In this paper, we have used two N,O‐ketiminato ligands ( L1 and L2 ) with biphenyl and terphenyl substituent on the nitrogen atom. Deprotonation of L1 with KN(SiMe3)2 and subsequent reaction with MgI2 led to a homoleptic dinuclear magnesium complex ( 1 ) with a Mg2O2 four‐membered ring. Deprotonation with nBuLi and subsequent reaction with MgI2 afforded a unusual dinuclear magnesium complex ( 2 ) with a Mg2O2 ring. Extension of the ligand for calcium resulted in a trinuclear calcium complex ( 3 ) with six four‐membered Ca2O2 rings. We could not isolate any chelating complex when L2 was used as a ligand, and only oxygen bound magnesium ( 4 ) and calcium ( 5 ) adducts were isolated. DFT studies were performed to understand this dissimilar behavior. More diverse results were obtained when lithiated L1 and L2 were treated with germanium dichloride. We were able to stabilize a monomeric germylene monochloride ( 7 ) with L1 . However, with L2 , an unusual ligand scrambling, and a C?C coupling take place, leading to the formation of a secondary carbocation with GeCl3‐ as a counter‐anion ( 8 ). Besides, a germanium dichloride adduct ( 9 ) bound to the oxygen center of the ligand was obtained as the minor product. 相似文献
A facile synthesis of nickel cobalt sulfide (NCS) nanoflowers have been deposited successfully onto binder free 3D nickel foam electrodes using simple successive ionic layer adsorption and reaction (SILAR) method for supercapacitor applications. The obtained NCS nanoflowers manifest ultrahigh specific capacitance of 1899 F g?1 at a scan rate of 5 mV s?1. The NCS nanoflowers exhibit a prominent energy density of 55.16 Wh kg?1 at power density of 495 W kg?1 and superior cyclic stability of 94% after 10000 cycles. In addition, the asymmetric supercapacitor (ASC) device is fabricated using NCS nanoflower as positive and reduced graphene oxide (rGO) as negative electrodes, respectively. The ASC (NCS//rGO) delivered good capacity with excellent energy and power densities within 1.6 V wider potential window. Hence, NCS nanoflowers are an outstanding material for energy storage applications in near future. 相似文献
AbstractA protocol based on Groebke-Blackburn-Bienayame (GBB) multicomponent reaction has been developed for efficient and atom economical synthesis of C-glucosides of 1-azaindolizine, i.e. 2-(β-D-glucopyranosyl)-3-N-alkylamino-1-azaindolizine. Thus, a series of fourteen novel 2-(β-D-glucopyranosyl)-3-N-alkylamino-1-azaindolizines have been synthesized in moderate to good yields by reaction of a perbenzylated β-C-glucopyranosyl aldehyde with differently substituted 2-aminopyridines and alkyl isocyanides using InCl3 as acid catalyst. All synthesized β-C-glucosides were unambiguously characterized with the help of spectroscopic (IR, 1H-NMR, 13C-NMR and mass spectra) data analysis. 相似文献
The GC-MS analysis of fractions of methanol extract of stem of Cuscuta reflexa (Family Convolvulaceae) was carried out using a THERMO TRACE 1300 Gas Chromatograph equipped and coupled to a mass detector THERMO TSQ 8000 spectrometer with an TG 5MS (30 m × 0.25 mm, 0.25 μm) of capillary column. Database of National Institute of Standards and Technology (NIST) library was used to identify the components. GC-MS revealed two known compounds i.e. 2-Methoxy-4-vinyl phenol (6.80%) and Benzofuran-2,3-dihydro (20.89%) and other 12 unknown compounds such as 3,5-di-tert-Butyl-4-hydroxyanisole (35.50%); Hexatriacontane (12.02%); n-Hexadecanoic acid (10.12%); Scoparone (7.97%); Hexadecanoic acid methyl ester (5.22%); 1,3-Benzenediamine, N, N, N′, N′ tetramethyl- (15.43%); Phenol, 4(3-hydroxy1propenyl), 2-methoxy (9.31%); Phenol, 2,4 bis (1,1dimethylethyl); 2,3,5,6-Tetramethyl para phenylene diamine (14.18%); Retinoic acid-5,6-epoxy-5,6-dihydro (20.46%); 2,4-Dihydroxy-2,5-dimethyl-3(2H)furan-3-one (10.13%); 2,3-dihydro-3,5-dihydroxy-6-methyl-2-Propyl-tetrahydro-pyran-3-ol (10.13%); Pregn-4-ene-18-oic acid (5.75%) as some of the major compounds in its different fractions. Retinoic acid-5,6-epoxy-5,6-dihydro found as major compound may be responsible for blood glucose lowering potency. 相似文献
Fast photochemical oxidation of proteins (FPOP) may be used to characterize changes in protein structure by measuring differences in the apparent rate of peptide oxidation by hydroxyl radicals. The variability between replicates is high for some peptides and limits the statistical power of the technique, even using modern methods controlling variability in radical dose and quenching. Currently, the root cause of this variability has not been systematically explored, and it is unknown if the major source(s) of variability are structural heterogeneity in samples, remaining irreproducibility in FPOP oxidation, or errors in LC-MS quantification of oxidation. In this work, we demonstrate that coefficient of variation of FPOP measurements varies widely at low peptide signal intensity, but stabilizes to ≈?0.13 at higher peptide signal intensity. We dramatically reduced FPOP variability by increasing the total sample loaded onto the LC column, indicating that the major source of variability in FPOP measurements is the difficulties in quantifying oxidation at low peptide signal intensities. This simple method greatly increases the sensitivity of FPOP structural comparisons, an important step in applying the technique to study subtle conformational changes and protein-ligand interactions.
The novel unsymmetrical 3,5-dialkoxycarbonyl-2,6-dimethyl-4-(7′,8′-dimethoxycoumarin-4′-yl)-1,4-dihydropyridines and 5-acetyl-3-alkoxycarbonyl-2,6-dimethyl-4-(7′,8′-dimethoxycoumarin-4′-yl)-1,4-dihydropyridines (coumarinyl-1,4-dihydropyridines) have been synthesized by Knoevenagel condensation of 4-formyl-7,8-dimethoxycoumarin with alkyl acetoacetates in the presence of AlCl3 followed by cyclization of the resulted Knoevenagel product with other alkyl acetoacetate or acetyl acetone and ammonium acetate. The structure of the intermediate Knoevenagel product and the cyclized unsymmetrical coumarinyl-1,4-dihydropyridines has been established on the basis of their spectral data analysis and single-crystal X-ray diffraction analysis. The observed conformation of the coumarinyl-1,4-dihydropyridines holds the key to promising calcium antagonistic activity of the synthesized coumarinyl-1,4-dihydropyridines. 相似文献
A new versatile and efficient strategy for the synthesis of 2,2-bis(dimethylamino)-3-alkyl or benzyl 2,3-dihydroquinazoline-4(1H)-one compounds has been developed by one-pot multicomponent reaction with isatoic anhydride, amines followed by in situ-generated Vilsmeier reagent. The reaction has also been studied with different amines and solvents. 相似文献
Connecting two columnar phase forming discotic mesogens via a short rigid spacer leads to the formation of a π-conjugated
discotic dimer snowing discotic nematic (ND) phase. Attaching branched-alkyl chains directly to the core in hexaalkynylbenzene resulted in the stabilisation of ND phase at ambient temperature. Pentalkynylbenzene derivatives possessing a combination of normal- and branched-alkoxy chains
display a very broad ND, phase which is stable well below and above the room temperature. 相似文献