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|3.4 Outlook, Exploratory Investigations and Perspectives| particle formation kinetics and size distributions. Nevertheless, a combination and correlation of DLS and other methods such as TEM and XPS may be necessary to clarify the complete mechanism of the catalysis. 3.4 Outlook, Exploratory Investigations and Perspectives After the completed work with the binuclear bbip-bridged complexes, a number of preliminary results and exploratory work will be presented in this following chapter of the thesis. A number of experiments were performed to fathom future developments of the imidazophenanthroline containing systems. To receive an impression of the potential thereof, it was attempted to increase the already high quantum yields of the ruthenium bbip-complexes. Furthermore, it was tried to change the electronic properties of the bridge, particularly of the electron storage capacity of the 3 MLCT-involved LUMO, by the introduction of electron withdrawing groups. Finally, an extension of the bridge was attempted to allow for additional chromophores or catalyst centers in the resulting oligonuclear photocatalyst. Note: it is not claimed that a complete characterization of the prepared substances or a full evaluation or explanation of observed results was given, therefore, only selected data will be presented. 3.4.1 Manipulations, Involving the bbip-System With bbip in hands, it was an interesting starting point to further explore the effect of this ligand on ruthenium type chromophores. From section 3.3.8 (page 138) it was known that Ru(bbip) has interesting photophysical properties such as far bathochromically shifted emission wavelength (λ Ru(bbip) em., ACN = 663 nm) and very strong emission intensity (ΦRu(bbip) ACN = 0.26). The usually high quantum yields of Ru(bbip) obviously correlate with the presence of one bbip ligand. Based on the developed synthetic expertise, it was attempted to prepare the trishomoleptic complex [Ru(bbip) 3 ] 2+ (Ru(bbip) 3 ) which should be even more electron deficient than Ru(bbip) and thus should show higher emission quantum yields. Furthermore, a reference compound would be generated to compare the photophysical and electrochemical characteristics (see figure 113). The reaction was performed with an excess of bbip to avoid an incomplete formation. [Ru(cod)Cl 2 ] and bbip were taken up in DMF and were heated for 2h in the microwave. Already after several minutes a colorchange into blue was observed, which is typically the indication for the |159|
signal intensity / a.u. |3.4 Outlook, Exploratory Investigations and Perspectives| 3 N N N N + [Ru(cod)Cl 2 ] n method C1 Ru 2+ N N N N bbip Ru(bbip) 3 3 method C1 Ru 2+ N N N N + X Ru(bip) 3 3 Figure 113: Attempted synthesis of [Ru(bbip) 3 ] 2+ . formation of the [Ru(̂LL)Cl 2 ]-type complexes. After two hours, DMF was removed and a mixture of ethanol/water was added to the dark residue. Refluxing for two more hours in the microwave according to method C1 gave a bright red product which was analyzed by 1 H-NMR spectroscopy (see figure 114). 9.0 8.0 7.0 6.0 2+ signal intensity / a.u. Ru N N N N 3 3.0 6.0 3.0 3.0 3.0 3.0 9.0 6.0 6.0 9.0 8.0 / ppm 7.0 6.0 Figure 114: 1 H-NMR spectrum of Ru(bip) 3 in methanol-d 4 . The analysis of the obtained product gives clear evidence for the decomposition of the |160|
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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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|3.2 Bisphenanthroline: A Suitable
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f f f f f f |3.2 Bisphenanthroline:
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Page 120 and 121: |3.2 Bisphenanthroline: A Suitable
Page 122 and 123: |3.3 NN-NHC-Ligand bbip: Toward Sec
Page 173 and 174: |3.4 Outlook, Exploratory Investiga
Page 185 and 186: |4 Summary| 4 Summary Against the b
Page 187 and 188: |4 Summary| The resulting complexes
Page 189 and 190: |4 Summary| 10 [TEA] + TEA visible
Page 191 and 192: |4 Summary| absorption between 430
Page 193 and 194: |4 Summary| additional NN- and NHC-
Page 195 and 196: |5 Zusammenfassung| Die Herstellung
Page 197 and 198: |5 Zusammenfassung| phenphen und Ru
Page 199 and 200: |5 Zusammenfassung| Fragment tragen
Page 201 and 202: |5 Zusammenfassung| [TEA] + TEA vis
Page 203 and 204: |5 Zusammenfassung| In einer abschl
Page 205 and 206: |6 Experimental Section| Spectroele
Page 207 and 208: |6 Experimental Section| 1.3648 was
Page 209 and 210: |6.1 Synthesis of the Organic Ligan
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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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