New Phthalimide-based Sensors for Chiral and Achiral Anions and Peroxides Inaugural-Dissertation Zur Erlangung des Doktorgrades der Mathematisch-Naturwissenschaftlichen Fakultät der Universität zu Köln vorgelegt von Yrene Hortencia Díaz Pérez aus Caracas (Venezuela) Köln 2009 Berichterstatter: Prof. Dr. A. G. Griesbeck Prof. Dr. B. Goldfuß Tag der mündlichen Prüfung: 3.02.2010 Gedruckt mit Unterstützung des Deutschen Akademischen Austauschdienstes For my Parents and Claus Miara Acknowledgements First of all, I would like to thank the Deutscher Akademischer Austausch Dienst (DAAD) for giving me the possibility to conduct my Ph.D in Germany in the research group of Prof. Dr. Axel Griesbeck and especially my referee Veronica Metje. Next, I would like to express my gratitude to Prof. Dr. Axel Griesbeck for giving me the opportunity to perform this work in his group and for his qualified and valuable help and the excellent working conditions in his group. I owe special thanks to Prof. Dr. Bernd Goldfuß for the fruitful cooperation and for accepting to act as referee of my thesis as well as Prof. Dr. Klaus Meerholz and Dr. Dirk Blunk for being part of the evaluation committee of my thesis. Another important person that I would like to thank is Dr. Franklin Vargas in Venezuela for his support and for his right orientation to my professional career. It is also important to me to thank my colleagues Dr. Angela Raabe, Elmar Zimmerman, Johannes Uhlig, Dr. Miyeon Cho, Dr. Raúl Pérez, Dr. Alberto Soldevilla, Dr. Oliver Höinck, Marco Franke, Olga Hinze, Alan de Kiff, Viktor Schlundt, Sarah Strohmeier and Nestor Nazarov for the very nice time together in the laboratory and the good atmosphere. Special thanks go to Dr. Angela Raabe, Elmar Zimmerman, Dr. Raúl Pérez, Dr. Alberto Soldevilla and Sebastian Hanft for the help and friendly cooperation on my work. I would like to give my thanks to the NMR department consisting of Dr. Nils Schlörer, Kathrin König and Gunter Arnold-Hässlich for the help by the NMR experiments, as well as Christoph Schmitz for his help with the elemental analysis and Andreas Adler for the micropipette. Dr. Jörg Neudörfl for the X-Ray measurements and Maria Schumacher for the theoretical calculations. In the Physical Chemistry department, I would like to thank Dr. Dirk Hertel for his help and dedication to the measurements of lifetimes and Georgios Liaptsis for conduction of the mass spectrometry. In the Biochemistry department, I would like to thank Dr. Kay Marin for his help and his availability in the chemoluminescence measurements. The luminol project was a joint work, which is why I would like to thank Robert Fichtler for the nice time that we worked together, for his help and collaboration. I would like to thank Dr. Axel Jacobi von Wangelin, who was a part of the Luminol project, for his help and friendship. I would like to thank Tobias Robert, Stefanie Ritter, Jutta Schütte, Dorina Köbele-Milas and Tobias Hermann for helping me correct my work and for the very, very nice time we have shared together. For their great support, I would like to say my Venezuelan friends thousand thanks. I would like to thank Inger Miara on becoming a great guide for me, now that my parents have become so far. For the support, understanding, help, dedication and thousand reasons more since I came to Germany and especially in the last months I would like to thank my husband Claus Miara. A last thank goes to my parents (Nery de Díaz and Aquiles Díaz) as well as my brother Pablo Díaz and all my familiy members for the absolute support and help during my study in Venezuela and during my Ph.D., I am very grateful for all that. Explanation This work was performed from October 2006 to December 2009 under the supervision of Prof. Dr. Axel G. Griesbeck at the Department of Chemistry, Institute of Organic Chemistry, University of Cologne. In the experimental part names in the format pydr[number] refer to the enumeration in the lab-journal. Abbreviations 1H NMR Proton Nuclear Magnetic Resonance Spectroscopy 13C NMR Carbon Nuclear Magnetic Resonance Spectroscopy Abs. Absorption Ar. Aromatic ACN/CH3CN Acetonitrile b.p. Boiling point (°C) cat. Catalyst Cbz Carbonylbenzyloxy CL Chemoluminescence CT Charge transfer n-Bu n-Butyl t-Bu t-Butyl d Doublet dd Doublet of Doublet DA Diels-Alder DABCO 1,4-Diazabicyclo[2,2,2]octane DBU 1,8-Diazabicyclo[5.4.0]undec-7-ene DCC Dicyclohexylcarbodiimide DCM Dichlormethan DMAP N,N-Dimethylaminopyridine DMBA N,N-Dimethyl(phenyl)methanamine 1,2-DMB 1,2-Dimethoxybenzene 1,3-DMB 1,3-Dimethoxybenzene 1,4-DMB 1,4-Dimethoxybenzene DMBA N,N-dimethyl(phenyl)methanamine DMPAA 2-(3,4-dimethoxyphenyl)acetic acid DMSO Dimethylsulfoxide Em. Emission equiv. Equivalent eq. Equation Es Singlet energy EtOAc Ethylacetate EtOH Ethanol Et3N Trimethylamine Exc. Excitation F Fluorescence intensity FRET Fluorescence Resonance Energy Transfer GC/MS Coupled gas chromatography-mass spectrometry GP General procedure h Hour HMQC Heteronuclear Multiple-Quantum Coherence Experiment HOMO Highest Occupied Molecular Orbital HRMs High Resolution Mass Spectrometry IC Internal conversion ICT Internal Charge Transfer IR Infrared spectrum ISC Intersystem Crossing J Coupling constant (Hz) KD Stern-Volmer constant kq Bimolecular quenching constant KCT Constant of CT complex kF Fluorescence rate constant LUMO Lowest Unoccupied Molecular Orbital MeOH Methanol M Molar concentration m Multiplet min. Minute mmol Milli mole M.p. Melting Point MPAA 2-(4-methoxyphenyl)acetic acid MS Mass Spectrometry NMP N-methyl-2-pyrrolidinone NMR Nuclear Magnetic Resonance ns Nano second (10-9 s) PET Photoinduced Electron Transfer Q Quencher q Quartet RET Resonance Electron Trensfer Rf Rate of flow (retention factor) r.t. Room Temperature s Second or singlet (in NMR) S0 Singlet ground state S1 First excited singlet state T Temperature T1 First excited triplet state TBA Tetrabutylammonium t Triplet THF Tetrahydrofuran TLC Thin-layer Chromatography TSA p-Toluenesulfonic acid UV Ultraviolet UV-vis Ultraviolet visible λ Wavelength ε Molar extinction coefficient µ Micro (10-6) τ Lifetime * Excited state Φf Fluorescence Quantum Yield Abstract The first part of this work describes the synthesis of fluorescent and non-fluorescent phthalimide derivatives via straightforward synthetic routes, including multicomponent reactions (MCRs) (scheme 1-a), and aromatic substitutions and reductions (scheme 1-b). a.- O O O R NH O R NH CO Me 1 R1 NH O 1 O O O 2 R2 R H N-R R2 + R + TSA, Ac2O,NMP O + 120 °C, toluene 2 O 2 3 2 MnO2 N R R1 NH2 H 3 120 °C, 24 h O O CO2Me R O R O 2 R2 O 2 b.- O NH O Ac O 2 N R NH2 O NO2 O NO2 O O NEt R 3 Pd/C N R O + NH2 N R + H2 toluene EtOH O O O O O NH OH O H O O N NH O O N R O Scheme 1 In the second part the synthesis of new photocages based on aminophthalimide-serine was carried out and the fluorescence quenching behaviour of these photocages was investigated (scheme 2) O O - R1 COO ν R1 h CO AcO- N N + 2 + R2 OAc R2 O O Scheme 2 In order to obtain new chiral sensors for achiral and chiral anion recognition the fluorescent sensors 107, 109-112 were synthesized in the third part of this work. The syntheses are based on urea-activated phthalimides with stereogenic centers that were synthesized using an efficient procedure involving a Curtius rearrangement (scheme 3). ii O O 1. PhOCOCl, NaN H H HO C 3 N N 2 t-BuONa/DME, 75°C R N N O 2. R-NH2 , 25 °C O O Scheme 3 The non-fluorescent sensor 123 based on a thiourea-activated phthalimide with a stereogenic center was synthesized following a synthetic route involving five steps each of which could be performed with good yields (scheme 4). O O O O H SO / HNO O2N O2N H2N 2 4 3 K2CO3, KI H2,Pd/C NH NH N N Br O O O O S Cl Cl O H H O SCN N N Dioxan, Ar N N S O O NH2 Scheme 4 This work demonstrates the capability of a new series of fluorescent and non-fluorescent chiral sensors obtained through the previously described synthetic routes to recognize achiral and chiral anions and peroxides. Photophysical properties of the sensors such as absorption (abs), excitation (exc), emission (em) wavelengths (λ), Stokes shifts, singlet energies (Es), fluorescence lifetimes (τF), quantum fluorescence yields (ΦF) and fluorescence rate constants (kF) were determined in several solvents in order to compare the solvent effects on the different photophysical properties of the sensor. The recognition of the achiral and chiral anions was performed through absorption, fluorescence and 1H NMR experiments. To consolidate the experimental results, theoretical calculations based on DFT methods at B31YP/6-31G* level were carried out. Recognition of peroxides was conducted by fluorescence experiments before and after irradiation of the sensor−peroxide solutions at 350 nm. iii NH O NH2 O 2 NH2 O NH2 O NH2 O i-Pr NH NH NH NH NH NH NH NH NH NH O O O O i-Pr O NH2 O NH2 O Bn NH NH NH S NH Bn O O Scheme 5 In the last part of this thesis the photophysical properties of luminol derivatives were compared with the parent luminol. Furthermore, comparative studies of the chemoluminescence efficiency of these luminol derivatives were carried out (scheme 5). Kurzzusammenfassung Im ersten Teil dieser Arbeit wurden verschiedene fluoreszierende und nicht-fluoreszierende Phthalimidderivate über vergleichsweise einfache synthetische Routen hergestellt.