Experimentelle und Quantenchemische Untersuchungen der Dipolmomente von Substituierten Stilbenen im Ersten Angercgten Singulettzustand / Experimental and Quantum Chemical Investigations of Dipole Moments of Substituted Stilbens in the First Excited Singlet State

1977 ◽  
Vol 32 (5) ◽  
pp. 420-425 ◽  
Author(s):  
A. Kawski ◽  
I. Gryczyński
Keyword(s):  
Dipole Moment ◽  
Excited States ◽  
Ground State ◽  
Quantum Chemical ◽  
Singlet State ◽  
Dipole Moments ◽  
Excited Singlet State ◽  
Excited Singlet ◽  
Fluorescent State ◽  
Experimental Values

Abstract The values a/a3 (α = polarizability), the Onsager cavity radii a and the dipole moments μe of six substituted stilbens in the fluorescent state have been determined. It is shown that if the dipole moment of the lowest excited singlet state μe is parallel to the dipole moment in the ground state μg, the values of μe and a can be determined from the solvent effects. Moreover, quantum chemical investigations of the dipole moments in the ground and excited states were carried out with the Pariser-Parr-Pople method and compared with the experimental values.

Theoretical and Experimental Dipole Moments of Purines

2002 ◽  
Vol 67 (8) ◽  
pp. 1109-1124 ◽  
Author(s):  
Cyril Párkányi ◽  
Christian Boniface ◽  
Jean-Jacques Aaron ◽  
Mihaela Bulaceanu-MacNair ◽  
Marwan Dakkouri
Keyword(s):  
Ab Initio ◽  
Ground State ◽  
Singlet State ◽  
Dipole Moments ◽  
Excited Singlet State ◽  
Excited Singlet ◽  
Solvatochromic Shift ◽  
Experimental Values ◽  
Vector Sum ◽  
Ground State Dipole Moments

As a follow-up on our previous study of a series of purines (purine, 6-chloropurine, purine-6-thiol, hypoxanthine, theobromine, theophylline, caffeine, and uric acid), we have investigated six additional biologically important purines (adenine, guanine, isoguanine, thioguanine, xanthine, and kinetin). Their ground-state dipole moments were measured in dioxane at 293 K. The first excited singlet-state dipole moments were obtained using the solvatochromic shift equations (McRae, Suppan, Bakhshiev, and Kawski-Chamma-Viallet). The theoretical dipole moments were calculated as a combination of the π-moment (PPP method) and the σ-moment (vector sum of the σ-bond and σ-group moments). The same approach was used to obtain their first excited singlet-state dipole moments (excited state π-moment; σ-moment assumed to be the same as in the ground state). Ab initio HF 6-31G** calculations were also used to obtain ground-state dipole moments for all the fourteen purines under study. In addition, a DFT/B3PW91/6311++(2df,2p) calculation has been carried out for purine for comparison. The different sets of theoretical dipole moments were compared with the respective experimental values. There is an approximately equally good agreement among the experimental dipole moments and the PPP + σ dipole moments (±6.9%) and the ab initio dipole moments (±7.4%). The effect of structure on the dipole moments is discussed.

A NEW BAND SYSTEM OF THE P2 MOLECULE ANALOGOUS TO THE LYMAN–BIRGE–HOPFIELD BANDS OF N2

1958 ◽  
Vol 36 (5) ◽  
pp. 565-570 ◽  
Author(s):  
A. E. Douglas ◽  
K. Suryanarayana Rao
Keyword(s):  
Excited States ◽  
Ground State ◽  
Singlet State ◽  
Band System ◽  
Excited Singlet State ◽  
Lower State ◽  
High Dispersion ◽  
Electron Configuration ◽  
Excited Singlet ◽  
New System

Five bands of a new band system of P2 have been photographed at high dispersion and analyzed. The upper state of the system is a 1П0 state and lies lower than any previously known excited singlet state. The lower state of the new system is the ground state of P2 and the analysis of the new bands has given improved constants for this state. The new system appears to be the analogue of the Lyman–Birge–Hopfield bands of N2. The electron configuration of the low excited states of P2 and of related molecules is discussed.

Base strengths of substituted 2- and 4-styrylpyridines in the ground and excited states

1969 ◽  
Vol 47 (13) ◽  
pp. 2355-2359 ◽  
Author(s):  
J. C. Doty ◽  
J. L. R. Williams ◽  
P. J. Grisdale
Keyword(s):  
Excited States ◽  
Ground State ◽  
Singlet State ◽  
Excited Singlet State ◽  
Hammett Equation ◽  
Excited Singlet

The base strengths of various 2- and 4-styrylpyridines in the ground state and first-excited-singlet state have been determined. The base strengths are found to conform to the Hammett equation if the proper σ values are chosen.

Ground-and Excited-State Dipole Moments of 6-Propionyl-2-(dimethylamino)naphthalene Determined from Solvatochromic Shifts

1999 ◽  
Vol 54 (6-7) ◽  
pp. 379-381 ◽  
Author(s):  
A. Kawski
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Ground State ◽  
Singlet State ◽  
Fluorescence Probe ◽  
Dipole Moments ◽  
Free Molecule ◽  
Excited Singlet ◽  
Solvatochromic Shifts ◽  
Excited State Dipole Moments

Abstract The dipole moments in the ground-and excited-state of the fluorescence probe 6-propionyl-2-(dim-ethylamino)naphthalene (PRODAN) are determined from solvatochromic shifts to μe = 2.1 D and μg = 6.4 D. These values concern the free molecule. In the first excited singlet state the dipole moment is only 3 times greater than in the ground state.

The Effect of ω-Substituted Acceptors in 4-Dimethylamino-trans-Styrenes on the Polarity in the Ground and Excited Singlet State

1990 ◽  
Vol 45 (11-12) ◽  
pp. 1230-1234 ◽  
Author(s):  
A. Kawski ◽  
D. Gloyna ◽  
P. Bojarski ◽  
J. Czajko ◽  
J. Gadomska-Lichacz
Keyword(s):  
Dipole Moment ◽  
Electric Dipole Moment ◽  
Electron Acceptor ◽  
Electric Dipole ◽  
Linear Relation ◽  
Singlet State ◽  
Dipole Moments ◽  
Excited Singlet State ◽  
Excited Singlet ◽  
Hammett Constants

ABSTRACTThe electric dipole moment in the ground (μg) and in the first excited singlet state (μe) of co-substituted acceptors in 4-dimethylamino-trans-styrenes (Z = P(S)Ph2 , P(O)Ph2 , SO2CH3 ) were determined by solvatochromic and thermochromic methods. The obtained values of μe and μg and the values for Z = CN and Z = NO 2 known from the literature [2] fulfill the linear relation between the dipole moments (μe or μg and the Hammett constants σp of the substituents. On pincreasing the electron-acceptor power of Z, μe grows faster than μg

Experimentelle und Quantenchemische Untersuchungen der Dipolmomente von Donator-substituierten 4-Isocyanat-trans- Stilbenen im nichtrelaxierten angeregten Singulettzustand

1982 ◽  
Vol 37 (3) ◽  
pp. 259-261
Author(s):  
I. Gryczyński ◽  
A. Kawski ◽  
Ch. Jung ◽  
I. Janić
Keyword(s):  
Solvent Effect ◽  
Electric Dipole ◽  
Quantum Chemical ◽  
Singlet State ◽  
Dipole Moments ◽  
Excited Singlet State ◽  
Excited Singlet ◽  
Electric Dipole Moments ◽  
Trans Stilbene

AbstractThe electric dipole moments of 4-isocyanate-4′-dimethyl-amino-trans-stilbene(I), 4-isocyanate- 4′-methoxy-trans-stilbene(II) and 4-isocyanate-3′,4′-dimethoxy-trans-stilbene(III) in the relaxationless first excited singlet state (μe) have been determined from the solvent effect and compared with the values calculated with the quantum chemical Parisser-Parr-Pople method.

The Effect of Substituents on the Polarity in the First Excited Singlet State of Some trans-Styryl-Methyl-Sulfones

1989 ◽  
Vol 44 (12) ◽  
pp. 1163-1166
Author(s):  
A. Kawski ◽  
A. Kubicki ◽  
J. Czajko
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Electron Donor ◽  
Ground State ◽  
Singlet State ◽  
Excited Singlet State ◽  
Excited Singlet ◽  
Hammett Constant ◽  
Effect Of Substituents ◽  
Donor Power

Abstract The effect of substituents R (R=N(CH3)2, OCH3, CH3, H, Cl, Br, CN) on the polarity of trans-styryl-methyl-sulfones in the first excited singlet state is investigated. Linear relations are found between the dipole moment in the excited state, μe, and the Hammett constant, σp+ , and also between μe and the dipole moment in the ground state, μg. On increasing the electron-donor power of R, μe grows faster than μg.

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