|
| Titre : |
Conformational analysis of molecules in excited states |
| Type de document : |
texte imprimé |
| Auteurs : |
Jacek Waluk |
| Editeur : |
New York : Wiley-vch |
| Année de publication : |
2000 |
| Importance : |
1 vol. (376 p.) |
| Présentation : |
ill. |
| Format : |
25 cm |
| ISBN/ISSN/EAN : |
978-0-471-29707-9 |
| Catégories : |
Chimie
|
| Mots-clés : |
Chimie théorique
Chimie des états excités
Structure moléculaire |
| Index. décimale : |
541.2 Chimie théorique |
| Résumé : |
Un regard unique sur certains des sujets les plus chauds de la photophysique et de la photochimie aujourd'hui
L'étude des molécules dans les états excités a explosé au cours de la dernière décennie, fournissant de nouvelles perspectives sur les changements conformationnels dans les molécules organiques et ouvrant des possibilités de recherche pour les scientifiques et les professionnels en chimie, physique, biologie, médecine et génie des matériaux.
En utilisant l'analyse conformationnelle comme concept unificateur, ce nouveau travail important fournit aux lecteurs un aperçu cohérent et de pointe de ce domaine fascinant et stimulant. Depuis les changements conformationnels qui accompagnent le transfert d'électrons photo-induits vers des processus photophysiques et photochimiques élémentaires dans les systèmes vivants, les thèmes les plus représentatifs et les plus stimulants sont abordés avec soin à partir de la vaste littérature. Des contributions détaillées et autorisées des expérimentateurs et des théoriciens incluent la couverture de:
* Changements conformationnels dans le transfert intramoléculaire d'électrons à états excités
* Aspects conformationnels du transfert de protons d'état excité
* Le nouveau sujet du frottement soluté-solvant dans les réactions chimiques
* Mécanismes et aspects structuraux des formations exciplex
* Aspects conformationnels de la photochimie organique
* Calcul des propriétés conformationnelles de l'état excité |
| Note de contenu : |
1. Conformational Changes Accompanying Intramolecular
Excited State Electron Transfer 1
Wolfgang Rettig and Michael Maus
1. Introduction 1
1.1 Twisting of Amino Groups 2
1.2 Biaromatic Compounds 3
1.3 Compounds with Several Flexible Bonds: Stilbenes,
Polyenes, Cyanines 4
2. Basic Principles 4
2.1 Mesomeric Interaction 4
2.2 Self-Decoupling Biradicaloid Interaction with the Ground State 5
2.3 Interaction with Locally Excited States 6
2.4 Steric Interaction 6
2.5 Pyramidalization at the Amino Nitrogen 6
2.6 Rehybridization in Nitrogen-Containing Acceptor Groups 8
3. Acceptor-Substituted Anilines: Evidence for Excited-State
Twisting in DMABN and Derivatives 8
3.1 Pretwisted and Planarized Model Compounds 11
3.2 The Dynamic Approach 14
3.3 The Emission Transition Moment 15
3.4 Open Questions 16
4. Aryl-Aryl Systems 17
4.1 From Biphenyl to Donor-Acceptor Biaryls 18
4.2 Tools for a Conformational Analysis Using Optical
Spectroscopy 22
4.3 Analysis of Different Charge Transfer Biaryl Compounds 27
5. Concluding Remarks 492. Conformational Aspects of Intra- and Intermolecular
Excited-State Proton Transfer 57
Jacek Waluk
1. Introduction 57
2. The Never-Ending Story of 7-Azaindole and Its Relatives 60
2.1 Excited State Double-Proton Transfer (ESPDT) in 7-Azaindole
Dimers 60
2.2 7-Azaindole and 1-Azacarbazole: Similarities and Differences 66
2.3 Excited-State Double Proton Transfer in Alcohol and
Water Complexes of 7-Azaindole 66
2.4 Excited-State Double-Proton Transfer in 2-(2'-Pyridyl)Indoles,
lH-pyrrolo[3,2-/z]Quinoline and Related Structures 71
3. 7-Hydroxyquinoline: The Case of Proton Relay 74
4. Rotational Isomerism and Proton Transfer 78
4.1 Salicylic Acid and Its Derivatives 78
4.2 2-(2'-Hydroxyphenyl)Benzazoles 83
4.3 2-(2'-Hydroxyphenyl)Benzotriazoles 85
5. Photochromic and Thermochromic Substances 86
5.1 Salicylideneanilines 86
5.2 Dinitrobenzylpyridines and Derivatives 88
6. Solvent Control of the Excited-State Proton Transfer 90
6.1 Solvent Interference with the Excited-State Intramolecular
Proton Transfer 90
6.2 Solvent-Assisted Excited-State Proton Transfer 93
6.3 Non-specific Solvent Effects 96
6.4 Excited-State Proton Transfer in Clusters 98
7. Concluding Remarks 98
3. The Role of Solute-Solvent Friction in Large-Amplitude
Motions 113
David H. Waldeck
1. Introduction 113
2. Rotational Relaxation 115
2.1 Continuum Models for the Friction 118
2.2 Molecular Models for the Friction 125
2.3 Experimental Studies of Solute-Solvent Frictional 3. Orientational Relaxation of Bimolecular Complexes 135
3.1 Theoretical Models 137
3.2 Experimental Examples 142
4. Isomerization and the Importance of Frictional Coupling 148
4.1 Models for the Rate Constant 150
4.2 Identifying an Intrinsic Barrier 154
4.3 Modeling the Friction 156
4.4 The Importance of Other Degrees of Freedom 162
4.5 Barrierless Reactions 163
5. Conclusion 164
4. Structural Aspects of Exciplex Formation 177
Fred Brouwer
1. Exciplexes and Other Excited-State Complexes 177
2. Formation and Decay of Exciplexes 181
2.1 Formation of Exciplexes 181
2.2 Rates of Electron Transfer Quenching 184
2.3 Fluorescence Solvatochromic Shift 190
2.4 Decay of Exciplexes 192
3. Electronic and Geometrie Structure of Exciplexes 204
3.1 Basic Considerations 204
3.2 Electronic Structure of Exciplexes 205
3.3 Singlet vs. Triplet Exciplexes 208
3.4 Exciplex Geometry 210
3.5 Exciplex Formation in Supersonic Jets 212
3.6 The Solvent-Separated Ion Pair: What Is It? 216
4. Intramolecular Exciplexes 217
4.1 Photoinduced Charge Separation in Linked Electron
Donor-Acceptor Systems 217
4.2 Intramolecular Exciplexes in Isolated Molecules 220
4.3 Conformational Changes Following Intramolecular
Charge Separation in Solution 223
5. Conformational Aspects of Organic Photochemistry 237
Giampiero Bartocci, Anna Spalletti, and Ugo Mazzucato
1. Introduction 237
1.1 Internal Rotation and Conformational Equilibria 237
1.2 Restricted Rotation About sp1
-sp2
Carbon-Carbon Single
Bonds 237 2. Methods of Investigation 239
2.1 Experimental Evidence of Ground-State Rotamers 239
2.2 Computational Techniques 241
2.3 Methods Based on Fluorimetry 242
2.4 Evidences of Rotamer Interconversion in the Excited State
(Non-NEER Behavior) 252
3. Typical Examples of Rotamerism in some Selected Series of
Olefins 254
3.1 Two-Component Systems: The Case of trans-Anthryl
Derivatives 255
3.2 Three-Component Systems: The Case of
trans- l-(2-Naphthyl),2-(6'-Quinolyl)Ethene 267
3.3 Rotamerism in a, cu-Diarylpolyenes 273
4. Conformational Control of Photochemistry 278
4.1 Effect on the Photoreaction Quantum Yield 278
4.2 Effect on the Direction of Photoreaction (Multiway
Cyclization of eis Isomers) 284
5. Concluding Remarks 291
6. Calculations of Excited-State Conformational
Properties 297
Massimo Olivucci, Michael A. Robb,
and Fernando Bernardi
1. Introduction 297
2. The Case of Buta-l,3-diene 300
2.1 The Structure of the S\ Buta-l,3-diene Energy Surface 307
2.2 Conical Intersection Conformers and Reaction Selectivity 311
2.3 Excited-State Conformations and Stereoselectivity of the
Photochemical s-cis Buta-1,3-diene Ring Closure 315
2.4 The Nonstereospecific Ring Opening of Cyclobutene 319
2.5 Ultrafast Photochemistry of Buta-1,3-diene 319
2.6 Buta-1,3-diene Triplet Conformers and Triplet Photochemistry 320
3. Methods for Excited-State Computations 321
3.1 The Potential Energy Surface Computation: The CAS-SCF
Method 322
3.2 Search and Computation of Excited-State Reaction Paths 326
4. Excited-State Conformations of Organic Chromophores 331
4.1 Linear Conjugated Hydrocarbons (Polyenes and Polyenyl
Radicals) 333 4.2 Adiabatic vs. Nonadiabatic Paths and Photochemical
Stereoselectivity 336
4.3 Photochemical Chemoselectivity and Regioselectivity:
The Case of Z-hexa-l,3,5-triene 344
4.4 Cyclic Conjugated Hydrocarbons 346
4.5 Conformational Effects of Conjugated Heteroatoms:
Protonated Schiff Bases 348
4.6 Conformational Effects of Conjugated Heteroatoms:
a, ß-Enones 350
4.7 7i vs a Conjugation: Oligosilanes 356
5. Conclusions 361
Index 367 |
Conformational analysis of molecules in excited states [texte imprimé] / Jacek Waluk . - New York : Wiley-vch, 2000 . - 1 vol. (376 p.) : ill. ; 25 cm. ISBN : 978-0-471-29707-9
| Catégories : |
Chimie
|
| Mots-clés : |
Chimie théorique
Chimie des états excités
Structure moléculaire |
| Index. décimale : |
541.2 Chimie théorique |
| Résumé : |
Un regard unique sur certains des sujets les plus chauds de la photophysique et de la photochimie aujourd'hui
L'étude des molécules dans les états excités a explosé au cours de la dernière décennie, fournissant de nouvelles perspectives sur les changements conformationnels dans les molécules organiques et ouvrant des possibilités de recherche pour les scientifiques et les professionnels en chimie, physique, biologie, médecine et génie des matériaux.
En utilisant l'analyse conformationnelle comme concept unificateur, ce nouveau travail important fournit aux lecteurs un aperçu cohérent et de pointe de ce domaine fascinant et stimulant. Depuis les changements conformationnels qui accompagnent le transfert d'électrons photo-induits vers des processus photophysiques et photochimiques élémentaires dans les systèmes vivants, les thèmes les plus représentatifs et les plus stimulants sont abordés avec soin à partir de la vaste littérature. Des contributions détaillées et autorisées des expérimentateurs et des théoriciens incluent la couverture de:
* Changements conformationnels dans le transfert intramoléculaire d'électrons à états excités
* Aspects conformationnels du transfert de protons d'état excité
* Le nouveau sujet du frottement soluté-solvant dans les réactions chimiques
* Mécanismes et aspects structuraux des formations exciplex
* Aspects conformationnels de la photochimie organique
* Calcul des propriétés conformationnelles de l'état excité |
| Note de contenu : |
1. Conformational Changes Accompanying Intramolecular
Excited State Electron Transfer 1
Wolfgang Rettig and Michael Maus
1. Introduction 1
1.1 Twisting of Amino Groups 2
1.2 Biaromatic Compounds 3
1.3 Compounds with Several Flexible Bonds: Stilbenes,
Polyenes, Cyanines 4
2. Basic Principles 4
2.1 Mesomeric Interaction 4
2.2 Self-Decoupling Biradicaloid Interaction with the Ground State 5
2.3 Interaction with Locally Excited States 6
2.4 Steric Interaction 6
2.5 Pyramidalization at the Amino Nitrogen 6
2.6 Rehybridization in Nitrogen-Containing Acceptor Groups 8
3. Acceptor-Substituted Anilines: Evidence for Excited-State
Twisting in DMABN and Derivatives 8
3.1 Pretwisted and Planarized Model Compounds 11
3.2 The Dynamic Approach 14
3.3 The Emission Transition Moment 15
3.4 Open Questions 16
4. Aryl-Aryl Systems 17
4.1 From Biphenyl to Donor-Acceptor Biaryls 18
4.2 Tools for a Conformational Analysis Using Optical
Spectroscopy 22
4.3 Analysis of Different Charge Transfer Biaryl Compounds 27
5. Concluding Remarks 492. Conformational Aspects of Intra- and Intermolecular
Excited-State Proton Transfer 57
Jacek Waluk
1. Introduction 57
2. The Never-Ending Story of 7-Azaindole and Its Relatives 60
2.1 Excited State Double-Proton Transfer (ESPDT) in 7-Azaindole
Dimers 60
2.2 7-Azaindole and 1-Azacarbazole: Similarities and Differences 66
2.3 Excited-State Double Proton Transfer in Alcohol and
Water Complexes of 7-Azaindole 66
2.4 Excited-State Double-Proton Transfer in 2-(2'-Pyridyl)Indoles,
lH-pyrrolo[3,2-/z]Quinoline and Related Structures 71
3. 7-Hydroxyquinoline: The Case of Proton Relay 74
4. Rotational Isomerism and Proton Transfer 78
4.1 Salicylic Acid and Its Derivatives 78
4.2 2-(2'-Hydroxyphenyl)Benzazoles 83
4.3 2-(2'-Hydroxyphenyl)Benzotriazoles 85
5. Photochromic and Thermochromic Substances 86
5.1 Salicylideneanilines 86
5.2 Dinitrobenzylpyridines and Derivatives 88
6. Solvent Control of the Excited-State Proton Transfer 90
6.1 Solvent Interference with the Excited-State Intramolecular
Proton Transfer 90
6.2 Solvent-Assisted Excited-State Proton Transfer 93
6.3 Non-specific Solvent Effects 96
6.4 Excited-State Proton Transfer in Clusters 98
7. Concluding Remarks 98
3. The Role of Solute-Solvent Friction in Large-Amplitude
Motions 113
David H. Waldeck
1. Introduction 113
2. Rotational Relaxation 115
2.1 Continuum Models for the Friction 118
2.2 Molecular Models for the Friction 125
2.3 Experimental Studies of Solute-Solvent Frictional 3. Orientational Relaxation of Bimolecular Complexes 135
3.1 Theoretical Models 137
3.2 Experimental Examples 142
4. Isomerization and the Importance of Frictional Coupling 148
4.1 Models for the Rate Constant 150
4.2 Identifying an Intrinsic Barrier 154
4.3 Modeling the Friction 156
4.4 The Importance of Other Degrees of Freedom 162
4.5 Barrierless Reactions 163
5. Conclusion 164
4. Structural Aspects of Exciplex Formation 177
Fred Brouwer
1. Exciplexes and Other Excited-State Complexes 177
2. Formation and Decay of Exciplexes 181
2.1 Formation of Exciplexes 181
2.2 Rates of Electron Transfer Quenching 184
2.3 Fluorescence Solvatochromic Shift 190
2.4 Decay of Exciplexes 192
3. Electronic and Geometrie Structure of Exciplexes 204
3.1 Basic Considerations 204
3.2 Electronic Structure of Exciplexes 205
3.3 Singlet vs. Triplet Exciplexes 208
3.4 Exciplex Geometry 210
3.5 Exciplex Formation in Supersonic Jets 212
3.6 The Solvent-Separated Ion Pair: What Is It? 216
4. Intramolecular Exciplexes 217
4.1 Photoinduced Charge Separation in Linked Electron
Donor-Acceptor Systems 217
4.2 Intramolecular Exciplexes in Isolated Molecules 220
4.3 Conformational Changes Following Intramolecular
Charge Separation in Solution 223
5. Conformational Aspects of Organic Photochemistry 237
Giampiero Bartocci, Anna Spalletti, and Ugo Mazzucato
1. Introduction 237
1.1 Internal Rotation and Conformational Equilibria 237
1.2 Restricted Rotation About sp1
-sp2
Carbon-Carbon Single
Bonds 237 2. Methods of Investigation 239
2.1 Experimental Evidence of Ground-State Rotamers 239
2.2 Computational Techniques 241
2.3 Methods Based on Fluorimetry 242
2.4 Evidences of Rotamer Interconversion in the Excited State
(Non-NEER Behavior) 252
3. Typical Examples of Rotamerism in some Selected Series of
Olefins 254
3.1 Two-Component Systems: The Case of trans-Anthryl
Derivatives 255
3.2 Three-Component Systems: The Case of
trans- l-(2-Naphthyl),2-(6'-Quinolyl)Ethene 267
3.3 Rotamerism in a, cu-Diarylpolyenes 273
4. Conformational Control of Photochemistry 278
4.1 Effect on the Photoreaction Quantum Yield 278
4.2 Effect on the Direction of Photoreaction (Multiway
Cyclization of eis Isomers) 284
5. Concluding Remarks 291
6. Calculations of Excited-State Conformational
Properties 297
Massimo Olivucci, Michael A. Robb,
and Fernando Bernardi
1. Introduction 297
2. The Case of Buta-l,3-diene 300
2.1 The Structure of the S\ Buta-l,3-diene Energy Surface 307
2.2 Conical Intersection Conformers and Reaction Selectivity 311
2.3 Excited-State Conformations and Stereoselectivity of the
Photochemical s-cis Buta-1,3-diene Ring Closure 315
2.4 The Nonstereospecific Ring Opening of Cyclobutene 319
2.5 Ultrafast Photochemistry of Buta-1,3-diene 319
2.6 Buta-1,3-diene Triplet Conformers and Triplet Photochemistry 320
3. Methods for Excited-State Computations 321
3.1 The Potential Energy Surface Computation: The CAS-SCF
Method 322
3.2 Search and Computation of Excited-State Reaction Paths 326
4. Excited-State Conformations of Organic Chromophores 331
4.1 Linear Conjugated Hydrocarbons (Polyenes and Polyenyl
Radicals) 333 4.2 Adiabatic vs. Nonadiabatic Paths and Photochemical
Stereoselectivity 336
4.3 Photochemical Chemoselectivity and Regioselectivity:
The Case of Z-hexa-l,3,5-triene 344
4.4 Cyclic Conjugated Hydrocarbons 346
4.5 Conformational Effects of Conjugated Heteroatoms:
Protonated Schiff Bases 348
4.6 Conformational Effects of Conjugated Heteroatoms:
a, ß-Enones 350
4.7 7i vs a Conjugation: Oligosilanes 356
5. Conclusions 361
Index 367 |
|  |
Conformational analysis of molecules in excited states
