Crystal structure and Hirshfeld surface analysis of (Z)-4-{[4-(3-methyl-3-phenylcyclobutyl)thiazol-2-yl]amino}-4-oxobut-2-enoic acid

The title cyclobutyl compound, C18H18N2O3S, was synthesized by the interaction of 4-(3-methyl-3-phenylcyclobutyl)thiazol-2-amine and maleic anhydride, and crystallizes in the orthorhombic space group P212121 with Z′ = 1. The molecular geometry is partially stabilized by an intramolecular N—H...O hydrogen bond forming an S 1 1(7) ring motif. The molecule is non-planar with a dihedral angle of 88.29 (11)° between the thiazole and benzene rings. In the crystal, the molecules are linked by O—H...N hydrogen bonds, forming supramolecular ribbons with C 1 1(9) chain motifs. To further analyze the intermolecular interactions, a Hirshfeld surface analysis was performed. The results indicate that the most important contributions to the overall surface are from H...H (43%), C...H (18%), O...H (17%) and N...H (6%), interactions.

Homoconjugation in Triptycenes: An Inquiry Through Photochromism

The spatial disposition of three benzene rings in triptycene permits through-space overlap of the orbitals of fused benzene sp2 carbons, leading to ‘homoconjugation’; the latter is a contentious issue in...

Real Structure of Benzene Molecule and the Thickness of Graphene

The problem of benzene molecular structure has not been solved for more than 100 years. This research proposes a new concept of covalent bond based on the existing theory: each electron shared by multiple atom nuclei corresponds to a half-valent bond. The half-valent bond can be formed between the spacer carbon atoms of the benzene ring. In this way, a new theory was established. Quantum mechanical calculations can quantitatively explain experimental results, such as the hydrogenation heat and ultraviolet spectrum of benzene. Using the dotted line to indicate the half-valent bond, benzene molecular structural forms and chemical reaction formulas as will as its dozens of homologues and derivatives are designed easily. The method not only has a wide range of adaptability, but can also record the chemical reaction process. If several stacked benzene rings can form a benzene tube under the guidance of the new theory, calculated thickness of the three-layer benzene tube is very close to the thickness of graphene. Therefore, referring to other characteristics of graphene, it is considered to be more like a three-layer structure.

Antibacterial Activity and Mesophase Identification of Azomethnine and Azo derivatives

A new mesogenic homologous series of liquid crystalline azomethnine and azo derivatives of 4ꞌ-nalkoxybenzylidiene- 4-aminoazobenzene has been synthesized and characterized by a combination of elemental analysis and standard spectroscopic methods. In the present series, nematic mesophase commences from n-propyloxy derivative as enantiotropic and persists up to the last member synthesized except in derivative C10. The smectic A (SmA) mesophases commences from n-pentyloxy derivative as enantiotropic and also persists up to ntetradecyloxy synthesized. Imine linkage (-CH═N-) between central and terminal benzene rings helping to understand the polarizability effect as well as nature of mesophase as stability gets reduced due to the presence of nitrogen in the ring. The mesomorphic properties of present series are of great importance to evaluate the effects of central linkage on mesomorphism. The mesomorphic properties of present series were compared with other structurally related mesogenic homologous series to evaluate the effects of central linkage on mesomorphism.

Two Benzene Rings with a Boron Atom Comprise the Core Structure of 2-APB Responsible for the Anti-Oxidative and Protective Effect on the Ischemia/Reperfusion-Induced Rat Heart Injury

To identify the core structure of 2-aminoethoxydiphenyl borate (2-APB) responsible for the anti-oxidative and protective effect on the ischemia/reperfusion (I/R)-induced heart injury, various 2-APB analogues were analyzed, and several antioxidant assays were performed. Cell viability was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Myocardial infarct size was quantified using triphenyl tetrazolium chloride (TTC) staining. The levels of tumor necrosis factor-alpha (TNF-α) and cleaved-caspase-3 protein were evaluated as an indicator for the anti-inflammatory and anti-apoptotic effect, respectively. Our data show that 2-APB, diphenylborinic anhydride (DPBA) and 3-(diphenylphosphino)-1-propylamine (DP3A) all exerted the anti-oxidative activity, but only 2-APB and DPBA can scavenge H2O2. 2-APB and DPBA can potently inhibit hydrogen peroxide (H2O2)- and hypoxanthine/xanthine oxidase (HX/XOD)-induced increases in intracellular H2O2 and H9c2 cell death. 2-APB and DPBA were able to decrease the I/R-induced adult rat cardiomyocytes death, myocardial infarct size, and the levels of malondialdehyde (MDA) and creatine kinase-MB (CK-MB). Our results suggest that the two benzene rings with a boron atom comprise the core structure of 2-APB responsible for the anti-oxidative effect mediated through the reaction with H2O2 and generation of phenolic compounds, which in turn reduced the I/R-induced oxidative stress and injury in the rat heart.

Infinitene: A Helically Twisted Figure-Eight [12]Circulene Topoisomer

New forms of molecular nanocarbons particularly looped polyarenes adopting various topologies contribute to the fundamental science and practical applications. Here we report on the synthesis of an infinity-shaped polycyclic aromatic hydrocarbon, infinitene 1 (cyclo[c.c.c.c.c.c.e.e.e.e.e.e]dodecakisbenzene) comprising consecutively fused 12-benzene rings forming an enclosed loop with a strain energy of 60.2 kcal·mol-1. Infinitene 1 represents a topoisomer of still-hypothetical [12]circulene, and its scaffold can be formally visualized as the outcome of the “stitching” of two homochiral [6]helicene subunits by their both ends. The synthetic strategy encompasses transformation of a rationally designed dithiacyclophane to cyclophadiene through the Stevens rearrangement and pyrolysis of the corresponding S,S′-bis(oxide) followed by the UV-light mediated twofold photocyclization. The structure of infinitene 1 is a unique hybrid of helicene and circulene with a molecular formula C48H24, which can be regarded as an isomer for kekulene, [6,6]carbon nanobelt ([6,6]CNB), [12]cyclacene, and tetrabenzo[8]circulene as well. Infinitene 1 is a bench-stable yellow solid with green fluorescence, and soluble to common organic solvents. The figure-eight molecular structure of 1 was unambiguously confirmed by X-ray crystallography. The scaffold of 1, reminiscent of a squeezed spring, stem from its enclosed, fully-fused architecture, is significantly compressed as manifested by a remarkably shortened distance (3.152–3.192 Å) between the centroids of two π-π stacked central benzene rings and the closest C···C distance of 2.920 Å. Combined lamellar and herringbone-like crystal packing suggested three-dimensional electronic inter-actions. Fundamental photophysical properties of infinitene 1 were thoroughly elucidated by means of UV-vis absorption and fluorescence spectroscopic studies as well as density functional theory (DFT) calculations. Its configurational stability enabled separation of the corresponding enantiomers (P,P) and (M,M) by a chiral HPLC. Circular dichroism (CD) and circularly polarized luminescence (CPL) measurements revealed that 1 has moderate |gCD| and |gCPL| values.

Degradation of 17β-estradiol by UV/persulfate in different water samples

Sulfate radical (•SO4−)-based advanced oxidation processes are widely used for wastewater treatment. This study explored the potential use of UV/persulfate (UV/PS) system for the degradation of 17β-estradiol (E2). The pH of the reaction system can affect the degradation rate of E2 by UV/PS and the optimum pH was 7.0; Br− and Cl− in water can promote the degradation rate, HCO3− has an inhibitory effect on the reaction, SO42− and cations (Na+, Mg2+, K+) have no effect on the degradation rate. The degradation of E2 by UV/PS was a mineralization process, with the mineralization rate reaching 90.97% at 8 h. E2 in the UV/PS system was mainly degraded by hydroxylation, deoxygenation, and hydrogenation. E2 reaction sites were mainly located on benzene rings, mainly carbonylation on quinary rings, and bond breakage between C10 and C5 resulted in the removal of benzene rings and carboxyl at C2 and C3 sites. In the presence of halogen ions, halogenated disinfection by-products were not formed in the degradation process of E2 by UV/PS. E2 in the UV/PS system could inhibit the formation of bromate. The results of this study suggest that UV/PS is a safe and reliable method to degrade E2.

Ethyl 2-[(E)-({2,4-dimethoxy-6-[2-(4-methoxyphenyl)ethenyl]benzylidene}amino)oxy]acetate

In the title compound, C22H25NO6, the C=C double bond linking the benzene rings adopts an E configuration and the dihedral angle between the rings is 47.1 (2)°. The oxime unit contains a C=N double bond, which also has an E configuration. In the crystal, pairs of C—H...N hydrogen bonds generate inversion dimers and weak C—H...O interactions link the dimers into chains propagating along the b-axis direction.

Superphanes: Facile and Efficient Preparation, Functionalization and Unique Properties

Superphanes, compounds in which the two benzene rings clamped parallel on top of each other by six bridges, have garnered considerable interest due to their aesthetically pleasing structures and unique chemical physical properties. However, until now progress in the research of superphane chemistry and beyond has been seriously hampered by their poor availability. Herein, we report the facile and scalable synthesis of a collection of superphanes with structural diversity and their unique photophysical properties, as well as their unusual host–guest behavior. Initially, a set of dodecaimino–containing super-phanes 7a–7e are obtained via dynamic self–assembly of a hexakis–amine and a series of readily derived aromatic dialde-hyde in one pot. The resulting superphanes are found capable of being reduced with NaBH4 to their corresponding second-ary–amine versions 3a–3e. Subsequently, superphane 3c bearing 12 amine–NHs was further subject to post–functionalization with various functional groups, e.g., ethyl, allyl, propargyl and but–2–yn–1–yl. Unprecedentedly, the sec-ondary amine–based superphanes 3a–3e were observed to exhibit genuine fluorescence both in solution and in the solid state while the imine–based superphanes 7a–7e were found to highly emissive only in solid state with fluorescent quantum yields of 3.5 ~ 17.1. Finally, fully protonated 3a was exemplified to encapsulate a 2Cl–·H2O cluster both in the solid state and in solution. With the easy and versatile synthesis, modification, as well as unique photophysical and host–guest properties, we believe that this study will break the bottleneck in superphane chemistry and open the door to a novel class of supramo-lecular hosts and advanced functional materials on the basis of superphanes.