72731-15-8Relevant academic research and scientific papers
Photoelectrochemical and thermal characterization of aromatic hydrocarbons substituted with a dicyanovinyl unit
Fabiańczyk, Aleksandra,Gnida, Pawe?,Kotowicz, Sonia,Kula, S?awomir,Ma?kowski, Sebastian,Ma?ecki, Jan Grzegorz,S?k, Danuta,Schab-Balcerzak, Ewa,Siwy, Mariola
, (2020/04/17)
Seven aromatic hydrocarbons bearing a dicyanovinyl unit were prepared to determine the relationship between both the number of aromatic rings and location of acceptor substituent on their thermal and optoelectronic properties. Additionally, the density functional theory calculations were performed. The obtained compounds showed temperatures of the beginning of thermal decomposition in the range of 137–289 °C, being above their respective melting points found between 88 and 248 °C. They were electrochemically active and showed quasi-reversible reduction process (except for 2-(phen-1-yl)methylene)malononitrile). Electrochemically estimated energy band gaps were below 3.0 eV, in the range of 2.10–2.50 eV. The absorption and emission spectra were recorded in CHCl3 and NMP and in solid state. All compounds strongly absorbed radiation with absorption maximum ranging from 307 to 454 nm ascribed to the intramolecular charge transfer between the donor and acceptor units. The aromatic hydrocarbons were luminescent in all investigated media and exhibited higher photoluminescence quantum yields in the solid state due to the aggregation induced emission phenomena. Electroluminescence ability of selected compounds was tested in a diode with guest-host configuration. Additionally, the selected compound together with a commercial N719 was applied in the dye-sensitized solar cell.
Bifunctional design of stable metal-organic framework bearing triazole–carboxylate mixed ligand: Highly efficient heterogeneous catalyst for knoevenagel condensation reaction under mild conditions
Kumar, Sandeep,Li, Shuangshuang,Liu, Feixiong,Ren, Peng,You, Hengzhi,Zhao, Limin
, (2020/05/25)
A highly water stable zinc metal–organic framework (ZnMOF), {[Zn(HL)2]}n, was synthesized using a triazole–carboxylate-based mixed ligand (L = 5-(4H-1,2,4-triazol-4-yl)isophthalic acid). A 2D MOF was formed by hydrothermal synthesis, and extended to a 3D supramolecular network through strong hydrogen bonding. This MOF was fully characterized by Fourier-transformation infrared spectroscopy, thermogravimetric analysis, single-crystal X-ray diffraction (XRD), powder XRD and elemental analysis. Owing to the d10 configuration of this ZnMOF, its luminescent properties were suitable for the sensing of the CN? ions over other anions, as inferred from the florescence result. However, regarding the catalytic mechanism, this ZnMOF showed a strong ability to react with CN?, which might be due to the hydrogen bonding between the COOH groups without coordination. This interaction behavior with CN? ions makes the ZnMOF a promising heterogeneous catalyst for Knoevenagel condensations using malononitrile and aldehyde derivatives as reactants under mild conditions. All reactions were conducted in water as a green solvent.
Coordination driven self-assembly of [2 + 2 + 2] molecular squares: Synthesis, crystal structures, catalytic and luminescence properties
Gupta, Vijay,Mandal, Sanjay K.
, p. 9742 - 9754 (2018/08/06)
The one-pot self-assembly of three components (metal acetates as the metal precursor, the tridentate polypyridyl ligand, N,N′-bis(2-pyridylmethyl)-tert-butylamine (bpta), as a capping ligand and bent dicarboxylic acids, 4,4′-(dimethylsilanediyl)bis-benzoi
Switching on Supramolecular Catalysis via Cavity Mediation and Electrostatic Regulation
Qiao, Yupu,Zhang, Long,Li, Jia,Lin, Wei,Wang, Zhenqiang
supporting information, p. 12778 - 12782 (2016/10/04)
Synthetic supercontainers constructed from divalent metal ions, carboxylate linkers, and sulfonylcalix[4]arene-based container precursors exhibit great promise as enzyme mimics that function in organic solvents. The capacity of these artificial hosts to catalyze Knoevenagel condensation can be switched on when the aldehyde substrate possesses a molecular size and shape matching the nanocavity of the supercontainers. In contrast, little reactivity is observed for other aldehydes that do not match the binding pocket. This substrate-dependent catalytic selectivity is attributed to the Br?nsted acidity of the metal-bound water molecules located inside the nanocavity, which is amplified when the size/shape of the aldehyde substrate fits the binding cavity. The electrostatic environment of the binding cavity and the Br?nsted acidity of the supercontainer can be further modulated using tetraalkylammonium-based regulators, leading to higher reactivity for the otherwise unreactive aldehydes.
Hierarchical high-silica zeolites as superior base catalysts
Keller, Tobias C.,Isabettini, Stephane,Verboekend, Danny,Rodrigues, Elodie G.,Perez-Ramirez, Javier
, p. 677 - 684 (2014/01/17)
For more than four decades, the design of zeolite base catalysts has relied on the application of aluminium-rich frameworks exchanged with alkali metal cations (preferably Cs+). However, moderate activity associated with access and diffusion limitations, and high manufacturing costs associated with high caesium content (typically over 30%) have hampered their industrial implementation so far. Herein, we have discovered that high-silica USY zeolites outperform their Al-rich counterparts in a variety of base-catalysed reactions of relevance in the fine chemical industry, as well as in the upgrading of biofuels. The benefits of this class of materials are amplified upon the alleviation of diffusion constraints through the introduction of a network of intracrystalline mesopores by post-synthetic modification. For example, the resulting cation-free hierarchical USY provides an up to 30-fold Knoevenagel condensation activity compared to the benchmark Cs-X, and similar observations were made upon application in liquid-phase (nitro)aldol reactions. Moreover, in the gas-phase aldol condensation of propanal, high-silica zeolites provide superior activity, selectivity, and lifetime compared to caesium-containing zeolites and even a strong solid base such as MgO. We decouple the complex interplay between mesoporosity and intrinsic zeolitic properties such as crystallinity, and quantify the increase in catalyst effectiveness upon hierarchical structuring as a function of reactant size. The obtained results are a major step to resolve the drawbacks of zeolites catalysis and thereby revitalise their potential for industrial application.
Intramolecular Charge Transfer Properties of Dicyanovinyl-Substituted Aromatics
Katritzky, Alan R.,Zhu, Dong-Wei,Schanze, Kirk S.
, p. 5737 - 5742 (2007/10/02)
A series of five dicyanovinyl (DCV)-substituted aromatic compounds (referred to collectively as Ar-DCV, where Ar = 1-phenyl, 1-naphthyl, 9-anthracenyl, 9-phenanthrenyl, and 1-pyrenyl) were prepared and their ground- and excited-state properties were examined.Solvent-dependent NMR studies indicate that the ground state of the Ar-DCV compounds is polar.Strong intramolecular charge transfer (ICT) absorption bands were observed for each compound.The position of the ICT absorption is nearly independent of solvent polarity and the molar absorptivity is related to the twist angle between the aromatic donor and the DCV acceptor.The fluorescence spectra are highly solvatochromatic and the fluorescence energy correlates with the solvent polarity parameter Δf in a variety of solvents.The fluorescence quantum yields are low and no emission was observed from phenyl-DCV.An excited state model is proposed which explains the solvent dependence of the ICT absorption and emission of the series of Ar-DCV compounds.
