21381-61-3Relevant articles and documents
Thermally triggered solid-state single-crystal-to-single-crystal structural transformation accompanies property changes
Li, Quan-Quan,Ren, Chun-Yan,Huang, Yang-Yang,Li, Jian-Li,Liu, Ping,Liu, Bin,Liu, Yang,Wang, Yao-Yu
, p. 4703 - 4711 (2015)
The 1D complex [(CuL0.5H2O)·H2O]n (1) (H4 L = 2,2′-bipyridine-3,3′ ,6,6′-tetracarboxylic acid) undergoes an irreversible thermally triggered single-crystal-to-single-crystal (SCSC) transformation to produce the 3D anhydrous complex [CuL0.5]n (2). This SCSC structural transformation was confirmed by single-crystal X-ray diffraction analysis, thermogravimetric (TG) analysis, powder X-ray diffraction (PXRD) patterns, variable-temperature powder X-ray diffraction (VT-PXRD) patterns, and IR spectroscopy. Structural analyses reveal that in complex 2, though the initial 1D chain is still retained as in complex 1, accompanied with the Cu-bound H2O removed and new O(carboxyl)-Cu bond forming, the coordination geometries around the CuII ions vary from a distorted trigonal bipyramid to a distorted square pyramid. With the drastic structural transition, significant property changes are observed. Magnetic analyses show prominent changes from antiferromagnetism to weak ferromagnetism due to the new formed Cu1-O-C-O-Cu4 bridge. The catalytic results demonstrate that, even though both solid-state materials present high catalytic activity for the synthesis of 2-imidazolines derivatives and can be reused, the activation temperature of complex 1 is higher than that of complex 2. In addition, a possible pathway for the SCSC structural transformations is proposed.
A cobalt coordination polymer from bulk to nanoscale crystals as heterogeneous catalysts for tandem reactions
Han, Suzhen,Wang, Wenjie,Lu, Guizhen,Wang, Di,Zhang, Ying-Ying,Shao, Zhichao,Huang, Chao
, (2021/04/23)
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.
Cu(II) immobilized on Fe3O4@Agarose nanomagnetic catalyst functionalized with ethanolamine phosphate–salicylaldehyde schiff base: A magnetically reusable nanocatalyst for preparation of 2-substituted imidazolines, oxazolines, and thiazolines
Zarei, Zeinab,Akhlaghinia, Batool
, p. 170 - 191 (2018/02/17)
Herein we synthesized Cu(II) immobilized on Fe 3 O 4 @Agarose functionalized with ethanolamine phosphate–salicylaldehyde Schiff base (Fe 3 O 4 @Agarose/SAEPH 2 /Cu(II)) as a new and cost-effective nanomagnetic catalyst. The nanomagnetic catalyst was characterized by FT- IR, XRD, VSM, SEM- EDX, TEM, TGA, and ICP techniques and it was found that the particles were about 9–25 nm in size and spherical with entrapment of the Fe 3 O 4 particles in the hollow pore structure of the agarose. The prepared nanomagnetic catalyst showed excellent activity for preparation of 2-substituted imidazolines, oxazolines, and thiazolines. The catalyst is easy to prepare and exhibits higher catalytic activity than some commercially available copper sources. More importantly, this nanomagnetic catalyst can be easily recovered by using a permanent magnet and reused for at least seven cycles without significant deactivation.
Solvent templates induced porous metal-organic materials: Conformational isomerism and catalytic activity
Ding, Ran,Huang, Chao,Lu, Jingjing,Wang, Junning,Song, Chuanjun,Wu, Jie,Hou, Hongwei,Fan, Yaoting
, p. 1405 - 1413 (2015/05/27)
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.
Efficient synthesis of 2-imidazolines in the presence of molecular iodine under ultrasound irradiation
Chen, Guo-Feng,Li, Hong-Yang,Xiao, Nan,Chen, Bao-Hua,Song, Ya-Li,Li, Ji-Tai,Li, Zhi-Wei
, p. 1516 - 1521 (2014/12/11)
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.
Pd-catalyzed N-arylation of 2-imidazolines provides convenient access to selective cyclooxygenase-2 inhibitors
Krasavin, Mikhail
, p. 235 - 239 (2013/07/26)
The re-emergence, in the recent years, of cyclooxygenase as a biological target in therapeutic areas other than inflammation is likely to require new optimized leads, particularly suited for the requirements of specific drug development programs. We devel
Microwave-assisted cascade cycloaddition for C-N bond formation: An approach to the construction of 1,4,5,6-tetrahydropyrimidine and 2-imidazoline derivatives
An, Shujuan,Yin, Bing,Liu, Ping,Li, Xiangnan,Li, Chen,Li, Jianli,Shi, Zhen
, p. 2525 - 2532 (2013/09/24)
An efficient strategy for the synthesis of various 1,4,5,6- tetrahydropyrimidine and 2-imidazoline derivatives has been reported. The reactions proceeded from nitriles with ethylenediamine or 1,3-diaminopropane via cascade cycloaddition in the presence of CuL2 (L = 2-hydroxy-2-phenylacetate) to afford the corresponding 1,4,5,6- tetrahydropyrimidine or 2-imidazoline derivatives under reflux conditions or microwave irradiation in excellent yields.
Novel diversely substituted 1-heteroaryl-2-imidazolines for fragment-based drug discovery
Krasavin, Mikhail
scheme or table, p. 2876 - 2880 (2012/07/28)
A palladium-catalyzed Buchwald-Hartwig arylation protocol has been applied to achieve high-yielding N-heteroarylation of a diverse set of privileged 2-imidazolines. The resulting compounds are of interest as a novel type of molecular tool for fragment-bas
Trichloroisocyanuric acid as an efficient homogeneous catalyst for the chemoselective synthesis of 2-substituted oxazolines, imidazolines and thiazolines under solvent-free condition
Hojati, Seyedeh Fatemeh,Nezhadhoseiny, Seyede Atefe
, p. 1181 - 1189,9 (2020/09/14)
Trichloroisocyanuric acid, as a commercially available and inexpensive catalyst, was used in a new, facile and efficient procedure for the synthesis of 2-oxazolines, 2-imidazolines and 2-thiazolines through the reaction of nitriles with 2-aminoethanol, ethylenediamine or 2-aminoethanethiol under solvent-free conditions.
Copper-catalyzed synthesis of 2-imidazolines and their N-hydroxyethyl derivatives under various conditions
Zhang, Jin,Wang, Xiao,Yang, Meipan,Wan, Kerou,Yin, Bing,Wang, Yunxia,Li, Jianli,Shi, Zhen
experimental part, p. 1578 - 1582 (2011/04/26)
A rapid and efficient method for the synthesis of 2-imidazolines and their N-hydroxyethyl derivatives from the reaction of aromatic nitriles with ethylenediamine (EDA) or N-(2-aminoethyl)ethanolamine (AEEA) using cupric indole-3-acetate (Cu(II)-(IAA)2) as a reusable catalyst under reflux and microwave conditions is reported. And seven new N-hydroxyethyl-imidazolines were reported for the first time.
