Photodissociation of diphenyldiazomethane and energy relaxation in the diphenylcarbene fragment

Dupuy, Charles; Korenowski, G. M.; McAuliffe, Michael J.; Hetherington, W. M.; Eisenthal, Kenneth B.

doi:10.1016/0009-2614(81)80144-3

Cited by 39 publications

(28 citation statements)

References 13 publications

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“…For example, for the subnanosecond time scale (17). This allows for subsequent carbene excitation within the single (-5 ns) 308 nm laser pulse.…”

Section: Resultsmentioning

confidence: 99%

Effect of ring substituents on the fluorescence spectra of substituted diarylcarbenes

Scaiano¹,

Weir²

1988

Can. J. Chem.

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. Can. J. Chem. 66, 491 (1988). The fluorescence spectra of a series of ring-substituted diarylcarbenes have been examined. The solution spectra are generally red shifted by 25-30 nm with respect to the band positions in matrices at 77 K. The difference is believed to reflect emission from non-relaxed conformations at 77 K. Both electron-withdrawing and -donating substituents lead to red shifts in the emission. These shifts are essentially additive, and the carbene emission data show an excellent correlation with free radical fluorescence data for the corresponding diarylmethyl radicals. The temperature dependence of excited carbene lifetimes have been examined for a few representative examples. J. C. SCAIANO et D. WEIR. Can. J. Chem. 66, 491 (1988) On a examine les spectres de fluorescence d'une sCrie de diarylcarbknes substitues sur le cycle. Par comparaison avec les spectres determines dans des matrices 5 77 K, les spectres determines en solution sont gCnCralement dCplacCs vers le rouge par 25 B 30 nm. On croit que la difference est le reflet d'une emission provenant de conformations qui ne sont pas soumises B la relaxation B 77 K. Tant les substituants Clectroaffinitaires que ceux qui sont 6.lectrodonneurs conduisent a des deplacements vers le rouge dans 1'Cmission. Essentiellement, ces deplacements sont additifs et les donnees d'emission des carbknes prtsentent une excellente correlation avec les donnies de fluorescence des radicaux libres diarylmethyles correspondants. Pour quclques exemples reprksentatifs, on a examine l'influence de la temperature sur les temps de vie des carbknes excites.[Traduit par la revue] Introduction chromatography or alumina (80-200 mesh from Fisher) using hexane

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“…For example, for the subnanosecond time scale (17). This allows for subsequent carbene excitation within the single (-5 ns) 308 nm laser pulse.…”

Section: Resultsmentioning

confidence: 99%

Effect of ring substituents on the fluorescence spectra of substituted diarylcarbenes

Scaiano¹,

Weir²

1988

Can. J. Chem.

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“…[15][16][17][18][19] As detailed in the previous chapter, collaborations among the Moore, Bergman, and Pimentel groups have taken advantage of the inertness of Xe to study metal complexes that react rapidly with the C-H bonds in alkanes. [20][21][22][23][24][25][26][27] The photoinduced chemistry of 5 and 9 in liquid Xe solution is described below.…”

Section: Discussionmentioning

confidence: 99%

“…Incorporation of 13 CO into [Rh(CO) 2 Cl] 2 was achieved by stirring a benzene solution of the Rh dimer under 1 atm of 13 CO for 8 h as detailed in the literature. 55 The boron-deuterated Bp* ligand was prepared as the sodium salt by subjecting NaBD 4 and 3,5-dimethylpyrazole to the procedure for synthesis of Bp*K. 22 The reaction was run two times using NaBD 4 Thermal ellipsoids are shown at 50% probability. (7) -0.7881 (3 (1) C (5) 1.363 (7) C ( (1) Rh ( (2) Rh (2) Formation of all of these species entails charge transfer from atomic xenon to a highly electronegative oxidant.…”

Section: Structurementioning

confidence: 99%

“…[22][23][24][25][26] The carbenes can be prepared in the singlet state by photoextrusion of N 2 from their diazo compound precursors, after which ISC to the triplet ground state occurs on a picosecond timescale. It was found that the singlet-to-triplet ISC rates of these carbenes vary inversely with solvent polarity, an effect attributed to a relative lowering of the singlet state energy in polar media.…”

Section: Chart 51mentioning

confidence: 99%

“…[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] The structural and kinetic features of the metal-alkane interaction prior to oxidative addition remain an area of active inquiry. Theory and experiments suggest that alkanes coordinate to transition metal centers with significant binding energies (ca.…”

Section: Introductionmentioning

confidence: 99%

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Flash kinetics in liquefied noble gases: Studies of alkane activation and ligand dynamics at rhodium carbonyl centers, and a search for xenon-carbene adducts

Yeston

2001

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Chapter 1. A general introduction is given to place the subsequent chapters in context for the nonspecialist.Chapter 2. Results are presented from a low temperature infrared (IR) flash kinetic study of C-H bond activation via photoinduced reaction of Cp*Rh(CO) 2 (1) with linear and cyclic alkanes in liquid krypton and liquid xenon solution. No reaction was observed with methane; for all other hydrocarbons studied, the rate law supports fragmentation of the overall reaction into an alkane binding step followed by an oxidative addition step. Chapter 5. Results are presented from a picosecond pump-probe study designed to measure the impact of added xenon on the singlet-to-triplet intersystem crossing rates of diarylcarbenes. Within the error margins of the measurements, no effect of added xenon was observed. ii

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1,4‐Naphthoquinonediazide‐2‐carboxylic acid: a diazo compound with a long‐lived triplet excited state

Bucher

Wandel

Sander

2001

J of Physical Organic Chem

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Laser flash photolysis (308 nm) of 1,4‐naphthoquinonediazide‐2‐carboxylic acid 1 in 2‐methyltetrahydrofuran (MTHF) leads to the detection of a long‐lived (5.3 μs) triplet excited state, whose triplet energy, obtained by measuring the phosphorescence spectrum of 1 in an Ar‐ matrix at 10 K, is ca 55 kcal mol−1 (1 kcal= 4.184 KJ). The first triplet excited state of 1 is quenched efficiently by 1,3‐dienes and molecular oxygen. By calculating the spin density distribution it can be shown that 31 is not a typical naphthalene triplet, as it bears significant spin density at the diazo moiety. Copyright © 2001 John Wiley & Sons, Ltd.

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Photodissociation of diphenyldiazomethane and energy relaxation in the diphenylcarbene fragment

Cited by 39 publications

References 13 publications

Effect of ring substituents on the fluorescence spectra of substituted diarylcarbenes

Effect of ring substituents on the fluorescence spectra of substituted diarylcarbenes

Flash kinetics in liquefied noble gases: Studies of alkane activation and ligand dynamics at rhodium carbonyl centers, and a search for xenon-carbene adducts

1,4‐Naphthoquinonediazide‐2‐carboxylic acid: a diazo compound with a long‐lived triplet excited state

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