Oxidative Coupling of Diaryldisulfides by MoCl<sub>5</sub> to Thianthrenes

Spurg, Anke; Schnakenburg, Gregor; Waldvogel, Siegfried R.

doi:10.1002/chem.200902466

Cited by 40 publications

(14 citation statements)

References 66 publications

(28 reference statements)

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“…TiCl 4 acts as a chlorine scavenger in the reaction mixture leading to fewer chlorinated byproducts 25. Similar results for the oxidative cyclization reaction to form seven‐ or eight‐membered ring systems, as well as thianthrenes, were recently found 23e. 26…”

Section: Resultssupporting

confidence: 65%

Oxidative Cyclization Reaction of 2‐Aryl‐Substituted Cinnamates To Form Phenanthrene Carboxylates by Using MoCl₅

Wehming

Schubert

Schnakenburg

et al. 2014

Chemistry A European J

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The oxidative cyclization reaction of 2-aryl cinnamates and derivatives thereof can be easily performed with MoCl5 as the oxidant. This powerful reagent allows oxidative coupling reactions for which other reagents fail. The best results are obtained when the 2-phenyl substituent of the cinnamate is equipped with two methoxy groups. Even iodo moieties in the bay region of phenanthrene are tolerated under the reaction conditions. If naphthalene moieties are involved, a rearrangement of the skeleton occurs, providing an elegant route to highly functionalized angular arenes. The cyclization is demonstrated for 15 example substrates with isolated yields of up to 99 % for the phenanthrene derivative. The broad scope of the reaction underlines the usefulness of MoCl5 and MoCl5 /TiCl4 in the oxidative coupling reaction.

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Section: Resultssupporting

confidence: 65%

Oxidative Cyclization Reaction of 2‐Aryl‐Substituted Cinnamates To Form Phenanthrene Carboxylates by Using MoCl₅

Wehming

Schubert

Schnakenburg

et al. 2014

Chemistry A European J

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“…The DBTH molecules were synthesized in a two‐step procedure from naphthalene‐2‐thiol (). First, oxidation of the thiol group to a disulfur‐bridged specie is achieved quantitatively with hydrogen peroxide in the presence of sodium iodide.…”

Section: Methodsmentioning

confidence: 99%

High‐resolution scanning tunneling and atomic force microscopy of stereochemically resolved dibenzo[a,h]thianthrene molecules

Pavliček

Herranz-Lancho

Fleury

et al. 2013

Physica Status Solidi (b)

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Recently, we reported on the bistable configurational switching of dibenzo[a,h]thianthrene (DBTH) molecules adsorbed on NaCl using combined low‐temperature scanning tunneling and atomic force microscopy (STM/AFM). Here, we discuss the intra‐molecular contrast in AFM images of the molecules as a function of the tip–molecule distance. Our experiments show that ridges in the frequency shift do not necessarily correlate with chemical bonds in this case of a non‐planar molecule. To explain this finding we compare images acquired at different tip–molecule distances to the calculated electron density of the molecules obtained from density functional theory calculations (DFT). In addition, we analyze the probability of finding different configurations after adsorption onto the surface. DBTH molecules in two configurations probed by a CO‐functionalized tip. Insets show AFM (left) and STM (right) images of a U molecule.

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“…All experiments were carried out on a double layer, and we denote this substrate system as NaClð2MLÞ= Cuð111Þ. The DBTH molecules were synthesized as described previously [11].Low coverages of CO (for tip functionalization) and DBTH molecules were adsorbed at sample temperatures below 10 K. Following a recently developed technique, the tip had been terminated with a CO molecule for all AFM measurements to enhance the resolution considerably [1]. …”

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confidence: 99%

“…All experiments were carried out on a double layer, and we denote this substrate system as NaClð2MLÞ= Cuð111Þ. The DBTH molecules were synthesized as described previously [11].…”

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confidence: 99%

Atomic Force Microscopy Reveals Bistable Configurations of Dibenzo[a,h]thianthrene and their Interconversion Pathway

et al. 2012

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We investigated dibenzo [a,h]thianthrene molecules adsorbed on ultrathin layers of NaCl using a combined low-temperature scanning tunneling and atomic force microscope. Two stable configurations exist corresponding to different isomers of free nonplanar molecules. By means of excitations from inelastic electron tunneling we can switch between both configurations. Atomic force microscopy with submolecular resolution allows unambiguous determination of the molecular geometry, and the pathway of the interconversion of the isomers. Our investigations also shed new light on contrast mechanisms in scanning tunneling microscopy. DOI: 10.1103/PhysRevLett.108.086101 PACS numbers: 68.43.Fg, 68.37.Ef, 68.37.Ps, 82.37.Gk Recently, the chemical structure of a pentacene molecule has been visualized by means of noncontact atomic force microscopy (AFM) [1]. Shortly after, this method assisted in identifying the structure of an organic molecule [2]. In conjunction with the capability of scanning tunneling microscopy (STM) to perform orbital imaging on ultrathin insulating films [3], it is possible to gain independent and complementary information of the molecular as well as of the adsorption geometry, but also of the electronic structure of individual molecules.Unambiguous identification of configurational changes of adsorbed molecules is a challenging task by means of STM alone [4], probing the local density of states rather than geometry. Usually, additional techniques such as nearedge x-ray adsorption fine structure measurements have to be employed [5,6].In this Letter, we present combined STM and AFM experiments of dibenzo[a,h]thianthrene (DBTH) molecules adsorbed on ultrathin layers of sodium chloride. We demonstrate controlled switching between two different molecular configurations by means of inelastic excitations. AFM images with submolecular resolution directly reveal the configurational changes. Stereochemistry could be utilized to determine their interconversion pathway in detail.All AFM measurements were carried out in a homebuilt combined STM and AFM operating in an ultrahigh vacuum (p < 10 À10 mbar) at T ¼ 5 K. The AFM, based on the qPlus tuning fork design (spring constant k 0 % 1:8 Â 10 3 N m À1 , resonance frequency f 0 ¼ 26 057 Hz, quality factor Q % 10 4 ) [7], was operated in the frequency modulation mode [8]. Sub-Å ngstrom oscillation amplitudes have been used to maximize the lateral resolution [9]. Some of the STM measurements ( Figs. 1 and 2) were performed in a similar modified commercial STM from SPS-CreaTec. The bias voltage V was applied to the sample.Sodium chloride was evaporated onto clean Cu(111) single crystals at sample temperatures of about 280 K [10]. All experiments were carried out on a double layer, and we denote this substrate system as NaClð2MLÞ= Cuð111Þ. The DBTH molecules were synthesized as described previously [11].Low coverages of CO (for tip functionalization) and DBTH molecules were adsorbed at sample temperatures below 10 K. Following a recently developed technique, the tip ha...

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Oxidative Coupling of Diaryldisulfides by MoCl₅ to Thianthrenes

Cited by 40 publications

References 66 publications

Oxidative Cyclization Reaction of 2‐Aryl‐Substituted Cinnamates To Form Phenanthrene Carboxylates by Using MoCl₅

Oxidative Cyclization Reaction of 2‐Aryl‐Substituted Cinnamates To Form Phenanthrene Carboxylates by Using MoCl₅

High‐resolution scanning tunneling and atomic force microscopy of stereochemically resolved dibenzo[a,h]thianthrene molecules

Atomic Force Microscopy Reveals Bistable Configurations of Dibenzo[a,h]thianthrene and their Interconversion Pathway

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Oxidative Coupling of Diaryldisulfides by MoCl5 to Thianthrenes

Cited by 40 publications

References 66 publications

Oxidative Cyclization Reaction of 2‐Aryl‐Substituted Cinnamates To Form Phenanthrene Carboxylates by Using MoCl5

Oxidative Cyclization Reaction of 2‐Aryl‐Substituted Cinnamates To Form Phenanthrene Carboxylates by Using MoCl5

High‐resolution scanning tunneling and atomic force microscopy of stereochemically resolved dibenzo[a,h]thianthrene molecules

Atomic Force Microscopy Reveals Bistable Configurations of Dibenzo[a,h]thianthrene and their Interconversion Pathway

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Oxidative Coupling of Diaryldisulfides by MoCl₅ to Thianthrenes

Oxidative Cyclization Reaction of 2‐Aryl‐Substituted Cinnamates To Form Phenanthrene Carboxylates by Using MoCl₅

Oxidative Cyclization Reaction of 2‐Aryl‐Substituted Cinnamates To Form Phenanthrene Carboxylates by Using MoCl₅