93-08-3Relevant articles and documents
Fluorescence and phosphorescence of α- and β-isomers of boron Difluoride naphthaloylacetonates
Fedorenko, Elena V.,Mirochnik, Anatolii G.,Gerasimenko, Andrey V.,Beloliptsev, Anton Yu.,Puzyrkov, Zakhar N.,Svistunova, Irina V.,Sergeev, Aleksander A.
, (2021)
A comparative study of the luminescence properties of solutions and crystals of two isomers: boron difluoride 1-(1′-naphthyl)butanedionate-1,3 (α-NAcBF2) and 1-(2′-naphthyl)butanedionate-1,3 (β-NAcBF2) has been performed. An interrelation between the molecular and crystal structure of the studied complexes and their luminescence properties has been revealed. In the α-NAcBF2 molecule, the plane of the naphthyl group was turned by 34.26° relatively to the chelate cycle, while the β-NAcBF2 molecule was planar. The difference in the luminescence properties of the crystals of α-NAcBF2 (452 nm) and β-NAcBF2 (537 nm) was related to different abilities to form excimers. In β-NAcBF2 crystals, J-aggregates consisted of dimers of antiparallel molecules comprising excimer traps. For the crystals and solutions of α-NAcBF2 at 77 K, in addition to phosphorescence, the delayed fluorescence was observed. In case of β-NAcBF2, the delayed fluorescence was detected only for crystals, whereas the phosphorescence – for both crystals and solutions.
1-butyl-3-methylimidazolium cobalt tetracarbonyl [bmim][Co(CO)4]: A catalytically active organometallic ionic liquid
Brown,Dyson,Ellis,Welton
, p. 1862 - 1863 (2001)
An ambient temperature liquid transition metal carbonyl anion has been prepared in a metathesis reaction between [bmim]Cl ([bmim]+ = 1-butyl-3-methylimidazolium cation) and Na[Co(CO)4]; the ionic liquid catalyses the debromination of 2-bromoketones.
Enantioselective electrocatalytic oxidation of racemic sec-alcohols using a chiral 1-azaspiro[5.5]undecane-N-oxyl radical
Kashiwagi, Yoshitomo,Kurashima, Futoshi,Kikuchi, Chikara,Anzai, Jun-ichi,Osa, Tetsuo,Bobbitt, James M.
, p. 6469 - 6472 (1999)
Nitroxyl radical (6S,7R,10R)-4-acetylamino-2,2,7-trimethyl-10-isopropyl- 1-azaspiro[5.5]-undecane-N-oxyl reveals a reversible redox peak in cyclic voltammetry at + 0.62 V vs. Ag/AgCl. A preparative electrocatalytic oxidation of racemic sec-alcohols on the nitroxyl radical yielded mixtures of 51.4 - 63.9 % ketones and 36.1 - 48.6 % alcohols by 10 h of electrolysis. The current efficiency and turnover number of the reactions were 85.6 - 87.9 % and 20.6 - 25.6, respectively. The enantiopurity of the remaining (R)-isomers was 50 - 70 % and the S values as a selective factor was 4.1 - 4.6.
Synthesis of Visible-Light–Activated Hypervalent Iodine and Photo-oxidation under Visible Light Irradiation via a Direct S0→Tn Transition
Matsuda, Yu,Matsumoto, Koki,Nagasawa, Sho,Nakajima, Masaya,Nemoto, Tetsuhiro
, p. 235 - 239 (2022/03/16)
Heavy atom-containing molecules cause a photoreaction by a direct S0→Tn transition. Therefore, even in a hypervalent iodine compound with a benzene ring as the main skeleton, the photoreaction proceeds under 365–400nm wavelength light, where UV-visible spectra are not observed by usual measurement method. Some studies, however, report hypervalent iodine compounds that strongly absorb visible light. Herein, we report the synthesis of two visible light-absorbing hypervalent iodines and their photooxidation properties under visible light irradiation. We also demonstrated that the S0→Tn transition causes the photoreaction to proceed under wavelengths in the blue and green light region.
Direct Hydrodecarboxylation of Aliphatic Carboxylic Acids: Metal- and Light-Free
Burns, David J.,Lee, Ai-Lan,McLean, Euan B.,Mooney, David T.
supporting information, p. 686 - 691 (2022/01/28)
A mild and inexpensive method for direct hydrodecarboxylation of aliphatic carboxylic acids has been developed. The reaction does not require metals, light, or catalysts, rendering the protocol operationally simple, easy to scale, and more sustainable. Crucially, no additional H atom source is required in most cases, while a broad substrate scope and functional group tolerance are observed.
Selective Activation of Unstrained C(O)-C Bond in Ketone Suzuki-Miyaura Coupling Reaction Enabled by Hydride-Transfer Strategy
Zhong, Jing,Zhou, Wuxin,Yan, Xufei,Xia, Ying,Xiang, Haifeng,Zhou, Xiangge
supporting information, p. 1372 - 1377 (2022/02/23)
A Rh(I)-catalyzed ketone Suzuki-Miyaura coupling reaction of benzylacetone with arylboronic acid is developed. Selective C(O)-C bond activation, which employs aminopyridine as a temporary directing group and ethyl vinyl ketone as a hydride acceptor, occurs on the alkyl chain containing a β-position hydrogen. A series of acetophenone products were obtained in yields up to 75%.
Photo-induced oxidative cleavage of C-C double bonds for the synthesis of biaryl methanoneviaCeCl3catalysis
Xie, Pan,Xue, Cheng,Du, Dongdong,Shi, SanShan
supporting information, p. 6781 - 6785 (2021/08/20)
A Ce-catalyzed strategy is developed to produce biaryl methanonesviaphotooxidative cleavage of C-C double bonds at room temperature. This reaction is performed under air and demonstrates high activity as well as functional group tolerance. A synergistic Ce/ROH catalytic mechanism is also proposed based on the experimental observations. This protocol should be the first successful Ce-catalyzed photooxidation reaction of olefins with air as the oxidant, which would provide inspiration for the development of novel Ce-catalyzed photochemical synthesis processes.
Selective oxidation of alkenes to carbonyls under mild conditions
Huo, Jie,Xiong, Daokai,Xu, Jun,Yue, Xiaoguang,Zhang, Pengfei,Zhang, Yilan
supporting information, p. 5549 - 5555 (2021/08/16)
Herein, a practical and sustainable method for the synthesis of aldehydes, ketones, and carboxylic acids from an inexpensive olefinic feedstock is described. This transformation features very sustainable and mild conditions and utilizes commercially available and inexpensive tetrahydrofuran as the additive, molecular oxygen as the sole oxidant and water as the solvent. A wide range of substituted alkenes were found to be compatible, providing the corresponding carbonyl compounds in moderate-to-good yields. The control experiments demonstrated that a radical mechanism is responsible for the oxidation reaction.
Decatungstate-mediated solar photooxidative cleavage of CC bonds using air as an oxidant in water
Du, Dongdong,Luo, Junfei,Shi, Sanshan,Xie, Pan,Xue, Cheng
, p. 5936 - 5943 (2021/08/23)
With the increasing attention for green chemistry and sustainable development, there has been much interest in searching for greener methods and sources in organic synthesis. However, toxic additives or solvents are inevitably involved in most organic transformations. Herein, we first report the combination of direct utilization of solar energy, air as the oxidant and water as the solvent for the selective cleavage of CC double bonds in aryl olefins. Various α-methyl styrenes, diaryl alkenes as well as terminal styrenes are well tolerated in this green and sustainable strategy and furnished the desired carbonyl products in satisfactory yields. Like heterogeneous catalysis, this homogeneous catalytic system could also be reused and it retains good activity even after repeating three times. Mechanism investigations indicated that both O2- and 1O2 were involved in the reaction. Based on these results, two possible mechanisms, including the electron transfer pathway and the energy transfer pathway, were proposed.
Visible-Light-Driven Oxidative Cleavage of Alkenes Using Water-Soluble CdSe Quantum Dots
Li, Jianing,Zhao, Jingnan,Ma, Cunfei,Yu, Zongyi,Zhu, Hongfei,Yun, Lei,Meng, Qingwei
, p. 4985 - 4992 (2021/10/16)
The oxidative cleavage of C=C bonds is an important chemical reaction, which is a popular reaction in the photocatalytic field. However, high catalyst-loading and low turnover number (TON) are general shortcomings in reported visible-light-driven reactions. Herein, the direct oxidative cleavage of C=C bonds through water-soluble CdSe quantum dots (QDs) is described under visible-light irradiation at room temperature with high TON (up to 3.7×104). Under the same conditions, water-soluble CdSe QDs could also oxidize sulfides to sulfoxides with 51–84 % yields and TONs up to 3.4×104. The key features of this photocatalytic protocol include high TONs, wide substrates scope, low catalyst loadings, simple and mild reaction conditions, and molecular O2 as the oxidant.
