Oxidative Aliphatic C-H Fluorination with Fluoride Ion Catalyzed by a Manganese Porphyrin

Liu, Wei; Huang, Xiongyi; Cheng, Mu Jeng; Nielsen, Robert J.; Goddard, William A.; Groves, John T.

doi:10.1126/science.1222327

Cited by 496 publications

(275 citation statements)

References 54 publications

(50 reference statements)

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“…Fluorine is absent in biological systems, but is widely used to tailor the properties or behaviours of drugs, biomacromolecules and cells [18][19][20][21][22] . Fluorination increases the therapeutic efficacy or pharmacokinetic behaviour of numerous drugs 18,19 , improves the stability of proteins without altering their structures and functions 21 , and allows the detection or imaging of the labelled compounds using magnetic resonance imaging or positron emission tomography imaging 23,24 .…”

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confidence: 99%

A fluorinated dendrimer achieves excellent gene transfection efficacy at extremely low nitrogen to phosphorus ratios

et al. 2014

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Polymers have shown great promise in the design of high efficient and low cytotoxic gene vectors. Here we synthesize fluorinated dendrimers for use as gene vectors. Fluorinated dendrimers achieve excellent gene transfection efficacy in several cell lines (higher than 90% in HEK293 and HeLa cells) at extremely low N/P ratios. These polymers show superior efficacy and biocompatibility compared with several commercial transfection reagents such as Lipofectamine 2000 and SuperFect. Fluorination enhances the cellular uptake of the dendrimer/DNA polyplexes and facilitates their endosomal escape. In addition, the fluorinated dendrimer shows excellent serum resistance and exhibits high gene transfection efficacy even in medium containing 50% FBS. The results suggest that fluorinated dendrimers are a new class of highly efficient gene vectors and fluorination is a promising strategy to design gene vectors without involving sophisticated syntheses.

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confidence: 99%

A fluorinated dendrimer achieves excellent gene transfection efficacy at extremely low nitrogen to phosphorus ratios

et al. 2014

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“…[11,12] Abiotic processes are believed to follow similar pathways and are responsible for the oxidation and oxygenation of organic matter. Copper-and iron-based oxygen activation and oxidation chemistry [8][9][10] are ubiquitous, high-valent manganese model chemistry is gaining more attention recently [13][14][15][16][17][18] and various studies on high-valent nickel chemistry also have recently been published. [19][20][21] Here, we concentrate on iron chemistry.…”

Section: Iron In Naturementioning

confidence: 99%

Iron-catalysed oxidation and halogenation of organic matter in nature

et al. 2015

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Environmental context. Natural organohalogens produced in and released from soils are of utmost importance for ozone depletion in the stratosphere. Formation mechanisms of natural organohalogens are reviewed with particular attention to recent advances in biomimetic chemistry as well as in radical-based Fenton chemistry. Iron-catalysed oxidation in biotic and abiotic systems converts organic matter in nature to organohalogens.Abstract. Natural and anthropogenic organic matter is continuously transformed by abiotic and biotic processes in the biosphere. These reactions include partial and complete oxidation (mineralisation) or reduction of organic matter, depending on the redox milieu. Products of these transformations are, among others, volatile substances with atmospheric relevance, e.g. CO 2 , alkanes and organohalogens. Natural organohalogens, produced in and released from soils and salt surfaces, are of utmost importance for stratospheric (e.g. CH 3 Cl, CH 3 Br for ozone depletion) and tropospheric (e.g. Br 2 , BrCl, Cl 2 , HOCl, HOBr, ClNO 2 , BrNO 2 and BrONO 2 for the bromine explosion in polar, marine and continental boundary layers, and I 2 , CH 3 I, CH 2 I 2 for reactive iodine chemistry, leading to new particle formation) chemistry, and pose a hazard to terrestrial ecosystems (e.g. halogenated carbonic acids such as trichloroacetic acid). Mechanisms for the formation of volatile hydrocarbons and oxygenated as well as halogenated derivatives are reviewed with particular attention paid to recent advances in the field of mechanistic studies of relevant enzymes and biomimetic chemistry as well as radical-based processes.

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“…[3][4][5] The alkyl radical then can rebound with M-OH to form the corresponding alcohol or for heterogeneous catalysts it can bind to other MQO bonds on the catalyst surface. 6 Recently, we determined the reaction mechanism for the highly selective direct oxidation of n-butane to maleic anhydride by the vanadium phosphate oxide (VPO) catalyst, in which O 2 is the oxidant.…”

Section: 2mentioning

confidence: 99%

Design and validation of non-metal oxo complexes for C–H activation

Cheng

Goddard

2014

Chem. Commun.

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We use our recent discovery of the reduction-coupled oxo activation (ROA) principle to design a series of organometallic molecules that activate C-H bonds through this unique proton/electron-decoupled hydrogen abstraction mechanism, in which the main group oxo moiety binds to the proton while the electron is transferred to the transition metal. Here we illustrate this general class of catalyst clusters with several examples that are validated through quantum mechanics calculations.The two major approaches for activating alkane C-H bonds are:Direct reaction with a metal centre; examples of which include oxidative addition, electrophilic substitution, s-bond metathesis, and 1,2-addition (Scheme 1(a)). These cases lead to formation of a metal-alkyl complex. 1,2Radical rebound, involving reaction at transition metal-oxo moieties (MQO) (Scheme 1(b)) to form a metal hydroxide-alkyl radical pair, in which the metal is reduced by one electron during the reaction.3-5 The alkyl radical then can rebound with M-OH to form the corresponding alcohol or for heterogeneous catalysts it can bind to other MQO bonds on the catalyst surface. 6Recently, we determined the reaction mechanism for the highly selective direct oxidation of n-butane to maleic anhydride by the vanadium phosphate oxide (VPO) catalyst, in which O 2 is the oxidant. 7 We found that the strong C-H bonds of n-butane are activated through a unique mechanism involving the OQP rather than the OQV moieties to cleave the butane C-H bond in a homolytic manner. This is most favourable because the proton transfers to OQP while the electron transfers simultaneously to the neighbouring vanadium (which is coupled to the P through oxygen), reducing it from V V to V IV (Scheme 2(a), M = V, n = 5). This PO-H bond is sufficiently strong that the reaction barrier to extract an H from n-butane is less than 14.0 kcal mol À1 ! For the VPO catalyst the butyl radical gets trapped on an adjacent VQO site and subsequent C-H bond breaking occurs through successive activation by additional PQO bonds, eventually producing maleic anhydride.

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Oxidative Aliphatic C-H Fluorination with Fluoride Ion Catalyzed by a Manganese Porphyrin

Cited by 496 publications

References 54 publications

A fluorinated dendrimer achieves excellent gene transfection efficacy at extremely low nitrogen to phosphorus ratios

A fluorinated dendrimer achieves excellent gene transfection efficacy at extremely low nitrogen to phosphorus ratios

Iron-catalysed oxidation and halogenation of organic matter in nature

Design and validation of non-metal oxo complexes for C–H activation

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