Distinguishing Alternative Reaction Pathways by Single‐Molecule Fluorescence Spectroscopy

Rybina, Arina; Lang, Carolin; Wirtz, Marcel; Grußmayer, Kristin S.; Kurz, Anton; Maier, Frank; Schmitt, Alexander; Trapp, Oliver; Jung, Gregor; Herten, Dirk‐Peter

doi:10.1002/anie.201300100

Cited by 65 publications

(72 citation statements)

References 40 publications

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“…(3)].I ts eems that the tellurium must be cationic to facilitate the reaction with the more highly electronegative carbon atoms of the alkyne.I nt he diboryne reaction, the presence of the anionic phenyltelluride in the product indicates ar eaction pathway wherein the B Bb ond acts as anucleophile,attacking one of the tellurium atoms of the ditelluride and forcing out a[PhTe] À leaving group.Such ap rocess has been suggested as the pathway for the epoxidation of alkenes with peracids, [22] although controversy surrounding this assertion still exists. [23] Theb oron-boron bond lengths in 5 and 6 were found to be 1.490(6) and 1.494(10) , respectively ( Figure 2). These are moderately longer than the B Bl ength in 4 (1.449-(3) ), [19] yet substantially shorter than those typically found in diborenes (ca.…”

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confidence: 99%

Highly Strained Heterocycles Constructed from Boron–Boron Multiple Bonds and Heavy Chalcogens

et al. 2016

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Abstract:The reactions of a diborene with elemental selenium or tellurium are shown to afford a diboraselenirane or diboratellurirane, respectively. These reactions are reminiscent of the sequestration of sub-valent oxygen and nitrogen in the formation of oxiranes and aziridines; however, such reactivity is not known between alkenes and the heavy chalcogens. While carbon is too electronegative to affect the reduction of elements of lower relative electronegativity, the highly reducing nature of the B=B double bond enables reactions with Se 0 and Te 0 . The capacity of multiple bonds between boron to donate electron density is highlighted in reactions where diborynes behave as nucleophiles, attacking one of the two Te atoms of diaryltellurides, forming salts consisting of diboratellurenium cations and aryltelluride anions.The energy stored in small, highly strained cyclic molecules has made them an integral part of modern synthetic chemistry. Since this "strain energy" increases with decreasing ring size, it is greatest for three-membered rings, and when these rings are heterocyclic the charge-asymmetry induced in the molecule provides sites ready for reaction. Accordingly, an enormous amount of research has gone into both the synthetic paths to, and reactions of, members of this class of compounds, most prominently oxiranes (C2O rings) and aziridines (C2N rings). The most common route to these materials is the oxidation of olefins using, in the case of oxirane formation, subvalent oxygen species such as O2, peroxides, peroxyacids, and ozone, or with reagents that impart a degree of electron deficiency to an oxygen atom, such as chlorite or iodosylbenzene. [1] Aziridination of olefins is most frequently accomplished through the in situ generation of nitrenes from azides or other electron deficient nitrogen sources such as iodinanes, hydroxylamines, and hydrazines. [1a,2] These alkene-oxidations are made possible by the relatively high electronegativity of oxygen and nitrogen, (χPauling = 3.44 and 3.04, respectively), relative to carbon (χPauling = 2.55).Thiiranes (C2S rings) are comparatively less common, and though examples of the direct addition of elemental sulfur to alkenyl double bonds are not unknown, [3] their syntheses are more likely than their first row neighbors to involve non-redox routes. [4] The similar electronegativities of carbon and sulfur (χPauling = 2.58) decreases the thermodynamic driving force for alkene oxidation, further exemplified by the noted willingness of thiiranes to thermally extrude atomic sulfur [5] and by their utility as sulfur atom transfer reagents. [6] Three-membered heterocycles featuring heavier chalcogens (Se and Te) are even less prevalent. Though seleniranes have been proposed as reactive intermediates in a handful of transformations, [7] the isolated examples of these compounds are few and none have been crystallographically verified. [8] To date, there are no known examples of telluriranes. The heavy chalcogens have roughly equal (χSe = 2.55) or smaller (χTe = 2.10...

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Highly Strained Heterocycles Constructed from Boron–Boron Multiple Bonds and Heavy Chalcogens

et al. 2016

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“…As for the chemical reactions in condensed phase, much less has been done about the molecular reaction dynamics due to the complexity of traditional methods 5,6 . Recent advances in single-molecule fluorescence microscopy have allowed the observations of individual molecules, such as their translational diffusion 7,8 , rotational diffusion 9 , spectral fluctuation 10 , conformational motion 11 , the studies of single enzyme or single nanoparticle catalysis [12][13][14][15][16][17] , and the distinguishing of alternative reaction pathways 18 . Single-molecule measurements can reveal the distributions of molecular static or dynamic properties in inhomogeneous system 19 .…”

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Single-molecule chemical reaction reveals molecular reaction kinetics and dynamics

Zhang

Song

et al. 2014

Nat Commun

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“…[1][2][3][4] As in operando detection with fluorescence microscopy reaches the ultimate sensitivity limit of individual molecules and particles-and now of individual chemical reactions-an increasing number of chemists are designing experiments to gardener unique insights into catalysis and stoichiometric reactivity via this technique. Identification of the active phase of the catalyst in rutheniumcatalyzed polymerization, 5 mechanisms responsible for polymer morphology, 6 local environments in radical polymerization, 7,8 crystal face selectivity in surface hydrolysis of esters, 9 mechanistic steps in epoxidation of olefins, 10,11 heterogeneous reactivity of gold nanocatalysts, [12][13][14][15][16] protonation of amines, 17 surface spatial distribution with kinetics of ligand exchange reactions at platinum, [18][19][20][21][22] and ordering within nanomaterials 23 have provided the first applications in purely chemical systems unrelated to biology. 24 In order to image a chemical process, however, this chemical process needs to result in a change in fluorescent output that is detectable.…”

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confidence: 99%

Location change method for imaging chemical reactivity and catalysis with single-molecule and -particle fluorescence microscopy

Blum

2014

Phys. Chem. Chem. Phys.

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In the last eight years, it has become possible to image chemical reactivity at the single-molecule and -particle level with fluorescence microscopy. This Perspective describes one of the imaging techniques that enabled this state-of-the-art application: imaging by the location change of molecules and particles. In this method, the microscope and experiment are configured to produce a signal when an individual molecule or particle changes location or changes mobility concurrently with a chemical change. This imaging technique has enabled observation of single chemical reactions and unraveled mechanisms of complex chemical and physical processes in transition metal and polymerization systems. This Perspective has three major goals:(1) to unify studies of different chemical processes or of different chemical questions, which, in spite of these differences, employ a similar microscopy detection method, (2) to explain the technique to nonexperts and those who might be interested in joining this nascent field, and (3) to highlight unique information available through this cross-disciplinary technique and the value this information has for chemical reaction development generally and catalysis specifically. To this end, application of the location change method to the investigation of polymerization reactions with radical initiators and separately with metal catalysts, and to ligand exchange reactions at platinum complexes are described.

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Distinguishing Alternative Reaction Pathways by Single‐Molecule Fluorescence Spectroscopy

Cited by 65 publications

References 40 publications

Highly Strained Heterocycles Constructed from Boron–Boron Multiple Bonds and Heavy Chalcogens

Highly Strained Heterocycles Constructed from Boron–Boron Multiple Bonds and Heavy Chalcogens

Single-molecule chemical reaction reveals molecular reaction kinetics and dynamics

Location change method for imaging chemical reactivity and catalysis with single-molecule and -particle fluorescence microscopy

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