Glucuronidation of Two Novel Metabolites of Benproperine with Trichloroacetimidate Donor

IntroductionGlucuronides are well known as phaseⅡ metabo-lites of xenobiotics, usually of phenols, alcohols, andacids, as well as those of hydroxylamines and tertiaryamine[1]. There is a growing interest in identifyingsuch metabolites and in establishing…     

Contorted Polycyclic Aromatic Hydrocarbons with Two Embedded Azulene Units

Polycyclic aromatic hydrocarbons (PAHs) that contain both five‐ and seven‐membered rings are rare, and those where these rings are annulated to each other and build azulene units have, to date, mainly been generated in minute amounts on surfaces. Herein, a rational approach to synthesize soluble contorted PAHs containing two embedded azulene units in the bulk is presented. By stepwise detachment of tert‐butyl groups, a series of three azulene embedded PAHs with different degrees of contortion has been made to study the impact of curvature on aromaticity and conjugation. Furthermore, the azulene PAHs showed high fluorescence quantum yields in the NIR regime.     

A Giant [8+12] Boronic Ester Cage with 48 Terminal Alkene Units in the Periphery for Postsynthetic Alkene Metathesis

Dynamic covalent chemistry (DCC) is a powerful synthetic tool to construct large defined molecules in one step from rather simple precursors. The advantage of the intrinsic dynamics of the applied reversible reaction steps is a self-correction under the chosen conditions, to achieve high yields of the target compound. To date, only a few examples are known, in which DCC was used to build up a molecular defined but larger product that was chemically transferred to a more stable congener in a second (irreversible) step. Here, we present a nanometer-sized [8+12] boronic ester cage containing 48 peripheral terminal alkene units which allows to put a hydrocarbon exoskeleton around the cage via alkene metathesis.     

A Shape‐Persistent Quadruply Interlocked Giant Cage Catenane with Two Distinct Pores in the Solid State

Discrete interlocked three‐dimensional structures are synthetic targets that are sometimes difficult to obtain with “classical” synthetic approaches, and dynamic covalent chemistry has been shown to be a useful method to form such interlocked structures as thermodynamically stable products. Although interlocked and defined hollow structures are found in nature, for example, in some viruses, similar structures have rarely been synthesized on a molecular level. Shape‐persistent interlocked organic cage compounds with dimensions in the nanometer regime are now accessible in high yields during crystallization through the formation of 96 covalent bonds. The interlocked molecules form an unprecedented porous material with intrinsic and extrinsic pores both in the micropore and mesopore regime.     

A Tin(IV) Porphyrin with Two Axial Organometallic NCN‐Pincer Platinum Units

A tin(IV) porphyrin was combined with two axial NCN‐pincer platinum(II) fragments by utilizing the oxophilicity of the apical positions on the tin atom and the acidic nature of the NCN‐pincer platinum derived benzoic acid. The solid‐state structure determined by X‐ray crystallography revealed some close contacts between the pincer complexes and the meso‐p‐tolyl subsitutents of the porphyrin. It was shown by ¹H NMR spectroscopy that these close contacts were not present in solution and that this compound can potentially act as a novel building block for supramolecular architectures.     

A Covalent Organic Helical Cage with Remarkable Chiroptical Amplification

Purely organic shape‐persistent chiral cages are designed through the use of rigid chiral axes. Covalent dimerization of a tripodal fragment bearing chiral allenes forms a molecular twisted prism with loop‐like lateral edges presenting 10‐fold chiroptical amplification compared to its isolated building blocks. The expected geometry of covalent organic helical cage (M,M)₃‐ 1 was confirmed by X‐ray crystal structure analysis. Comparison of the chiroptical responses of this shape‐persistent molecular container with more flexible analogues highlights how the control of the conformational freedom of the molecule can be used to obtain molecular cages with strong chiroptical responses. Selective inclusion‐complex formation with ferrocenium ions [(P,P)₃‐ 1 @Fc⁺] was confirmed and quantified with HR‐ESI‐MS and NMR spectroscopy.     

Synthesis of Heterocycle Compounds Containing Two Pyridazinone Units

Four novel compounds containing two pyridazinone units attached to one benzene or pyridine ring, protected and deprotected 1,5-di[3（2H）-pyridazinon-6-yl]benzene and 2,6-di[3（2H）-pyridazinon-6-yl]pyridine were synthesized in eight steps, which provided a useful method for the preparation of pyridazinone derivatives via the Stetter and cyclization reactions. Their structures were characterized by ^1H NMR, ^13C NMR, and HRMS.     

Near-Infrared Electrochromic Behavior of Dibenzothiepin Derivatives Attached with Two Michler's Hydrol Blue Units

10,11-Bis[bis(4-dimethylaminophenyl)methylene]dibenzo[bf]thiepin ( 1 ) and -oxepin ( 2 ) were prepared as stable yellow crystalline compounds, which are the cyclic analogues of electron-donating hexaarylbutadienes. Upon two-electron oxidation, they are reversibly transformed into the title dications ( 1 ²⁺ and 2 ²⁺) exhibiting near-infrared (NIR) absorptions, which were also isolated as stable salts. These redox pairs can serve as new entries into less well-explored organic NIR-electrochromic systems, and the separation of redox peaks (electrochemical bistability) was attained for 1 / 1 ²⁺ and 2 / 2 ²⁺, thanks to drastic geometrical changes between neutral and dicationic states, as revealed by a series of X-ray analyses. Thiepin-S,S-dioxide analogue ( 3 / 3 ²⁺) exhibits quite similar dynamic redox behavior due to nonaromatic nature of the dibenzothiepin and -oxepin unit in 1 ²⁺ and 2 ²⁺, whereas the thiepin-S-oxide derivative ( 4 / 4 ²⁺) does not exhibit bistability due to the smaller change in geometry upon electron transfer, showing that a subtle change of a bridging atom in the central seven-membered ring can modify the redox properties.     

Syntheses and Optical Properties of Perfluorophenyl Containing Benzimidazole Derivatives: The Effect of Donor Units

Synthesis of two novel donor – acceptor – donor type monomers containing benzimidazole as the acceptor unit and thiophene and 3,4-ethylenedioxythiophene (EDOT) as the donor units were performed. 2-(Perfluorophenyl)-4,7-di(thiophen-2-yl)-1H-benzo[d]imidazole and 4,7-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-2-(perfluorophenyl)-1H-benzo[d]imidazole were synthesized successfully and polymerized electrochemically. The electrochemical and spectroelectrochemical studies of the polymers were studied. The effect of electron donating moieties on the optical properties of electrochemically polymerized polymers was investigated. Both polymers were p type dopable and possessed multi-chromic property. Optical studies demonstrated that the polymer based on EDOT unit (P2) resulted in lower band gap since EDOT is higher electron donating group than thiophene.     

Development of Yellow-to-Orange Photoluminescence Molecules Based on Alterations in the Donor Units of Fluorinated Tolanes

Since the aggregation-induced emission (AIE) phenomenon was first reported by Tang et al., much effort has been devoted to the development of solid-state luminescent molecules by chemists worldwide. Our group successfully developed fluorinated tolanes as novel compact π-conjugated luminophores with blue photoluminescence (PL) in the crystalline state. Moreover, we reported the yellow-green PL molecules based on their electron-density distributions. In the present study, we designed and synthesized fluorinated tolanes with various amine-based donors and evaluated their photophysical properties. The carbazole-substituted fluorinated tolane exhibited strong PL in the solution state, whereas piperidine- or phenothiazine-substituted fluorinated tolanes showed a dramatic decrease in PL efficiency. Notably, fluorinated tolanes with piperidine or phenothiazine substituents displayed yellow-to-orange PL in the crystalline state; this may have occurred because these tolanes exhibited tightly packed structures formed by intermolecular interactions, such as H···F hydrogen bonds, which suppressed the non-radiative deactivation process. Moreover, fluorinated tolanes with amine-based donors exhibited AIE characteristics. We believe that these yellow-to-orange solid PL molecules can contribute to the development of new solid luminescent materials.     

Two New Coordination Polymers with UO22+ Units and Fluorinated Aromatic Carboxylate Linkers

A new coordination polymer, namely ²_∞[(U^VIO₂)₂(L)(DMA)₃] ( 1 ) (C2/c, Z = 8) with L = 4-monofluorobiphenyl-3,3',5,5'-tetracarboxylate (4-mF-BPTC^4–) was synthesized by solvothermal reaction in DMA (N,N'-dimethylacetamide). Its crystal structure was solved and refined from single-crystal X-ray diffraction data. It contains two different types of UO₂²⁺ units, which are connected by fluorinated tetracarboxylate ligands to form a layered structural motif. Three DMA molecules are coordinated to one UO₂²⁺ unit (CN = 7), whereas the other is solely coordinated by oxygen atoms of the tetracarboxylate linkers (CN = 8). The layers are held together by van der Waals interactions, which do not include any hydrogen bonds. An isostructural coordination polymer is formed with L' = 4,4'-difluorobiphenyl-3,3',5,5'-tetracarboxylate (4,4'-dF-BPTC^4–), as confirmed by XRPD (X-ray powder diffraction), IR/Raman spectroscopy and elemental analysis. The DSC/TG analyses of both compounds show that they are stable up to approx. 300 °C in an inert argon atmosphere.     

A Tetrameric Cage with D2h Symmetry through Alkyne Metathesis

Shape‐persistent covalent organic polyhedrons (COPs) with ethynylene linkers are usually prepared through kinetically controlled cross‐coupling reactions. The high‐yielding synthesis of ethynylene‐linked rigid tetrameric cages via one‐step alkyne metathesis from readily accessible triyne precursors is presented. The tetrameric cage contains two macrocyclic panels and exhibits D_2h symmetry. The assembly of such a COP is a thermodynamically controlled process, which involves the initial formation of macrocycles as key intermediates followed by the connection of two macrocycles with ethynylene linkages. With a large internal cavity, the cage exhibits a high binding selectivity toward C₇₀ (K=3.9×10³ L mol^?1) over C₆₀ (no noticeable binding).     

A Permanent Mesoporous Organic Cage with an Exceptionally High Surface Area

Recently, porous organic cage crystals have become a real alternative to extended framework materials with high specific surface areas in the desolvated state. Although major progress in this area has been made, the resulting porous compounds are restricted to the microporous regime, owing to the relatively small molecular sizes of the cages, or the collapse of larger structures upon desolvation. Herein, we present the synthesis of a shape‐persistent cage compound by the reversible formation of 24 boronic ester units of 12 triptycene tetraol molecules and 8 triboronic acid molecules. The cage compound bears a cavity of a minimum inner diameter of 2.6 nm and a maximum inner diameter of 3.1 nm, as determined by single‐crystal X‐ray analysis. The porous molecular crystals could be activated for gas sorption by removing enclathrated solvent molecules, resulting in a mesoporous material with a very high specific surface area of 3758 m² g^?1 and a pore diameter of 2.3 nm, as measured by nitrogen gas sorption.