20439-47-8Relevant academic research and scientific papers
Chiral redox-Active isosceles triangles
Nalluri, Siva Krishna Mohan,Liu, Zhichang,Wu, Yilei,Hermann, Keith R.,Samanta, Avik,Kim, Dong Jun,Krzyaniak, Matthew D.,Wasielewski, Michael R.,Stoddart, J. Fraser
, p. 5968 - 5977 (2016)
Designing small-molecule organic redox-active materials, with potential applications in energy storage, has received considerable interest of late. Herein, we report on the synthesis, characterization, and application of two rigid chiral triangles, each of which consist of non-identical pyromellitic diimide (PMDI) and naphthalene diimide (NDI)-based redox-active units. 1H and 13C NMR spectroscopic investigations in solution confirm the lower symmetry (C2 point group) associated with these two isosceles triangles. Single-crystal X-ray diffraction analyses reveal their rigid triangular prism-like geometries. Unlike previously investigated equilateral triangle containing three identical NDI subunits, both isosceles triangles do not choose to form one-dimensional supramolecular nanotubes by dint of [C-H···O] interaction-driven columnar stacking. The rigid isosceles triangle, composed of one NDI and two PMDI subunits, forms in the presence of N,N-dimethylformamidetwo different types of intermolecular NDI-NDI and NDI-PMDI stacked dimers with opposite helicities in the solid state. Cyclic voltammetry reveals that both isosceles triangles can accept reversibly up to six electrons. Continuous-wave electron paramagnetic resonance and electron-nuclear double-resonance spectroscopic investigations, supported by density functional theory calculations, on the single-electron reduced radical anions of the isosceles triangles confirm the selective sharing of unpaired electrons among adjacent redox-active NDI subunit(s) within both molecules. The isosceles triangles have been employed as electrode-active materials in organic rechargeable lithium-ion batteries. The evaluation of the structure-performance relationships of this series of diimide-based triangles reveals that the increase in the number of NDI subunits, replacing PMDI ones, within the molecules improves the electrochemical cell performance of the batteries.
Using enantioselective dispersive liquid–liquid microextraction for the microseparation of trans-cyclohexane-1,2-diamine enantiomers
Hashemi, Majid,Hadjmohammadi, Mohammad Reza
, p. 454 - 459 (2017)
A new chiral separation system effective for the enantioselective extraction of racemic trans-cyclohexane-1,2-diamine is presented. Enantioselective dispersive liquid–liquid microextraction has been used for the chiral microseparation of trans-cyclohexane-1,2-diamine, with a chiral azophenolic crown ether being identified as a versatile chiral selector. The influence of various process conditions on the extraction performance was studied experimentally. It was found that the operational selectivity in one extraction step is mainly related to the type and volume of the solvents, chiral selector concentration, extraction time, temperature of sample solution, and pH. At optimum conditions (300?μL of diethyl ether as the extraction solvent 1?mL of methanol as the disperser solvent, with 5?mmol?L?1 chiral selector concentration, pH of the sample equal to 4.5, 30?min extraction time and a temperature of 10?°C), the distribution ratio of (R,R)- and (S,S)-trans-cyclohexane-1,2-diamine was 18.3 and 1.8, respectively, while the enantioselectivity value of 10.2 was found at the optimum condition.
Pd-Catalyzed asymmetric allylation involving bis(diamidophosphite) based on the salen-type chiral diamine
Gavrilov,Chuchelkin,Gavrilov,Zheglov,Firsin,Trunina,Maximychev,Perepukhov
, p. 336 - 339 (2021)
New bis(diamidophosphite) ligand with stereogenic phosphorus atoms in the 1,3,2-diaza-phospholidine rings was synthesized based on (1R,2R)-[N, N′-bis(3-hydroxybenzylidene)]-1,2-diaminocyclohexane. This ligand provided up to 73% ee in Pd-catalyzed asymmetric allylic alkylation of (E)-1,3-diphenylallyl acetate with dimethyl malonate and up to 80% ee in its amination with pyrrolidine, with the starting substrate conversion being quantitative.
Synthesis, characterization, and nucleophilic ring opening reactions of cyclohexyl-substituted β-haloamines and aziridinium ions
Chong, Hyun-Soon,Sun, Xiang,Chen, Yunwei,Wang, Meng
, p. 946 - 948 (2015)
Cyclohexyl-substituted β-haloamines and aziridinium ions were prepared and characterized. Stereospecific ring opening of aziridinium ions was applied for efficient synthesis of vicinal amine, β-amino acid, and tetrahydroisoquinoline (THIQ) analogues. Nucleophilic ring opening reactions of aziridinium ions and N-protected aziridine analogues were for the first time comparatively studied. The result of nucleophilic reactions clearly indicates that aziridinium ions were significantly more reactive toward nucleophilic ring opening than the aziridine analogues.
Spectroscopic exploration of binding of new imidazolium-based palladium(II) saldach complexes with CT-DNA as anticancer agents against HER2/neu overexpression
Alfaifi, Mohammad Y.,Elbehairi, Serag Eldin I.,Hafez, Hani S.,Elshaarawy, Reda F.M.
, p. 118 - 128 (2019)
The HER2/neu has shown a potential role in the choice of active chemotherapy for breast tumors because of its prognostic relevance and putative role in predicting drug resistance. Moreover, suppressing DNA replication has become an attractive strategy for treating cancer patients. In this attempt, the present study aimed to prepare new series of bis-imidazolium-based saldach {H2(Et)2saldach (nBu-Im+-X–)2} and their cis-Pd(II) complexes (saldach = N,N′-bis-(salicylidene)-R,R-1,2-diaminocyclohexane; X = Cl, PF6, BF4) as anticancer agents. The in vitro cytotoxicity activity of new cis-Pd(II) complexes against human breast adenocarcinoma cell lines (MCF-7) revealed higher growth-inhibitory effect than the native ligands. They induced a significant decrease for the protein HER2/neu expression with p 50 = 8.5 ± 0.2 μM) in inhibition of cell proliferation. Additionally, in vitro studies of Pd(II) complex (5a) using UV–Vis spectroscopy and binding affinity toward the calf thymus (CT) DNA) showed a combination of covalent, intercalation, hydrogen bonding interactions through formation of (CT-DNA).
Thermochemical and Structural Studies of New Chiral and Achiral Long Alkyl Chain Functionalized Imidazolinium Ionic Liquids
Seidl, Vera,Sternberg, Michelle,Heinemann, Frank W.,Schmiele, Martin,Unruh, Tobias,Wasserscheid, Peter,Meyer, Karsten
, p. 6276 - 6288 (2021/10/20)
Adding to the versatile class of ionic liquids (ILs), an entirely new series of imidazolinium-based ionic liquids is reported herein, offering chirality and important thermal characteristics, such as polymorphism, glass transition, and plastic crystalline behavior. An efficient and general procedure for the preparation of long N,N′-alkyl chain-substituted compounds with either saturated (s) or chiral (c) cyclohexyl (cyC6)-substituted imidazolium (Im) backbones, namely, [C12C12RsIm][A] (A = Br-, [BF4]-, [ClO4]-, [PF6]- R = H, Me, iPr) and [C12C12cIm-cyC6][A] (A = Br-, I-, [I3]-, [BF4]-, [ClO4]-, [PF6]-, [SbF6]-, [BPh4]-), was developed, and the novel compounds were studied by thermochemical methods (DSC, TGA), X-ray diffraction in the small angle regime (SAXS), single-crystal X-ray diffraction (SC-XRD), and specific rotation analysis.
Design and synthesis of cage-like NADH model molecule intermediate with multi-chiral centers
Zhang, Tong,Bai, Cui-Bing,Wu, Yue-Hua,Wang, Nai-Xing,Xu, Bao-Cai,Yan, Zhan,Xing, Yalan
supporting information, p. 410 - 416 (2019/02/05)
Studying NADH molecules is one of the most active areas in biomimetic research. It is important to design novel and efficient chiral NADH model molecules. Herein, a cage-like NADH model with multi-chiral centers was designed, and key intermediates have been synthesized. In this study, we found that pentafluorophenoxy group is an excellent leaving group for our synthetic route.
Synthesis of Chiral Triazole-Based Halogen Bond Donors
Kaasik, Mikk,Kaabel, Sandra,Kriis, Kadri,J?rving, Ivar,Kanger, T?nis
supporting information, p. 2128 - 2135 (2019/05/10)
The number of applications that use halogen bonding in the fields of self-assembly, supramolecular aggregation, and catalysis is growing. However, the accessibility of chiral halotriazoles shows that there is still a lot more to explore. The simple click-chemistry is applied for the straightforward synthesis of enantiomerically pure mono- and bidentate as well as multifunctional iodotriazole-based XB donors. The methodology is characterized by a wide variability due to easy access of chiral azides.
Discrete Dimers of Redox-Active and Fluorescent Perylene Diimide-Based Rigid Isosceles Triangles in the Solid State
Mohan Nalluri, Siva Krishna,Zhou, Jiawang,Cheng, Tao,Liu, Zhichang,Nguyen, Minh T.,Chen, Tianyang,Patel, Hasmukh A.,Krzyaniak, Matthew D.,Goddard, William A.,Wasielewski, Michael R.,Stoddart, J. Fraser
supporting information, p. 1290 - 1303 (2019/01/21)
The development of rigid covalent chiroptical organic materials, with multiple, readily available redox states, which exhibit high photoluminescence, is of particular importance in relation to both organic electronics and photonics. The chemically stable, thermally robust, and redox-active perylene diimide (PDI) fluorophores have received ever-increasing attention owing to their excellent fluorescence quantum yields in solution. Planar PDI derivatives, however, generally suffer from aggregation-caused emission quenching in the solid state. Herein, we report on the design and synthesis of two chiral isosceles triangles, wherein one PDI fluorophore and two pyromellitic diimide (PMDI) or naphthalene diimide (NDI) units are arranged in a rigid cyclic triangular geometry. The optical, electronic, and magnetic properties of the rigid isosceles triangles are fully characterized by a combination of optical spectroscopies, X-ray diffraction (XRD), cyclic voltammetry, and computational modeling techniques. Single-crystal XRD analysis shows that both isosceles triangles form discrete, nearly cofacial PDI-PDI π-dimers in the solid state. While the triangles exhibit fluorescence quantum yields of almost unity in solution, the dimers in the solid state exhibit very weak - yet at least an order of magnitude higher - excimer fluorescence yield in comparison with the almost completely quenched fluorescence of a reference PDI. The triangle containing both NDI and PDI subunits shows superior intramolecular energy transfer from the lowest excited singlet state of the NDI to that of the PDI subunit. Cyclic voltammetry suggests that both isosceles triangles exhibit multiple, easily accessible, and reversible redox states. Applications beckon in arenas related to molecular optoelectronic devices.
Controlled Exchange of Achiral Linkers with Chiral Linkers in Zr-Based UiO-68 Metal-Organic Framework
Tan, Chunxia,Han, Xing,Li, Zijian,Liu, Yan,Cui, Yong
supporting information, p. 16229 - 16236 (2018/11/27)
The development of highly robust heterogeneous catalysts for broad asymmetric reactions has always been a subject of interest, but it remains a synthetic challenge. Here we demonstrated that highly stable metal-organic frameworks (MOFs) with potentially acid-labile chiral catalysts can be synthesized via postsynthetic exchange. Through a one- or two-step ligand exchange, a series of asymmetric metallosalen catalysts with the same or different metal centers are incorporated into a Zr-based UiO-68 MOF to form single- and mixed-M(salen) linker crystals, which cannot be accomplished by direct solvothermal synthesis. The resulting MOFs have been characterized by a variety of techniques including single-crystal X-ray diffraction, N2 sorption, CD, and SEM/TEM-EDS mapping. The single-M(salen) linker MOFs are active and efficient catalysts for asymmetric cyanosilylation of aldehydes, ring-opening of epoxides, oxidative kinetic resolution of secondary alcohols, and aminolysis of stilbene oxide, and the mixed-M(salen) linker variants are active for sequential asymmetric alkene epoxidation/epoxide ring-opening reactions. The chiral MOF catalysts are highly enantioselective and completely heterogeneous and recyclable, making them attractive catalysts for eco-friendly synthesis of fine chemicals. This work not only advances UiO-type MOFs as a new platform for heterogeneous asymmetric catalysis in a variety of syntheses but also provides an attractive strategy for designing robust and versatile heterogeneous catalysts.
