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|3.3 NN-NHC-Ligand bbip: Toward Second Generation Catalysts| experiments without a sign of a successful conversion. Finally, the low driving force of AgOH- or AgPF 6 -formation was identified as disadvantage for a successful reaction, yielding [(tbbpy) 2 Ru(µbbip)AgX][PF 6 ] 2 (X = OH, PF 6 ) or [(tbbpy) 2 Ru(bbip)Ag(bbip)Ru(tbbpy) 2 ][PF 6 ] 5 . The application of higher reaction temperatures (60°C), exchange of the solvent by acetonitrile and longer reaction times (two weeks) gave the first reaction mixture, where 1 H-NMR experiments gave a clear indication at least for a partial formation of the desired product. The prominent sign for the performed complexation is the appearance of a new set of signals in the 1 H-NMR spectrum which can be assigned to a second Ru(bbip)-type complex in the reaction mixture, indicated by slightly shifted signals and one missing signal which refers to the N-CH-N-proton in 2-position. Rather unclear is the constitution of the new complex [(tbbpy) 2 Ru(µ-bbip)AgX] 3+ with respect to the second ligand at the silver center (X = OH − , {(µ-bbip)Ru(tbbpy) 2 } 2+ or [PF 6 ] − ). The formation of the hydroxo complex from silver oxide is the most plausible interpretation of the result, because [PF 6 ] − is considered to be a noncoordinating anion and the complexation of a second metal fragment is sterically more demanding. Nevertheless, according to the NMRspectrum no clean product but a 20:80-mixture of starting material and product was obtained after two weeks, therefore, a different technique had to be applied. To increase the driving force the chloride salt of Ru(bbip) was prepared. Counter ion exchange of [PF 6 ]-salt of Ru(bbip) with (Bu) 4 NCl in acetone/ethyl acetate gave the corresponding chloride salt [(tbbpy) 2 Ru(bbip)]Cl 3 in quantitative yield. The reaction the Ru(bbip)-chloride together with silver oxide and a sufficient amount of molecular sieves in dry dichloromethane, finally succeeded. After stirring the mixture for 16 hours in the dark, the chloride salt of [(tbbpy) 2 Ru(µ-bbip)AgCl] 2+ (Ru(bbip)Ag) was obtained with full conversion (see figure 90 on page 128) as determined by 1 H- MNR. Separation of the precipitates and the molecular sieve beads and removal of the solvent gave the pure product as indicated by NMR spectroscopy and mass spectrometry. Disappearance of the characteristic 1 H-NMR-signal of the proton at 2-position (see figure 86 on page 123) and the typical high field shift in the 13 C-NMR of the N-CH-N-carbon signal (196.50 ppm) supports the proposed carbene complex formation. The detailed mass spectrometric analysis were performed in cooperation with Jing Li from the group of Prof. Dr. T. Drewello (Erlangen). This assumption of the successful carbene complex formation was further confirmed by detailed ESI-MS and MS n studies. An example is shown in figure 91 for the relevant fragment ion |129|
|3.3 NN-NHC-Ligand bbip: Toward Second Generation Catalysts| {[(tbbpy) 2 Ru(bbip)AgCl]Cl} + (m/z = 1216.8). Intensety / a.u. x10 6 1.25 1.00 0.75 0.50 0.25 0 2000 meas. calc. 1211.8 1208.8 1210.8 1209.9 1212.8 1213.8 1214.8 1215.8 1216.8 1218.8 1217.8 1217.3 1219.8 1220.8 +MS, 0.5-1.7min #(8-28) 1221.8 1222.8 1223.8 C H N RuAgCl , M ,1215.30 63 68 8 2 Intensity / a.u. 1500 1000 500 0 1213.3 1212.3 1209.3 1211.3 1210.3 1214.3 1215.3 1216.3 1219.3 1218.3 1220.3 1221.3 1222.3 1223.3 1205.0 1210.0 1215.0 1220.0 1225.0 m/z Figure91:Measured and calculated isotopic pattern of {Ru(bbip)Ag+Cl} + in the ESI-MS experiment. Finally, it was possible to obtain X-ray suitable crystals of Ru(bbip)Ag by crystallization from chloroform/dichloromethane under inert conditions. The detailed discussion is given in the following chapter (see figure 93 on page 132 and table 13 on page 133). 3.3.6 Structural Characterization of Ruthenium ip-Type Complexes Due to the fortunate fact that ruthenium complexes of all stages of the ligand transformation were obtained it was possible to identify trends and tendencies within the series Ru(ip), Ru(bip), Ru(bbip), and Ru(bbip)Ag (see figures 92 on page 131 and 93 on page 132 for the solid state structures and table 13 on page 133 for relevant data) and to compare them to the series of preligands ip, bip, and bbip (compare chapter 3.3.3 on page 118). The structural features observed for the ruthenium complexes combine both, the general patterns of other ruthenium NN-complexes and that of the performed transformations at the imidazole part of the ligands respectively. For the characterization of the new ip-type complexes it is useful to focus on the two coordination sites. Therefore, important distances |130|
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Development of Novel Catalysts for
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Diese Arbeit entstand auf Anregung
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Den Arbeisgruppen von Prof. Dr. U.
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Contents 1 Introduction 1 1.1 Fossi
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|Contents| 6 Experimental Section 1
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|1 Introduction| 1 Introduction The
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|1.1 Fossil Fuels and Nuclear Power
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|1.2 Renewable Fuels| of natural ga
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|1.3 Energy Transformation and Stor
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|1.4 Solar Energy Conversion| A fra
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|1.5 Photosynthesis| Figure 9: Mole
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|1.6 Photocatalyzed Reactions| 2 NA
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|1.6 Photocatalyzed Reactions| (1)
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|1.7 Mimicking Photosynthesis| So t
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|1.8 Formalisms of Photocatalytic S
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|1.9 Multicomponent Systems from Fu
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|1.10 Intramolecular Photoredoxcata
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|2 Scope of the Thesis| motifs with
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|3.1 Brominated Phenanthrolines - A
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Page 90 and 91: |3.1 Brominated Phenanthrolines - A
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|4 Summary| absorption between 430
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|4 Summary| additional NN- and NHC-
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|5 Zusammenfassung| Die Herstellung
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|5 Zusammenfassung| phenphen und Ru
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|5 Zusammenfassung| Fragment tragen
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|5 Zusammenfassung| [TEA] + TEA vis
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|5 Zusammenfassung| In einer abschl
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|6 Experimental Section| Spectroele
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|6 Experimental Section| 1.3648 was
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|6.1 Synthesis of the Organic Ligan
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|6.2 Synthesis of the Metal Complex
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|7 Appendix| 7 Appendix dd ddd DEI
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|7 Appendix| Ru(tpphz)Os [Ru(bpy) 2
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|References| [26] M. Chanon, M. Sch
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|References| [81] S. Tschierlei, M.
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|References| [138] L. Pazderski, J.
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|References| [194] C. Liu, J. Li, B
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Selbstständigkeitserklärung: Ich
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