2633-66-1Relevant articles and documents
Backbone Boron-Functionalized Imidazoles/Imidazolium Salts: Synthesis, Structure, Metalation Studies, and Fluoride Sensing Properties
Anantharaman, Ganapathi,Avinash, Iruthayaraj,Parveen, Sabeeha
, (2020)
Incorporation of a Lewis acidic BMes2 (Mes = mesityl) moiety at the backbone of the imidazole ring was achieved by metal-halogen exchange procedure. Among them, two isomeric boron-phosphine functionalized imidazoles (3 and 6), monoboron-functionalized imidazoles (4 and 5), and its corresponding imidazolium salts were synthesized and thoroughly characterized. The solid-state structure of 3 reveals a dimeric B-N adduct that possesses six-membered [C-B-N]2 ring, and 5 crystallizes as tetrameric B-N adduct that forms an interesting 16-membered macrocycle, whereas 4 and 6 were obtained as monomeric BMes2-substituted imidazoles. 6 behaves as a P^N-type ligand upon the coordination with CuI to afford luminescent L2Cu4I4-type metal complexes (10 and 11) whose photophysical properties were also studied. The presence (in 10) and the absence (in 11) of BMes2 made a remarkable impact on fluorescence emission causing shift from the green (10) to orange (11) region. The fluoride sensing properties of BMes2-containing imidazoles (4 to 9) were studied using UV-vis and fluorescence spectroscopy.
Palladium-Based Hydroamination Catalysts Employing Sterically Demanding 3-Iminophosphines: Branched Kinetic Products by Prevention of Allylamine Isomerization
Thakuri, Rajendr S.,Schmidt, Joseph A. R.
, p. 1917 - 1927 (2019/05/21)
A new allylpalladium triflate catalyst with a dimesitylphosphine moiety was synthesized, isolated, and characterized. The greatly increased steric bulk on the phosphine of this palladium catalyst inhibited product isomerization, which is often observed after hydroamination of terminal allenes with secondary amines. The considerably reduced rate of isomerization facilitated the isolation of many previously unknown branched allylamines, products that were inaccessible when using other, more active 3-iminophosphine palladium catalysts.
A combined m?ssbauer, magnetic circular dichroism, and density functional theory approach for iron cross-coupling catalysis: Electronic structure, in situ formation, and reactivity of iron-mesityl-bisphosphines
Daifuku, Stephanie L.,Al-Afyouni, Malik H.,Snyder, Benjamin E. R.,Kneebone, Jared L.,Neidig, Michael L.
, p. 9132 - 9143 (2014/07/08)
While iron-bisphosphines have emerged as effective catalysts for C-C cross-coupling, the nature of the in situ formed iron species, elucidation of the active catalysts and the mechanisms of catalysis have remained elusive. A combination of 57Fe M?ssbauer and magnetic circular dichroism (MCD) spectroscopies of well-defined and in situ formed mesityl-iron(II)-SciOPP species combined with density functional theory (DFT) investigations provides the first direct insight into electronic structure, bonding and in situ speciation of mesityl-iron(II)-bisphosphines in the Kumada cross-coupling of MesMgBr and primary alkyl halides using FeCl2(SciOPP). Combined with freeze-trapped solution M?ssbauer studies of reactions with primary alkyl halides, these studies demonstrate that distorted square-planar FeMes 2(SciOPP) is the active catalyst for cross-coupling and provide insight into the molecular-level mechanism of catalysis. These studies also define the effects of key reaction protocol details, including the role of the slow Grignard addition method and the addition of excess SciOPP ligand, in leading to high product yields and selectivities.
Cyclopalladation of telluro ether ligands: Synthesis, reactivity and structural characterization
Kolay, Siddhartha,Kumar, Mukesh,Wadawale, Amey,Das, Dasarathi,Jain, Vimal K.
supporting information, p. 16056 - 16065 (2015/01/09)
Treatment of [PdCl2(PhCN)2] with diaryl telluride in 1:2 molar ratio gave mononuclear palladium complexes, trans-[PdCl2(TeR2)2] (1) (R = Mes (1a) (Mes = 2,4,6-trimethylphenyl), Ph (1b), o-tol (1c) (o-tol = ortho-tolyl)). Reaction of [PdCl2(TeMes2)2] with one equivalent of [PdCl2(PhCN)2] or Na2PdCl4 with TeRR′ afforded chloro-bridged binuclear complexes, [Pd2(μ-Cl)2Cl2(TeRR′)2] (2) (R/R′ = Mes/Mes (2a); Mes/Ph (2b); Ph/Ph (2c)). A toluene-methanol solution of trans-[PdCl2(TeMes2)2] on refluxing for 30 minutes yielded a binuclear cyclopalladated complex, [Pd2(μ-Cl)2{CH2C6H2(4,6-Me2)TeMes)}2] (3). When the refluxing was prolonged, a mononuclear complex cis-[PdCl2{MesTeCH2C6H2(4,6-Me2)TeMes}] (4) was isolated. Treatment of palladium acetate with TeMes2 afforded an acetato-bridged analogue of 3, [Pd2(μ-OAc)2{CH2C6H2(4,6-Me2)TeMes}2] (5a) together with a very minor component, a tetranuclear complex, [Pd(μ-OAc)(μ-TeMes)]4 (6). This reaction with unsymmetrical tellurides, MesTeR, also gave cyclopalladated complexes [Pd2(μ-OAc)2{CH2C6H2(4,6-Me2)TeR}2] (R = o-tol (5b) and Ph (5c)) in which 2-methyl of the mesityl group of the telluride was exclusively metallated. The complex trans-[PdCl2(TeMes2)2] on refluxing in xylene gave palladium telluride, Pd7Te3. These complexes were characterized by elemental analyses, IR and NMR (1H, 13C and 125Te) spectroscopy. The molecular structures of trans-[PdCl2(TeMes2)2] (1a), [Pd2(μ-Cl)2Cl2(TeMes2)2]·2acetone (2a·2acetone), cis-[PdCl2{MesTeCH2C6H2(4,6-Me2)TeMes}] (4), [Pd2(μ-OAc)2{CH2C6H2(4,6-Me2)TeMes)}2]·toluene (5a·toluene), [Pd2(μ-OAc)2{CH2C6H2(4,6-Me2)Tetol-o}2] (5b) and [Pd(μ-OAc)(μ-TeMes)]4 (6) were established by single crystal X-ray diffraction analyses. The mononuclear complex 1a was isolated in two polymorphic forms each with the trans configuration. This journal is
Cyclometalated iridium complexes of bis(aryl) phosphine ligands: Catalytic C-H/C-D exchanges and C-C coupling reactions
Campos, Jesus,Espada, Maria F.,Lopez-Serrano, Joaquin,Carmona, Ernesto
supporting information, p. 6694 - 6704 (2013/07/19)
This work details the synthesis and structural identification of a series of complexes of the (η5-C5Me5)Ir(III) unit coordinated to cyclometalated bis(aryl)phosphine ligands, PR′(Ar) 2, for R′ = Me and Ar = 2,4,6-Me3C6H 2, 1b; 2,6-Me2-4-OMe-C6H2, 1c; 2,6-Me2-4-F-C6H2, 1d; R′ = Et, Ar = 2,6-Me2C6H3, 1e. Both chloride-and hydride-containing compounds, 2b-2e and 3b-3e, respectively, are described. Reactions of chlorides 2 with NaBArF (BArF = B(3,5-C 6H3(CF3)2)4) in the presence of CO form cationic carbonyl complexes, 4+, with ν(CO) values in the narrow interval 2030-2040 cm-1, indicating similar π-basicity of the Ir(III) center of these complexes. In the absence of CO, NaBArF forces κ4-P,C,C′,C″ coordination of the metalated arm (studied for the selected complexes 5b, 5d, and 5e), a binding mode so far encountered only when the phosphine contains two benzylic groups. A base-catalyzed intramolecular, dehydrogenative, C-C coupling reaction converts the κ4 species 5d and 5e into the corresponding hydrido phosphepine complexes 6d and 6e. Using CD3OD as the source of deuterium, the chlorides 2 undergo deuteration of their 11 benzylic positions whereas hydrides 3 experience only D incorporation into the Ir-H and Ir-CH 2 sites. Mechanistic schemes that explain this diversity have come to light thanks to experimental and theoretical DFT studies that are also reported.
Cross-coupling of aryl/alkenyl silyl ethers with grignard reagents through nickel-catalyzed CO bond activation
Zhao, Fei,Yu, Da-Gang,Zhu, Ru-Yi,Xi, Zhenfeng,Shi, Zhang-Jie
supporting information; experimental part, p. 1001 - 1003 (2011/12/05)
CO activation and its application have drawn much attention since oxygen-based electrophiles are easily available, less toxic, and more environmentally benign. This letter presents systematically results on the Ni-catalyzed KumadaTamaoCorriu coupling based on siloxy arenes/alkenes, which provides a new strategy of silyl protection/CC bond formation sequence in organic synthesis.
Mesostructured organosilica with a 9-mesityl-10-methylacridinium bridging unit: Photoinduced charge separation in the organosilica framework
Mizoshita, Norihiro,Yamanaka, Ken-Ichi,Shimada, Toyoshi,Tani, Takao,Inagaki, Shinji
supporting information; experimental part, p. 9235 - 9237 (2011/02/22)
Polycondensation of 9-mesityl-10-methylacridinium-bridged organosilane in the presence of a nonionic surfactant yielded a mesostructured organosilica solid with a functional framework that exhibited long-lived photoinduced charge separation.
Arylzinc species by microwave assisted Grignard formation-transmetallation sequence: Application in the Negishi coupling
Mutule, Ilga,Suna, Edgars
, p. 11168 - 11176 (2007/10/03)
Arylmagnesium species can be efficiently generated from magnesium turnings and aryl chlorides or aryl bromides under dielectric heating conditions. Subsequent microwave assisted transmetallation using ZnCl2-TMEDA afforded the corresponding arylzinc reagents. A sequential microwave assisted arylmagnesium formation-transmetallation-Negishi coupling protocol suitable for automated multiple parallel synthesis has been developed.
