Triplet carbenes react with molecular oxygen rates that approach diffusion control to carbonyl O-oxides, whereas triplet nitrenes much slower. For investigating the reaction of phenylnitrene O2, nitrene was generated by flash vacuum thermolysis (FVT) phenylazide and subsequently isolated in O2-doped matrices. FVT azide produces high yield only minor contaminations rearranged products are frequently observed if is produced photolysis. The solid Ar, Xe, mixtures these rare gases even pure O2....

Solvation is a complex phenomenon involving electrostatic and van der Waals forces as well chemically more specific effects such hydrogen bonding. To disentangle global solvent (macrosolvation) from local (microsolvation), we studied the UV–vis IR spectra of solvatochromic pyridinium-N-phenolate dye (a derivative Reichardt's dye) in rare gas matrices, mixtures argon water, water ice. The π–π* transition betaine visible region its C–O stretching vibration are highly sensitive to effects. By...

5-Methoxy-2H-benzazirine was prepared via irradiation of the corresponding phenyl azide, isolated in an argon matrix at cryogenic temperatures. It undergoes ring expansion to ketenimine dark T < 30 K despite a calculated activation barrier 4.9 kcal mol-1 [B3LYP/6-311++G(d,p)]. Since this rearrangement proceeds with rate constant order 10-4 s-1, exhibiting only shallow temperature dependence, results are interpreted terms heavy-atom tunneling. Of four isomeric benzazirines resulting from...

The septet ground state trinitrenes 1,3,5-trichloro-2,4,6-trinitrenobenzene and 1,3,5-tribromo-2,4,6-trinitrenobenzene were isolated in inert (Ar, Ne, Xe) as well reactive matrices (H2 , O2 H2 O) at cryogenic temperatures. These obtained high yields by UV photolysis of the corresponding triazides characterized IR UV/Vis spectroscopy. trinitrenes, despite bearing six unpaired electrons, are remarkably unreactive towards molecular oxygen hydrogen persistent water ice up to 160 K where matrix...

The chemistry of arylnitrenes is dominated by their triplet ground states and excited open-shell singlet states. This results in radical-type reactions unwanted rearrangements, which diminish the use as intermediates organic synthesis. While closed-shell are expected to undergo useful chemical transformations (comparable carbenes), these too high energy be chemically accessible. When pentafluorophenylnitrene interacting with Lewis acid BF3 under conditions matrix isolation, a acid-base...

Chlorophenylcarbene and fluorophenylcarbene were generated in water-doped argon matrices at cryogenic temperatures by photolysis of the corresponding matrix-isolated diazirines. When diffusion H2O solid was induced annealing above 20 K, hydrogen-bonded complexes between carbenes water formed. UV these resulted formation benzaldehyde hydrogen halides HX. The same products obtained after diazirines amorphous ice. Obviously, primary insertion product into H-OH is unstable under conditions,...

The reactive phenylethynyl radical, a key to PAHs in the ISM, was detected and spectroscopically characterized along with its singlet triplet cations, thermal products revealing complex puzzle containing C 8 H 5 , 4 2 species.

Abstract The hydrogenation reactions of diphenylcarbene 1 , fluorenylidene 2 and dibenzocycloheptadienylidene 3 were investigated in solid H D matrices ‐ ‐doped argon at cryogenic temperatures. reactivity the carbenes towards increases order &lt; . Whereas is stable react fast under same conditions via quantum chemical tunneling. In both are stable, whereas slowly reacts. different three rationalized terms differing carbene stabilization energies.

The ring-opening of a highly strained cyclopropene to carbene proceeds via heavy-atom tunneling. This rearrangement is accelerated in the presence H 2 O, ICF 3 or BF , resulting novel Lewis-acid catalyzed tunneling reaction.

A new sextet ground state molecule, the 2,4,6‐trichloro‐1,3‐dinitrenophenoxyl radical, was obtained upon UV photolysis of corresponding diazido precursor in argon at 5 K. The molecule is formed stepwise with triplet nitrene, quartet nitreno and quintet dinitrene as intermediates that were detected by EPR spectroscopy. IR UV–Vis measurements only allowed us to observe main product, dinitrene. coupling between two nitrene centers oxygen centered radical results zero‐field splitting (zfs)...

The control of the spin states molecules opens path to tuning selectivity in chemical reactions and developing novel magnetically switchable materials. 3-Methoxy-9-fluorenylidene is a carbene that generated cryogenic matrices both its lowest energy singlet triplet states, ratio these can be shifted by selective irradiation. interconversion nearly degenerate induced conformational change methoxy group: switching group into "up" position results state "down" state. via remote functional makes...

The photoionization of phenylnitrene was investigated by photoion mass-selected threshold photoelectron spectroscopy in the gas phase. Flash vacuum pyrolysis phenyl azide at 480 °C produces nitrene, which subsequently rearranges higher temperatures affording three isomeric cyanocyclopentadienes, contrast to low-temperature trapping experiments. Temperature control reactor and spectra allows for optimizing generation or its thermal rearrangement products, as well obtaining vibrational...

Abstract The control of the spin states molecules opens path to tuning selectivity in chemical reactions and developing novel magnetically switchable materials. 3‐Methoxy‐9‐fluorenylidene is a carbene that generated cryogenic matrices both its lowest energy singlet triplet states, ratio these can be shifted by selective irradiation. interconversion nearly degenerate induced conformational change methoxy group: switching group into “up” position results state “down” state. via remote...

Abstract The septet ground state trinitrenes 1,3,5‐trichloro‐2,4,6‐trinitrenobenzene and 1,3,5‐tribromo‐2,4,6‐trinitrenobenzene were isolated in inert (Ar, Ne, Xe) as well reactive matrices (H 2 , O H O) at cryogenic temperatures. These obtained high yields by UV photolysis of the corresponding triazides characterized IR UV/Vis spectroscopy. trinitrenes, despite bearing six unpaired electrons, are remarkably unreactive towards molecular oxygen hydrogen persistent water ice up to 160 K where...

Understanding the structure and properties of heterocyclic radicals their cations is crucial for elucidating reaction mechanisms as they serve versatile synthetic intermediates. In this work,

The thermal decomposition of 2- and 4-iodobenzyl iodide at high temperatures was investigated by mass-selective threshold photoelectron spectroscopy (ms-TPES) in the gas phase, as well matrix isolation infrared cryogenic matrices. Scission benzylic C-I bond precursors 850 K affords radicals (ortho- para-IC6H4CH2•), respectively, yields. adiabatic ionization energies ortho-IC6H4CH2• to X̃+(1A') ã+(3A') cation states were determined be 7.31 ± 0.01 8.78 eV, whereas those para-IC6H4CH2• measured...

Unveiling new spectroscopic and mechanistic insights into interstellar chemistry: photoionization of triplet 2-napthylnitrene its thermal rearrangement to 2- 3-cyanoindene, as monitored with threshold photoelectron spectroscopy.

Abstract The dinitrene 2,3,5,6‐tetrafluoro‐1,4‐phenylenedinitrene was synthesized by photolysis of matrix‐isolated 1,4‐diazido‐2,3,5,6‐tetrafluorobenzene at 365 or 405 nm in high yields cryogenic temperatures and characterized FT‐IR, UV‐Vis, EPR spectroscopy. electronic structure the is described best as a quinoidal diradical with an open‐shell singlet ground state triplet laying only 650 ± 5 cal/mol higher energy. Irradiation λ = 254 results fragmentation into FCCF several olefins which on...

Überraschend stabile organische Trinitrene wurden in nahezu quantitativen Ausbeuten aus ihren Triazidvorläufern synthetisiert. W. Sander et al. zeigen ihrer Zuschrift auf S. 13128 ff., dass die mit sechs ungepaarten Elektronen und elektronischen Grundzuständen inerten Matrizen, aber auch amorphem Wasser bei kryogenen Temperaturen synthetisiert werden können. Unter diesen Bedingungen erwiesen sie sich als stabil gegenüber Sauerstoff, Wasserstoff Wasser, was diese Moleküle zu...

Der Spin-Zustand (Singulett oder Triplett) eines magnetisch bistabilen Carbens wird von einer entfernten Methoxygruppe als Konformationsschalter gesteuert. In ihrer Zuschrift auf Seite 14997 zeigen W. Sander et al., wie diese konformative Spinumschaltung verwendet werden kann, um die Spinabhängigkeit Reaktionen zu untersuchen. Potenzielle Anwendungen bei der Entwicklung neuartiger schaltbarer magnetischer Materialien aufgezeigt.