Aromaticity and Chemical Bonding of Chalcogen-Bonded Capsules Featuring Enhanced Magnetic Anisotropy

We present a theoretical study of chalcogen bonded container capsules ( A_X+A_X ) where X=O, S, Se, and Te, and their encapsulation complexes with n-C₉H₂₀ (n-C₉H₂₀@ A_X+A_X ). Both Se and Te encapsulation complexes have significant experimental and computed binding energies, analogous to the hydrogen bonded counterparts, while the S and O capsules and their encapsulation complexes show only weak binding energies, which are attributed to different types of bonding: chalcogen S⋅⋅⋅N bonds for S-capsules and π–π stacking and weak hydrogen bonds for the O case. All A_X+A_X and C₉H₂₀@ A_X+A_X present unusually high magnetic anisotropies in their interiors. The ¹H NMR spectra of the encapsulation complexes display the proton signals of the encapsulated n-nonane highly upfield shifted, in agreement with the available experimental data for the Se capsule. We found that different factors contribute to the observed magnetic anisotropy of the capsule's interior: for the Te capsule the most important factor is Te's large polarizability; for the O analogue the inductive effects produced by the electronegative nature of the O and N heteroatoms; and for the S and Se capsules, the polarizability of the heteroatoms combines with electric field effects.     

Synthesis and Characterization of Naphthalene‐Based Banana‐Shaped Liquid Crystals for Photoswitching Properties

A series of banana‐shaped monomers containing naphthalene as central units, azobenzene in side arms with terminal alkenes were synthesized and characterized. Polarizing optical microscopy, DSC and X‐ray diffraction measurements reveal that one compound processes a nematic phase while other four compounds exhibit B₆ phase. The absorption spectrum of trans‐azobenzene displays high‐intensity π‐π* transition at 365 and low‐intensity n‐π* transition at 450 nm. These molecules exhibit strong photoisomerisation behaviour in solutions in which trans to cis isomerisation takes 55 seconds whereas reverse process takes about 32 hours. Such a long thermal back relaxation is useful for creation of optical image storage devices.     

H_3PW_(12)O_(40)催化水相介质中苯并恶嗪和喹唑啉合成（英文）

A heteropolyacid efficiently catalyzed the cyclocondensation reaction of 2‐aminobenzamide and salicylamide with aldehydes and ketones to afford good yields of benzoxazine and quinazoline ring systems in an aqueous medium. The method gives clean reactions, has simple workup procedure, and uses environment friendly conditions.     

Acetone sensor based on solvothermally prepared ZnO doped with Co3O4 nanorods

This paper describes a reliable and sensitive method for sensing dissolved acetone using doped nanomaterials. Large-scale synthesis of ZnO nanorods (NRs) doped with Co₃O₄ was accomplished by a solvothermal method at low temperature. The doped NRs were characterized in terms of their morphological, structural, and optical properties by using field-emission scanning electron microscopy coupled with energy-dispersive system, UV-Vis., Fourier transform IR, X-ray diffraction, and Xray photoelectron spectroscopy. The calcinated (at 400 °C) doped NRs are shown to be an attractive semiconductor nanomaterial for detecting acetone in aqueous solution using silver electrodes. The sensor exhibits excellent sensitivity, stability and reproducibility. The calibration plot is linear over a large concentration range (66.8 μM to 0.133 mM), displays high sensitivity (~3.58 μA cm^?2 mM^?1) and a low detection limit (~14.7?±?0.2 μM; at SNR of 3).

An Efficient Synthesis of (±)-Cycloillicinone

An efficient synthesis of (±)-cycloillicinone was accomplished in five steps from sesamol. The title compound was obtained via a biomimetic Diels–Alder cycloaddition between illicinone A and β-trans-ocimene as the key step.     

Solvent‐Free Conversion of Alcohols into Iodides with NaI Supported on KSF Clay

A variety of allylic, benzylic, primary, and secondary saturated alcohols have been converted into the corresponding iodides using NaI supported on KSF clay. Selective conversion of allylic and benzylic alcohols in the presence of primary and secondary saturated alcohols has also been demonstrated.     

Efficient and Regioselective Bromination of Aromatic Compounds with Ethylenebis(N-methylimidazolium) Ditribromide (EBMIDTB)

A regioselective and highly efficient method for bromination of phenol and aniline derivatives using ethylenebis(N-methylimidazolium) ditribromide (EBMIDTB) as an efficient reagent in dichloromethane at ambient temperature is reported. The reagent can be recovered and reused several times.     

Efficient Synthesis of Symmetrical Bisamides from Aldehydes and Amides Catalyzed by Silica-Bonded S-Sulfonic Acid Nanoparticles

Silica-bonded S-sulfonic acid nanoparticles (SBSSANPs) were easily synthesized from silica nanoparticles and showed to be an efficient catalyst in the synthesis the symmetrical N,N′-alkylidene bisamides. Reaction of aldehydes and amides in the presence of the catalyst afforded the corresponding bisamides in good to excellent yields. The extensive range of substrates suggests general applicability of the method. Reusability of the catalyst, simple workup procedure, and short reaction times are other advantages of this protocol.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications ^® to view the free supplemental file.     

Interaction of the Amphiphilic Drug Amitriptyline Hydrochloride with Gemini and Conventional Surfactants: A Physicochemical Approach

Pyrene fluorescence measurements were carried out on various binary mixtures of the antidepressant amphiphilic drug amitriptyline hydrochloride (AMT) with conventional (TTAB and CTAB) and gemini surfactants (14-4-14 and 16-4-16). In all cases mixed micellar aggregates were formed and the mixed critical micelle concentration (cmc) of various mixtures was computed from the I ₁/I ₃ versus total surfactant concentration plots. In the region where mixed micelles are formed, the interaction of the amphiphlic drug and four surfactants showed synergistic behavior. The results were analyzed using an interaction parameter, β, which characterize the interaction in the mixed micelle and is introduced by a regular solution theory. The β values are negative in all binary mixtures, and their magnitudes increase with increasing hydrophobicity of the amphiphile. The micellar mole fraction of AMT in the mixed micelle (x ₁) and in the ideal sate (x _ideal) were evaluated and their values (x ₁ > x _ideal) suggest that the contribution of the AMT component is greater in binary mixtures as compared to that in the ideal state. Activity coefficients (f ₁ and f ₂) and excess Gibbs energy (G _ex) were also calculated. The values of micelle aggregation numbers (N _agg) and various other parameters like the Stern–Volmer constant (K _sv), micropolarity and dielectric constant of mixed systems have also been evaluated from the ratios of respective peak intensities (I ₁/I ₃ or I ₀/I ₁).