A Refinement of the Crystal Structure of cis-Azobenzene.

Mostad, Asbjørn; Rømming, Chr.; Hammarström, Sten; Lousberg, R. J. J. C.; Weiß, Ulrich

doi:10.3891/acta.chem.scand.25-3561

Cited by 225 publications

(149 citation statements)

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“…As a general tendency, the excitation energies are overestimated, compared to the corresponding experimental values. 17,20 On the other hand, optimized geometries are almost in good agreement with the experimental ones, 41,42 although the NNCC dihedral angle for cisazobenzene is ϳ10°larger than the experimental value. We also examined potential energy curves along NNC bond angle ͑a NNC ͒, CNNC dihedral angle ͑d CNNC ͒, and NNCC dihedral angle ͑d NNCC ͒ in the S 0 and S 1 states, and verified that potential energy curves calculated with STO-3G qualitatively reproduce those calculated with TK/NOSeC-V-DZP at the CASSCF level.…”

Section: A Preliminary Calculationssupporting

confidence: 53%

Ab initio molecular dynamics simulation of photoisomerization in azobenzene in the nπ∗ state

Ootani

Satoh

Nakayama

et al. 2009

The Journal of Chemical Physics

112

131

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Photoisomerization mechanism of azobenzene in the lowest excited state S 1 ͑n ‫ء‬ ͒ is investigated by ab initio molecular dynamics ͑AIMD͒ simulation with the RATTLE algorithm, based on the state-averaged complete active space self-consistent field method. AIMD simulations show that cis to trans isomerization occurs via two-step rotation mechanism, accompanying rotations of the central NN part and two phenyl rings, and this process can be classified into two types, namely, clockwise and counterclockwise rotation pathways. On the other hand, trans to cis isomerization occurs via conventional rotation pathway where two phenyl rings rotate around the NN bond. The quantum yields are calculated to be 0.45 and 0.28Ϯ 0.14 for cis to trans and trans to cis photoisomerizations, respectively, which are in very good agreement with the corresponding experimental results.

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Section: A Preliminary Calculationssupporting

confidence: 53%

Ab initio molecular dynamics simulation of photoisomerization in azobenzene in the nπ∗ state

Ootani

Satoh

Nakayama

et al. 2009

The Journal of Chemical Physics

112

131

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“…angles of the conformationaUy related azobenzenes (Mostad & Romming, 1971). The large C-C=C angle (126 °) found in trans-stilbene (Finder et al, 1974;Bernstein, 1975) probably arises from disor- …”

Section: C-n=nmentioning

confidence: 99%

Structural studies of polychlorinated hydrocarbons. III. The cis and trans isomers of tetrachlorostilbene

Norrestam¹,

Hovmöller²,

Palm³

et al. 1977

Acta Crystallogr Sect B

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The c/s and trans isomers of 1,2-bis(4-chlorophenyl)-1,2-dichloroethylene, C14HsC14, are monoclinic, space group P21/c. The 107 parameters describing the trans isomer [a = 6.002 (5), b = 14.500 (12), c = 7.630 (5) A,/~ = 94.55 (2) °, Z = 2, Dx = 1. 596 g cm-31 were refined versus the 854 most significant single-crystal Xray reflexions to an R of 0.043. The 195 parameters of the cis isomer [a = 8.062 (8), b = 28.560 (12), c = 6.118 (6) A,/3 = 97.60 (2) °, Z = 4, Dx = 1.513 g cm-31 were refined versus the 1017 most significant reflexions to an R of 0.048. The molecules of both isomers were found to be nonplanar. The C-C=C bond angles at the ethylene bridge were significantly greater than 120 (125) for the cis isomer and less than 120 ° ( 118 o) for the trans isomer.

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] An earlier study on the absorption spectra indicated that the first and second excited states of both cis-and trans-azobenzene were attributed to nπ * and ππ * excitations, respectively. 1,4,11 Quantum yields of the isomerizations for cis-and trans-azobenzene were reported to be different between nπ * and ππ * excitations.…”

Section: Introductionmentioning

confidence: 99%

A multireference perturbation study of the NN stretching frequency of trans-azobenzene in nπ* excitation and an implication for the photoisomerization mechanism

Harabuchi

Ishii

Nakayama

et al. 2013

The Journal of Chemical Physics

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A multireference second-order perturbation theory is applied to calculate equilibrium structures and vibrational frequencies of trans-azobenzene in the ground and nπ * excited states, as well as the reaction pathways for rotation and inversion mechanism in the nπ * excited state. It is found that the NN stretching frequency exhibits a slight increase at the minimum energy structure in the nπ * state, which is explained by the mixing of the NN stretching mode with the CN symmetric stretching mode. We also calculate the NN stretching frequency at several selected structures along the rotation and inversion pathways in the nπ * state, and show that the frequency decreases gradually along the rotation pathway while it increases by ca. 300 cm −1 along the inversion pathway. The frequencies and energy variations along the respective pathways indicate that the rotation pathway is more consistent with the experimental observation of the NN stretching frequency in nπ * excitation.

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A Refinement of the Crystal Structure of cis-Azobenzene.

Cited by 225 publications

References 0 publications

Ab initio molecular dynamics simulation of photoisomerization in azobenzene in the nπ∗ state

Ab initio molecular dynamics simulation of photoisomerization in azobenzene in the nπ∗ state

Structural studies of polychlorinated hydrocarbons. III. The cis and trans isomers of tetrachlorostilbene

A multireference perturbation study of the NN stretching frequency of trans-azobenzene in nπ* excitation and an implication for the photoisomerization mechanism

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