“…Similar systems have been analyzed by variable temperature NMR to detect conformational mobility of a pendant aromatic substituent. [30][31][32] For the mixed ligand complex of 2-phenylphen (Figure 2), raising the temperature to +65 °C effects coalescence of the ortho and meta phenyl protons and reveals a rotational energy barrier of 16.3 kcal/mol.…”
Section: Behavior As Ligandsmentioning
confidence: 99%
“…From the NMR spectrum of this complex, we find that rotation about the 2,2‘-bond is restricted at room temperature. Similar systems have been analyzed by variable temperature NMR to detect conformational mobility of a pendant aromatic substituent. − For the mixed ligand complex of 2-phenylphen (Figure ), raising the temperature to +65 °C effects coalescence of the ortho and meta phenyl protons and reveals a rotational energy barrier of 16.3 kcal/mol. 2 Molecular mechanics simulation of [Ru( L )(bpy) 2 ] 2+ (left) and [Ru( 6b )(bpy) 2 ] + (right) where L = 2-phenyl-1,10-phenanthroline.…”
A series of ligands are prepared that are analogues of benzo-fused derivatives of 2,2'-bipyridine (bpy), in which pyrrole has been substituted for a pyridine ring. These ligands include 2-(2'-pyridyl)-indole, 2-(2'-pyrrolyl)-quinoline, and pyrrolo[3,2-h]quinoline. A novel reductive cyclization approach to the latter species is presented. All these ligands react with [Ru(bpy-d8)2Cl2], undergoing cyclometalation with concurrent deprotonation, to form complexes of the type [Ru(L)(bpy-d8)2]+ where L binds as a monoanionic ligand. The complexes are readily characterized by their 1H NMR spectra. Changes in the redox potentials and the electronic absorption spectra of both the ligands and the complexes are interpreted in terms of charge delocalization on the ligand.
“…Similar systems have been analyzed by variable temperature NMR to detect conformational mobility of a pendant aromatic substituent. [30][31][32] For the mixed ligand complex of 2-phenylphen (Figure 2), raising the temperature to +65 °C effects coalescence of the ortho and meta phenyl protons and reveals a rotational energy barrier of 16.3 kcal/mol.…”
Section: Behavior As Ligandsmentioning
confidence: 99%
“…From the NMR spectrum of this complex, we find that rotation about the 2,2‘-bond is restricted at room temperature. Similar systems have been analyzed by variable temperature NMR to detect conformational mobility of a pendant aromatic substituent. − For the mixed ligand complex of 2-phenylphen (Figure ), raising the temperature to +65 °C effects coalescence of the ortho and meta phenyl protons and reveals a rotational energy barrier of 16.3 kcal/mol. 2 Molecular mechanics simulation of [Ru( L )(bpy) 2 ] 2+ (left) and [Ru( 6b )(bpy) 2 ] + (right) where L = 2-phenyl-1,10-phenanthroline.…”
A series of ligands are prepared that are analogues of benzo-fused derivatives of 2,2'-bipyridine (bpy), in which pyrrole has been substituted for a pyridine ring. These ligands include 2-(2'-pyridyl)-indole, 2-(2'-pyrrolyl)-quinoline, and pyrrolo[3,2-h]quinoline. A novel reductive cyclization approach to the latter species is presented. All these ligands react with [Ru(bpy-d8)2Cl2], undergoing cyclometalation with concurrent deprotonation, to form complexes of the type [Ru(L)(bpy-d8)2]+ where L binds as a monoanionic ligand. The complexes are readily characterized by their 1H NMR spectra. Changes in the redox potentials and the electronic absorption spectra of both the ligands and the complexes are interpreted in terms of charge delocalization on the ligand.
“…This is consistent with the formation of the cis‐Ru(bpy) 2 species. It is unlikely the trans‐species was formed as it is highly insoluble and no precipitates were observed .…”
Fast, robust, and cost‐effective means of detecting spectroscopically inactive metal species are necessary for field detection and applications within a variety of areas including industry and the nuclear safeguards fields. A sensor based on spectroelectrochemistry is an excellent candidate to meet these needs as it provides improved selectivity for specifically quantifying metal ions by simultaneously monitoring at least two physio‐chemical properties. Ruthenium was chosen as a model system for this study due to its spectroscopic and electrochemical characteristics as well as its relevance within the fuel cycle and industrial fields. Aqueous Ru displays multiple redox couples in which all available oxidation states have poor sensitivity for detection by visible absorption spectroscopy because of the low molar absorptivities. Ru can, however, form complexes with sensitizing ligands such as 2,2′‐bipyridine, where the resulting [Ru(ligand)3]2+ complex displays a red luminescence with a high quantum yield of emission. This significantly improves detection limits for Ru and allows for the spectroelectrochemical detection of the otherwise hard‐to‐detect metal ion. This work explores the in‐situ generation of Ru(bpy)3 complexes in simulated field samples and their subsequent spectroelectrochemical sensing using our sensor methodology.
“…Die Ruthenium-Ausgangsverbindungen wurden nach Litera turmethoden dargestellt [5], Die verwendeten Diazadiene wurden bereits früher beschrieben [3]. Das er forderliche RuCl^-SHoO wurde von der Firma D e gussa bezogen.…”
Section: Experimenteller Teilunclassified
“…Ein weiteres farbgebendes Prinzip ergibt sich aus der Kombination von Übergangsmetallen mit geschlossener Elektronenschale und ungesättig ten Chelatliganden vom Typ der Diazadiene R N = C R '-C R '= N R (D A D ) oder des 2,2'-Bipyridins [3], Wir berichten im folgenden über die Synthe se eines zweikernigen Rutheniumkomplexes, der beide Chromophore in sich vereinigt und der sich von der bereits bekannten Vielfalt dimerer Diazadien-verbrückter Ruthenium-Komplexe [4] struktu rell grundsätzlich unterscheidet.…”
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