- Quenching processes of aromatic hydrocarbons in the higher triplet excited states-energy transfer vs. electron transfer
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Quenching processes of several aromatic hydrocarbons (AH) such as naphthalene (NAP), dibenz[a,h]anthracene (DBA), and chrysene (CHR) in the higher triplet excited states (T2) by different quenchers (Q) such as p-dichlorobenzene, o-dicyanobenzene aromatic compounds, and chloroalkanes (RCl), have been investigated by the two-color two-laser excitation method. AH in the higher triplet excited states (AH(Tn, n ≥ 2)) initially generated by the excitation of AH(T1) at the wavelength tuned to the absorption of AH(T1). AH(Tn) decays to a AH(T2) with the longest lifetime among AH(Tn) through the fast internal conversion. In the presence of Q, the competition of triplet energy transfer (TENT) and electron transfer (ELT) reactions between AH(T2) and Q are expected. However, no AH radical cation was observed, especially when the quenchers were chloroalkanes such as carbon tetrachloride (CCl4), methylene dichloride (CH2Cl2), 1,2-dichloroethane, which are good electron acceptors. It is suggested that the TENT is important during the quenching of AH(Tn) by Q. The lifetimes of NAP(T2), DBA(T2), and CHR(T2) were calculated from the TENT quenching experiments. It was found that the lifetimes of AH(T2) increase in the order of NAP(T2) (4.5 ps) 2) (16 ps) 2) (60 ps), which is consistent very well with the energy gap law for the transition from AH(T2) to AH(T1).
- Cai, Xichen,Sakamoto, Masanori,Hara, Michihiro,Tojo, Sachiko,Kawai, Kiyohiko,Endo, Masayuki,Fujitsuka, Mamoru,Majima, Tetsuro
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- From Esters to Ketones via a Photoredox-Assisted Reductive Acyl Cross-Coupling Strategy
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A method was developed for ketone synthesis via a photoredox-assisted reductive acyl cross-coupling (PARAC) using a nickel/photoredox dual-catalyzed cross-electrophile coupling of two different carboxylic acid esters. A variety of aryl, 1°, 2°, 3°-alkyl 2-pyridyl esters can act as acyl electrophiles while N-(acyloxy)phthalimides (NHPI esters) act as 1°, 2°, 3°-radical precursors. Our PARAC strategy provides an alternative and reliable way to synthesize various sterically congested 3°-3°, 3°-2°, and aryl-3° ketones under mild and highly unified conditions, which have been otherwise difficult to access. The combined experimental and computational studies identified a Ni0/NiI/NiIII pathway for ketone formation.
- Chen, Yukun,Li, Weirong,Luo, Yixin,Qi, Xiaotian,Xi, Xiaoxiang,Xu, Minghao,Yuan, Weiming,Zhao, Hongping,Zheng, Songlin
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- Site-Selective Acceptorless Dehydrogenation of Aliphatics Enabled by Organophotoredox/Cobalt Dual Catalysis
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The value of catalytic dehydrogenation of aliphatics (CDA) in organic synthesis has remained largely underexplored. Known homogeneous CDA systems often require the use of sacrificial hydrogen acceptors (or oxidants), precious metal catalysts, and harsh reaction conditions, thus limiting most existing methods to dehydrogenation of non- or low-functionalized alkanes. Here we describe a visible-light-driven, dual-catalyst system consisting of inexpensive organophotoredox and base-metal catalysts for room-temperature, acceptorless-CDA (Al-CDA). Initiated by photoexited 2-chloroanthraquinone, the process involves H atom transfer (HAT) of aliphatics to form alkyl radicals, which then react with cobaloxime to produce olefins and H2. This operationally simple method enables direct dehydrogenation of readily available chemical feedstocks to diversely functionalized olefins. For example, we demonstrate, for the first time, the oxidant-free desaturation of thioethers and amides to alkenyl sulfides and enamides, respectively. Moreover, the system's exceptional site selectivity and functional group tolerance are illustrated by late-stage dehydrogenation and synthesis of 14 biologically relevant molecules and pharmaceutical ingredients. Mechanistic studies have revealed a dual HAT process and provided insights into the origin of reactivity and site selectivity.
- Zhou, Min-Jie,Zhang, Lei,Liu, Guixia,Xu, Chen,Huang, Zheng
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supporting information
p. 16470 - 16485
(2021/10/20)
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- Efficient base-free hydrodehalogenation of organic halides catalyzed by a well-defined diphosphine-ruthenium(II) complex
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A base-free, robust catalytic system based on the diphosphine-ruthenium(II) complex cation has been developed for the hydrodehalogenation of a wide range of aryl- and alkyl-chlorides/bromides (27 examples) with molecule hydrogen. Notably, the reaction proceeds at 120 °C with low catalyst loading (0.1 mol%) and exhibits a good tolerance toward functional groups, such as amido, carboxyl, sulfonyl, methoxyl, ester groups. All dehalogenation products are confirmed by GC, GC–MS and NMR spectroscopy. Moreover, a mechanism for the diphosphine-ruthenium(II) complex cation catalyzed dehalogenation process has been proposed. This hydrodehalogenation methodology shows a potential application for the organic transformation and degradation of organic halides.
- Gao, Pengxiang,Liu, Qingbin,Liu, Yahuan,Ma, Ning,Wang, Zheng,Zhao, Ziwei
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- Nickel-Catalyzed Photodehalogenation of Aryl Bromides
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Herein, we describe a Ni-catalyzed photodehalogenation of aryl bromides under visible-light irradiation that utilizes tetrahydrofuran as hydrogen source. The protocol obviates the need for exogeneous amine reductants or photocatalysts and is characterized by its simplicity and broad scope, including challenging substrate combinations.
- Higginson, Bradley,Sanjosé-Orduna, Jesus,Gu, Yiting,Martin, Ruben
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supporting information
p. 1633 - 1636
(2021/04/23)
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- Cross-Coupling Reactions of Aryl Halides with Primary and Secondary Aliphatic Alcohols Catalyzed by an O,N,N-Coordinated Nickel Complex
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A synthesis of alkyl aryl ethers was achieved via the cross-coupling of aryl halides with primary and secondary aliphatic alcohols catalyzed by a bench-stable nickel complex supported by a monoanionic O,N,N-tridentate ligand. This nickel-catalyzed reaction proceeds smoothly in the absence of a phosphine ligand, affording alkyl aryl ethers in moderate to good yields. (Figure presented.).
- Hashimoto, Toru,Shiota, Keisuke,Funatsu, Kei,Yamaguchi, Yoshitaka
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supporting information
p. 1625 - 1630
(2021/01/26)
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- A New Protocol for Catalytic Reduction of Alkyl Chlorides Using an Iridium/Bis(benzimidazol-2′-yl)pyridine Catalyst and Triethylsilane
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The reduction of alkyl chlorides using triethylsilane is investigated. Primary, secondary, tertiary, and benzylic C-Cl bonds are effectively converted into C-H bonds using an [IrCl(cod)] 2/2,6-bis(benzimidazol-2′-yl)pyridine catalyst system. This catalyst system is quite simple since the tridentate N-ligand can be easily prepared in one step from commercially available reagents.
- Fukuyama, Takahide,Hamada, Yuki,Ryu, Ilhyong
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p. 3404 - 3408
(2021/07/14)
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- Reduced Phenalenyl in Catalytic Dehalogenative Deuteration and Hydrodehalogenation of Aryl Halides
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Dehalogenative deuteration reactions are generally performed through metal-mediated processes. This report demonstrates a mild protocol for hydrodehalogenation and dehalogenative deuteration of aryl/heteroaryl halides (39 examples) using a reduced odd alternant hydrocarbon phenalenyl under transition metal-free conditions and has been employed successfully for the incorporation of deuterium in various biologically active compounds. The combined approach of experimental and theoretical studies revealed a single electron transfer-based mechanism.
- Singh, Bhagat,Ahmed, Jasimuddin,Biswas, Amit,Paira, Rupankar,Mandal, Swadhin K.
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p. 7242 - 7255
(2021/05/29)
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- Metal-Free Heterogeneous Semiconductor for Visible-Light Photocatalytic Decarboxylation of Carboxylic Acids
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A suitable protocol for the photocatalytic decarboxylation of carboxylic acids was developed with metal-free ceramic boron carbon nitrides (BCN). With visible light irradiation, BCN oxidize carboxylic acids to give carbon-centered radicals, which were trapped by hydrogen atom donors or employed in the construction of the carbon-carbon bond. In this system, both (hetero)aromatic and aliphatic acids proceed the decarboxylation smoothly, and C-H, C-D, and C-C bonds are formed in moderate to high yields (35 examples, yield up to 93%). Control experiments support a radical process, and isotopic experiments show that methanol is employed as the hydrogen atom donor. Recycle tests and gram-scale reaction elucidate the practicability of the heterogeneous ceramic BCN photoredox system. It provides an alternative to homogeneous catalysts in the valuable carbon radical intermediates formation. Moreover, the metal-free system is also applicable to late-stage functionalization of anti-inflammatory drugs, such as naproxen and ibuprofen, which enrich the chemical toolbox.
- Shi, Jiale,Yuan, Tao,Zheng, Meifang,Wang, Xinchen
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p. 3040 - 3047
(2021/03/09)
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- Exploiting a silver-bismuth hybrid material as heterogeneous noble metal catalyst for decarboxylations and decarboxylative deuterations of carboxylic acids under batch and continuous flow conditions
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Herein, we report novel catalytic methodologies for protodecarboxylations and decarboxylative deuterations of carboxylic acids utilizing a silver-containing hybrid material as a heterogeneous noble metal catalyst. After an initial batch method development, a chemically intensified continuous flow process was established in a simple packed-bed system which enabled gram-scale protodecarboxlyations without detectable structural degradation of the catalyst. The scope and applicability of the batch and flow processes were demonstrated through decarboxylations of a diverse set of aromatic carboxylic acids. Catalytic decarboxylative deuterations were achieved on the basis of the reaction conditions developed for the protodecarboxylations using D2O as a readily available deuterium source.
- ?tv?s, Sándor B.,Fül?p, Ferenc,Kónya, Zoltán,Kukovecz, ákos,Márton, András,Mészáros, Rebeka,Pálinkó, István,Szabados, Márton,Varga, Gábor
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p. 4685 - 4696
(2021/07/12)
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- Ni-catalyzed reductive decyanation of nitriles with ethanol as the reductant
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A nickel-catalyzed reductive decyanation of aromatic nitriles has been developed, in which the readily available and abundant ethanol was applied as the hydride donor. Various functional groups on the aromatic rings, such as alkoxyl, amino, imino and amide, were compatible in this catalytic protocol. Heteroaryl, benzylic and alkenyl nitriles were also tolerated. Mechanistic investigation indicated that ethanol provided hydride efficientlyviaβ-hydride elimination in this reductive decyanation.
- Wu, Ke,Ling, Yichen,Sun, Nan,Hu, Baoxiang,Shen, Zhenlu,Jin, Liqun,Hu, Xinquan
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supporting information
p. 2273 - 2276
(2021/03/09)
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- Chromium-Catalyzed Reductive Cleavage of Unactivated Aromatic and Benzylic C-O Bonds
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Reductive cleavage of aromatic and benzylic C-O bonds by chromium catalysis is reported. This deoxygenative reaction was promoted by low-cost CrCl 2precatalyst combined with poly(methyl hydrogen siloxane) as the mild reducing agent, providing a strategy in forming reduced motifs by cleavage of unactivated C-O bonds. A range of functional groups such as bromide, chloride, fluoride, hydroxyl, amino, and alkoxycarbonyl can be retained in the reduction.
- Yuan, Shuqing,Ling, Liang,Tang, Jinghua,Luo, Meiming,Zeng, Xiaoming
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supporting information
p. 3343 - 3350
(2021/07/02)
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- Selective C-O Bond Reduction and Borylation of Aryl Ethers Catalyzed by a Rhodium-Aluminum Heterobimetallic Complex
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We report the catalytic reduction of a C-O bond and the borylation by a rhodium complex bearing an X-Type PAlP pincer ligand. We have revealed the reaction mechanism based on the characterization of the reaction intermediate and deuterium-labeling experiments. Notably, this novel catalytic system shows steric-hindrance-dependent chemoselectivity that is distinct from conventional Ni-based catalysts and suggests a new strategy for selective C-O bond activation by heterobimetallic catalysis.
- Hara, Naofumi,Nakao, Yoshiaki,Saito, Teruhiko,Seki, Rin
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supporting information
p. 6388 - 6394
(2021/05/31)
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- AIR-STABLE NI(0)-OLEFIN COMPLEXES AND THEIR USE AS CATALYSTS OR PRECATALYSTS
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The present invention relates to air stable, binary Ni(0)-olefin complexes and their use in organic synthesis.
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Page/Page column 21-22
(2021/02/05)
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- Heterogeneously Catalyzed Selective Decarbonylation of Aldehydes by CeO2-Supported Highly Dispersed Non-Electron-Rich Ni(0) Nanospecies
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Aldehyde decarbonylation has been extensively investigated, primarily using noble-metal catalysts; however, nonprecious-base-metal-catalyzed aldehyde decarbonylation has been hardly reported. We have established an efficient selective aldehyde decarbonylation reaction with a broad substrate scope and functional group tolerance utilizing a heterogeneous Ni(0) nanospecies catalyst supported on CeO2. The high catalytic performance is attributable to the highly dispersed and non-electron-rich Ni(0) nanospecies, which possibly suppress a side reaction producing esters and adsorbed CO-derived inhibition of the catalytic turnover, according to detailed catalyst characterization and kinetic evaluation.
- Matsuyama, Takehiro,Yatabe, Takafumi,Yabe, Tomohiro,Yamaguchi, Kazuya
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p. 13745 - 13751
(2021/11/17)
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- H2-Free Selective Dehydroxymethylation of Primary Alcohols over Palladium Nanoparticle Catalysts
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The dehydroxymethylation of primary alcohols is a promising strategy to transform biomass-derived oxygenates into hydrocarbon fuels. In this study, a novel, highly efficient, and reusable heterogeneous catalyst system was established for the H2-free dehydroxymethylation of primary alcohol using cerium oxide-supported palladium nanoparticles (Pd/CeO2). A wide range of aliphatic and aromatic alcohols including biomass-derived alcohols were converted into the corresponding one-carbon shorter hydrocarbons in high yields in the absence of any additives, accompanied by the production of H2 and CO. Pd/CeO2 was easily recovered from the reaction mixture and reused, retaining its high activity, thus, providing a simple and sustainable methodology to produce hydrocarbon fuels from biomass-derived oxygenates.
- Yamaguchi, Sho,Kondo, Hiroki,Uesugi, Kohei,Sakoda, Katsumasa,Jitsukawa, Koichiro,Mitsudome, Takato,Mizugaki, Tomoo
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p. 1135 - 1139
(2020/12/29)
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- Electrochemical Activation of Diverse Conventional Photoredox Catalysts Induces Potent Photoreductant Activity**
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Herein, we disclose that electrochemical stimulation induces new photocatalytic activity from a range of structurally diverse conventional photocatalysts. These studies uncover a new electron-primed photoredox catalyst capable of promoting the reductive cleavage of strong C(sp2)?N and C(sp2)?O bonds. We illustrate several examples of the synthetic utility of these deeply reducing but otherwise safe and mild catalytic conditions. Finally, we employ electrochemical current measurements to perform a reaction progress kinetic analysis. This technique reveals that the improved activity of this new system is a consequence of an enhanced catalyst stability profile.
- Chernowsky, Colleen P.,Chmiel, Alyah F.,Wickens, Zachary K.
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supporting information
p. 21418 - 21425
(2021/08/25)
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- Heterogeneous copper-catalyzed synthesis of diaryl sulfones
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A carbon-supported copper nanoparticle (Cu-NP) with high catalytic activity for the synthesis of diaryl sulfones is reported. For the first time, this Cu-NP is proved to be able to effectively promote the reaction of arylboronic acids and arylsulfonyl hydrazides to generate diaryl sulfones at room temperature. The reaction shows excellent substrate universality, and substrates with different substituents can undergo the reaction smoothly, leading to the desired products in good yields. The Cu-NP is found to be made of low valence Cu based on XRD. Hence, the reaction catalyzed by the Cu-NP is believed to involve a Cu-mediated organometallic cycle.
- Gong, Xinchi,Qu, Lingling,Shen, Zhengqi,Wang, Ganghu,Zhu, Chunyin
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supporting information
p. 10662 - 10668
(2021/12/27)
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- Dual Active Sites on Molybdenum/ZSM-5 Catalyst for Methane Dehydroaromatization: Insights from Solid-State NMR Spectroscopy
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Methane dehydroaromatization (MDA) on Mo/ZSM-5 zeolite catalyst is promising for direct transformation of natural gas. Understanding the nature of active sites on Mo/ZSM-5 is a challenge for applications. Herein, using 1H{95Mo} double-resonance solid-state NMR spectroscopy, we identify proximate dual active sites on Mo/ZSM-5 catalyst by direct observation of internuclear spatial interaction between Br?nsted acid site and Mo species in zeolite channels. The acidic proton–Mo spatial interaction is correlated with methane conversion and aromatics formation in the MDA process, an important factor in determining the catalyst activity and lifetime. The evolution of olefins and aromatics in Mo/ZSM-5 channels is monitored by detecting their host–guest interactions with both active Mo sites and Br?nsted acid sites via 1H{95Mo} double-resonance and two-dimensional 1H–1H correlation NMR spectroscopy, revealing the intermediate role of olefins in hydrocarbon pool process during the MDA reaction.
- Gao, Wei,Qi, Guodong,Wang, Qiang,Wang, Weiyu,Li, Shenhui,Hung, Ivan,Gan, Zhehong,Xu, Jun,Deng, Feng
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supporting information
p. 10709 - 10715
(2021/04/09)
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- Nonoxidative Methane Conversion on Granulated Mo/ZSM-5 Catalysts
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Abstract: Nonoxidative conversion of methane to aromatic hydrocarbons on granulatedМо/ZSM-5 catalysts was studied. The catalysts prepared using zeolites with thehierarchic pore system surpass in activity the catalysts prepared by thetraditional method, mi
- Stepanov,Kuvatova,Korobitsyna,Travkina,Vosmerikov,Kutepov
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p. 370 - 377
(2021/02/16)
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- Coupling conversion of methane with carbon monoxideviacarbonylation over Zn/HZSM-5 catalysts
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Efficient direct transformation of methane into value-added chemicals has great significance for long-term sustainability of fuels and chemicals, but remains a major challenge due to its high inertness. Reported here is that methane can be activated effectivelyviacarbonylation with CO over Zn/HZSM-5 catalysts under mild conditions. The selectivity to aromatics alone reaches 80% among all hydrocarbon products at 823 K, whereas as high as 92% ethane selectivity is achieved at a lower temperature of 673 K.13CO isotope labelling experiments demonstrate that approximately 50% of the carbon atoms in all the products originate from carbon monoxide, whereas another half of the carbons come from methane, indicating that the precursors of hydrocarbon products are acyl compounds and/or acetic acid formed by carbonylation of methane with carbon monoxide. This provides potential for transformation of methane into value-added chemicals under mild reaction conditions.
- Wen, Fuli,Zhang, Jin,Chen, Zhiyang,Zhou, Ziqiao,Liu, Hongchao,Zhu, Wenliang,Liu, Zhongmin
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p. 1358 - 1364
(2021/03/14)
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- Nickel-Catalyzed Amination of Aryl Nitriles for Accessing Diarylamines through C?CN Bond Activation
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A nickel-catalyzed amination to access diarylamines has been developed through C?CN bond activation of aryl nitriles with anilines. In this developed catalytic protocol, various aromatic and heteroaromatic nitriles could be utilized as the electrophiles to couple with substituted anilines. A diversity of diarylamines were obtained in 15–95% yields. (Figure presented.).
- Wu, Ke,Rong, Qiang,Sun, Nan,Hu, Baoxiang,Shen, Zhenlu,Jin, Liqun,Hu, Xinquan
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supporting information
p. 4708 - 4713
(2021/08/27)
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- Reactors for Preparing Valuable Hydrocarbons and Hydrogen From Methane Through Non-Oxidative Pyrolysis
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According to this disclosure, there is provided a pyrolysis reaction system and a direct non-oxidative methane coupling process using the same by which it is possible to reach the selectivity for good C≤10 hydrocarbons and at the same time to inhibit coke from being generated while a good methane conversion is maintained during direct conversion of methane into C2+ hydrocarbons through non-oxidative pyrolysis.
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Paragraph 0084-0091; 0099
(2021/10/11)
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- Preliminary investigations on the catalytic hydrogenation of polycyclic aromatic hydrocarbons via WGSR
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The water-gas shift reaction (WGSR) is a crucial reaction in the direct liquefaction of lignite in a syngas (CO + H2) system. In this study, anthracene was utilized as a polycyclic model compound of lignite, to which hydrogen is donated by the H2/D2 produced from CO and H2O/D2O via the WGSR. The results show that the model compound of the polycyclic aromatic hydrocarbon in coal (anthracene) undergoes partial cracking and polycondensation under non-hydrogen-donor conditions at 400 °C. In addition, WGSR catalyzed by NiO can generate hydrogen for the hydrogenation of anthracene. Comparing the mass spectra of deuterated products with those of conventional hydrogenation products by isotope labeling, the alkyl side chain positions of toluene, 1,4-xylene, methylnaphthalene, 1,1-diphenylethylene, methylanthracene and other compounds are prone to deuteration, enabling speculation of the main hydrogenation route of anthracene, which provides theoretical support for the catalytic hydrogenation in direct liquefaction of lignite in a syngas (CO + H2) system.
- Chen, Dabo,Gu, Jiale,Huang, Sheng,Li, Huan,Wu, Shiyong,Wu, Youqing
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- Intermolecular C?H Activation at the Allylic/Benzylic and Homoallylic/Homobenzylic Positions of Cyclic Hydrocarbons by a Stable Divalent Silicon Species
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Direct activation of inert C(sp3)?H bonds by main group element species is yet a formidable challenge. Herein, the dehydrogenation of cyclohexene and 1,2,3,4-tetrahydronaphthalene through the allylic/benzylic and homoallylic/homobenzylic C?H bond activation by cyclic (alkyl)(amino)silylene 1 in neat conditions is reported to yield the corresponding aromatic compounds. As for the reaction of cyclohexene, allylsilane 3 and 7-silanorbornene 4 were also observed, which could be interpreted as a direct dehydrogenative silylation reaction of monoalkenes at the allylic positions. Experimental and computational studies suggest that the dehydrogenation of cyclohexene at the homoallylic position was accomplished by a combination of silylene 1 and radical intermediates such as hydrosilyl radical INT1 or cyclohexenyl radical H, which are generated in the initial step of the reaction.
- Koike, Taichi,Kosai, Tomoyuki,Iwamoto, Takeaki
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p. 724 - 734
(2020/12/11)
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- Palladium-Catalyzed Cross-Coupling of Superbase-Generated C(sp3) Nucleophiles
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A range of methods has been investigated recently for the arylation of weakly acidic C(sp3)-H bonds, primarily exploiting directed metalation with a transition metal catalyst or radical formation via hydrogen atom transfer. In this work, a classical base-mediated approach is taken, exploiting the ability of organometallic superbases to metalate very weakly acidic (pKa> 40) C-H bonds. Conditions are developed with eithern-BuLi/diamine orn-BuLi/KOtBu superbases to enable metalation to occur with high selectivity. Organolithium nucleophiles can be directly used in cross-coupling, or organozincs can be formed to enable reactions with functional group-dense organohalides.
- Freure, Garrett P. R.,Lavertu, Jean-Danick E.,Newman, Stephen G.,Skrotzki, Eric A.
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p. 12258 - 12263
(2021/10/26)
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- Direct Evidence on the Mechanism of Methane Conversion under Non-oxidative Conditions over Iron-modified Silica: The Role of Propargyl Radicals Unveiled
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Radical-mediated gas-phase reactions play an important role in the conversion of methane under non-oxidative conditions into olefins and aromatics over iron-modified silica catalysts. Herein, we use operando photoelectron photoion coincidence spectroscopy to disentangle the elusive C2+ radical intermediates participating in the complex gas-phase reaction network. Our experiments pinpoint different C2-C5 radical species that allow for a stepwise growth of the hydrocarbon chains. Propargyl radicals (H2C?C≡C?H) are identified as essential precursors for the formation of aromatics, which then contribute to the formation of heavier hydrocarbon products via hydrogen abstraction–acetylene addition routes (HACA mechanism). These results provide comprehensive mechanistic insights that are relevant for the development of methane valorization processes.
- ?ot, Petr,Hemberger, Patrick,Pan, Zeyou,Paunovi?, Vladimir,Puente-Urbina, Allen,van Bokhoven, Jeroen Anton
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supporting information
p. 24002 - 24007
(2021/10/01)
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- Photooxidase Mimicking with Adaptive Coordination Molecular Capsules
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One important feature of enzyme catalysis is the induced-fit conformational change after binding substrates. Herein, we report a biomimetic water-soluble molecular capsule featuring adaptive structural change toward substrate binding, which offers an ideal platform for efficient photocatalysis. The molecular capsule was coordination-assembled from three anthracene-bridged bis-TPT [TPT = 2,4,6-tris(4-pyridyl)-1,3,5-triazine] ligands and six (bpy)Pd(NO3)2(bpy = 2,2′-bipyridine). Once substrates bind to its hydrophobic cavity, this capsule would undergo quantitative capsule-to-bowl transformation. Visible-light absorption brought about by both the anthracene units and the charge-transfer absorption on the late-formed quintuple π-π stacked host-guest complex efficiently facilitates aerobic photooxidation for the sulfide guests by visible-light irradiation under mild conditions. Desired turnover numbers and product selectivity (sulfoxide over sulfone) have been achieved by the transformable nature of the catalyst and the hydrophilicity of the sulfoxide product. Such a photocatalytic process enabled by an adaptive coordination capsule and substrates as the allosteric effector paves the way for constructing artificial systems to mimic enzyme catalysis.
- Cai, Li-Xuan,Cheng, Pei-Ming,Hu, Shao-Jun,Sun, Qing-Fu,Yan, Dan-Ni,Zhou, Li-Peng
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supporting information
p. 16087 - 16094
(2021/10/12)
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- Catalytic Dehydrogenative Cyclization of o-Teraryls under pH-Neutral and Oxidant-Free Conditions
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A cobaloxime-catalyzed acceptorless dehydrogenative cyclization of o-teraryls was developed. In stark contrast to the established methods such as the Scholl or Mallory reactions, this method does not require any strong acids or oxidants, and shows high atom economy and a broad substrate scope. It operates at near room temperature with light as the source of energy. Acid- or oxidant-sensitive functional groups, such as 4-methoxyphenyl, unprotected benzyl alcohol, silyl ether, and thiophene groups are tolerated. Remarkably, aryls with electron-withdrawing groups, and electron-poor heteroarenes, such as pyridine and pyrimidine, can also react. Preliminary mechanistic study reveals that hydrogen gas is released during the reaction, and both light and the cobalt catalyst are important for the dehydrogenation step.
- Dong, Guangbin,Tsukamoto, Tatsuhiro
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supporting information
p. 15249 - 15253
(2020/06/30)
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- A Direct S0→Tn Transition in the Photoreaction of Heavy-Atom-Containing Molecules
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According to the Grotthuss–Draper law, light must be absorbed by a substrate to initiate a photoreaction. There have been several reports, however, on the promotion of photoreactions using hypervalent iodine during irradiation with light from a non-absorbing region. This contradiction gave rise to a mystery regarding photoreactions involving hypervalent iodine. We demonstrated that the photoactivation of hypervalent iodine with light from the apparently non-absorbing region proceeds via a direct S0→Tn transition, which has been considered a forbidden process. Spectroscopic, computational, and synthetic experimental results support this conclusion. Moreover, the photoactivation mode could be extended to monovalent iodine and bromine, as well as bismuth(III)-containing molecules, providing new possibilities for studying photoreactions that involve heavy-atom-containing molecules.
- Kuribara, Takahito,Matsumoto, Koki,Muranaka, Atsuya,Nagasawa, Sho,Nakajima, Masaya,Nemoto, Tetsuhiro,Uchiyama, Masanobu
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supporting information
p. 6847 - 6852
(2020/03/23)
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- Hydrodebromination of Aromatic Bromides Catalyzed by Unsupported Nanoporous Gold: Heterolytic Cleavage of Hydrogen Molecule
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Unsupported nanoporous gold (AuNPore) is a highly efficient, practically applicable, and recyclable catalyst for hydrodebromination of aromatic bromides. The AuNPore-catalyzed hydrodebromination of aromatic bromides proceeded smoothly at relatively low hydrogen pressure and temperature to achieve good to excellent yields of the corresponding non-bromine variants. The selective hydrodebromination reaction occurred exclusively in the coexistence of chlorine atom. For the first time, a mechanistic study revealed that the H?H bond splits in a heterolysis manner on the surface of AuNPore to generate Au?H hydride species.
- Bao, Ming,Feng, Xiujuan,Yamamoto, Yoshinori,Zhang, Sheng,Zhao, Yuhui
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p. 4951 - 4957
(2020/09/09)
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- Exploiting the radical reactivity of diazaphosphinanes in hydrodehalogenations and cascade cyclizations
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The remarkable reducibility of diazaphosphinanes has been extensively applied in various hydrogenations, based on and yet limited by their well-known hydridic reactivity. Here we exploited their unprecedented radical reactivity to implement hydrodehalogenations and cascade cyclizations originally inaccessible by hydride transfer. These reactions feature a broad substrate scope, high efficiency and simplicity of manipulation. Mechanistic studies suggested a radical chain process in which a phosphinyl radical is generated in a catalytic cycle via hydrogen-atom transfer from diazaphosphinanes. The radical reactivity of diazaphosphinanes disclosed here differs from their well-established hydridic reactivity, and hence, opens a new avenue for diazaphosphinane applications in organic syntheses.
- Cheng, Jin-Pei,Yang, Jin-Dong,Zhang, Jingjing
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p. 4786 - 4790
(2020/06/18)
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- Pd catalysts supported on dual-pore monolithic silica beads for chemoselective hydrogenation under batch and flow reaction conditions
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Two different types of palladium catalysts supported on dual-pore monolithic silica beads [5% Pd/SM and 0.25% Pd/SM(sc)] for chemoselective hydrogenation were developed. Alkyne, alkene, azide, and nitro functionalities and the aromatic N-Cbz protecting group were chemoselectively hydrogenated using 5% Pd/SM. On the other hand, 0.25% Pd/SM(sc) showed unique and higher hydrogenation catalyst activity toward a wide variety of reducible functionalities. Furthermore, the catalyst activities of both 5% Pd/SM and 0.25% Pd/SM(sc) under flow hydrogenation conditions were also evaluated. A pre-packed 5% Pd/SM cartridge could be used continuously for at least 72 h without any loss of catalyst activity. The 0.2% Pd/SM(sc) catalyst prepacked in a cartridge showed high catalyst activity for the flow hydrogenation of trisubstituted alkenes under mild reaction conditions. This journal is
- Yamada, Tsuyoshi,Ogawa, Aya,Masuda, Hayato,Teranishi, Wataru,Fujii, Akiko,Park, Kwihwan,Ashikari, Yosuke,Tomiyasu, Noriyuki,Ichikawa, Tomohiro,Miyamoto, Riichi,Bai, Hongzhi,Matsuyama, Kiyoshi,Nagaki, Aiichiro,Sajiki, Hironao
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p. 6359 - 6367
(2020/11/03)
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- Synthesis of dimeric molecules via ag-catalyzed electrochemical homocoupling of organic bromides paired with electrooxidation of urea
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We present a sacrificial anode-free approach to reductive homocoupling of organohalides that does not require a co-catalyst. In this approach, a divided electrochemical cell with aprotic and aqueous compartments separated by an anion exchange membrane enables coupling of the cathodic homocoupling reaction with anodic oxidation of urea. We show that, in contrast with traditional one-compartment cells relying on sacrificial anodes, the proposed cell configuration maintains stable cell voltage in the course of galvanostatic electrolysis. A synthetic potential of this method was assessed using a series of 13 organic bromides that demonstrated a strong dependence of the reaction outcome on the structure of the organic substrate, more specifically, the dissociation energy of the C–Br bond and the redox properties of formed radicals, which are discussed in detail. While not being suitable for the synthesis of byarylstructures, this method is excellent for C(sp3)-C(sp3) coupling to corresponding dimeric products with up to quantitative yields. Simultaneous electrochemical treatment of nitrogenous waste in the adjacent half-cell provides an additional incentive for wide adaptation of this sustainable synthetic approach.
- Klinkova, Anna,Krivoshapkina, Elena F.,Medvedev, Jury J.,Medvedeva, Xenia V.,Pivovarova, Yekaterina,Steksova, Yulia P.
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- Transition-Metal-Free and Visible-Light-Mediated Desulfonylation and Dehalogenation Reactions: Hantzsch Ester Anion as Electron and Hydrogen Atom Donor
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Novel approaches for N- and O-desulfonylation under room temperature (rt) and transition-metal-free conditions have been developed. The first methodology involves the transformation of a variety of N-sulfonyl heterocycles and phenyl benzenesulfonates to the corresponding desulfonylated products in good to excellent yields using only KOtBu in dimethyl sulfoxide (DMSO) at rt. Alternately, a visible light method has been used for deprotection of N-methyl-N-arylsulfonamides with Hantzsch ester (HE) anion serving as the visible-light-absorbing reagent and electron and hydrogen atom donor to promote the desulfonylation reaction. The HE anion can be easily prepared in situ by reaction of the corresponding HE with KOtBu in DMSO at rt. Both protocols were further explored in terms of synthetic scope as well as mechanistic aspects to rationalize key features of desulfonylation processes. Furthermore, the HE anion induces reductive dehalogenation reaction of aryl halides under visible light irradiation.
- Heredia, Micaela D.,Guerra, Walter D.,Barolo, Silvia M.,Fornasier, Santiago J.,Rossi, Roberto A.,Budén, Mariá E.
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p. 13481 - 13494
(2020/12/15)
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- Luminescent tungsten(vi) complexes as photocatalysts for light-driven C-C and C-B bond formation reactions
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The realization of photocatalysis for practical synthetic application hinges on the development of inexpensive photocatalysts which can be prepared on a large scale. Herein an air-stable, visible-light-absorbing photoluminescent tungsten(vi) complex which can be conveniently prepared at the gram-scale is described. This complex could catalyse photochemical organic transformation reactions including borylation of aryl halides, such as aryl chloride, reductive coupling of benzyl bromides for C-C bond formation, reductive coupling of phenacyl bromides, and decarboxylative coupling of redox-active esters of alkyl carboxylic acid with high product yields and broad functional group tolerance.
- Chan, Kaai-Tung,Che, Chi-Ming,Du, Lili,Liu, Yungen,Phillips, David Lee,To, Wai-Pong,Tong, Glenna So Ming,Wu, Liang-Liang,Yu, Daohong
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p. 6370 - 6382
(2020/07/15)
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- The Electronic Properties of Ni(PNN) Pincer Complexes Modulate Activity in Catalytic Hydrodehalogenation Reactions
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Three chloronickel(II) complexes of PNN- pincer ligands with pyrazolyl and diphenylphosphino donors appended to different arms of diarylamido anchors were prepared and fully characterized. The three derivatives (1-OMe, 1-Me, 1-CF3) differ only by the identity of the para-aryl substituent on the pyrazolyl arm with 1-OMe being 310 mV easier to oxidize than 1-CF3. All three complexes are competent catalysts for hydrodehalogenation reactions of 1-bromooctane and a variety of aryl halides in dimethylacetamide using NaBH4 as both base and hydride source. Comparative studies using diverse substrates showed that catalytic activity correlates with electron donor properties; 1-OMe was superior to the other two. Deuterium labeling studies verified NaBD4 as the deuteride source and excluded solvent-assisted radical pathways.
- Wang, Denan,Gardinier, James R.
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p. 4425 - 4434
(2020/10/19)
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- Development and Mechanistic Studies of Iron-Catalyzed Construction of Csp2-B Bonds via C-O Bond Activation
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Herein we describe an iron-catalyzed borylation of alkenyl and aryl carbamates through the activation of a C-O bond. This protocol exhibits high efficiency, a broad substrate scope, and the late-stage borylation of biorelevant compounds, thus providing potential applications in medicinal chemistry. Moreover, this method enables orthogonal transformations of phenol derivatives and also offers good opportunities for the synthesis of multisubstituted arenes. Preliminary mechanistic studies suggest that a FeII/FeIII catalytic cycle via a radical pathway might be involved in the reaction.
- Geng, Shasha,Zhang, Juan,Chen, Shuo,Liu, Zhengli,Zeng, Xiaoqin,He, Yun,Feng, Zhang
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p. 5582 - 5588
(2020/07/08)
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- Metal-Free Visible-Light-Mediated Aromatization of 1,2–Dihydronaphthalenes
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A series of polyaromatic naphthalenes have been synthesized through the dehydrogenation of the corresponding 1,2-dihydroarylnaphthalenes by using 9-mesityl-10-methylacridinium perchlorate as a photocatalyst and diphenyliodonium triflate as an external oxidant under visible light irradiation. The reaction proceeds smoothly under metal-free conditions and tolerates some functionalities. Interestingly, the reaction is also amenable to the aromatization of tetrahydronaphthalenes and fair conversions were obtained. Preliminary mechanistic investigations have been conducted and a reasonable mechanism is proposed.
- Rammal, Fatima,Gaumont, Annie-Claude,Lakhdar, Sami
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supporting information
p. 1482 - 1485
(2019/12/12)
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- Visible-Light-Induced, Base-Promoted Transition-Metal-Free Dehalogenation of Aryl Fluorides, Chlorides, Bromides, and Iodides
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We report a simple and efficient visible-light-induced transition-metal-free hydrogenation of aryl halides. The combined visible light and base system is used to initiate the desired radical-mediated hydrogenation. A variety of aryl fluorides, chlorides, bromides, and iodides could be reduced to the corresponding (hetero)arenes with excellent yields under mild conditions. Various functional groups and other heterocyclic compounds are tolerated.
- Ding, Ting-Hui,Qu, Jian-Ping,Kang, Yan-Biao
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supporting information
p. 3084 - 3088
(2020/04/10)
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- A visible-light-photocatalytic water-splitting strategy for sustainable hydrogenation/deuteration of aryl chlorides
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Hydrogenation/deuteration of carbon chloride (C?Cl) bonds is of high significance but remains a remarkable challenge in synthetic chemistry, especially using safe and inexpensive hydrogen donors. In this article, a visible-light-photocatalytic watersplitting hydrogenation technology (WSHT) is proposed to in-situ generate active H-species (i.e., Had) for controllable hydrogenation of aryl chlorides instead of using flammable H2. When applying heavy water-splitting systems, we could selectively install deuterium at the C?Cl position of aryl chlorides under mild conditions for the sustainable synthesis of high-valued added deuterated chemicals. Sub-micrometer Pd nanosheets (Pd NSs) decorated crystallined polymeric carbon nitrides (CPCN) is developed as the bifunctional photocatalyst, whereas Pd NSs not only serve as a cocatalyst of CPCN to generate and stabilize H (D)-species but also play a significant role in the sequential activation and hydrogenation/deuteration of C?Cl bonds. This article highlights a photocatalytic-WSHT for controllable hydrogenation/deuteration of low-cost aryl chlorides, providing a promising way for the photosynthesis of high-valued added chemicals instead of the hydrogen evolution.
- Ling, Xiang,Xu, Yangsen,Wu, Shaoping,Liu, Mofan,Yang, Peng,Qiu, Chuntian,Zhang, Guoqiang,Zhou, Hongwei,Su, Chenliang
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p. 386 - 392
(2020/02/25)
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- Photocatalytic Reductive Defluorination of Fluorinated Compounds in Aqueous Alcohol Suspensions of a Metal-loaded Titanium(IV) Oxide
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Selective elimination of the fluorine element in organic fluorinated compounds under mild conditions is desired in order to resolve the environment and energy resource issues. Selective reductive defluorination of fluorine-containing organic compounds in 2-propanol-water suspensions of metal-loaded titanium(IV) oxide (TiO2) photocatalysts is described in this paper. The effects of different types of metal co-catalysts, adsorption behavior of fluorobenzene (FB), stoichiometry, redox balance, scope, chemoselectivity and reaction temperature were examined. Photocatalytic defluorination of FB occurred over platinum-loaded TiO2 at room temperature, and benzene and fluoride ion were produced with a high stoichiometry without degradation of the benzene structure, while hydrogen (H2) production occurred as a competitive electron-consuming reaction. A slight elevation in the reaction temperature greatly accelerated defluorination and suppressed H2 evolution, resulting in FB defluorination free from H2 production at 333 K. Kinetic parameters of FB defluorination and H2 evolution were determined, and the results obtained are explained on the basis of these parameters.
- Fukui, Makoto,Tanaka, Atsuhiro,Kominami, Hiroshi
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p. 3298 - 3305
(2020/05/18)
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- The cyano group of the aromatic compound production (by machine translation)
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[Problem] to reduce toxicity, treatment after reaction is easy, and a high selectivity, a manufacturing method of an aromatic nitrile compound. [Solution] the formula illustrated, unsubstituted or substituted with electron donating groups 1a and aromatic halogen compounds, cyanide 4 · quaternary ammonium nitrile with a second agent, a transition metal-free catalyst phenanthroline compound, such as dimethyl sulfoxide with a mixture containing an aprotic organic solvent, the reaction temperature range of the reaction is heated to 110 c 180 °C cyano, aromatic nitrile compound 2a of production. [Drawing] no (by machine translation)
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Paragraph 0054-0056
(2020/05/14)
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- Initial Carbon?Carbon Bond Formation during the Early Stages of Methane Dehydroaromatization
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Methane dehydroaromatization (MDA) is among the most challenging processes in catalysis science owing to the inherent harsh reaction conditions and fast catalyst deactivation. To improve this process, understanding the mechanism of the initial C?C bond formation is essential. However, consensus about the actual reaction mechanism is still to be achieved. In this work, using advanced magic-angle spinning (MAS) solid-state NMR spectroscopy, we study in detail the early stages of the reaction over a well-dispersed Mo/H-ZSM-5 catalyst. Simultaneous detection of acetylene (i.e., presumably the direct C?C bond-forming product from methane), methylidene, allenes, acetal, and surface-formate species, along with the typical olefinic/aromatic species, allow us to conclude the existence of at least two independent C?H activation pathways. Moreover, this study emphasizes the significance of mobility-dependent host–guest chemistry between an inorganic zeolite and its trapped organic species during heterogeneous catalysis.
- ?a?layan, Mustafa,Abou-Hamad, Edy,Baldus, Marc,Chowdhury, Abhishek Dutta,Gascon, Jorge,Lucini Paioni, Alessandra,Pustovarenko, Alexey,Shterk, Genrikh
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supporting information
p. 16741 - 16746
(2020/07/24)
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- Transition metal catalyzed nitro-aromatic denitration method
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The invention provides a transition metal catalyzed nitro-aromatic denitration method, which comprises the following steps: in a nitrogen atmosphere, taking nitro-aromatic as a substrate in an organicsolvent, reacting under the action of alkali and a reducing agent under the action of a transition metal catalyst and a ligand, and carrying out column chromatography separation to obtain an aromaticcompound. The method can directly convert nitro aromatic hydrocarbon into corresponding aromatic hydrocarbon compounds, is high in catalytic efficiency, low in cost and convenient to operate, and canbe compatible with various functional groups. In addition, the directional reduction nitro group, position and number of the nitro group of the polynitro compound are regulated and controlled throughthe proportion and addition amount of the reducing agent and the catalytic system, so that the directional conversion of the polynitro group is realized.
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Paragraph 0027; 0029-0032; 0049-0052
(2020/08/18)
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- Aromatization of Ethylene – Main Intermediate for MDA?
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Methane dehydroaromatization (MDA) over Mo/HZSM-5 has been hypothesized in literature to proceed via a two-step mechanism: methane is first converted to ethylene on the molybdenum (Mo) functionality and then ethylene is oligomerized, cyclized and dehydrogenated on the Br?nsted acid sites (BAS) of the HZSM-5 support. This hypothesis is tested by studying the conversion of ethylene at the same conditions as used for MDA, namely 700 °C, atmospheric pressure, and by co-feeding experiments with H2 and CH4. Our results suggest that ethylene is not the main intermediate for MDA, because the aromatic selectivities obtained from methane conversion are higher than selectivities measured during ethylene conversion. Furthermore, carbonaceous deposits formed during MDA have a lower density, are more hydrogenated and more active than the ones formed during ethylene aromatization (EDA). Similarly as for MDA, an activation period in which Mo carburizes to its active phase and an induction period, in which aromatics formation rates increase to their maximum are observed for ethylene conversion. The induction period, which was explained by the buildup of a hydrocarbon pool (HCP) is much faster with methane than with ethylene. This period, is attributed to a slow buildup of hydrocarbons, strongly adsorbed on Mo sites, because it is only observed with catalysts containing Mo. Hydrogen co-feeding with ethylene leads to the formation of more reactive coke species and a significantly prolonged lifetime of the catalyst, but not to a faster buildup of the HCP.
- Vollmer, Ina,Abou-Hamad, Edy,Gascon, Jorge,Kapteijn, Freek
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p. 544 - 549
(2019/11/28)
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- Exploration of mechanochemical activation in solid-state fluoro‐grignard reactions
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Owing to the strength of the C–F bond, the ‘direct’ preparation of Grignard reagents, i.e., the interaction of elemental magnesium with an organic halide, typically in an ethereal solvent, fails for bulk magnesium and organofluorine compounds. Previously described mechanochemical methods for preparing Grignard reagents have involved ball milling powdered magnesium with organochlorines or bromines. Activation of the C–F bond through a similar route is also possible, however. For example, milling 1- and 2-fluoronaphthalene with an excess of magnesium metal for 2 h, followed by treatment with FeCl3 and additional milling, produces the corresponding binaphthalenes, albeit in low yields (ca. 20%). The yields are independent of the particular isomer involved and are also comparable to the yields from corresponding the bromonaphthalenes. These results may reflect similar charges that reside on the α-carbon in the naphthalenes, as indicated by density functional theory calculations.
- Hanusa, Timothy P.,Speight, Isaiah R.
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- Pt-Pd nanoalloy for the unprecedented activation of carbon-fluorine bond at low temperature
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Carbon-fluorine bonds are considered the most inert organic functionality and their selective transformation under mild conditions remains challenging. Herein, we report a highly active Pt-Pd nanoalloy as a robust catalyst for the transformation of C-F bonds into C-H bonds at low temperature, a reaction that has hitherto often required harsh conditions. The alloying of Pt with Pd is crucial to promote the overall C-F bond. DFT calculations elucidated that the key step is the selective oxidative addition of the O-H bond of 2-propanol to a Pd center prior to C-F bond activation at a Pt site, which crucially reduces the activation energy of the C-F bond cleavage. Therefore, both Pt and Pd work independently but synergistically to promote the overall reaction.
- Dhital, Raghu Nath,Ehara, Masahiro,Haesuwannakij, Setsiri,Nomura, Keigo,Sakurai, Hidehiro,Sato, Yoshinori
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p. 1180 - 1185
(2020/10/18)
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- A Nickel-Doped Dehydrobenzoannulene-Based Two-Dimensional Covalent Organic Framework for the Reductive Cleavage of Inert Aryl C-S Bonds
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The development of metalated covalent organic frameworks (COFs) is useful for generating recyclable catalytic systems for practical applications. Herein, we report the synthesis, characterization, and catalytic properties of an azine-linked two-dimensional (2D) COF containing nickel-doped dehydrobenzoannulene (DBA) units. We demonstrate that Ni-DBA-2D-COF can be used to reductively cleave the aryl C-S bonds of several organosulfur compounds utilizing dimethylethylsilane as the reducing agent. The Ni-DBA-2D-COF catalytic system displays excellent recyclability and good yields. This work highlights a rare example of utilizing metalated DBA complexes to perform catalytic transformations.
- Haug, W. Karl,McGrier, Psaras L.,Morman, Blake T.,Thomas, Christine M.,Wolfson, Eric R.
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supporting information
p. 5521 - 5525
(2020/04/09)
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- Rongalite as a sulfone source: A novel copper-catalyzed sulfur dioxide anion incorporation process
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A novel copper-catalyzed sulfur dioxide anion incorporation cascade for the synthesis of 1-thiaflavanone sulfones has been disclosed using rongalite as an economic and safe sulfone source. A series of 1-thiaflavanone sulfones were synthesized from easily prepared 2′-iodochalcone derivatives in excellent yields. This transformation proceeds through consecutive formation of two C-S bonds, which is the first example of SO22- being used to construct sulfone motifs under copper-catalyzed conditions.
- Chen, Xiang-Long,Tang, Bo-Cheng,He, Cai,Ma, Jin-Tian,Zhuang, Shi-Yi,Wu, Yan-Dong,Wu, An-Xin
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supporting information
p. 13653 - 13656
(2020/11/13)
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- Tetraethylphosphorodiamidate-Directed Metalation Group: Directed Ortho and Remote Metalation, Cross Coupling, and Remote Phospha Anionic Fries Rearrangement Reactions
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The linked directed ortho and remote metalation (DoM and DreM) and cross-coupling reactions of aryl phosphorodiamidates (Ar-OP(O)(NEt2)2) is reported. The o-iodo and o-boronato aryl tetraethylphosphorodiamidates 3, prepared by DoM, undergo orthogonal Ni- and Pd-catalyzed Suzuki-Miyaura cross coupling to furnish biaryls 4 and 5 in good to excellent yields. Silicon group protection of biaryl 4 via DoM followed by previously unobserved DreM phospha anionic Fries rearrangement affords biaryls 11 which, under acidic conditions, furnish oxaphosphorine oxides 12.
- Alessi, Manlio,Blackburn, Thomas,Patel, Jignesh J.,Sawinski, Hannah,Snieckus, Victor
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