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|3.2 Bisphenanthroline: A Suitable Molecular Bridge?| about the purity of the particular complexes the dominant singlet signals, resulting from isolated protons in 6-position (d-position, ) were the most useful. The racemic mixture of the homobinuclear Ru(phenphen)Ru-complexes represents the example with high chemical resemblance of the phenanthroline moieties. In this case, all differences in terms of chemical shifts in the NMR-spectra of Ru(phenphen)Ru with respect to a specific phenanthroline proton result from a differing field anisotropy in the different stereoisomers. For example, in acetonitrile-d 3 two sets of, in each case, four closely spaced similar proton signals were identified in the 1 H-NMR spectrum for the characteristic phenanthroline c-position with 3 J = 8.0 Hz and 4 J = 1.6 Hz (4 × dd, δC(4) Ru Ru = [8.66 – 8.78] ppm and 4 × dd, δC(7) = [8.10 - 8.30] ppm) which refer to the 4- and 7-positions of the four inhomotopic phenphen-moieties (a, b, c, d in figure 64). The widest scattering of proton signals (∆δC Ru = 0.2 ppm) in Ru(phenphen)Ru is found for the eight protons in the phenanthroline-c-positions which experience the strongest field anisotropy due to the chiral environment/conformational differences within this set of stereoisomers. The monometallic ruthenium complex Ru(phenphen) exists according to figure 63 in two inisochronic variants which might interconvert at a low rate. For the ruthenium coordinated side, chemical shifts were observed which were very similar to the Ru(phenphen)Ru-shifts. The formal loss of a {Ru(tbbpy) 2 } 2+ -fragment gives rise to a second pair of phenanthroline signals (f) which roughly resemble the chemical shifts of phenphen. For example, the far low-field shifted positions of the a-protons were found in the same region as the phenphen-signals (δ f A(2) = [9.20 – 9.26] ppm ≈ δ phenphen A(2) = 9.20 ppm, and δA(9) f phenphen = [9.14 – 9.22] ppm ≈ δA(9) = 9.13 ppm respectively). The same accounts for the slightly low-field shifted b-protons and the high-field shifted c-protons (see table 7). In Ru(phenphen)Pt the achiral, square planar, neutral {PtCl 2 }-fragment is present at the formerly free phenanthroline sphere of Ru(phenphen). This results in a retention of the possible stereoisomers as discussed for Ru(phenphen). Furthermore, only slight changes in the chemical shift of the platinum substituted coordination sphere, in comparison to the unsubstituted phenanthroline moiety, are the result. The most significant difference in the 1 H-NMR-spectra between Ru(phenphen) and Ru(phenphen)Pt is the typical low-field shift of the signals in a- position (δA(2) f Pt = [9.20 – 9.26] ppm < δA(2) = [9.22 – 9.28] ppm, and δ A(9) f = [9.14 – 9.22] ppm < δ Pt A(9) = [9.28 – 9.38] ppm) due to platinide coordination.[138] Furthermore, the chemical shift of |91|
|3.2 Bisphenanthroline: A Suitable Molecular Bridge?| Table 7: Selected 1 H-NMR-shifts of phenphen-compounds in acetonitrile-d 3 . Signal Coordinated phenphen Ru(phenphen)Ru Ru(phenphen) Ru(phenphen)Pt (Position) Fragment δ [ppm] δ [ppm] δ [ppm] δ [ppm] A (2) f / Pt 9.20 9.20 - 9.26 9.22 - 9.28 Ru 8.15 - 8.20 8.12 - 8.16 8.06 - 8.10 A (9) f / Pt 9.13 9.14 - 9.22 9.28 - 9.38 Ru 8.08 - 8.15 8.04 - 8.10 8.00 - 8.04 B (3) f / Pt 8.43 7.92 - 7.98 7.84 - 7.90 Ru 7.80 - 7.90 7.80 - 7.86 7.72 - 7.78 B (8) f / Pt 7.84 7.62 - 7.74 7.66 - 7.76 Ru 7.54 - 7.72 7.52 - 7.56 7.46 - 7.52 C (4) f / Pt 7.78 8.66 - 8.70 8.76 - 8.84 Ru 8.66 - 8.78 8.60 - 8.66 8.54 - 8.50 C (7) f / Pt 7.49 8.00 - 8.14 8.18 - 8.30 Ru 8.10 - 8.30 8.00 - 8.04 8.08 - 8.20 f = free coordination sphere, Pt = {PtCl 2 }, Ru = {Ru(tbbpy) 2 } 2+ . the platinum atom of Ru(phenphen)Pt was determined by 195 Pt-NMR experiments to be at - 2334 ppm which is exactly in the expected region for [Pt(bpy)Cl 2 ]-type complexes. [138, 139] The interpretation of the 13 C-NMR spectra was difficult because of the closely lying peaks due to stereoisomerization and the extensively broadened signals in the related two dimensional HMBC and HSQC spectra and, thus, did not lead to a further-reaching understanding of the structural properties of the prepared compounds. For the identification and affirmation of the purity of all prepared compounds, as well as for further characterization of the obtained products, different mass spectrometric experiments were performed. The examination of the three ruthenium complexes with the ESI method revealed very clear mass spectra which allowed for the straight forward assignment of the obtained signals according to the match in shape and intensity between calculated and measured isotopic patterns. Predominant in all spectra are the strong signals for the molecular ions [M-PF 6 ] + , where one or two counter ion were lost ([Ru(phenphen)-PF 6 ] + = 1141.1 m/z, [Ru(phenphen)Ru- PF 6 ] + = 2069.2 m/z and [Ru(phenphen)Pt-2 PF 6 ] + = 1261.1 m/z). |92|
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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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|3.3 NN-NHC-Ligand bbip: Toward Sec
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|3.4 Outlook, Exploratory Investiga
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|4 Summary| 4 Summary Against the b
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|4 Summary| The resulting complexes
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|4 Summary| 10 [TEA] + TEA visible
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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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