THÈSE Pour obtenir le grade de DOCTEUR DE LA COMMUNAUTÉ UNIVERSITÉ GRENOBLE ALPES Spécialité : Chimie physique moléculaire et structurale Arrêté ministériel : 25 mai 2016 Présentée par Wathiq Sattar ABDUL-HASSAN Thèse dirigée par Eric SAINT AMAN et Guy ROYAL Préparée au sein du Département de Chimie Moléculaire dans l'École Doctorale de Chimie et Sciences du Vivant Matériaux moléculaire électro-stimulables et assemblages organisés reposant sur des briques élémentaires de type pi-dimères Electron-responsive molecular materials and organized assemblies based on elementary pi-dimer bricks Thèse soutenue publiquement le14 février 2018, devant le jury composé de : Madame Eleonora-Mihaela UNGUREANU Professeur, Université Polytechnique de Bucarest (Rapporteur) Monsieur Charles DEVILLERS Maître de Conférences, Université de Bourgogne (Rapporteur) Madame Isabelle MALFANT Professeur, Université Toulouse III(Examinateur) Monsieur Michael HOLZINGER Directeur de Recherche, Université Grenoble Alpes ((cid:51)(cid:85)(cid:112)(cid:86)(cid:76)(cid:71)(cid:72)(cid:81)(cid:87)) Monsieur Guy ROYAL Professeur, Université Grenoble Alpes (Directeur de thèse) Monsieur Eric SAINT AMAN Professeur, Université Grenoble Alpes (Directeur de thèse) Monsieur Denis Roux Maître de Conférences, Université Grenoble Alpes (Invité) (cid:1) (cid:2) Symbols and Abbreviations TTF: tetrathiafulvalene V2+: dimethyl viologen V+•: dimethyl viologen radical K : dimerization constant Dim SOMO: singly occupied molecular orbital ESR: electron spin resonance spectroscopy (cid:1)H : dimerization enthalpy Dim (cid:1)S : dimerization entropy Dim CV: cyclic voltammetry VRDE: voltammetry with rotating disc electrode (cid:1)E : potential separation (= E - E ) p pa pc E : cathodic peak potential pc E : anodic peak potential pa E : half-wave potential (= (E + E )/2) 1/2 pa pc E : fixed applied potential at electrolysis app DMF: dimethylformamide ACN: acetonitrile DMSO: dimethyl sulfoxide CB[8]: cucurbit[8]uril DOSY: diffusion ordered spectroscopy COSY: correlation spectroscopy ROESY: rotating frame overhause effect spectroscopy DEPTQ: distorsionless enhancement by polarization transfer including the detection of quaternary nuclei HRMS-ESI: high resolution mass spectrometry-electrospray ionization MALDI-Tof: Matrix-assisted laser desorption/ionization-Time of Flight Mass Spectrometry CBPQT4+: cyclobis(paraquate-p-phenylene) DNP: 1,5-dioxynaphthalene K : disproportionation constant Disp TBAP: tetrabutylammonium perchlorate NIR: near infrared region M: metal ion DP: degree of polymerization DMA: dimethylacetamide TCE: 1,1,2,2-tetrachloroethane LS: low-spin state LB: Langmuir-Blodgett technique DEAD: diethyl azodicarboxylate NTf-: (trifluoromethylsulfonyl)imide ion OTf-: triflate ion (cid:2)(cid:2)(cid:1) (cid:1) TEOA: triethanolamine CHTT: (1,8-di (p-2,2': 6', 2''- terpyridin-4-yl) tolyl)-1,4,8,11-tetraazacyclotetradecane MLCT: metal to ligand charge transfer band (cid:2)(cid:2)(cid:2)(cid:1) (cid:1) Table of Contents (cid:1) General Introduction…………………………….……………...…………………...…...2(cid:1) (cid:1) Chapter I: Redox controlled viologen-based assemblies A literature survey 1. Preamble ............................................................................................................................. 6 2.1 Dimeric systems based on viologens ................................................................................. 7 2.2 The three common redox states of viologen ...................................................................... 8 2.3 Dimerization of viologen radical cations ........................................................................... 9 2.4 Thermodynamics of dimerization .................................................................................... 12 2.5 Spectro-electrochemistry and electron-transfer reactions of viologens ........................... 14 3. Alkyl spacered viologens ................................................................................................. 17 4. Inclusion complexes of viologens with cucurbit[8]uril .................................................... 22 5. Viologen-containing catenanes ........................................................................................ 25 6. Pre-organized multi-viologen derivatives ........................................................................ 27 7. Conclusion, Perspectives and Objectives ......................................................................... 32 References ................................................................................................................................ 33 (cid:1) Chapter II: Electrochemical and spectroelectrochemical investigation of flexible bis-viologen cyclophanes and their inclusion complexes (cid:1) Preamble ................................................................................................................................... 42 1. Introduction ...................................................................................................................... 42 1.1 Viologen-cyclopyridinophane .......................................................................................... 42 1.2 The cyclo(bis(paraquat-p-phenylene) system (CBPQT4+) ............................................... 42 1.3 Rotaxane and pseudorotaxane .......................................................................................... 46 2. Objectives of this chapter ................................................................................................. 52 3. Bis-viologen cyclophananes ............................................................................................. 53 3.1 Electrochemical studies .................................................................................................... 53 (cid:2)(cid:3)(cid:1) (cid:1) 3.2 Spectroelectrochemical studies ........................................................................................ 60 4. Study of inclusion complexes .......................................................................................... 63 4.1 Spectrovoltammetric titrations of R54+ and R74+ by V2+ ................................................. 64 4.2 Spectrovoltammetric titration of R52(+•) with V+• ............................................................ 68 5. Some insights on bis-viologen cyclophane structures ...................................................... 71 6. Conclusions and perspective ............................................................................................ 74 References ................................................................................................................................ 75 (cid:1) Chapter III: Redox Responsive coordination polymers based on the viologen units (cid:1) Preamble ................................................................................................................................... 80 1. Coordination polymers ..................................................................................................... 80 2. Responsive coordination polymers .................................................................................. 87 3. Objectives ......................................................................................................................... 93 4. Synthesis and characterization of the ligands .................................................................. 96 4.1 Synthesis ........................................................................................................................... 96 4.2 NMR characterization ...................................................................................................... 98 4.3 Characterization by mass spectrometry .......................................................................... 100 4.4 Electrochemical studies .................................................................................................. 100 4.5 Spectroelectrochemical studies ...................................................................................... 106 4.6 Characterization by ESR spectroscopy .......................................................................... 109 5. Preparation and characterization of the metallopolymers .............................................. 110 5.1 UV-visible spectroscopy characterization ...................................................................... 110 5.2 1H-NMR titration of C 4+ and C 4+ with Zinc(II) and iron(II) salts ............................... 114 3 2 5.3 Study of the coordination polymers formation by spectroelectrochemistry .................. 117 5.4 Photo-assisted reductions followed by absorption spectroscopy ................................... 123 5.5 Study of the coordination polymers by ESR spectroscopy ............................................ 127 5.6 Study of the coordination polymers by viscometry ....................................................... 128 6. Conclusions and Perspective .......................................................................................... 131 References .............................................................................................................................. 134 (cid:1) (cid:3)(cid:1) (cid:1) (cid:1) General conclusion……………………………………………………….....................138 Chapter IV: Experimental part (cid:1) 1. Solvents and reagents ..................................................................................................... 142 2. Nuclear Magnetic resonance .......................................................................................... 142 3. Mass spectrometry analyses ........................................................................................... 142 4. Electron Spin Resonance spectroscopy .......................................................................... 142 5. UV-visible absorption spectroscopy .............................................................................. 142 6. Elemental analyses ......................................................................................................... 142 7. Electrochemistry ............................................................................................................. 143 8. Irradiation experiments .................................................................................................. 144 9. Viscosity experiments .................................................................................................... 144 10. Syntheses ........................................................................................................................ 145 References .............................................................................................................................. 151 Annexe 1: Electrochemistry of molecules with multiple redox centers ............................... 152 Annexe 2: Supplementary spectra ........................................................................................ 156 Annexe 3: Synthesis of alkyl viologens ................................................................................ 158 (cid:3)(cid:2)(cid:1) (cid:1) (cid:4)(cid:1) (cid:1) General Introduction The development of civilization has always been strictly related to the design and construction of devices - from wheel to jet engine - capable of facilitating the movement and travel of human. Nowadays, the miniaturization race leads scientists to investigate the possibility of designing and constructing machines and motors at the nanometer scale, that is, at the molecular level. Research on supramolecular chemistry has shown that molecules are convenient nanometer-scale building blocks that can be used to construct ultraminiaturized devices and machines. Chemists are in an ideal position to develop such a molecular approach to functional nanostructures because they are able to design, synthesize, investigate and operate with molecules. Much attention has been devoted in the last few years to the design, construction and evaluation of a wide range of wonderful molecules that can be regarded as “Molecular Devices and Machines”. This domain was fully recognized in 2016, when the Nobel Prize in Chemistry was awarded to Jean-Pierre Sauvage, Sir J. Fraser Stoddart and Bernard L. Feringa for their work on molecular machines. Currently, a very active field of research concerns the study of switchable molecules used to control the properties of a material. The integration of these structures in a device where they behave as an active component or the preparation of an active material by molecular assembly is the first motivation of these studies. The nature of the molecular switches and their incorporation into the material or devices are defined by the possible fields of application. However, if a wide variety of multifunctional molecules is now available; many conceptual and technical obstacles remain and hamper the implementation of the corresponding functional molecular materials. Indeed, beyond their synthesis, the real challenge now is to connect these molecules to the macroscopic world and to "communicate" with them. This implies to integrate them into devices and materials while retaining their specific properties. It is also possible to create macroscopic effects using the properties of small molecules. In this thesis work, we are interested in development of new redox molecular switches based on non-covalent association or (cid:2)-dimerization among radicals of viologen bricks (viologen = bis-alkylated 4,4'-bipyridine). In a first bibliographic chapter, we describe main characteristics of viologen moieties and their multiple uses as active components in redox-switchable molecular systems and we will present some significant examples from the literature. Chapter II presents two complementary parts. First, our goal was to investigate the redox properties of new cyclophanes containing two viologen units in their structures and to (cid:5)(cid:1) (cid:1) evaluate their ability to generate intramolecular (cid:2)-dimers in organic solvents following their electrochemical reduction. Then, these compounds have been investigated by electrochemistry and spectroelectrochemistry to demonstrate the possible formation of redox- activated inclusion complexes. These latters result from the encapsulation of dimethyl viologen radicals within the cavities of cyclic bis-viologen radicals. Chapter III is devoted to the preparation and study of novel redox responsive coordination polymers. These dynamic polymers were prepared by spontaneous association of polytopic organic ligands containing viologen units with transitions metal cations. The strategy was to control the morphology of the metallopolymers using the redox properties of the viologen groups that are incorporated in their main chains. The synthesis of the ligands and their switching properties will be presented first. Then, the preparation of the metallopolymers by self-assembly and their properties will be exposed. The interesting switching properties and movement of the polymers in solution have been investigated by electrochemical study, absorption and ESR spectroscopy and viscosity measurements. Chapter IV concerns the experimental part. The synthesis and characterization of the molecular systems and materials are presented and the different techniques and methods used for their characterization are detailed. Annexes have also been added. In particular, the synthesis of several viologen derivatives that were prepared during this work (but not used in the work reported in this manuscript) is described. (cid:6)(cid:1) (cid:1)