Dawn of Calcium Batteries

Calcium batteries are a potentially sustainable, high‐energy‐density battery technology beyond Li ion batteries. Now the development of Ca batteries has become possible with a newly invented Ca electrolyte capable of reversible Ca deposition/stripping at room temperature.     

Direct separation of the enantiomers of ramosetron on a chlorinated cellulose‐based chiral stationary phase in hydrophilic interaction liquid chromatography mode

Ramosetron is an enantiopure active pharmaceutical ingredient marketed in Japan since 1996 and later in a few Southeast Asian countries predominantly as an antiemetic for patients receiving chemotherapy. In this study, a simple and rapid high‐performance liquid chromoatography method for the separation of ramosetron and its related enantiomeric impurity by using hydrophilic interaction liquid chromatography mode is presented. Chiral resolution was performed on an analytical column (100 mm × 4.6 mm id) packed with 3 μm particles of cellulose‐based Chiralpak IC‐3 chiral stationary phase. Using a mobile phase containing acetonitrile–water–diethylamine (100:10:0.1, v/v/v) and setting the column temperature at 35°C, the resolution value was 7.35. At a flow rate of 1 mL/min, the enantioseparation was completed within 5 min. The proposed method was partially validated and it has proven to be sensitive with limit of detection and limit of quantitation of the (S)‐enantiomer impurity of 44.5 and 133.6 ng/mL.     

Unraveling the reactivity of a cationic iminoborane: avenues to unusual boron cations

A cationic terminal iminoborane [Mes*N B ← IPr₂Me₂][AlBr₄] (3⁺[AlBr₄]⁻) (Mes* = 2,4,6-tri-tert-butylphenyl and IPr₂Me₂ = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) has been synthesized and characterized. The employment of an aryl group and N-heterocyclic carbene (NHC) ligand enables 3⁺[AlBr₄]⁻ to exhibit both B-centered Lewis acidity and BN multiple bond reactivities, thus allowing for the construction of tri-coordinate boron cations 5⁺–12⁺. More importantly, initial reactions involving coordination, addition, and [2 + 3] cycloadditions have been observed for the cationic iminoborane, demonstrating the potential to build numerous organoboron species via several synthetic routes.

An NHC-stabilized aryliminoboryl cation exhibits both boron-centered Lewis acidity and multiple bond reactivity and could be utilized as an effective synthon for unusual cationic boron species.     

Extreme and critical transition events in the memristor based Liénard system

The European Physical Journal Special Topics - We study extreme and critical events in the forced Liénard systems with charge control memristor. It has been found that the system exhibits...     

Effect of Tomato Peel Extract Grown under Drought Stress Condition in a Sarcopenia Model

Tomatoes and their derivates represent an important source of natural biologically active components. The present study aims to investigate the protective effect of tomato peel extracts, grown in normal (RED-Ctr) or in drought stress (RED-Ds) conditions, on an experimental model of sarcopenia. The phenolic profile and total polyphenols content (TPC) of RED-Ctr and RED-Ds were determined by Ultra High-Performance Liquid Chromatography (UHPLC) analyses coupled to electrospray ionization high-resolution mass spectrometry (ESI-HR-MS). Human skeletal muscle myoblasts (HSMM) were differentiated in myotubes, and sarcopenia was induced by dexamethasone (DEXA) treatment. Differentiation and sarcopenia were evaluated by both real-time PCR and immunofluorescent techniques. Data show that myosin heavy chain 2 (MYH2), troponin T (TNNT1), and miogenin (MYOG) were expressed in differentiated myotubes. 5 μg Gallic Acid Equivalent (GAE/mL) of TPC from RED-Ds extract significantly reduced muscle atrophy induced by DEXA. Moreover, Forkhead BoxO1 (FOXO1) expression, involved in cell atrophy, was significantly decreased by RED-Ds extract. The protective effect of tomato peel extracts depended on their qualitative polyphenolic composition, resulting effectively in the in vitro model of sarcopenia.     

The structure of propadienone (CH2CCO)

A complete r_o structure has been obtained for propadienone (CH₂CCCO) with the aid of ab initio molecular-orbital calculations. The effect of electron correlation has been investigated using third order Møller-Plesset perturbation theory. The molecule is found to be planar bent (CCC145°) and the calculated structure yields rotational constants which are in good agreemant with experimental values.     

An ab initio molecular orbital study of structures and energies of spirocompounds: spiro[3.3]heptane and spiro[3.3]hepta-1,5-diene

Ab initio molecular orbital theory with the STO-3G and 4-31G basis sets is used to determine the equilibrium geometries, enthalpies of formation, strain energies and spiro-interactions for spiro[3.3]heptane and spiro[3.3]hepta -1,5 - diene. For spiro[3.3]heptane, molecular mechanics calculations suggest that the component cyclobutane rings are puckered to a greater extent than in cyclobutane itself. For spiro[3.3]hepta - 1,5 - diene, STO-3G calculations predict that the component cyclobutene rings deviate slightly from an orthogonal arrangement. Spiro-interactions in spiro[3.3]hepta - 1,5 - diene are revealed by comparing the calculated structural parameters and strain energies with those of appropriate reference systems. The π-orbitals in spiro[3.3]hepta -1,5 -diene are predicted to be split by about 0.4 eV.     

A theoretical approach to substituent effects: Stabilities and conformational preferences in β-substituted ethyl radicals

Ab initio molecular orbital theory is used to study substituent effects in a series of β-substituted Et radicals XCH₂CH₂. For X = BH₂ (plan.), CH₃, NH₂, OH and F, only slight conformational preferences and weak stabilizations are indicated. Such behaviour may be rationalized, using a PMO model, in terms of opposing changes, accompanying variation in X, in positive and negative hyperconjugation between the XCH₂ group and the CH₂ centre. On the other hand, for groups containing an appropriately oriented, low-lying vacant orbital, viz. X = Li, BeH and BH₂ (perp.), there is a pronounced preference for the perpendicular conformation of the radical. This is attributed to 1,3-interaction between the singly-occupied 2p(C) orbital and the vacant 2p(X) orbital.     

The geometric and electronic structures of oxocarbons. An ab initio molecular orbital study

Ab initio molecular orbital calculations with the STO-3G and 4-31G basis sets have been carried out for the neutral oxocarbons C_nO_n (n = 3, 4, 5, 6 and 7), the dianions C_nO_n^2- (n = 3, 4, 5, 6 and 7), the monoanions C_nO_nH^? (n = 3 and 4) and the related acids C_nO_nH₂ (n = 3 and 4). Fully optimised geometries have been obtained for all species. The geometries, stabilities and acidities are discussed.