Metallorganische CO<sub>2</sub>‐Speichersysteme aus Nickel(0)‐1‐azadieneinheiten und ihre Reaktivität bei der Carboxylierung von Acetophenon

Walther, Dirk; Geßer, Susann; Ritter, Uwe; Schmidt, A.; Hamza, Khairi; Imhof, Wolfgang; Görls, Helmar; Sieler, Joachim

doi:10.1002/cber.19951280312

Cited by 10 publications

(1 citation statement)

References 9 publications

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“…Under these conditions, the monodentately coordinated Schiff bases were displaced and the bridging carboxylato groups were cleaved which resulted in the monomeric metallacyclic products 4 and 5 , respectively. These monomeric complexes can also be prepared from ligand A , CO 2 , Ni 0 and bpy or ptmeda analogous to the formation of other oxidative coupling products 20–22. Scheme illustrates the formation reactions and shows the constitution for 5 .…”

Section: Resultsmentioning

confidence: 99%

Reversible Fixation of Carbon Dioxide at Nickel(0) Centers: A Route for Large Organometallic Rings, Dimers, and Tetramers

et al. 2001

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The reaction between bis(cycloocta-1,5-diene)nickel(0), carbon dioxide and benzaldehyde-N-furfurylideneimine (A) in 1,4-dioxane or THF results in the formation of the 24-membered organometallic macrocycles of the type [(A)Ni(-CH(R1)-N(R2)-COO-)]6(solv)n (R1: phenyl, R2: furfurylidene, solv: 1,4-dioxane in 1a, THF in 1b). According to the X-ray analyses, six monomeric nickelacyclic units are connected through six Ni-mu2-OCO-Ni bridges in these macrocycles. The cavities of the metallomacrocycles (diameter: 9.410(1) A in 1a, 9.250(1) A in 1b) each contain one solvent molecule. Reaction of 1b with Me3P results in the displacement of the peripheral ligands A by the phosphine to form the 24-membered organometallic macrocycle 1c. Both 1a and 1b isomerize in benzene to form the dimeric complex [(A)Ni(-CH(R1)-N(R2)-COO-)]2(solv)n (2). The X-ray crystal structure reveals that 2 consists of the same monomeric units as found in 1a and 1b. However two Ni-mu2-O-Ni bonds link the carboxylato groups. The solvent-dependent isomerization of 1b yielding 2 is a reversible reaction. Furthermore, the macrocycle 1b partially eliminates carbon dioxide above 20 degrees C, followed by elimination of half of the monodentately coordinated Schiff base ligands to form the planar tetrameric complex 6. This is also a reversible process.

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Section: Resultsmentioning

confidence: 99%

Reversible Fixation of Carbon Dioxide at Nickel(0) Centers: A Route for Large Organometallic Rings, Dimers, and Tetramers

et al. 2001

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Metal 4‐Alkylidene‐4H‐pyridin‐1‐ides and 2H‐Imidazol‐4‐ones from Novel HighlyN‐(Pyridin‐4‐yl)methyl‐Substituted Azomethines

et al. 2004

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Novel azomethines 3 synthesized from 4‐(aminomethyl)pyridine (1) and various ketones 2 exhibit a higher acidity of the Cα‐protons compared with other 4‐alkylpyridines like 4‐benzylpyridine or 4‐(tosylmethyl)pyridine. Therefore, they can easily be metalated to give a variety of specific anions 3(−), which deserve interest for further synthetic applications. Important properties of compounds 3 and their lithiated derivatives 4 (lithium 4H‐pyridin‐1‐ides, synthesized by deprotonation of the α‐CH2 group in 3) can be controlled by the carbonyl reactant 2. These carbanions 3(−) are remarkable intermediates regarding their NMR properties. Comparing the NMR spectra of the lithium 4H‐pyridin‐1‐ides 4 with their parent azomethines 3 reveal very distinct changes in the chemical shifts from which important structural and electronic properties of the carbanions can be deduced. The observation of E/Z isomers in the case of 3c and their mutual conversion at higher temperature inspire DFT calculations on the B3LYP/6‐311++G(d,p) level of theory to get insight into the energetic demand of such isomerization processes. Moreover, calculations on the same level of theory were carried out on the model azomethine anion 5 and different monomeric lithium coordination isomers 6a−d. Experimentally, two selected examples will exemplify the reactivity of 4H‐pyridin‐1‐ide anions towards heterocumulenes. The 2‐(pyridin‐4‐yl)acetate 7 obtained from the reaction of 4e with carbon dioxide appears to be a CO2 storage molecule as it easily releases CO2 under protolysis conditions comparable with the vitamin B6 reaction mode. Interesting five‐membered heterocycles were isolated after reaction of 4 with isocyanates followed by hydrolysis and oxidation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

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Kupfer(I)‐Komplexe mit 1‐Azadien‐Chelatliganden und ihre Reaktion mit Sauerstoff

Walther¹,

Hamza²,

Görls³

et al. 1997

Zeitschrift anorg allge chemie

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Die Reaktion der zweizähligen 1‐Azadienliganden Me2N(CH2)nNCHCHCHPh mit CuX führt zu den dimeren Komplexen [ACuX]2 and [BCuX]2 (A: n = 2, B: n = 3, X: I, Cl). Die Struktur des Komplexes 1 [ACuI]2 wurde durch Kristallstrukturanalyse bestimmt. 1 enthält zwei tetraedrisch koordinierte Cu‐Atome, die über zwei Iodobrücken miteinander verknüpft sind CuCu‐Bindungslänge: (261 pm). Der Ligand MeN(CH2CH2NCHCHCHPh)2 (C) reagiert mit CuX unter Bildung der monomeren Komplexe [CCuX] (5: X = I, 6: XCl). Die Kristallstruktur von 5 zeigt, daß der Ligand dreizählig koordiniert. Die Bindungslängen der CuN(sp2)‐Bindungen sind signifikant kleiner als der CuN‐(sp3)‐Abstand. Die Reaktion der Podand‐Liganden N(CH2CH2NCHR)3 (D: RPh, E: R‐CHCHPh) mit CuX führt zu den ionischen Komplexen 7 [DCu][CuCl2] bzw. 8 [ECu][CuCl2]. 7 wurde durch Röntgenstrukturanalyse charakterisiert, die ausweist, daß D als vierzähliger Ligand fungiert. Die Komplexe 1−8 sind gegenüber CO2 nicht reaktiv, nehmen aber O2 schon bei tiefen Temperaturen auf. Bei −78°C reagiert der orangerote Komplex 4 [BCuCl]2 mit O2 in CH2Cl2 zu einer tiefvioletten Lösung, das Primärprodukt der Oxidation konnte jedoch nicht isoliert werden. Es reagiert bei Raumtemperatur zu dem grünen Komplex 9 [μ‐Cl, μ‐OH][BCuCl]2. Die Kristallstrukturanalyse belegt, daß ein dimerer CuII‐Komplex gebildet wird, in dem eine Chloro‐ und eine Hydroxobrücke die Monomereinheiten verbrücken. Die CuII‐Zentren weisen eine verzerrt tetragonal‐pyramidale Koordination auf. Der Reaktionsweg der Umsetzung mit O2 wird diskutiert.

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Metallorganische CO₂‐Speichersysteme aus Nickel(0)‐1‐azadieneinheiten und ihre Reaktivität bei der Carboxylierung von Acetophenon

Cited by 10 publications

References 9 publications

Reversible Fixation of Carbon Dioxide at Nickel(0) Centers: A Route for Large Organometallic Rings, Dimers, and Tetramers

Reversible Fixation of Carbon Dioxide at Nickel(0) Centers: A Route for Large Organometallic Rings, Dimers, and Tetramers

Metal 4‐Alkylidene‐4H‐pyridin‐1‐ides and 2H‐Imidazol‐4‐ones from Novel HighlyN‐(Pyridin‐4‐yl)methyl‐Substituted Azomethines

Kupfer(I)‐Komplexe mit 1‐Azadien‐Chelatliganden und ihre Reaktion mit Sauerstoff

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Metallorganische CO2‐Speichersysteme aus Nickel(0)‐1‐azadieneinheiten und ihre Reaktivität bei der Carboxylierung von Acetophenon

Cited by 10 publications

References 9 publications

Reversible Fixation of Carbon Dioxide at Nickel(0) Centers: A Route for Large Organometallic Rings, Dimers, and Tetramers

Reversible Fixation of Carbon Dioxide at Nickel(0) Centers: A Route for Large Organometallic Rings, Dimers, and Tetramers

Metal 4‐Alkylidene‐4H‐pyridin‐1‐ides and 2H‐Imidazol‐4‐ones from Novel HighlyN‐(Pyridin‐4‐yl)methyl‐Substituted Azomethines

Kupfer(I)‐Komplexe mit 1‐Azadien‐Chelatliganden und ihre Reaktion mit Sauerstoff

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Metallorganische CO₂‐Speichersysteme aus Nickel(0)‐1‐azadieneinheiten und ihre Reaktivität bei der Carboxylierung von Acetophenon