Spectroscopic properties of cyclic and bicyclic azoalkanes

Mirbach, Manfred J.; Liu, Kou-Chang; Mirbach, Marlis F.; Cherry, W. R.; Turro, Nicholas J.; Engel, Paul S.

doi:10.1021/ja00484a035

Cited by 55 publications

(38 citation statements)

References 4 publications

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“…To obtain CC3 reference values, we have first selected quite compact molecules and, in particular, n → π* chromogens. 112 Indeed, our set includes members of the nitroso ( 1 113 and 2 ( 113 )), thiorcarbonyl ( 3 , 114 4 115 and 5 ( 116 )), and diazo ( 6 , 117 7 , 118 and 8 ( 118 )) families. We also added a bicyclic aromatic ( 9 119 ), a well-known solvatochromic probe ( 10 120 ), two of the most popular fluorophores ( 11 121 and 12 ( 122 )), and the photoactive trans -azobenzene ( 13 123 ) to represent medium-sized dyes.…”

Section: Resultsmentioning

confidence: 99%

Benchmarking the Bethe–Salpeter Formalism on a Standard Organic Molecular Set

Jacquemin

Duchemin

Blase

2015

J. Chem. Theory Comput.

201

315

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We perform benchmark calculations of the Bethe–Salpeter vertical excitation energies for the set of 28 molecules constituting the well-known Thiel’s set, complemented by a series of small molecules representative of the dye chemistry field. We show that Bethe–Salpeter calculations based on a molecular orbital energy spectrum obtained with non-self-consistent G0W0 calculations starting from semilocal DFT functionals dramatically underestimate the transition energies. Starting from the popular PBE0 hybrid functional significantly improves the results even though this leads to an average −0.59 eV redshift compared to reference calculations for Thiel’s set. It is shown, however, that a simple self-consistent scheme at the GW level, with an update of the quasiparticle energies, not only leads to a much better agreement with reference values, but also significantly reduces the impact of the starting DFT functional. On average, the Bethe–Salpeter scheme based on self-consistent GW calculations comes close to the best time-dependent DFT calculations with the PBE0 functional with a 0.98 correlation coefficient and a 0.18 (0.25) eV mean absolute deviation compared to TD-PBE0 (theoretical best estimates) with a tendency to be red-shifted. We also observe that TD-DFT and the standard adiabatic Bethe–Salpeter implementation may differ significantly for states implying a large multiple excitation character.

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Section: Resultsmentioning

confidence: 99%

Benchmarking the Bethe–Salpeter Formalism on a Standard Organic Molecular Set

Jacquemin

Duchemin

Blase

2015

J. Chem. Theory Comput.

201

315

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“…31 The triplet energy of benzophenone was taken as 290 kJ mol Ϫ1 , corresponding to the 0,0 phosphorescence band in 2-methyltetrahydrofuran glass at 77 K. 32 The singlet excitation energy of DBO was taken as 318 kJ mol Ϫ1 . 33 Due to a rather large singlet-triplet energy gap (92 ± 8 kJ mol Ϫ1 ) 34-37 DBO itself undergoes no intersystem crossing (ISC). Moreover, its triplet state is too short lived (ca.…”

Section: Excitation Energiesmentioning

confidence: 99%

Structure-reactivity relationships in the photoreduction of n,π*-excited ketones and azoalkanes: the effect of reaction thermodynamics, excited-state electrophilicity, and antibonding character in the transition state

Pischel

Nau

2002

Photochem Photobiol Sci

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The reaction enthalpies for the photoreduction of n,pi*-excited states (acetone, benzophenone, 2.3-diazabicyclo[2.2.2]oct-2-ene, and a 2,3-diazabicyclo[2.2.1]hept-2-ene derivative) by model hydrogen donors (methanol and dimethylamine) were calculated on the basis of a critically evaluated data set of bond dissociation energies for donors and reduced acceptors. These were compared with the observed photoreactivity, which can be assessed through quenching rate constants of the excited states by hydrogen donors. The intriguing observation of a preferential attack at electrophilic hydrogen atoms, i.e., N-H or O-H, by n,pi*-excited azoalkanes is rationalised on the basis of the calculated thermochemical data, differences in electrophilicity, and varying contributions of antibonding character in the transition state. Singlet-excited azoalkanes act as nucleophilic species, while excited ketones display an electrophilic reactivity. This is in line with the pictorial description of the electron distribution in these excited states.

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“…-13C-NMR. '): 16,5,17,9,18,0,20,0,25,9,26,3 (6 qa,6 CH3);44,9 (t, C (6)); 109,6 (I, CH>=C(CH3)); 44,5 (d, C (7)); 121, 5, 122,4, 12?,4 ( 3 4 C(3), C(4), C (8)); 131, 7, 132,5, 134,O (3s, c(2), CH2=C(CH3), C (9)); 148,6 c (5)). -MS.: 218 (7, Mt, C16H?6), 110 (12), 109 (loo), 81 (ll), 67 (25), 55 (lo), 43 (12), 41 (12).…”

Section: -Isopropyl-5-mefhyl-4-hexen-2-onmentioning

confidence: 99%

“…(2)); 1,24 (s, 2 H3C-C(4)); 1,67-1,84 (m, H3C-C (7)); 2,94 (qi, /=7, H-C(2)); 4,6-4,7 und 4,83-4,95 (2m, 2 H-C(8)); 5.6 (AB-System, V A = 5,41, v B = 5,80, J = 12, B-Teil durch allylische Kopplung verbreitert, H-C (5), H-C (6)). -MS.: 180 (24, M + , C12H200), 110 (19), 109 (IOO), 81 (19), 70 (64), 67 (50), 55 (18), 43 (loo), 41 (29).…”

Section: -Isopropyl-5-mefhyl-4-hexen-2-onunclassified

Photochemische Reaktionen. 109. Mitteilung [1]. Zur Photochemie konjugierter δ‐Keto‐enone und β,γ,δ,ϵ‐ungesättigter Ketone

Eichenberger

Tsutsumi

Weck

et al. 1980

Helvetica Chimica Acta

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On '71, n*-excitation the 6-keto-enones 5-8 are isomerized to compounds B (18, 22, 26, 28) via 1,3-acyl shift and to compounds C (19, 23, 27, 29) via 1,2-acyl shift, whereas the p, y , 6, E-unsaturated ketone 9 gives the isomers 32 and 33 by 1,2-and 1,5-acyl shift, respectively. Furthermore, isomerization of 6 to 24, dimerization of 8 to 30 and addition of methanol to 8 (8 -+ 31) is observed. Unlike 7 and 8 the acyclic ketones 5, 6 and 9 undergo photodecarbonylation on '71, 71"-excitation Evidence is given, that the conversion to B as well as the photodecarbonylation of 5, 6 and 9 arise from an excited singulet state, but the conversion to C as well as the dimerization of 8 from the T,-state.

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Spectroscopic properties of cyclic and bicyclic azoalkanes

Cited by 55 publications

References 4 publications

Benchmarking the Bethe–Salpeter Formalism on a Standard Organic Molecular Set

Benchmarking the Bethe–Salpeter Formalism on a Standard Organic Molecular Set

Structure-reactivity relationships in the photoreduction of n,π*-excited ketones and azoalkanes: the effect of reaction thermodynamics, excited-state electrophilicity, and antibonding character in the transition state

Photochemische Reaktionen. 109. Mitteilung [1]. Zur Photochemie konjugierter δ‐Keto‐enone und β,γ,δ,ϵ‐ungesättigter Ketone

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