162435-06-5Relevant academic research and scientific papers
Pyrazole-based ligands for the [copper-TEMPO]-mediated oxidation of benzyl alcohol to benzaldehyde and structures of the Cu coordination compounds
Uber, Jorge Salinas,Vogels, Yorick,Van Den Helder, Dave,Mutikainen, Ilpo,Turpeinen, Urho,Fu, Wen Tian,Roubeau, Olivier,Gamez, Patrick,Reedijk, Jan
, p. 4197 - 4206 (2007)
New pyrazole-based ligands have been designed, and the catalytic performances of their copper(II) complexes for the [copper/TEMPO]-mediated oxidation of benzyl alcohol to benzaldehyde have been examined. The pyridine-pyrazole ligands give efficient catalysts, while the use of naphthol-pyrazole ligands results in inactive catalytic systems. Single-crystals of four Cu coordination compounds obtained from pyridine-pyrazole ligands and a free ligand have been isolated and were characterized by X-ray diffraction. Thus, the solid-state structures of three copper(II) complexes are described, together with a copper(I) coordination chain, exhibiting luminescent properties. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
Enhancing the phosphorescence decay pathway of Cu(
Atvars, Teresa Dib Zambon,Bechtold, Ivan H.,Bortoluzzi, Adailton J.,Duarte, Luís Gustavo Teixeira Alves,Farias, Giliandro,Gallardo, Hugo,Girotto, Edivandro,Salla, Cristian A. M.,Toigo, Jéssica,de Souza, Bernardo
supporting information, p. 1008 - 1018 (2022/02/01)
Speeding up the phosphorescence channel in luminescent copper(i) complexes has been extremely challenging due to the copper atoms relatively low spin–orbit coupling constant compared to heavier metals such as iridium. Here, we report the synthesis and characterization of three mononuclear copper(i) complexes with diimines, triphenylphosphine, and iodide ligands to evaluate the effect of the copper–iodide (Cu–I) moiety into the phosphorescence decay pathway. Temperature-dependent photophysical studies revealed combined thermally activated delayed fluorescence and phosphorescence emission, with a phosphorescence decay rate of the order of 104 s?1. Density functional theory calculations indicate very high spin–orbit coupling matrix elements between the low-lying states of these complexes. Compared to the classical [Cu(phen)(POP)]+, our results demonstrate that Cu–I is a versatile moiety to speed up the phosphorescence decay pathway in about one order of magnitude, and it can be prepared by a simplified synthetic route with few synthetic steps. Furthermore, the SOC matrix elements and the phosphorescence decay rates of these complexes are comparable to those of extensively applied coordination complexes based on heavier metals, making them a promising alternative as active layers of organic light-emitting diodes.
A Highly Selective Manganese-Catalyzed Synthesis of Imines under Phosphine-Free Conditions
Chai, Huining,Yu, Kun,Liu, Bo,Tan, Weiqiang,Zhang, Guangyao
, p. 217 - 226 (2020/01/31)
An efficient and highly selective phosphine-free NN-manganese(I) complex catalyst system was developed for the acceptorless dehydrogenative coupling of alcohols with amines to form imines. The coupling reactions underwent at 3 mol % catalyst loading, and a large range of alcohols and amines with diverse functional groups was applied, including challenging diol and diamine. The target imine products were obtained in good to excellent yields. The present work provides an alternative method to construct highly active nonprecious metal complex catalysts based on phosphine-free ligands.
Cooperative Au/Ag Dual-Catalyzed Cross-Dehydrogenative Biaryl Coupling: Reaction Development and Mechanistic Insight
Li, Weipeng,Yuan, Dandan,Wang, Guoqiang,Zhao, Yue,Xie, Jin,Li, Shuhua,Zhu, Chengjian
supporting information, p. 3187 - 3197 (2019/02/19)
An operationally simple and highly selective Au/Ag bimetallic-catalyzed cross-dehydrogenative biaryl coupling between pyrazoles and fluoroarenes has been developed. With this reaction, a wide range of biheteroaryl products can be obtained in moderate to good yields with excellent functional group compatibility. The exact role of silver salts, previously overlooked in most gold-catalyzed transformations, has been carefully investigated in this biaryl coupling. Insightful experimental and theoretical studies indicate that silver acetate is the actual catalyst for C-H activation of electron-poor arenes, rather than the previously reported gold(I)-catalyzed process. An unprecedented Au/Ag dual catalysis is proposed, in which silver(I) is responsible for the activation of electron-poor fluoroarenes via a concerted metalation-deprotonation pathway, and gold(III) is responsible for the activation of electron-rich pyrazoles via an electrophilic aromatic substitution process. Kinetic studies reveal that ArFnAu(III)-mediated C-H activation of pyrazoles is most likely the rate-limiting step.
Enantioselective Excited-State Photoreactions Controlled by a Chiral Hydrogen-Bonding Iridium Sensitizer
Skubi, Kazimer L.,Kidd, Jesse B.,Jung, Hoimin,Guzei, Ilia A.,Baik, Mu-Hyun,Yoon, Tehshik P.
supporting information, p. 17186 - 17192 (2017/12/06)
Stereochemical control of electronically excited states is a long-standing challenge in photochemical synthesis, and few catalytic systems that produce high enantioselectivities in triplet-state photoreactions are known. We report herein an exceptionally effective chiral photocatalyst that recruits prochiral quinolones using a series of hydrogen-bonding and π-π interactions. The organization of these substrates within the chiral environment of the transition-metal photosensitizer leads to efficient Dexter energy transfer and effective stereoinduction. The relative insensitivity of these organometallic chromophores toward ligand modification enables the optimization of this catalyst structure for high enantiomeric excess at catalyst loadings as much as 100-fold lower than the optimal conditions reported for analogous chiral organic photosensitizers.
Iridium Complexes with Proton-Responsive Azole-Type Ligands as Effective Catalysts for CO2 Hydrogenation
Suna, Yuki,Himeda, Yuichiro,Fujita, Etsuko,Muckerman, James T.,Ertem, Mehmed Z.
, p. 4535 - 4543 (2017/11/30)
Pentamethylcyclopentadienyl iridium (Cp*Ir) complexes with bidentate ligands consisting of a pyridine ring and an electron-rich diazole ring were prepared. Their catalytic activity toward CO2 hydrogenation in 2.0 m KHCO3 aqueous solutions (pH 8.5) at 50 °C, under 1.0 MPa CO2/H2 (1:1) have been reported as an alternative to photo- and electrochemical CO2 reduction. Bidentate ligands incorporating an electron-rich diazole ring improved the catalytic performance of the Ir complexes compared to the bipyridine ligand. Complexes 2, 4, and 6, possessing both a hydroxy group and an uncoordinated NH group, which are proton-responsive and capable of generating pendent bases in basic media, recorded high initial turnover frequency values of 1300, 1550, and 2000 h?1, respectively. Spectroscopic and computational investigations revealed that the reversible deprotonation changes the electronic properties of the complexes and causes interactions between pendent base and substrate and/or solvent water molecules, resulting in high catalytic performance in basic media.
A spectroscopic study on the coordination and solution structures of the interaction systems between biperoxidovanadate complexes and the pyrazolylpyridine-like ligands
Yu, Xian-Yong,Deng, Lin,Zheng, Baishu,Zeng, Bi-Rong,Yi, Pinggui,Xu, Xin
, p. 1524 - 1533 (2014/01/06)
In order to understand the substitution effects of pyrazolylpyridine (pzpy) on the coordination reaction equilibria, the interactions between a series of pzpy-like ligands and biperoxidovanadate ([OV(O2)2(D 2O)]-/[OV(O2)2(HOD)]-, abbrv. bpV) have been explored using a combination of multinuclear ( 1H, 13C, and 51V) magnetic resonance, heteronuclear single quantum coherence (HSQC), and variable temperature NMR in a 0.15 mol L-1 NaCl D2O solution that mimics the physiological conditions. Both the direct NMR data and the equilibrium constants are reported for the first time. A series of new hepta-coordinated peroxidovanadate species [OV(O2)2L]- (L = pzpy-like chelating ligands) are formed due to several competitive coordination interactions. According to the equilibrium constants for products between bpV and the pzpy-like ligands, the relative affinity of the ligands is found to be pzpy > 2-Ester-pzpy ≈ 2-Me-pzpy ≈ 2-Amide-pzpy > 2-Et-pzpy. In the interaction system between bpV and pzpy, a pair of isomers (Isomers A and B) are observed in aqueous solution, which are attributed to different types of coordination modes between the metal center and the ligands, while the crystal structure of NH4[OV(O2)2(pzpy)]·6H 2O (CCDC 898554) has the same coordination structure as Isomer A (the main product for pzpy). For the N-substituted ligands, however, Isomer A or B type complexes can also be observed in solution but the molar ratios of the isomer are reversed (i.e., Isomer B type is the main product). These results demonstrate that when the N atom in the pyrazole ring has a substitution group, hydrogen bonding (from the H atom in the pyrazole ring), the steric effect (from alkyl) and the solvation effect (from the ester or amide group) can jointly affect the coordination reaction equilibrium. The Royal Society of Chemistry.
COMPOUNDS THAT MODULATE INTRACELLULAR CALCIUM
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Paragraph 00485, (2014/05/07)
Described herein are compounds and pharmaceutical compositions containing such compounds, which modulate the activity of store-operated calcium (SOC) channels. Also described herein are methods of using such SOC channel modulators, alone and in combination with other compounds, for treating diseases or conditions that would benefit from inhibition of SOC channel activity.
Palladium(0)-catalysed cross-coupling of 2-trimethylsilylpyridine with aryl halides
Blakemore, David C.,Marples, Louise A.
supporting information; experimental part, p. 4192 - 4195 (2011/09/19)
A general method for the Hiyama coupling reaction between aryl halides and 2-trimethylsilylpyridine has been developed. These conditions have been successfully applied to the synthesis of bis-heteroaryl systems, a key disconnection for the pharmaceutical industry in the synthesis of drug-like molecules.
Design and synthesis of novel 3,4-disubstituted pyrazoles for nanomedicine applications against malignant gliomas
Comes Franchini, Mauro,Bonini, Bianca Flavia,Camaggi, Carlo Maurizio,Gentili, Denis,Pession, Annalisa,Rani, Monica,Strocchi, Elena
experimental part, p. 2024 - 2033 (2010/06/20)
A series of novel 3,4-disubstituted pyrazoles were synthesized. The cytotoxicity against U87MG glioma cell line have been investigated in vitro and three of these compounds showed promising inhibitory activity on cell growth with an IC50 lower
