Solvent effects on electronic absorption spectra of nitrochlorobenzenes, nitrophenols and nitroanilines—II. Studies in polar solvents

Prabhumirashi, L. S.; Kunte, Soumitra

doi:10.1016/0584-8539(88)80245-9

Cited by 10 publications

(4 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[12][13][14][15][16][17][18] Furthermore, derivatives of NB and nitro substituted aromatic hydrocarbons have attracted the interest many scientists because of their unique properties such as the prominent charge transfer phenomena. [19][20][21][22][23][24][25] In spite of the fundamental importance of the photophysical characters of NB, the photophysical properties, dynamics, and nature of the excited states of NB have not been well understood. In 1970, Khalil et al reported phosphorescence at low temperature with a lifetime 0.1-1 s, 26 which suggested that the lowest excited triplet (T 1 ) state is of 3 ππ* character.…”

Section: Introductionmentioning

confidence: 99%

“…Nitrobenzene (NB) is one of the most fundamental molecules and it possesses a variety of unique optical properties. For example, NB is one of the well-known optical Kerr media and used as the standard substance for new nonlinear optical spectroscopies. − NB is frequently used as an energy acceptor, such as an excited state or fluorescence quencher, − and as an optical heat source in photoacoustic and photothermal spectroscopies. − Furthermore, derivatives of NB and nitro substituted aromatic hydrocarbons have attracted the interest many scientists because of their unique properties such as the prominent charge transfer phenomena. − In spite of the fundamental importance of the photophysical characters of NB, the photophysical properties, dynamics, and nature of the excited states of NB have not been well understood. In 1970, Khalil et al reported phosphorescence at low temperature with a lifetime 0.1−1 s, which suggested that the lowest excited triplet (T 1 ) state is of 3 ππ* character.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Nonradiative Relaxation Processes and Electronically Excited States of Nitrobenzene Studied by Picosecond Time-Resolved Transient Grating Method

1997

View full text Add to dashboard Cite

The exothermic nonradiative relaxation processes from photoexcited nitrobenzene (NB) are studied by the picosecond time-resolved transient grating method. The decay rate constants and energy of the excited NB are determined. The lifetime of the lowest excited singlet state is found to be very short (≤10 ps) and a surprisingly short lifetime of the lowest excited triplet state (∼480 ps) is detected. From quantitative measurements of the thermal energies released from the excited states of NB, the lowest excited triplet state is determined to be located at (22−27) × 103 cm-1. The triplet formation is very efficient and its quantum yield is found to be grater than 0.80. From the temperature and solvent dependence of the triplet lifetime, it is suggested that motions of the nitro group may cause the surprisingly rapid relaxation from the lowest excited triplet state to the ground state. The photophysical properties and excited states of monosubstituted nitrobenzenes are also discussed.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Nonradiative Relaxation Processes and Electronically Excited States of Nitrobenzene Studied by Picosecond Time-Resolved Transient Grating Method

1997

View full text Add to dashboard Cite

show abstract

“…The characters of the excited states have been investigated mostly from the absorption spectra in various solvents. For example, the character, , and dipole moments − of the excited singlet states were estimated from the peak shifts of absorption spectra in several solvents. The lowest excited triplet (T 1 ) state was assigned to be of nπ* character from the reactivity, and the energy of the T 1 state was estimated to be greater than 20.6 × 10 3 cm -1 using the energy transfer from NB to piperylene .…”

Section: Introductionmentioning

confidence: 99%

Geometries and Energies of Nitrobenzene Studied by CAS-SCF Calculations

et al. 1997

View full text Add to dashboard Cite

Optimized geometries and energies in the ground (S0) and excited states of nitrobenzene were calculated using the CAS-SCF method. The optimized geometries in the S1, S2, T1, T2, and T3 states are very different from that in the S0 state. Most significantly, the nitro group is largely bent out of the phenyl plane in the excited states. The potential curves along the nitro rotation coordinate around the C−N bond and the out-of-plane bending mode of the nitro group in the S0, S1, T1, and T2 states were calculated in relation to the excited states dynamics. It is found that the potential curves along the bending mode in the excited states are very flat compared with that in the S0 state. The mechanisms for the fast relaxation from the S1 and T1 states are discussed based on the ab initio results.

show abstract

“…The high and negative values of the IT* sensitivity coefficients, s, are as expected, considering the important increase of dipole moment upon excitation for these solutes (36).…”

Section: (B) Studies In Pure Solventsmentioning

confidence: 55%

Dielectric enrichment in binary solvent mixtures. The intramolecular hydrogen bond in N-alkyl-substituted o-nitroanilines. Substituent effects

Cattana¹,

Silber²,

Anunziata³

1992

Can. J. Chem.

View full text Add to dashboard Cite

In this work we report solvatochromism studies on o-nitroaniline and several N-alkyl-o-nitroaniline derivatives used as solutes in solvent mixtures of an "inert" nonpolar cosolvent, cyclohexane, and THF as a solvent with hydrogen bond acceptor ability. These studies allowed us to establish the competition between inter-and intramolecular hydrogen bond in solutes. This was done by comparing the magnitude of the local inhomogeneity induced by the solute-in-solvent mixture, that is, "preferential solvation," using Suppan's dielectric enrichment model as modified by us to be applied to electronic transitions. Since preferential solvation accounts for dielectric as well as specific interactions while dielectric enrichment only for the former, it was shown by comparison that it is possible to separate both effects and even quantify them. It was deduced that N-alkyl-o-nitroanilines form a strong intramolecular hydrogen bond, which remains unbroken even in polar solvents and hydrogen bond acceptors such as dimethyl sulfoxide. This was also confirmed by solvatochromic studies in pure solvents. On the other hand, a symmetrical dependence of the effects of alkyl substituents and solvents on the shifts of the absorption spectra was observed. [Traduit par la redaction]

show abstract

Solvent effects on electronic absorption spectra of nitrochlorobenzenes, nitrophenols and nitroanilines—II. Studies in polar solvents

Cited by 10 publications

References 34 publications

Nonradiative Relaxation Processes and Electronically Excited States of Nitrobenzene Studied by Picosecond Time-Resolved Transient Grating Method

Nonradiative Relaxation Processes and Electronically Excited States of Nitrobenzene Studied by Picosecond Time-Resolved Transient Grating Method

Geometries and Energies of Nitrobenzene Studied by CAS-SCF Calculations

Dielectric enrichment in binary solvent mixtures. The intramolecular hydrogen bond in N-alkyl-substituted o-nitroanilines. Substituent effects

Contact Info

Product

Resources

About