A Facile Synthesis of Hexakis(bromomethyl)benzene from Mesitylene

Závada, Jiřı́; Pánková, M.; Holý, Petr; Tichý, M.

doi:10.1055/s-1994-25653

Cited by 62 publications

(31 citation statements)

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“…For example, 1,2,3,4-tetramethylbenzene was bromomethylated with hydrogen bromide and formaldehyde in acetic acid to give 1,2-bis(bromomethyl)tetramethylbenzene. 16 Then 2,5-dimethoxytoluene was arylmethylated 17 with 1,2-bis(bromomethyl)tetramethylbenzene in anhydrous benzene in the presence of silver perchlorate as a promoter and calcium carbonate as the acid scavenger to afford 3 in 47% yield. …”

Section: Discussionmentioning

confidence: 99%

“…The attachment of T to the o-xylylene bridge in 3 was effected by treatment of 1,2-bis(bromomethyl)tetramethylbenzene with stoichiometric amounts of TH and silver(I) perchlorate 16 and the isomeric bridged donors 4 and 5 were prepared by an analogous procedure from the m-and pdibromo precursors. 17 To modulate the steric hindrance at the planar redox center, it was modified by bicyclic annulation as in redox center S and by tert-butyl substitution as in redox centers U and V (Chart 4); the corresponding mixed-valence donors 7, 9, and 10 were synthesized by essentially the same procedure (see the Experimental Section). .…”

Section: Chartmentioning

confidence: 99%

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Intervalence (Charge-Resonance) Transitions in Organic Mixed-Valence Systems. Through-Space versus Through-Bond Electron Transfer between Bridged Aromatic (Redox) Centers

et al. 2003

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Intervalence absorption bands appearing in the diagnostic near-IR region are consistently observed in the electronic spectra of mixed-valence systems containing a pair of aromatic redox centers (Ar •+ /Ar) that are connected by two basically different types of molecular bridges. The through-space pathway for intramolecular electron transfer is dictated by an o-xylylene bridge in the mixed-valence cation radical 3•+ with Ar = 2,5-dimethoxy-p-tolyl (T), in which conformational mobility allows the proximal syn disposition of planar T•+ /T redox centers. Four independent experimental probes indicate the large through-space electronic interaction between such cofacial Ar•+ /Ar redox centers from the measurements of (a) sizable potential splitting in the cyclic voltammogram, (b) quinonoidal distortion of T•+ /T centers by X-ray crystallography, (c) "doubling" of the ESR hyperfine splittings, and (d) a pronounced intervalence charge-resonance band. The through (br)-bond pathway for intramolecular electron transfer is enforced in the mixed-valence cation radical 2a•+ by the p-phenylene bridge which provides the structurally inflexible and linear connection between Ar•+ /Ar redox centers. The direct comparison of intramolecular rates of electron transfer (kET) between identical T•+ /T centers in 3•+ and 2a•+ indicates that through-space and through-bond mechanisms are equally effective, despite widely different separations between their redox centers. The same picture obtains for 3•+ and 2a•+ from theoretical computations of the first-order rate constants for intramolecular electron transfer from Marcus−Hush theory using the electronic coupling elements evaluated from the diagnostic intervalence (charge-transfer) transitions. Such a strong coherence between theory and experiment also applies to the mixed-valence cation radical 7•+ , in which the aromatic redox S center is sterically encumbered by annulation.

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Section: Discussionmentioning

confidence: 99%

Section: Chartmentioning

confidence: 99%

Intervalence (Charge-Resonance) Transitions in Organic Mixed-Valence Systems. Through-Space versus Through-Bond Electron Transfer between Bridged Aromatic (Redox) Centers

et al. 2003

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“…16 Thiophosphorylacetonitrile 1b was synthesized by the reaction of the corresponding phos phoryl derivative with Lawesson's reagent. 17 Bromomethyl arenes, viz., 1,2 bis(bromomethyl)benzene, 18 1,2 bis(bromo methyl)naphthalene, 19 2,3 bis(bromomethyl)naphthalene, 20 1,8 bis(bromomethyl)naphthalene, 21 1,2,3,4 and 1,2,4,5 tetra kis(bromomethyl)benzenes, 22 2,2´ bis(bromomethyl) 1,1´ bi phenyl, 23 and 1,3,5 tris(bromomethyl) 2,4,6 trimethylben zene, 24 were prepared according to known procedures by bromi nation of the corresponding methylarenes. The physicochemical constants of the starting reagents are identical with the data published in the literature.…”

Section: Methodsmentioning

confidence: 99%

Reactions of phosphoryl- and thiophosphorylacetonitriles with poly(bromomethyl)arenes containing closely-spaced bromomethyl groups. New types of phosphorus-substituted fused systems

et al. 2005

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Reactions of phosphoryl and thiophosphorylacetonitriles with poly(bromomethyl)arenes containing closely spaced bromomethyl groups under conditions of phase transfer catalysis occur as cycloalkylation to form new types of fused systems, in which aromatic rings are annelated with a five , six , or seven membered ring containing the exocyclic phosphorus containing and cyano substituents. The reaction pathway is independent of the reagent ratio. Under the same conditions, the reaction with 1,3,5 tris(bromomethyl) 2,4,6 trimethylbenzene affords products of monoalkylation at all electrophilic groups of the starting substrate. In the resulting compounds, the alkoxy groups at the phosphorus atom are easily transformed into the hydroxy groups via the corresponding silyl ethers to give the corresponding phosphorus acids, whereas the cyano group is chemically inert.

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“…Solvents and raw materials were of analytical grade and were used as received, with the exception of MeCN, which was filtered over activated alumina and distilled from P 2 O 5 immediately prior to use. 4,5-Diazafluoren-9-one [16], 9-(2-hydroxy)phenylimino-4,5-diazafluorene [17], tetrabutylammonium perchlorate (TBAP) [18], pentaerythrityl tetratosylate [19], 1,1,1-tris(p-tosyloxymethyl)-propane [20], and Ru(bpy) 2 Cl 2 Á2H 2 O [21] were prepared according to literature procedures.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, photophysical, and electrochemical properties of two polynuclear ruthenium(II) polypyridyl complexes containing diazafluorene

Cheng

Chen

Wang

et al. 2011

Transition Met Chem

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Two polypodands, tetrakis[2-(4,5-diazafluoren-9-ylimino)phenoxymethyl]methane (L 1 ) and 1,1,1-tris[2-(4,5-diazafluoren-9-ylimino)phenoxymethyl]propane (L 2 ), and their corresponding Ru(II) polypyridyl complexes have been synthesized and characterized. The photophysical behaviors of the two complexes were investigated by UV-vis absorption and emission spectroscopy. They display metal-to-ligand charge transfer (MLCT) absorptions at around 443 nm in MeCN solution at room temperature and emission at around 573 nm in EtOH:MeOH (4:1) glassy matrix at 77 K. Electrochemical studies of the two complexes show one Ru(II)-centered oxidation at around 1.35 V and three ligand-centered reductions.

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A Facile Synthesis of Hexakis(bromomethyl)benzene from Mesitylene

Cited by 62 publications

References 0 publications

Intervalence (Charge-Resonance) Transitions in Organic Mixed-Valence Systems. Through-Space versus Through-Bond Electron Transfer between Bridged Aromatic (Redox) Centers

Intervalence (Charge-Resonance) Transitions in Organic Mixed-Valence Systems. Through-Space versus Through-Bond Electron Transfer between Bridged Aromatic (Redox) Centers

Reactions of phosphoryl- and thiophosphorylacetonitriles with poly(bromomethyl)arenes containing closely-spaced bromomethyl groups. New types of phosphorus-substituted fused systems

Synthesis, photophysical, and electrochemical properties of two polynuclear ruthenium(II) polypyridyl complexes containing diazafluorene

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