- A cobalt coordination polymer from bulk to nanoscale crystals as heterogeneous catalysts for tandem reactions
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Constructing nanoscale coordination polymers (CPs) with different micro- or nanoscale morphologies and sizes is crucial for the functionalization of CPs-based heterogeneous catalysts. Herein, surfactant polyvinylpyrrolidone (PVP), surface-supported frameworks (filter paper or Ni foam), and Co-based CPs (1), [Co2(pdpa)(py)4(H2O)]n (H4pdpa ?= ?5,5’-(pentane-1,2-diyl)-bis(oxy)diisophthalic; py ?= ?pyridine)) were employed to develop highly ordered micro- or nanoscale CPs, achieving microscale 1a (without surface-supported framework) and nanoscale 1b-c (filter paper and Ni foam as surface-supported frameworks for 1b and 1c, respectively). Furthermore, the catalytic performance of nanoscale 1c with spheric particles for the tandem conversion reactions of aromatic nitriles and diamines into imidazoline or tetrahydropyrimidine frameworks was much more prominent than that of large scale 1, microscale 1a, and nanoscale 1b because of the easily accessible catalytic active sites in the nanoscale spheric particles, which offered a functionalizable platform for the tandem reactions by minimizing the diffusion distance but did little for their activity.
- Han, Suzhen,Wang, Wenjie,Lu, Guizhen,Wang, Di,Zhang, Ying-Ying,Shao, Zhichao,Huang, Chao
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- Anti-corrosive property of bioinspired environmental benign imidazole and isoxazoline heterocyclics: A cumulative studies of experimental and DFT methods
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In the present study, four imidazoline (IDZ) and four isoxazolines (ISO) heterocyclics differing in the nature of methoxy (-OCH3) and aromatic (phenyl and naphthyl) moieties are synthesized, characterized and evaluated as corrosion inhibitors for mild steel in acidic solution of 1 M HCl. Results showed that imidazoline based heterocyclic compounds are better corrosion inhibitors than isoxazoline based heterocyclics and both classes of compounds showed inhibition efficiency of more than 85% at 20 mgL?1 concentration. Results further showed that inhibitors containing methoxy, phenyl, and naphthyl moieties showed higher protection efficiency as compared to the inhibitors without these moieties. PDP Study revealed that investigated IDZs and ISOs acted as mixed type inhibitors and their adsorption on the metallic surface followed the Langmuir adsorption isotherm model. All the experimental results were corroborated by density function theory (DFT) based quantum chemical calculations. Numerous DFT based indices calculated for neutral as well as protonated forms of the IDZs and ISOs in order to get better insight about metal-IDZs/ISOs interactions. Outcomes of the DFT analysis showed that protonated (cationic) form of the all the inhibitors are more strongly adsorbed on the metallic surface as compared to their neutral form.
- Ramkumar, Sowmya,Nalini,Quraishi, Mumtaz A.,Ebenso, Eno E.,Verma, Chandrabhan
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supporting information
p. 103 - 119
(2019/12/24)
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- Solvent templates induced porous metal-organic materials: Conformational isomerism and catalytic activity
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Solvent templates induced Co-based metal-organic materials; conformational isomers {[Co2(pdpa)(CH3CN)(H2O)3]·CH3OH·H2O}n (1) and {[Co2(pdpa)(CH3CN)(H2O)3]}n (2) and {[Co5(pdpa)2(μ3-OH)2(H2O)6]·2H2O}n (3) [H4pdpa = 5,5′-(pentane-1,2-diyl)-bis(oxy)diisophthalic acid] were synthesized under the same solvothermal conditions except with different concentrations of cyclic ethers (1,4-dioxane or tetrahydrofuran) as structure-directing agents. Structural transformations from a three-dimensional (3D) framework of 1 containing channels with dimensions of μ6 ? × 6 ? to a two-dimensional layer structure of 2 consisting of large open channels with a size of μ15 ? × 8 ? and then to a 3D nonporous framework of 3, resulting from the different concentrations of cyclic ethers, were observed. The anion-π interactions between electron-efficient oxygen atoms of cyclic ethers and electron-deficient dicarboxylic acid aromatic cores in H4pdpa imported into the synthetic process accounted for the conformational change of the ligand H4pdpa and the following structural variations. A systematic investigation was conducted to explore how different concentrations of structure-directing agents affected the frameworks of resultant metal-organic frameworks. Furthermore, 1-3 were shown to be available heterogeneous catalysts for the synthesis of 2-imidazoline and 1,4,5,6-tetrahydropyrimidine derivatives by the cascade cycloaddition reactions of aromatic nitriles with diamines. The results showed that the catalytic activity of 2 was much higher than that of 1 and 3, because of its unique structural features, including accessible catalytic sites and suitable channel size and shape. In addition, a plausible mechanism for these catalytic reactions was proposed, and the reactivity-structure relationship was further clarified.
- Ding, Ran,Huang, Chao,Lu, Jingjing,Wang, Junning,Song, Chuanjun,Wu, Jie,Hou, Hongwei,Fan, Yaoting
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p. 1405 - 1413
(2015/05/27)
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- Efficient synthesis of 2-imidazolines in the presence of molecular iodine under ultrasound irradiation
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An efficient one-pot synthesis process for preparing 2-imidazolines from aldehydes and ethylenediamine using molecular iodine and potassium carbonate in absolute ethanol at 25-30°C under ultrasound irradiation is described. The synthetic strategy has the following advantages: mild conditions and low costs requirements, readily available catalyst, short reaction times, simplicity of operation, and good-to-excellent yields.
- Chen, Guo-Feng,Li, Hong-Yang,Xiao, Nan,Chen, Bao-Hua,Song, Ya-Li,Li, Ji-Tai,Li, Zhi-Wei
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p. 1516 - 1521
(2014/12/11)
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- Facile preparation of 2-imidazolines from aldehydes with tert-butyl hypochlorite
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An efficient and high-yield preparation of 2-imidazolines was achieved from aldehydes and ethylenediamines in the presence of tert-butyl hypochlorite. By this method, 1,3-bis(imidazolin-2-yl)benzene and 2,6-bis(imidazolin-2-yl) pyridine, which act as chiral ligands, could be prepared directly from the corresponding dialdehydes in high yields. Georg Thieme Verlag Stuttgart.
- Ishihara, Midori,Togo, Hideo
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p. 1939 - 1942
(2008/02/10)
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- Direct oxidative conversion of aldehydes and alcohols to 2-imidazolines and 2-oxazolines using molecular iodine
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Aldehydes were converted to the corresponding 2-imidazolines and 2-oxazolines in good yields by the reaction with ethylenediamine and aminoethanol, respectively, using molecular iodine and potassium carbonate. Moreover, primary alcohols were directly converted to the corresponding 2-imidazolines and 2-oxazolines via aldehydes in one-pot manner with ethylenediamine and aminoethanol, respectively, using molecular iodine and potassium carbonate.
- Ishihara, Midori,Togo, Hideo
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p. 1474 - 1480
(2007/10/03)
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- A convenient synthesis of oxazolines and imidazolines from aromatic aldehydes with pyridinium hydrobromide perbromide in water
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Various 2-oxazolines were prepared from aromatic aldehydes and 2-aminoethanol with pyridinium hydrobromide perbromide in water at room temperature. 2-Imidazolines were also obtained in good yields from aromatic aldehydes and ethylenediamine under the same reaction conditions. Georg Thieme Verlag Stuttgart.
- Sayama, Shinsei
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p. 1479 - 1484
(2007/10/03)
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- Synthesis and pharmacological evaluation of imidazoline sites I1 and I2 selective ligands
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Several series of 2-aryl or heterocyclic-imidazoline compounds have been prepared and evaluated in vitro as imidazoline sites (I1 and I2) and α-adrenergic (α1 and α2) receptor ligands. Their pKi values indicate that linkage of the imidazoline moiety at the 2-position with an aromatic substituent dramatically decreases α-adrenergic affinity. I1 sites are more accessible by phenyl imidazolines substituted by a methyl or a methoxy group at the ortho or meta position. Indeed, 2-(2′-methoxyphenyl)-imidazoline (17) is one of the best I1 ligands ever reported (pKi=8.53 and I1/I2>3388). On the other hand, I2 selectivity increases in the presence of a methyl group in the para position. The original compound, 2-(3′-fluoro-4′-tolyl)-imidazoline (31) is a new potent ligand for the I2 sites with high selectivity (pKi=8.53 and I2/I1>3388). Copyright
- Anastassiadou, Maria,Danoun, Sada,Crane, Louis,Baziard-Mouysset, Genevieve,Payard, Marc,Caignard, Daniel-Henri,Rettori, Marie-Claire,Renard, Pierre
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p. 585 - 592
(2007/10/03)
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- Imidazoline receptors: Qualitative structure-activity relationships and discovery of tracizoline and benazoline. Two ligands with high affinity and unprecedented selectivity
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The observation that all the attempts to characterize imidazoline (I) receptors have been carried out with non-selective or poorly selective ligands prompted us to undertake research aimed at developing selective ligand(s). In previous work using, as a st
- Pigini, Maria,Bousquet, Pascal,Carotti, Angelo,Dontenwill, Monique,Giannella, Mario,Moriconi, Roberta,Piergentili, Alessandro,Quaglia, Wilma,Tayebati, Seyed K.,Brasili, Livio
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p. 833 - 841
(2007/10/03)
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