Cerium(IV) Ammonium Nitrate–Mediated Oxidation of Mono-aryl-substituted Methylenecyclobutanes: A Convenient Method for the Synthesis of Spirocyclobutyl-1,2-dioxethanes

Cerium(IV) ammonium nitrate (CAN)-mediated oxidation of methylenecyclobutanes was investigated. Compared with the similar reactions of methylenecyclopropanes, the reaction products were quite different. Instead of the desired ring-enlarged product cyclopentanones, a cyclobutyl ring-intact product, spirocyclobutyl-1,2-dioxethane, was obtained. The structures of these spiroheterocycle-containing compounds are interesting, and the reactions are potentially valuable in both organic synthesis and mechanism research.

Efficient Synthesis of Aryl Hydroxylactams by Reducing Imides With Activated Zinc Dust

A series of aryl hydroxylactams (2a, 2b, 2d–2g, 2i–2k, 2m, and 2n) was synthesized by partially reducing aryl cyclic imides in moderate to excellent yields with activated zinc dust alone in acetic acid. This method was regiospecific and can be employed as an alternative for reported methods to partially reduce aryl cyclic imides.     

A Convenient and Efficient Preparation of 2‐Acetyl‐4,5‐difluorothiophene

A convenient, five‐step preparation of 2‐acetyl‐4,5‐difluorothiophene from 2,3‐dibromothiophene is described.     

Syntheses of Novel Chiral Calix[4]crown: Lariat Calix[4]-1,3-aza-crowns with Chiral Amino Acid Groups as Branched Chains

The first examples of lariat calix[4]-1,3-aza-crowns with chiral amino acid groups as branched chains (5a and 5b) were designed and synthesized via a 1 + 1 addition reaction of calix[4]-1,3-substituted benzaldehyde derivative (4) and amino acid hydrazide derivatives (3a and 3b) in yields of 70% and 75%, respectively. The preliminary extraction experiments suggested that hosts 5a and 5b possessed good complexation abilities for α-amino acids.      

Supramolecular organogelators based on Janus type AT nucleosides

J-AT nucleoside-based organogelators 1a and 1b were designed and synthesized. They were endowed with unparalleled superiority to natural nucleobase analogues 2–6 to gelate aromatic solvents due to their excellent self-assembly properties. The J-AT nucleoside-based organogelators showed a specific self-complementary base pair recognition characteristic. The gel stabilities of 1a and 1b were drastically influenced by adenine analogue 2, hardly affected by thymine analogue 3, uracil analogue 4, cytosine analogue 5, and mildly interrupted by guanine analogue 6.     

Two Zinc(II) Coordination Polymers Based on the Ligand 1, 4‐Bis[(2‐methyl‐imidazol‐1‐yl)methyl]benzene: Syntheses,Crystal Structures and Properties

Two coordination polymers (CPs), {[Zn₂(BMB)(5‐AIPA)₂] · 2H₂O}_n( 1 ) and [Zn(BMB)(5‐NIPA)]_n( 2 ) {BMB = 1, 4‐bis[(2‐methyl‐imidazol‐1‐yl)methyl]benzene, 5‐AIPA = 5‐aminoisophthalic acid, 5‐NIPA = 5‐nitroisophthalic acid}, were synthesized under hydrothermal conditions. Compound 1 displays a 2D double‐layer structure, which is packed into a 3D supramolecule by interlayer hydrogen bonds and π–π stacking interactions. Compound 2 displays a threefold interpenetrating 3D network, which is composed of left‐handed helical chains and two types of meso‐helical chains along different directions.     

Preparation,Crystal Structure,and Thermal Decomposition of the Intriguing Five‐coordinated Compound [Cu(IMI)4Cl]Cl (IMI = Imidazole)

The intriguing multi‐ligand compound [Cu(IMI)₄Cl]Cl ( 1 ) with the ligand imidazole (IMI) was synthesized and characterized by elemental analysis and FT‐IR spectroscopy. The crystal structure was determined by X‐ray single crystal diffraction and the crystallographic data showed that the compound belongs to the monoclinic P2₁/n space group [α = 8.847(2) Å, b = 13.210(3) Å, c = 13.870(3) Å, and β = 90.164(3)°]. Furthermore, the Cu^II ion is five‐coordinated by four nitrogen atoms from four imidazole ligands and a chlorine atom. The thermal decomposition mechanism was determined based on differential scanning calorimetry (DSC) and thermogravimetric (TG‐DTG) analysis. The non‐isothermal kinetics parameters were calculated by the Kissinger's method and Ozawa's method, respectively. The energy of combustion, enthalpy of formation, critical temperature of thermal explosion, entropy of activation (ΔS^≠), enthalpy of activation (ΔH^≠), and free energy of activation (ΔG^≠) were measured and calculated.     

Synthesis,Structures, Luminescent and Magnetic Properties of Heterometallic 5p‐4f Compounds with Ethylenediaminetetra­acetate

A series of heterometallic Ln^III–Sb^III edta‐containing compounds with the formulas [Sb₂(edta)₂Ln]NO₃ · nH₂O [edta = ethylenediaminetetraacetate; Ln = Eu, n = 7 ( 1 ); Gd, n = 7.5 ( 2 ) and Tb, n = 8 ( 3 )] were synthesized and characterized by elemental analyses (EA), powder X‐ray diffraction (PXDP), Fourier transform infrared spectroscopy (FT‐IR), and thermogravimetric analyses (TGA). Their fluorescence and magnetic properties were also studied. The thermal analysis demonstrates the compounds formation of the antimony, lanthanide ions, and edta^4– ligands. FT‐IR spectra reveal that the antimony and lanthanide ions are connected through the carboxylate bridges. The studies of luminescence properties show that compounds 1 and 3 exhibit typical luminescence in the visible region. Furthermore, magnetic properties reveal compounds 2 and 3 have weak ferromagnetic behavior.     

Drawing Out the Structural Information About the First Hydration Layer of the Isolated Cl− Anion Through the FTIR-ATR Difference Spectra

The Fourier transform infrared-attenuated total reflectance (FTIR-ATR) difference spectra of aqueous MgSO₄, Na₂SO₄, NaCl and MgCl₂ solutions against pure water were obtained at various concentrations. The difference spectra of the solutions showed distinct positive bands and negative bands in the O–H stretching region, indicating the influences of salts on structures of hydrogen-bonds between water molecules. Furthermore the difference spectra of MgCl₂ solutions against NaCl solutions and those of MgSO₄ solutions against Na₂SO₄ solutions with the same concentrations of anions (Cl^? or SO ₄ ^2? , respectively) allowed extracting the structural difference of the first hydration layer between Mg²⁺ and Na⁺. Using SO ₄ ^2? as a reference ion, structural information of the first hydration layer of the Cl^? anion was obtained according to the difference spectra of MgCl₂ solutions against MgSO₄ solutions and those of NaCl solutions against Na₂SO₄ solutions containing the same concentrations of cations (Mg²⁺ or Na⁺, respectively). The positive peak at ~3,407 cm^?1 and negative peak at ~3,168 cm^?1 in these spectra indicated that adding Cl^? decreased the strongest hydrogen-bond component and increased the relatively weaker one.