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Tris(Pyrazolyl)Borate-Containing Complexes of Ruthenium and Tungsten As Covalent Labels for Biomolecules

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Tris(Pyrazolyl)Borate-Containing Complexes of Ruthenium and Tungsten As Covalent Labels for Biomolecules Tris(pyrazolyl)borate-containing Complexes of Ruthenium and Tungsten as Covalent Labels for Biomolecules Dissertation zur Erlangung des Grades eines Doktors der Naturwissenschaften der Fakultät für Chemie und Biochemie der Ruhr-Universität Bochum vorgelegt von Master of Science (M. Sc.) Johannes Zagermann Bochum, Januar 2011 Diese Arbeit wurde von November 2007 bis Januar 2011 am Lehrstuhl für Anorganische Chemie I der Ruhr-Universität Bochum angefertigt. Referent: Prof. Dr. Nils Metzler-Nolte Koreferent: Prof. Dr. William S. Sheldrick Meiner Familie und Janine You live and learn. At any rate, you live. Douglas Adams ACKNOWLEDGEMENTS Ich bedanke mich herzlichst bei: Nils Metzler-Nolte für die Vergabe eines vielseitigen und interessanten Themas, den Freiraum und die Unterstützung bei der Erstellung dieser Arbeit und die Erfindung von Nils@Nine, Matt Kuchta for introducing me to the world of scorpionates and the CalTex life-style, Klaus Merz und Mariusz Molon für die Lösung und Deutung der Kristallstrukturen, Johanna Niesel für späte CV- und ESI-Messungen und die Kultur in Büro und Stadion, Andrea Ewald für ESI-Messungen und Fußballfachgespräche, Bauke Albada für Hilfe bei der HPLC und „zijn vriendschap“, Christian Gemel für aufschlussreiche Diskussionen und Anregungen zur [TpRu]-Chemie, Kathrin Klein für ihre Mitarbeit und die Ergebnisse ihrer Bachelor-Arbeit, Max Lieb und Malay Patra für ihre Zeit nicht nur am Montagmorgen, Nina, Jessica, Maya, Andrea G. und Jan für die entspannte Atmosphäre im „Kopflabor rechts“ und das Ertragen meiner Musik, Gregor Barchan, Martin Gartmann und Hans-Jochen Hauswald für Hilfe und Antworten rund ums NMR, Jochen Lügger und Gerd Bollmann für „gelebten Ruhrpott“ und Beistand in technischen Fragen, Kerstin Brauner und Veronika Hiltenkamp für Elementaranalysen, allen Mitarbeitern der AC I für die gute Zusammenarbeit und unterhaltsame außeruniversitäre Aktivitäten, meinem Freundeskreis für ein Leben außerhalb der Chemie, sowie den Jungs von milhaven für unvergessliche Momente und Melodien. Besonderer Dank gilt meiner Familie, die mein Leben und Studium bedingungslos unterstützt und durch ihr reges Interesse bereichert hat, sowie meiner liebsten Janine für alles, was wir in den letzten Jahren zusammen erlebt und erreicht haben. Ohne euch wäre ich nicht so weit gekommen. Table of contents TABLE OF CONTENTS 1. INTRODUCTION 1 1.1. Scorpionate ligands 1 1.2. Tp and Tpm ligand syntheses 4 1.3. Bioorganometallic and bioinorganic chemistry 6 1.3.1. Bioorganometallic chemistry of group 8 metallocenes 6 1.3.2. Bioorganometallic chemistry of carbonyl complexes 8 2. TASK FORMULATION 10 3. RESULTS AND DISCUSSION 11 3.1. Group 1, magnesium and thallium p-BrC6H4Tp transfer agents 11 3.1.1. Syntheses and characterization 11 3.1.2. Solid-state structure of compounds 4, 6, and 10 14 3.2. Syntheses and characterization of ruthenocene analogues 19 3.2.1. Mixed ligand CpR/Tp’ ruthenocene analogues 19 3.2.2. Mixed ligand Tp/Tp‘ ruthenocene analogues 22 3.2.3. Mixed ligand Tpm/Tp’ ruthenocene analogues 25 3.3. Mixed sandwich Cp/Tp‘,Tp/Tp‘ and Tpm/Tp’ bioconjugates 31 3.3.1. Application of acid-functionalized 16 and 20 in SPPS 31 3.3.2. Application of mixed sandwich Tp'/Tpm azide 25 in CuAAC 34 3.4. Seven-coordinate Tp*WI(CO)(η2-alkyne) complexes 36 3.4.1. Syntheses and characterization of tungsten “building blocks” 36 3.4.2. Application of tungsten “building blocks” 29 and 30 in SPPS 39 4. SUMMARY AND CONCLUSION 43 5. EXPERIMENTAL PART 48 5.1. Technical equipment 48 5.2. Methods and materials 49 5.3. Chemicals and solvents 49 5.4. Solid-Phase Supported Peptide Synthesis (SPPS) 49 5.5. Syntheses and characterization 50 5.5.1. Alternative preparation of p-BrC6H4TpNa 1 50 5.5.2. p-BrC6H4TpK 2 51 5.5.3. p-BrC6H4TpRb 3 52 5.5.4. p-BrC6H4TpCs 4 53 5.5.5. p-BrC6H4TpTl 5 54 5.5.6. (p-BrC6H4Tp)2Mg 6 55 Table of contents Me 5.5.7. p-BrC6H4Tp K 7 56 Me 5.5.8. p-BrC6H4Tp Tl 8 57 5.5.9. p-BrC6H4Tp*K 9 58 5.5.10. p-BrC6H4Tp*Tl 10 59 5.5.11. CpRu(p-BrC6H4Tp) 11 60 Me 5.5.12. CpRu(p-BrC6H4Tp ) 12 61 5.5.13. Cp*Ru(p-BrC6H4Tp) 13 62 5.5.14. CpiPrRuCl(COD) 14 63 iPr 5.5.15. Cp Ru(p-BrC6H4Tp) 15 64 iPr 5.5.16. Cp Ru(p-(CO2H)-C6H4Tp) 16 65 iPr 5.5.17. Cp Ru(p-(CO-Phe-OMe)C6H4Tp) 17 66 iPr 5.5.18. Cp Ru(p-(CO-Tyr-Gly-Gly-Phe-Leu-OH) C6H4Tp) 18 67 5.5.19. TpRu(p-BrC6H4Tp) 19 68 5.5.20. TpRu(p-(CO2H)-C6H4Tp) 20 69 5.5.21. TpRu(p-(CO-Val-OtBu)C6H4Tp) 21 70 5.5.22. TpRu(p-(CO-Tyr-Gly-Gly-Phe-Leu-OH)-C6H4Tp) 22 71 5.5.23. (p-BrC6H4Tp)RuCl(COD) 23 72 5.5.24. [(p-BrC6H4Tp)RuTpm]Cl 24 73 2 5.5.24.1. [(p-BrC6H4Tp)Ru(κ -N,N-Tpm]Cl 24a 74 5.5.25. [(p-N3C6H4Tp)RuTpm]Cl 25 75 5.5.26. HCC(CH2)2CO-Val-OtBu 26 76 5.5.27. [TpmRu((p-C2N3H-(CH2)2-CO-Val-OtBu)-C6H4Tp)]Cl 27 77 5.5.28. [TpmRu((p-C2N3H-(CH2)2-CO-Tyr-Gly-Gly-Phe-Leu-OH)-C6H4Tp)]Cl 28 78 2 5.5.29. [Tp*WI(CO)(η -HCC(CH2)2CO2H)] 29 79 5.5.30. [Tp*W(I)(CO)(η2-Fmoc-Pgl)] 30 80 2 5.5.31. [Tp*WI(CO)(η -HCC(CH2)2CO-NH-Lys-Lys-Pro-Tyr-Ile-Leu-OH)] 31 81 2 5.5.32. [Tp*WI(CO)(η -HCC(CH2)2CO-NH-Tyr-Gly-Gly-Phe-Leu-OH)] 32 82 2 5.5.33. H2N-Tyr-Gly-[Tp*W(I)(CO)(η -Pgl)]-Phe-Leu-OH 33 83 6. REFERENCES 84 7. LIST OF PUBLICATIONS 92 8. SUPPORTING INFORMATION 94 8.1. Crystallographic data 94 Abbreviations ABBREVIATIONS AND SYMBOLS 2-Cl-Trt 2-chloro-trityl Å Ångström ACN acetonitrile APT attached proton test asym asymmetric ca circa CCDC Cambridge crystallographic data centre CMIA carbonyl metallo immuno assay COD 1,5-cyclooctadiene CO-RM carbon monoxide releasing molecule Cp cyclopentadienyl Cp* pentamethylcyclopentadienyl CpCO2H cyclopentadienyl carboxylic acid CpiPr iso-propylcyclopentadienyl CuAAC Copper Catalyzed Azide-Alkyne Cycloaddition dba dibenzylidenacetone DIPEA N,N-diisopropylethylamine DMF N,N-dimethylformamide dmtc N,N-dimethylthiocarbamate d distance, doublet DMSO dimethylsulfoxide e.g. exempli gratia, for example Enk enkephalin eq equivalent ESI electro spray ionisation Et ethyl et al. et alii Et2O diethylether fac facial Fc ferrocene Fig figure Fmoc (9H-fluoren-9-yl-methoxy)carbonyl Gly glycine HMBA 4-hydroxymethylbenzoic acid HOBt 1-hydroxy-1H-benzotriazole HPLC high pressure/performance liquid chromatography HSQC heteronuclear single quantum coherence Hz Hertz Ile isoleucine IR infrared iPr iso-propyl J coupling constant KOtBu potassium tert-butoxide L ligand, liter Leu leucine Lys lysine m mass, multiplet M molar mass, metal Abbreviations Me methyl mer meridional m/z mass over charge n-Bu Butyl NCPh benzonitrile neg negative NEt3 triethylamine NMR nuclear magnetic resonance ORTEP Oak Ridge Thermal Ellipsoid Plot p.a. pro analisi p-BrC6H4 para-bromophenyl Pgl propargylglycine Ph phenyl Phe phenylalanine p-IC6H4 para-iodophenyl pNT pseudo-neurotensin pos positive ppm parts per million Pro proline pz pyrazolyl pz- pyrazolide pzH pyrazole q quartet RES resin RP reverse phase RT room temperature Rc ruthenocene s singlet sept septett SPPS solid phase peptide synthesis sym symmetric t triplet TBTU benzotriazol-1-yl-N-tetramethyl-uronium tetrafluoroborate t-Bu tert-butyl t-BuOH tert-butanol tert tertiary TFA trifluoroacetic acid THF tetrahydrofuran TIS triisopropylsilane TlOEt thallium ethoxide TMS tetramethylsilane Tyr tyrosine V volume v/v volume to volume Val valine δ chemical shift Δ temperature increase ρ density ν frequency Abbreviations ABBREVIATIONS FOR SCORPIONATE LIGANDS [1,2] Following the system proposed by Curtis et al., tris(pyrazolyl)borate ligand HB(pz)3 is abbreviated as Tp, tris(pyrazolyl)methane ligand HC(pz)3 as Tpm, and heteroscorpionate ligands R2B(pz)2 as Bp. The positions of the pyrazole rings are numbered, following IUPAC rules for heterocycles, starting with the nitrogen bound to boron. In general, any non-hydrogen substituent in the pyrazole 3- position, the one closest to the coordinated metal, is denoted as a superscript, e.g. tris(3-methyl- Me pyrazolyl)borate HB(3-Mepz)3 is abbreviated as Tp . Non-hydrogen 5-substituents follow the 3- substituent as a superscript, separated by a comma. When the 3- and 5-substituents are identical, the superscript R-substituent is followed by 2. In the case of tris(3,5-dimethyl-pyrazolyl)borate Me2 (HB(3,5-Me2pz)3), the common abbreviation Tp* will be used instead of Tp . Substituents replacing hydrogen on the central boron atom are written preceding “Tp”: for instance, pyrazol-tris(pyrazolyl)borate or tetrakis(pyrazolyl)borate is abbreviated as pzTp. The p-BrC6H4-substituted ligands p-BrC6H4B(pz)3, p-BrC6H4B(3-Mepz)3, and p-BrC6H4B(3,5-Me2pz)3 are abbreviated as Tp’, Tp’Me and Tp’*, respectively. Introduction 1. INTRODUCTION 1.1. Scorpionate ligands In the late 1960‘s, S. Trofimenko reported a class of molecules,[3-9] that would soon become one of the most studied ligand systems in coordination chemistry: Poly(pyrazolyl)borate anions.[10] Reminiscent of a scorpions pincers, these tripodal ligands bind a metal with the nitrogen heteroatoms of two pyrazole rings attached to a central boron atom. As outlined in figure 1, a third pyrazole ring (or the R group), also attached to the boron-atom, ”stings” the metal like a scorpions tail, hence the commonly used name ”scorpionates”.[11,12] Figure 1 The scorpionate ligand system The most commonly used members of this ligand class are the tris(pyrazolyl)borate ligands [2] (HB(pz)3 or Tp), which are formally analogous to the cyclopentadienyl (Cp) ligand in that both [13] [14] are six-electron anions or L2X ligands.
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