A classical ionic inorganic complex Na2[Cu(mnt)2] (mnt2− = maleonitriledithiolate = 1,2-dicyanoethylenedithiolate), that acts as a template in assembling neutral [Cu(salen)] (salen = bis(salicylidene)ethylenediamine) complexes forming a framework type arrangement, is accommodated in the channel formed in the crystal structure of a new type of host–guest compound [Cu(salen)]4 · Na2[Cu(mnt)2] (1). The non-covalent supramolecular interactions among [Cu(salen)] complexes and between [Cu(salen)] and [Cu(mnt)2]2− complexes in the crystal lattice of 1 result in weak antiferromagnetic coupling. 相似文献
A cationic gold(I)‐catalyzed decarboxylative etherification of propargyl carbonates to selectively produce propargyl ethers is reported. In the reaction the gold(I) catalyst shows a distinct σ‐Lewis acidity rather than the commonly observed π‐Lewis acidity, and thus catalyzes the decarboxylation of a variety of propargyl carbonates to give the corresponding propargyl ethers with high selectivity. This reaction represents a rare example of the tunable reactivity of cationic gold(I) complexes between σ‐Lewis acidity and π‐Lewis acidity.
Nicotinic acetylcholine receptors (nAChRs) play an important role in many central nervous system disorders such as Alzheimer’s and Parkinson’s diseases, schizophrenia, and mood disorders. The α4β2 subtype has emerged as an important target for the early diagnosis and amelioration of Alzheimer’s disease symptoms. Herein we report a new class of α4β2 receptor ligands characterized by a basic pyrrolidine nucleus, the basicity of which was properly decreased through the insertion of a fluorine atom at the 3‐position, and a pyridine ring carrying at the 3‐position substituents known to positively affect affinity and selectivity toward the α4β2 subtype. Derivatives 3‐(((2S,4R)‐4‐fluoropyrrolidin‐2‐yl)methoxy)‐5‐(phenylethynyl)pyridine ( 11 ) and 3‐((4‐fluorophenyl)ethynyl)‐5‐(((2S,4R)‐4‐fluoropyrrolidin‐2‐yl)methoxy)pyridine ( 12 ) were found to be the most promising ligands identified in this study, showing good affinity and selectivity for the α4β2 subtype and physicochemical properties predictive of a relevant central nervous system penetration. 相似文献
A flexible metal‐free flash memory device with reduced graphene oxide films as electrodes and diarylfluorene‐based π‐conjugation‐interrupted hyperbranched polymers (CIHPs) as active switches is reported. Two CIHPs, named PCzPF and PCzPF‐PF, are synthesized via BF3?Et2O‐catalyzed fluorenol’s Friedel–Crafts reaction, where the PCzPF‐PF is designed by the decoration of hindrance functional groups, i.e., bulky 9‐phenyl‐fluorenyl (PF) moieties, at the end‐groups of PCzPF. Both of the two CIHPs exhibit excellent solubility and thermal stability. The PCzPF‐based device exhibits no switching effect while the PCzPF‐PF‐based device shows a flash type memory effect, indicating the incorporation of PF groups plays a critical role in realizing electrically bistable behaviors. In particular, the optimized memory exhibits a high ON/OFF ratio of > 3.0 × 103, long retention time of up to 1.2 × 104 s, and high mechanical stability. This work opens a new avenue for metal‐free memory electronics through a low‐cost and full‐solution process approach. 相似文献
Following the concept of conformationally restriction of ligands to achieve high receptor affinity, we exploited the propellane system as rigid scaffold allowing the stereodefined attachment of various substituents. Three types of ligands were designed, synthesized and pharmacologically evaluated as σ1 receptor ligands. Propellanes with (1) a 2-methoxy-5-methylphenylcarbamate group at the “left” five-membered ring and various amino groups on the “right” side; (2) benzylamino or analogous amino moieties on the “right” side and various substituents at the left five-membered ring and (3) various urea derivatives at one five-membered ring were investigated. The benzylamino substituted carbamate syn,syn-4a showed the highest σ1 affinity within the group of four stereoisomers emphasizing the importance of the stereochemistry. The cyclohexylmethylamine 18 without further substituents at the propellane scaffold revealed unexpectedly high σ1 affinity (Ki = 34 nM) confirming the relevance of the bioisosteric replacement of the benzylamino moiety by the cyclohexylmethylamino moiety. Reduction of the distance between the basic amino moiety and the “left” hydrophobic region by incorporation of the amino moiety into the propellane scaffold resulted in azapropellanes with particular high σ1 affinity. As shown for the propellanamine 18, removal of the carbamate moiety increased the σ1 affinity of 9a (Ki = 17 nM) considerably. Replacement of the basic amino moiety by H-bond forming urea did not lead to potent σ ligands. According to molecular dynamics simulations, both azapropellanes anti-5 and 9a as well as propellane 18 adopt binding poses at the σ1 receptor, which result in energetic values correlating well with their different σ1 affinities. The affinity of the ligands is enthalpy driven. The additional interactions of the carbamate moiety of anti-5 with the σ1 receptor protein cannot compensate the suboptimal orientations of the rigid propellane and its N-benzyl moiety within the σ1 receptor-binding pocket, which explains the higher σ1 affinity of the unsubstituted azapropellane 9a. 相似文献
A series of new π-conjugated organic dyes (HKK-BTZ1, HKK-BTZ2, HKK-BTZ3 and HKK-BTZ4), comprising triphenylamine (TPA) moieties as the electron donor and benzothiadiazole moieties as the electron acceptor/anchoring groups, was synthesized for the use in dye-sensitized solar cells (DSSCs). TPA units are bridged to benzothiadiazole with single(S), double(D) and triple bonds(T) in different derivatives. And HKK-BTZ1 was modified by introducing alkoxy group of TPA unit, because the bulky alkoxy group is a strong donating group for the more red shift and for reducing aggregation of dyes in TiO2 film. The structure-property relationship was investigated. Under standard global AM 1.5 G illumination, a maximum photo-to-electron conversion efficiency of 7.30% was achieved with the DSSC based on dye HKK-BTZ4 (JSC = 17.9 mA/cm−2, VOC = 0.62 V, FF = 0.66), while the Ru dye N719-sensitized DSSC showed an efficiency of 7.82% with a JSC of 17.5 mA/cm−2, a VOC of 0.62 V, and a FF of 0.72. 相似文献
We describe an efficient ruthenium‐catalyzed oxidation of the β,β′‐pyrrolic ring on the porphyrin periphery. Through the conversion of a β,β′‐double bond to a lactone moiety, the direct preparation of porpholactones from porphyrins is achieved, which previously suffered from needing toxic reagents, multiple synthetic steps and low yields. The generality of this method has been investigated with various porphyrins with different electronic and steric effects, even some metalloporphyrins, and so represents a general and efficient approach for the synthesis of the intriguing porpholactone derivatives. 相似文献
The Wittig reaction of isatin derivatives with Morita–Baylis–Hillman bromides of cinnamaldehydes afforded 3‐dienylidene‐2‐oxindoles. These trienes were converted into the corresponding spirooxindoles in a stereoselective manner in refluxing toluene in good yields. The diastereomeric spirooxindoles could be obtained stereoselectively by adding a catalytic amount of palladium(II) acetate via the palladium‐catalyzed isomerization of EEE‐trienes to ZEE‐trienes followed by a more facile 6π‐electrocyclization process. The obtained spirooxindoles could be further functionalized by palladium‐catalyzed oxidative arylation, thionation with Lawesson’s reagent, catalytic hydrogenation and Friedel–Crafts‐type reaction.
Mesoporous silicas with vesicular and onion-like morphologies were assembled through hydrogen-bonding pathway from sodium silicate as silica source and electrically neutral α,ω-diamine, Jeffamine D2000 surfactant (H2NCH(CH3)CH2[OCH2CH(CH3)]33NH2) as template in aqueous media at different synthesis temperatures (25, 60 and 100 °C). Assembling the material at 100 °C afforded onion-like core shell mesoporous silica, while at relatively lower temperature, e.g. 25 and 60 °C, multilamellar vesicles were obtained. Mesoporous silica with onion-like morphology was also obtained by a two-step synthesis involving an aging period of 20 h at room temperature followed by a hydrothermal stage (1–12 h) at 100 °C. The heavily cross-linked (Q4/Q3 ratio of 4.43) onion-like mesophase silica exhibited high hydrothermal stability. The BET surface area, pore volume and KJS (Kruk-Jaroniec-Sayari) pore diameter of the onion-like mesoporous silica were found to be 464 m2 g−1, 1.16 m3 g−1 and 7.2 nm, respectively. 相似文献
Electron-donating or electron-withdrawing substituents at the porphyrin rings considerably increase the catalytic activity of the manganese monomeric and μ-oxo porphyrins in the oxidation of cyclooctane with molecular oxygen without the use of sacrificial co-reductant. The change in the catalytic activity is due to the nature and number of the substituents in the porphyrin ring. 相似文献
A series of unusual fused tetraheterocyclic compounds 3 , consisting of a thiopyran (ring A), a thiophene (ring B), a pyridine (ring C), and an imidazole or a pyrimidine (ring D) core, with a bridgehead nitrogen and an angular methyl group, were successfully synthesized by a catalyst‐free, one‐pot, two‐component domino reaction of 4‐(4‐methyl‐1,3‐dithiol‐2‐ylidene)‐1,7‐bis(aryl/heteroaryl)hepta‐1,6‐diene‐3,5‐dione 2 and diamines. In this reaction, up to five new bonds were formed accompanied by the C S bond cleavage of the 1,3‐dithiole ring of 2 , with water as the only by‐product. 相似文献
A new framework coordination polymer {[Cd3(tr2ad)6](NCSe)6·12H2O}n [tr2ad-4,4′-(adamantane-1,3-diyl)bis(1,2,4-triazole)] exhibits 3D primitive cubic topology adopted by trinuclear [Cd3(tr)12] net nodes and tridentate tr2ad links. The structure reveals unprecedented multiple anion ···π interactions employing the soft Se site of the ambifunctional NCSe? anion and three triazole groups pre-arranged on a tricadmium matrix. The framework generates hydrophobic pockets serving for hosting the uncoordinated anions by a concerted action of Se···π and CH···Se interactions. 相似文献
The ρ‐containing γ‐aminobutyric acid type A receptors (GABAARs) play an important role in controlling visual signaling. Therefore, ligands that selectively target these GABAARs are of interest. In this study, we demonstrate that the partial GABAAR agonist imidazole‐4‐acetic acid (IAA) is able to penetrate the blood–brain barrier in vivo; we prepared a series of α‐ and N‐alkylated, as well as bicyclic analogues of IAA to explore the structure–activity relationship of this scaffold focusing on the acetic acid side chain of IAA. The compounds were prepared via IAA from l ‐histidine by an efficient minimal‐step synthesis, and their pharmacological properties were characterized at native rat GABAARs in a [3H]muscimol binding assay and at recombinant human α1β2γ2S and ρ1 GABAARs using the FLIPR? membrane potential assay. The (+)‐α‐methyl‐ and α‐cyclopropyl‐substituted IAA analogues ((+)‐ 6 a and 6 c , respectively) were identified as fairly potent antagonists of the ρ1 GABAAR that also displayed significant selectivity for this receptor over the α1β2γ2S GABAAR. Both 6 a and 6 c were shown to inhibit GABA‐induced relaxation of retinal arterioles from porcine eyes. 相似文献