- Two Faces of the Same Coin: Coupling X-Ray Absorption and NMR Spectroscopies to Investigate the Exchange Reaction Between Prototypical Cu Coordination Complexes
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The satisfactory rationalization of complex reactive pathways in solution chemistry may greatly benefit from the combined use of advanced experimental and theoretical complementary methods of analysis. In this work, we combine X-Ray Absorption and 1H NMR spectroscopies with state-of-the-art Multivariate Curve Resolution and theoretical analyses to gain a comprehensive view on a prototypical reaction involving the variation of the oxidation state and local structure environment of a selected metal ion coordinated by organic ligands. Specifically, we investigate the 2-cyano-2-phenylpropanoic acid reduction of the octahedral complex established by the Cu2+ ion with terpyridine to the tetrahedral complex formed by Cu+ and neocuproine. Through our interdisciplinary approach we gain insights into the nature, concentration time evolution and structures of the key metal (XAS measurements) and organic (1H NMR measurements) species under reaction. We believe our method may prove to be useful in the toolbox necessary to understand the mechanisms of reactive processes of interest in solution.
- Busato, Matteo,Cenesi, Flavia,D'Angelo, Paola,Del Giudice, Daniele,Di Berto Mancini, Marika,Di Stefano, Stefano,Frateloreto, Federico,Lanzalunga, Osvaldo,Oliveira De Souza, Danilo,Tavani, Francesco
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supporting information
(2021/12/22)
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- The synthesis and stereospecific solid-state photodecarbonylation of hexasubstituted meso- and d,l-ketones
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Tertiary carbanions were trapped with half an equivalent of diphosgene to give meso- and d,l-hexasubstituted ketones in moderate yields and modest diastereoselectivities. The ketones were also synthesized by a step-wise synthesis in which the carbonyl group was first installed as an acid before activation and the second nucleophilic attack. This second method gave lower yields but similar diastereoselectivites. Steric limits of both methods were also determined. The photolysis of the resulting crystalline ketones gave a mixture of products in solution, but took place chemoselectively and diastereospecifically in the solid-state. The Royal Society of Chemistry and Owner Societies.
- Shiraki, Saori,Natarajan, Arunkumar,Garcia-Garibay, Miguel A.
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p. 1480 - 1487
(2012/06/01)
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- Metalated nitriles: Organolithium, -magnesium? and -copper exchange of α-halonitriles
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(Chemical Equation Presented) α-Halonitriles react with alkyllithium, organomagnesium, and lithium dimethylcuprate reagents generating reactive, metalated nitriles. The rapid halogen-metal exchange with alkyllithium and Grignard reagents allows selective exchange in the presence of reactive carbonyl electrophiles, including aldehydes, providing a high-yielding alkylation protocol. Lithiated and magnesiated nitriles react with propargyl bromide by SN2 displacement whereas organocopper nitriles react by S N2′ displacement, correlating with the formation of a C-metalated nitrile.
- Fleming, Fraser F.,Zhang, Zhiyu,Liu, Wang,Knochel, Paul
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p. 2200 - 2205
(2007/10/03)
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- Oxidative nucleophilic substitution of hydrogen in nitroarenes
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Carbanions of 2-phenylpropionitrile were found to add to nitroarenes in liquid ammonia to form σ(H) adducts, which were oxidized with KMnO4 to yield products of oxidative nucleophilic substitution of hydrogen (ONSH) in the position para to the nitro group. Treatment of the carbanion-nitroarene system with methyl iodide at -70°C indicated that the addition proceeds almost to completion. Thus, for the first time, the persistence of σ(H) adducts, formed between free anions and mononitroarenes, has been demonstrated. It was also shown that KMnO4, oxidizes σ(H) adducts to nitrobenzene faster than it does carbanions. This selective ONSH in the para positions of nitroarenes is a general process. However, some substituents hinder or inhibit the oxidation step.
- Makosza, Mieczyslaw,Stalinski, Krzysztof
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p. 2025 - 2031
(2007/10/03)
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- Oxidative nucleophilic substitution of hydrogen in nitrobenzene with 2-phenylpropionitrile carbanion and potassium permanganate oxidant
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The carbanion of 2-phenylpropionitrile adds to nitrobenzene in the p-position in liquid ammonia to give the relative stable σH-adduct which is oxidised with KMnO4 to 2-phenyl-2-(4-nitrophenyl)propionitrile; the relationships of rates of various reactions in these systems are estimated.
- Makosza, Mieczyslaw,Stalinski, Krzysztof,Klepka, Cezary
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p. 837 - 838
(2007/10/03)
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- DICHLORO(2,2-DIMETHYLCYCLOPROPYL)METHYL PHENYL SULFONE - A RADICAL PROBE FOR DETECTING SINGLE ELECTRON TRANSFER PROCESSES
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The title compound was synthesized and was shown to be a fast radical probe for studying single electron transfer processes in reactions with polyhaloalkanes.It has a universal character-being originally an electron acceptor, upon dehalogenation forms car
- Makosza, Mieczyslaw,Kwast, Andrzej
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p. 445 - 448
(2007/10/02)
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- Die Isocyanid-Cyanid-Umlagerung - Mechanismus und praeparative Anwendung
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Bis vor kurzem war die Isocyanid-Cyanid-Umlagerung hauptsaechlich als Beispiel fuer eine unimolekular verlaufende Gasphasenreaktion bekannt und nur fuer einfache Systeme kinetisch untersucht.Kinetikstudien in Loesung wurden erst moeglich, als man eine ueberlagerte, zum gleichen Produkt fuehrende Radikalkette erkannte und diese inhibieren konnte.Die Geschwindigkeit der Isomerisierung erwies sich als kaum von der Struktur und von Substituenten abhaengig.Allenfalls starke sterische Hinderung in drei Dimensionen wie in tris-α-substituierten Triptylcylisocyaniden fuehrt zu einer deutlichen Erhoehung der Aktivierungsenthalpie.Die Ergebnisse lassen sich mit einem rein sigmatropen Mechanismus deuten und sind damit in Einklang mit Voraussagen aus ab-initio-Rechnungen.Auch praeparativ laesst sich diese Umlagerung inzwischen nutzen.Bei der Blitzpyrolyse sind die Ausbeuten an Cyanid nahezu quantitativ.Allylisocyanide reagieren ohne Allylisomerisierung und optisch aktive Isocyanide unter vollstaendiger Retention.Die Umlagerung kann sowohl Bestandteil wirtschaftlich interessanter Synthesen, z.B. der Entzuendungshemmer Ibuprofen und (S)-Naproxen, sein als auch beim Aufbau optisch aktiver β-Acyloxycyanide, die nuetzliche Synthesebausteine sind, aus optisch aktiven α-Aminosaeuren helfen.
- Ruechardt, Christoph,Meier, Michael,Haaf, Klaus,Pakusch, Joachim,Wolber, Erwin K. A.,Mueller, Barbara
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p. 907 - 915
(2007/10/02)
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