- Iridium luminophore complexes for unimolecular oxygen sensors
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In this study, a series of novel luminescent cyclometalated Ir(III) complexes has been synthesized and evaluated for use in unimolecular oxygen-sensing materials. The complexes Ir(C6)2(vacac), 1, Ir(ppy)2-(vacac), 2, fac-Ir(ppy)2(vppy), 3, and mer-Ir(ppy)2(vppy), 4, where C6 = Coumarin 6, vacac = allylaceto-acetate, ppy = 2-phenylpyridine, and vppy = 2-(4-vinylphenyl) pyridine, all have pendent vinyl or allyl groups for polymer attachment via the hydrosilation reaction. These luminophore complexes were characterized by NMR, absorption, and emission spectroscopy, luminescence lifetime and quantum yield measurements, elemental analysis, and cyclic voltammetry. Complex 1 was structurally characterized using X-ray crystallography, and a series of 1-D (1H, 13C) and 2-D (1H-1H, 1H-13C) NMR experiments were used to resolve the solution structure of 4. Complexes 1 and 3 displayed the longest luminescence lifetimes and largest quantum efficiencies in solution (τ = 6.0 μs, φ = 0.22 for 1; τ = 0.4 μs, φ = 0.2 for 3) and, as result, are the most promising candidates for future luminescence-quenching-based oxygen-sensing studies.
- DeRosa, Maria C.,Hodgson, Derek J.,Enright, Gary D.,Dawson, Brian,Evans, Christopher E. B.,Crutchley, Robert J.
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- ‘Aggregation-Induced Emission’ Active Mono-Cyclometalated Iridium(III) Complex Mediated Efficient Vapor-Phase Detection of Dichloromethane
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Selective vapor-phase detection of dichloromethane (DCM) is a challenge, it being a well-known hazardous volatile organic solvent in trace amounts. With this in mind, we have developed an ‘Aggregation-induced Emission’ (AIE) active mono-cyclometalated iri
- Kachwal, Vishal,Laskar, Inamur Rahaman,Raichure, Pramod C.
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- Desulfonative Suzuki–Miyaura Coupling of Sulfonyl Fluorides
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Sulfonyl fluorides have emerged as powerful “click” electrophiles to access sulfonylated derivatives. Yet, they are relatively inert towards C?C bond forming transformations, notably under transition-metal catalysis. Here, we describe conditions under which aryl sulfonyl fluorides act as electrophiles for the Pd-catalyzed Suzuki–Miyaura cross-coupling. This desulfonative cross-coupling occurs selectively in the absence of base and, unusually, even in the presence of strong acids. Divergent one-step syntheses of two analogues of bioactive compounds showcase the expanded reactivity of sulfonyl fluorides to encompass both S?Nu and C?C bond formation. Mechanistic experiments and DFT calculations suggest oxidative addition occurs at the C?S bond followed by desulfonation to form a Pd-F intermediate that facilitates transmetalation.
- Bahadori, Maryam,Brykczyńska, Daria,Chatelain, Paul,Moran, Joseph,Muller, Cyprien,Rowley, Christopher N.,Sau, Abhijit
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supporting information
p. 25307 - 25312
(2021/10/25)
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- Catalytic α-Selective Deuteration of Styrene Derivatives
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We report an operationally simple protocol for the catalytic α-deuteration of styrenes. This process proceeds via the base-catalyzed reversible addition of methanol to styrenes in DMSO-d6 solvent. The concentration of methanol is shown to be critical for high yields and selectivities over multiple competing side reactions. The synthetic utility of α-deuterated styrenes for accessing deuterium-labeled chiral benzylic stereocenters is demonstrated.
- Puleo, Thomas R.,Strong, Alivia J.,Bandar, Jeffrey S.
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supporting information
p. 1467 - 1472
(2019/01/25)
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- Suzuki-Miyaura cross-coupling for efficient synthesis of aryl-substituted N-heteroarenes catalyzed by recyclable N-phenylpiperazine-Palladium(II) complex
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Polystyrene supported N-phenylpiperazine-Pd(II) complex D was synthesized and characterized by various techniques, including Fourier transform infrared spectroscopy (FTIR), scanning electronmicroscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and thermal analysis (TG-DTA). This heterogeneous Pd(II) complex showed high catalytic efficiency for the Suzuki-Miyaura coupling of arylboronic acids with aryl bromides, aryl chlorides to give the corresponding 2-arylpyridines and heteroarenes. The coupled products were formed in excellent yields at low catalyst loadings under mild reaction conditions. Further, this heterogeneous catalyst showed excellent recyclability and reused for four cycles with no significant decrease in its activity.
- Perumgani, Pullaiah C.,Kodicherla, Balaswamy,Mandapati, Mohan Rao,Parvathaneni, Sai Prathima
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p. 227 - 232
(2018/04/02)
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- Ru-Catalyzed Regioselective Direct Hydroxymethylation of (Hetero)Arenes via C-H Activation
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An efficient and direct ruthenium-catalyzed regioselective hydroxymethylation of (hetero)arenes via C-H activation with paraformaldehyde as a hydroxymethylating reagent is described. The corresponding products can be obtained in good to excellent yield. A number of aryl aldehydes can also be used in place of paraformaldehyde giving the desired alcohol products with similarly good results.
- Zhang, Guo-Fu,Li, Yue,Xie, Xiao-Qiang,Ding, Cheng-Rong
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supporting information
p. 1216 - 1219
(2017/03/14)
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- Cross-coupling study of iodo/chloropyridines and 2-chloroquinoline with atom-economic triarylbismuth reagents under Pd-catalysis
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This study describes the palladium-catalyzed couplings of iodopyridines, chloropyridines, and chloroquinoline with atom-economic BiAr3 reagents in sub-stoichiometric loadings. Mono-arylations of iodo and chloropyridines produced arylpyridines i
- Rao, Maddali L.N.,Dhanorkar, Ritesh J.
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p. 338 - 349
(2015/03/04)
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- Comparative Catalytic Activity of Group 9 [CpMIII] Complexes: Cobalt-Catalyzed C-H Amidation of Arenes with Dioxazolones as Amidating Reagents
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A procedure for the [CpCoIII]-catalyzed direct C-H amidation of arenes with dioxazolone has been developed. This reaction proceeds under straightforward and mild conditions with a broad range of substrates, including anilides. A comparative study on the catalytic activity of Group 9 [{CpMCl2}2] complexes revealed the unique efficiency of the cobalt catalyst. Pick of the bunch: A variety of arenes, including anilides, underwent direct C-H amidation with dioxazolones in the presence of a cobalt catalyst with a Cp? ligand under mild and straightforward reaction conditions (see scheme; Piv=pivaloyl). A comparative study of Group 9 [CpMIII] complexes revealed the unique ability of the cobalt catalyst to promote this transformation efficiently.
- Park, Juhyeon,Chang, Sukbok
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supporting information
p. 14103 - 14107
(2016/01/25)
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- A monolith immobilised iridium Cp catalyst for hydrogen transfer reactions under flow conditions
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An immobilised iridium hydrogen transfer catalyst has been developed for use in flow based processing by incorporation of a ligand into a porous polymeric monolithic flow reactor. The monolithic construct has been used for several redox reductions demonstrating excellent recyclability, good turnover numbers and high chemical stability giving negligible metal leaching over extended periods of use.
- Rojo, Maria Victoria,Guetzoyan, Lucie,Baxendale, Ian. R.
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p. 1768 - 1777
(2015/02/19)
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- Triarylbismuthanes as threefold aryl-transfer reagents in regioselective cross-coupling reactions with bromopyridines and quinolines
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Cross-coupling studies using bromopyridines and bromoquinolines with triarylbismuths as threefold coupling reagents in substoichiometric amounts under Pd-catalysed conditions are disclosed. The reactivity was high with both mono- and dibromopyridyl substrates, and mono- and bis-couplings were carried out regioselectively. A library of monoaryl and diaryl pyridines was formed in high yields. A one-pot strategy provided a simple and straightforward synthesis of both symmetrical and unsymmetrical diarylpyridines. Arylations of 2-bromo- and 3-bromoquinolines were achieved with triarylbismuth reagents. This study demonstrates that triarylbismuths may be used as threefold arylating reagents for the synthesis of aryl pyridines and quinolines through couplings with bromopyridines and bromoquinolines under Pd-catalysed conditions. Copyright
- Rao, Maddali L.N.,Dhanorkar, Ritesh J.
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supporting information
p. 5214 - 5228
(2014/10/15)
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- Copper-catalyzed direct C-H arylation of pyridine N-oxides with arylboronic esters: One-pot synthesis of 2-arylpyridines
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The first example of the copper-catalyzed direct C-H arylation of pyridine N-oxides with arylboronic esters has been developed, leading to a wide range of 2-arylpyridines in a one-pot synthesis with moderate to good yields without an additional reductant. This transformation allows for rapid access to a variety of 2-arylpyridines using an inexpensive catalytic system that would be more difficult to access with traditional methods. Thus, this method represents a simple and practical procedure to access 2-arylpyridines.
- Shen, Yan,Chen, Jiuxi,Liu, Miaochang,Ding, Jinchang,Gao, Wenxia,Huang, Xiaobo,Wu, Huayue
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supporting information
p. 4292 - 4295
(2014/04/17)
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- Efficient visible light-mediated cross-dehydrogenative coupling reactions of tertiary amines catalyzed by a polymer-immobilized iridium-based photocatalyst
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The immobilization of an iridium-based heterogeneous photocatalyst via a radical polymerization process is described, and its catalytic activity was evaluated for the aerobic phosphonylation reaction of N-aryl tetrahydroisoquinolines under visible light i
- Yoo, Woo-Jin,Kobayashi, Shu
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p. 2438 - 2442
(2014/05/06)
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- Cu-catalyzed direct amidation of aromatic C-H bonds: An access to arylamines
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A Cu-catalyzed aromatic C-H amidation with phthalimide under oxygen as a terminal oxidant without using additional additives has been achieved. This reaction has the broad substrate scope and shows moderate to good yields in most cases. This method is complementary to the previously reported metal-catalyzed C-H amination systems.
- Xu, Hui,Qiao, Xixue,Yang, Shiping,Shen, Zengming
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p. 4414 - 4422
(2014/06/09)
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- N -substituted hydroxylamines as synthetically versatile amino sources in the iridium-catalyzed mild C-H amidation reaction
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N-Substituted hydroxylamines such as aroyloxy- or acyloxycarbamates were successfully employed as synthetically versatile amino precursors in the iridium-catalyzed direct C-H amidation of arenes. The reaction proceeds smoothly at room temperature over a broad range of substrates with high functional group tolerance to afford N-substituted arylamine products.
- Patel, Pitambar,Chang, Sukbok
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supporting information
p. 3328 - 3331
(2014/07/08)
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- A rapid and efficient catalysis system for the synthesis of 4-vinylbiphenyl derivatives
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A series of 4-vinylbiphenyl derivatives were synthesized by Pd(OAc) 2/PCy3-catalyzed Suzuki-Miyaura reaction in the presence of K3PO4.3H2O as base in toluene at 80°C for only 10-30 min, and the corresponding products achieved 65-98% yields. According to this efficient C - C bond-forming method, the obtained yields of 4-vinylbiphenyl liquid crystal compounds were up to 92-96%. Copyright
- Ma, Xiaowei,Liu, Yan,Liu, Ping,Xie, Jianwei,Dai, Bin,Liu, Zhiyong
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p. 707 - 710
(2013/12/04)
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- Rhodium(I)-catalyzed direct carboxylation of arenes with CO2 via chelation-assisted C-H bond activation
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Rh-catalyzed direct carboxylation of unactivated aryl C-H bond under atmospheric pressure of carbon dioxide was realized via chelation-assisted C-H activation for the first time. Variously substituted and functionalized 2-arylpyridines and 1-arylpyrazoles underwent the carboxylation in the presence of the rhodium catalyst and a stoichiometric methylating reagent, AlMe 2(OMe), to give carboxylated products in good yields. The catalysis is proposed to consist of methylrhodium(I) species as the key intermediate, which undergoes C-H activation to afford rhodium(III), followed by reductive elimination of methane to give nucleophilic arylrhodium(I). This approach demonstrates promising application of C-H bond activation strategy in the field of carbon dioxide fixation.
- Mizuno, Hajime,Takaya, Jun,Iwasawa, Nobuharu
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supporting information; experimental part
p. 1251 - 1253
(2011/04/16)
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- TRANSITION METAL-CATALYZED ALKYLATION OF C-H BONDS WITH ORGANOBORON REAGENTS
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One aspect of the present invention relates to methods for functionalization of 2-arylpyridine and arylpyrazoles with organoboron reagents in the presence of a transition metal catalyst to furnish alkylated arylpyridines and arylpyrazoles via regioselective functionalization of sp2 -hybridized C-H bonds at a position ortho to the point of attachment of the pyridine or pyrazole ring to the aromatic nucleus, hi other embodiments, the present invention provides for alkylation of sp3-hybridized C-H bonds in alkylpyridines.
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Page/Page column 61
(2008/06/13)
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- Vinyl-phenyl pyridine monomers and polymers prepared thereform
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The present invention relates to vinyl-phenyl monomers and polymers prepared therefrom. More particularly, the present invention is to provide the vinyl-phenyl monomers expressed by formula (1) which are capable of various polymerization such as radical p
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