast films are reported, which is the first step towards controlling SMMs through their spins for applications in single‐molecular memory and spintronics devices.