64291-96-9Relevant articles and documents
Effect of substitution of methyl groups on the luminescence performance of IrIII complexes: Preparation, structures, electrochemistry, photophysical properties and their applications in organic light-emitting diodes (OLEDs)
Jung, Sungouk,Kang, Youngjin,Kim, Hyung-Sun,Kim, Yun-Hi,Lee, Chang-Lyoul,Kim, Jang-Joo,Lee, Sung-Koo,Kwon, Soon-Ki
, p. 3415 - 3423 (2004)
A series of dimethyl-substituted tris(pyridylphenyl)iridium(III) derivatives [(n-MePy-n′-MePh)3Ir] [n = 3, n′ = 4 (1); n = 4, n′ = 4 (2); n = 4, n′ = 5 (3); n = 5, n′ = 4 (4); n = 5, n′ = 5 (5)] have been synthesized and characterized to investigate the effect of the substitution of methyl groups on the solid-state structure and photo- and electroluminescence. The absorption, emission, cyclic voltammetry and electroluminescent performance of 1-5 have also been systematically evaluated. The structures of 2 and 4 have been determined by a single-crystal X-ray diffraction analysis. Under reflux (> 200 °C) in glycerol solution, fac-type complexes with a distorted octahedral geometry are predominantly formed as the major components in all cases. Electrochemical studies showed much smaller oxidation potentials relative to Ir(ppy)3 (Hppy = 2-phenylpyridine). All complexes exhibit intense green photoluminescence (PL), which has been attributed to metal-to-ligand charge transfer (MLCT) triplet emission. The maximum emission wavelengths of thin films of 1, 3, 4 and 5 at room temperature are in the range 529-536 nm, while 2 displays a blue-shifted emission band (λmax = 512 nm) with a higher PL quantum efficiency (ΦPL = 0.52) than those of complexes 1 and 3-5; this is attributed to a decrease of the intermolecular interactions. Multilayered organic light-emitting diodes (OLEDs) were fabricated by using three (2, 3 and 4) of these IrIII derivatives as dopant materials. The electroluminescence (EL) spectra of the devices, which have the maximum peaks at 509-522 nm, with shoulder peaks near 552 nm, are consistent with the PL spectra in solution at 298 K. The devices show operating voltages at 1 mA/cm 2 of 4,9, 5.6, 5,1, and 4.6 V for Ir(ppy)3, 2, 3, and 4, respectively. In particular, the device with 2 shows a higher external quantum efficiency (ηext = 11% at 1 mA/cm2) and brightness (4543 cd/m2 at 20 mA/cm2) than Ir(ppy)3 (ηext = 6.0% at 1 mA/cm2; 3156 cd/m2 at 20 mA/cm2) and other Ir(dmppy)3 derivatives, (dmppy = dimethyl-substituted ppy), under the same conditions. The methyl groups at the meta (Ph) and para (Py) positions to the Ir metal atom have a great influence on absorption, emission, redox potentials and electroluminescence. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
Direct suzuki-miyaura coupling with naphthalene-1,8-diaminato (dan)-substituted organoborons
Yoshida, Hiroto,Seki, Michinari,Kamio, Shintaro,Tanaka, Hideya,Izumi, Yuki,Li, Jialun,Osaka, Itaru,Abe, Manabu,Andoh, Hiroki,Yajima, Tomoki,Tani, Tomohiro,Tsuchimoto, Teruhisa
, p. 346 - 351 (2019/12/24)
The actually direct Suzuki-Miyaura coupling with "protected" R-B(dan) (dan = naphthalene-1,8-diaminato) was demonstrated to smoothly occur without in situ deprotection of the B(dan) moiety. The use of t-BuOK (Ba(OH)2 in some cases) as a base under anhydrous conditions is the key to the successful cross-coupling, where R-B(dan) is readily converted into a transmetalation-active borate-form, regardless of the well-accepted diminished boron-Lewis acidity.
Stereodivergent Synthesis of Alkenylpyridines via Pd/Cu Catalyzed C-H Alkenylation of Pyridinium Salts with Alkynes
Chen, Hua,Haiyan, Fu,Jiang, Weidong,Li, Ruixiang,Li, Shun,Li, Wenjing,Tang, Juan,Xu, Bin,Yuan, Maolin,Zheng, Xueli
supporting information, p. 7814 - 7819 (2020/11/03)
The first Pd/Cu catalyzed selective C2-alkenylation of pyridines with internal alkynes has been developed via the pyridinium salt activation strategy. Importantly, the configuration of the product alkenylpyridines could be tuned by the choice of the proper N-alkyl group of the pyridinium salts, thus allowing for both the Z- and E-alkenylpyridines synthesized with good regio- and stereoselectivity. A plausible mechanism was proposed based on the Hammett study and KIE experiment.
Ruthenium-Catalyzed Reductive Cleavage of Unstrained Aryl-Aryl Bonds: Reaction Development and Mechanistic Study
Zhu, Jun,Chen, Peng-hao,Lu, Gang,Liu, Peng,Dong, Guangbin
supporting information, p. 18630 - 18640 (2019/11/21)
Cleavage of carbon-carbon bonds has been found in some important industrial processes, for example, petroleum cracking, and has inspired development of numerous synthetic methods. However, nonpolar unstrained C(aryl)-C(aryl) bonds remain one of the toughest bonds to be activated. As a detailed study of a fundamental reaction mode, here a full story is described about our development of a Ru-catalyzed reductive cleavage of unstrained C(aryl)-C(aryl) bonds. A wide range of biaryl compounds that contain directing groups (DGs) at 2,2′ positions can serve as effective substrates. Various heterocycles, such as pyridine, quinoline, pyrimidine, and pyrazole, can be employed as DGs. Besides hydrogen gas, other reagents, such as Hantzsch ester, silanes, and alcohols, can be employed as terminal reductants. The reaction is pH neutral and free of oxidants; thus a number of functional groups are tolerated. Notably, a one-pot C-C activation/C-C coupling has been realized. Computational and experimental mechanistic studies indicate that the reaction involves a ruthenium(II) monohydride-mediated C(aryl)-C(aryl) activation and the resting state of the catalyst is a η4-coordinated ruthenium(II) dichloride complex, which could inspire development of other transformations based on this reaction mode.
Palladium-Catalyzed Electrochemical C-H Alkylation of Arenes
Yang, Qi-Liang,Li, Chuan-Zeng,Zhang, Liang-Wei,Li, Yu-Yan,Tong, Xiaofeng,Wu, Xin-Yan,Mei, Tian-Sheng
, p. 1208 - 1212 (2018/10/20)
Palladium-catalyzed electrochemical C-H functionalization reactions have emerged as attractive tools for organic synthesis. This process offers an alternative to conventional methods that require harsh chemical oxidants. However, this electrolysis requires divided cells to avoid catalyst deactivation by cathodic reduction. Herein, we report the first example of palladium-catalyzed electrochemical C-H alkylation of arenes using undivided electrochemical cells in water, thereby providing a practical solution for the introduction of alkyl groups into arenes.
Heterocyclic Allylsulfones as Latent Heteroaryl Nucleophiles in Palladium-Catalyzed Cross-Coupling Reactions
Markovic, Tim,Murray, Philip R.D.,Rocke, Benjamin N.,Shavnya, Andre,Blakemore, David C.,Willis, Michael C.
, p. 15916 - 15923 (2018/11/23)
Heterocyclic sulfinates are effective reagents in palladium-catalyzed coupling reactions with aryl and heteroaryl halides, often providing high yields of the targeted biaryl. However, the preparation and purification of complex heterocylic sulfinates can be problematic. In addition, sulfinate functionality is not tolerant of the majority of synthetic transformations, making these reagents unsuitable for multistep elaboration. Herein, we show that heterocyclic allylsulfones can function as latent sulfinate reagents and, when treated with a Pd(0) catalyst and an aryl halide, undergo deallylation, followed by efficient desulfinylative cross-coupling. A broad range of allyl heteroarylsulfones are conveniently prepared, using several complementary routes, and are shown to be effective coupling partners with a variety of aryl and heteroaryl halides. We demonstrate that the allylsulfone functional group can tolerate a range of standard synthetic transformations, including orthogonal C- and N-coupling reactions, allowing multistep elaboration. The allylsulfones are successfully coupled with a variety of medicinally relevant substrates, demonstrating their applicability in demanding cross-coupling transformations. In addition, pharmaceutical agents crizotinib and etoricoxib were prepared using allyl heteroaryl sulfone coupling partners, further demonstrating the utility of these new reagents.
Copper-catalyzed cross-coupling of aryl-, primary alkyl-, and secondary alkylboranes with heteroaryl bromides
Bergmann, Allison M.,Oldham, Adam M.,You, Wei,Brown, M. Kevin
supporting information, p. 5381 - 5384 (2018/06/01)
A method for the Cu-catalyzed cross-coupling of both aryl and alkylboranes with aryl bromides is described. The method employs an inexpensive Cu-catalyst and functions for a variety of heterocyclic as well as electron deficient aryl bromides. In addition, aryl iodides of varying substitution patterns and electronic properties work well.
Scope of regioselective Suzuki reactions in the synthesis of arylpyridines and benzylpyridines and subsequent intramolecular cyclizations to azafluorenes and azafluorenones
Laha, Joydev K.,Patel, Ketul V.,Saima,Pandey, Surabhi,Solanke, Ganesh,Vashisht, Vanya
supporting information, p. 16069 - 16074 (2018/10/04)
The current investigation on regioselective Suzuki reactions of 2,3-dihalopyridines and 2-halo-3-halomethylpyridines yielded the unexplored synthesis of arylpyridines and benzylpyridines bearing synthetic handles for further functionalization. Indeed, the scope of intramolecular cyclizations of arylpyridines and benzylpyridines prepared in this study for the synthesis of azafluorenes and azafluorenones has been investigated.
Catalyst Selection Facilitates the Use of Heterocyclic Sulfinates as General Nucleophilic Coupling Partners in Palladium-Catalyzed Coupling Reactions
Markovic, Tim,Rocke, Benjamin N.,Blakemore, David C.,Mascitti, Vincent,Willis, Michael C.
, p. 6033 - 6035 (2017/11/27)
A range of 5- and 6-membered heterocycle-derived sulfinates are shown to be effective nucleophilic coupling partners with aryl chlorides and bromides using Pd(0) catalysis. The use of optimal reaction conditions, specifically incorporating a P(t-Bu)2Me-derived Pd catalyst, allowed reactions to be performed at moderate temperatures and enabled the inclusion of a variety of sensitive functional groups. Challenging heterocyclic sulfinates, including pyrazine, pyridazine, pyrimidine, pyrazole, and imidazole, were all shown to perform well.
Pyridine sulfinates as general nucleophilic coupling partners in palladium-catalyzed cross-coupling reactions with aryl halides
Markovic, Tim,Rocke, Benjamin N.,Blakemore, David C.,Mascitti, Vincent,Willis, Michael C.
, p. 4437 - 4442 (2017/07/11)
Pyridine rings are ubiquitous in drug molecules; however, the pre-eminent reaction used to form carbon-carbon bonds in the pharmaceutical industry, the Suzuki-Miyaura cross-coupling reaction, often fails when applied to these structures. This phenomenon is most pronounced in 2-substituted pyridines, and results from the difficulty in preparing, the poor stability of, and low efficiency in reactions of pyridine-2-boronates. We demonstrate that by replacing these boronates with pyridine-2-sulfinates, a cross-coupling process of unrivalled scope and utility is realized. The corresponding 3-And 4-substituted pyridine variants are also efficient coupling partners. In addition, we apply these sulfinates in a library format to the preparation of medicinally relevant derivatives of the drugs varenicline (Chantix) and mepyramine (Anthisan).
