Camouflaging Structural Diversity: Co‐crystallization of Two Different Nanoparticles Having Different Cores But the Same Shell

Two ligand‐protected nanoscale silver moieties, [Ag₄₆(SPhMe₂)₂₄(PPh₃)₈](NO₃)₂ and [Ag₄₀(SPhMe₂)₂₄(PPh₃)₈](NO₃)₂ (abbreviated as Ag₄₆ and Ag₄₀, respectively) with almost the same shell but different cores were synthesized simultaneously. As their external structures are identical, the clusters were not distinguishable and become co‐crystallized. The occupancy of each cluster was 50 %. The outer shell of both is composed of Ag₃₂S₂₄P₈, which is reminiscent of fullerenes, and it encapsulates a well‐studied core, Ag₁₄ and a completely new core, Ag₈, which correspond to a face‐centered cube and a simple cube, respectively, resulting in the Ag₄₆ and Ag₄₀ clusters. The presence of two entities (Ag₄₀ and Ag₄₆ clusters) in a single crystal and their molecular formulae were confirmed by detailed electrospray ionization mass spectrometry. The optical spectrum of the mixture showed unique features which were in good agreement with the results from time‐dependent density functional theory (TD‐DFT).     

CuSO4/sodium ascorbate catalysed synthesis of benzosuberone and 1,2,3-triazole conjugates: Design,synthesis and in vitro anti-proliferative activity

A novel series of conjugates of benzosuberone and 1,2,3-triazole i.e. 3-(4-phenyl-1H-1,2,3-triazol-1-yl)propyl-9-chloro-2,3-dimethyl-6,7-dihydro-5H-benzo[7]annulene-8-carboxylic acids (8a-j) were synthesized in good to excellent yields catalysed by CuSO₄ under milder reaction conditions and evaluated for their anti-proliferative activity. The structural elucidation of the prepared compounds was carried out using IR, ¹H NMR, ¹³C NMR and Mass spectral analysis. The newly synthesized derivatives (8a-j) were evaluated for their anti-proliferative activity against four human cell lines and the novel derivatives showed moderate to excellent activity. The obtained results suggest that these compounds can be considered as new hits for anti-proliferative drug development programme and further SAR studies can help obtain better anticancer agents.     

Single step modification of copper electrode for the highly sensitive and selective non-enzymatic determination of glucose

A non-enzymatic sensor was developed for the determination of glucose in alkaline medium by anodisation of copper in sodium potassium tartrate solution. The morphology of the modified copper electrode was studied by scanning electron microscopy, and its electrochemical behavior by cyclic voltammetry and electrochemical impedance spectroscopy. The electrode enables direct electrocatalytic oxidation of glucose on a CuO/Cu electrode at 0.7 V in 0.1 M sodium hydroxide. At this potential, the sensor is highly selective to glucose even in the presence of ascorbic acid, uric acid, or dopamine which are common interfering species. The sensor displays a sensitivity of 761.9 μA mM^?1 cm^?2, a linear detection range from 2 μM to 20 mM, a response time of <1 s, and a detection limit of 1 μM (S/N = 3). It was tested for determination of glucose level in blood serum.     

Synthesis of 3‐(substituted)‐2,4,8,15‐tetroxa‐3‐phosphadispiro[5.2.5]hexadecane‐3‐oxides

Novel 3‐(substituted)‐2,4,8,15‐tetroxa‐3‐phosphadispiro[5.2.5]hexadecane‐3‐oxides (3‐12) have been synthesized by cyclization of 1,5‐dioxaspiro[5.5]undecande‐3,3‐dimethanol (1) with various substituted aryl phosphorus dichloridates (2) in dry toluene‐THF in the presence of triethylamine at 40‐60 ^oC. Their molecular structures were determined by ir, nmr and mass spectral studies and were screened for antifungal activity against Curvularia lunata and Aspergillus niger, and antibacterial activity on Staphylococcus aureus and Escherichia coli. Most of them possess significant activity.     

Cationic carbohydroxylation of alkenes and alkynes using the cation pool method

The reactions of an N-acyliminium ion pool with alkenes and alkynes gave gamma-amino alcohols and beta-amino carbonyl compounds, respectively, after treatment with H(2)O/Et(3)N. The present reaction serves as an efficient method for cationic carbohydroxylation of alkenes and alkynes. When vinyltrimethylsilane was used as an alkene, the reaction was highly diastereoselective and served as an access to an enantiomerically pure alpha-silyl-gamma-amino alcohol. [reaction: see text]     

Asymmetric synthesis of 2,3-dihydrofurans and of unsaturated bicyclic tetrahydrofurans through alpha-elimination and migratory cyclization of silyloxy alkenyl aminosulfoxonium salts. Generation and intramolecular O,Si-bond insertion of chiral disubstituted beta-silyloxy alkylidene carbenes

Treatment of the bis(allylsulfoximine)titanium complexes derived from the beta-methyl-substituted acyclic allylic sulfoximines 13a and 13b with aldehydes gave with high selectivities the corresponding sulfoximine-substituted homoallylic alcohols which were isolated as the silyl ethers 15a-h. Methylation of sulfoximines 15a-h afforded the aminosulfoxonium salts 5a-h which upon treatment with LiN(H)tBu gave in high yields the enantio- and diastereomerically pure silyl-substituted 2,3-dihydrofurans 4a-h. Treatment of the titanium complexes derived from the cyclic allylic sulfoximines 17a, 17b, and ent-17c with p-MeOC(6)H(4)CHO delivered with high selectivities the corresponding sulfoximine-substituted cyclic homoallylic alcohols which were isolated as the silyl ethers 18a, 18b, and ent-18c, respectively. Methylation of sulfoximines 18a, 18b, and ent-18c furnished the aminosulfoxonium salts 8a, 8b, and ent-8c, respectively, whose treatment with LiN(H)t-Bu gave the enantio- and diastereomerically pure fused bicyclic 2,3-dihydrofurans 6a, 6b, and ent-6c, respectively, in good yields. It is proposed that the 1-alkenyl aminosulfoxonium salts 5a-h, 8a, 8b, and ent-8c react with the base under alpha-elimination and formation of the acyclic and cyclic beta-silyloxy alkylidene carbenes 2a-h, 7a, 7b, and ent-7c, respectively, which then undergo a 1,5-O,Si-bond insertion and 1,2-silyl migration. The cyclic aminosulfoxonium salts 8a, 8b, and ent-8c upon treatment with 1,8-diazabicyclo[5.4.0]-7-undecene did not undergo an alpha-elimination but suffered a novel migratory cyclization with formation of the enantio- and diastereomerically pure bicyclic tetrahydrofurans 9a, 9b, and ent-9c, respectively. It is proposed that the 1-alkenyl sulfoxonium salts 8a, 8b, and ent-8c are isomerized to the allylic aminosulfoxonium salts 10a, 10b, and ent-10c, respectively, which then suffer an intramolecular substitution of the (dimethylamino)sulfoxonium group by the silyloxy group followed by a desilylation. The syntheses of the 2,3-dihydrofurans 4a-h, 6a, and 6b and of the tetrahydrofurans 9a and 9b are accompanied by the formation of sulfinamide 16 of >or=98% ee, which can be converted via sulfoxide 28 of >or=98% to the starting sulfoximine 11 of >or=98% ee.     

Paintable Room‐Temperature Phosphorescent Liquid Formulations of Alkylated Bromonaphthalimide

Organic phosphors have been widely explored with an understanding that crystalline molecular ordering is a requisite for enhanced intersystem crossing. In this context, we explored the room‐temperature phosphorescence features of a solvent‐free organic liquid phosphor in air. While alkyl chain substitution varied the physical states of the bromonaphthalimides, the phosphorescence remained unaltered for the solvent‐free liquid in air. As the first report, a solvent‐free liquid of a long swallow‐tailed bromonaphthalimide exhibits room‐temperature phosphorescence in air. Doping of the phosphor with carbonyl guests resulted in enhanced phosphorescence, and hence a large‐area paintable phosphorescent liquid composite with improved lifetime and quantum yield was developed.     

Self-assembly of inorganic nanoparticle vesicles and tubules driven by tethered linear block copolymers

Controllable self-assembly of nanoscale building blocks into larger specific structures provides an effective route for the fabrication of new materials with unique optical, electronic, and magnetic properties. The ability of nanoparticles (NPs) to self-assemble like molecules is opening new research frontiers in nanoscience and nanotechnology. We present a new class of amphiphilic "colloidal molecules" (ACMs) composed of inorganic NPs tethered with amphiphilic linear block copolymers (BCPs). Driven by the conformational changes of tethered BCP chains, such ACMs can self-assemble into well-defined vesicular and tubular nanostructures comprising a monolayer shell of hexagonally packed NPs in selective solvents. The morphologies and geometries of these assemblies can be controlled by the size of NPs and molecular weight of BCPs. Our approach also allows us to control the interparticle distance, thus fine-tuning the plasmonic properties of the assemblies of metal NPs. This strategy provides a general means to design new building blocks for assembling novel functional materials and devices.     

2-Arylethenyl-2″-Arylethynyl Sulfones: A Potential Source for New Heterocycles

Abstract

Different heteroatoms viz., N, S & Se have been incorporated into 2-arylethenyl-2′-arylethynyl sulfones by nucleophilic reaction with benzylmine, hydrogen sulfide and sodium hydrogen selenide.