99765-49-8Relevant academic research and scientific papers
Synthesis, conformational parameters and packing considerations of methyl bispyridyl ketones
Weck, Christian,Katzsch, Felix,Gruber, Tobias
, p. 261 - 266 (2015)
The crystal structures of two bispyridyl ketones featuring either two methyl residues or one methyl and one bromomethyl residue, respectively, are presented. In order to elucidate the influence of the substituents, a comprehensive comparison with the non-methylated mother compound has been performed. A special focus lies thereby on the relative position of the heteroatoms and their free electron pairs. The two methyl groups at the bispyridyl ketone result in two molecules in the asymmetric unit adopting rather different conformations. Due to the fast crystallization conditions and a melting point differing from the literature, a polymorph close to a local minimum in the energy hypersurface seems possible. After introducing a bromine atom to one of the two methyl groups, the molecular conformation is very similar to the unsubstituted molecule. The packing of both title compounds is dominated by weak contacts of the C-H...π and C-H...Y type (Y = O, N) and C-H...Br- and Br...π-contacts for the brominated molecule.
Contextualizing yellow light-emitting electrochemical cells based on a blue-emitting imidazo-pyridine emitter
Fresta, Elisa,Volpi, Giorgio,Garino, Claudio,Barolo, Claudia,Costa, Rubén D.
, p. 129 - 137 (2018)
This work provides the synthesis, structural characterization, electrochemical and photophysical features, as well as the application in light-emitting electrochemical cells (LECs) of a novel small molecule belonging to the pyridilimidazo[1,5-a]pyridine family, namely 3-(2-methoxyphenyl)-5-methyl-1-(6-methylpyridin-2-yl)H-imidazo[1,5-a]pyridine (Me-impy). This compound shows a low-cost and facile synthesis, excellent redox properties, and a high photoluminescence quantum yield (Φ) of 0.4 associated to a blue emission (～436 nm) in solution. Despite these appealing features, the emission in solid state is red-shifted to the yellow region, owing to its aggregation character. Additionally, the electroluminescence response shows a broader and red-shifted emission even upon dilution of Me-impy thin films with polymethyl methacrylate (PMMA). Herein, we report an in-depth study on the aggregation features and their impact on the electroluminescence response of Me-impy, providing relevant information to design small-molecule based LECs.
Interplay Between Steric and Electronic Effects: A Joint Spectroscopy and Computational Study of Nonheme Iron(IV)-Oxo Complexes
Mukherjee, Gourab,Alili, Aligulu,Barman, Prasenjit,Kumar, Devesh,Sastri, Chivukula V.,de Visser, Sam P.
supporting information, p. 5086 - 5098 (2019/03/17)
Iron is an essential element in nonheme enzymes that plays a crucial role in many vital oxidative transformations and metabolic reactions in the human body. Many of those reactions are regio- and stereospecific and it is believed that the selectivity is guided by second-coordination sphere effects in the protein. Here, results are shown of a few engineered biomimetic ligand frameworks based on the N4Py (N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine) scaffold and the second-coordination sphere effects are studied. For the first time, selective substitutions in the ligand framework have been shown to tune the catalytic properties of the iron(IV)-oxo complexes by regulating the steric and electronic factors. In particular, a better positioning of the oxidant and substrate in the rate-determining transition state lowers the reaction barriers. Therefore, an optimum balance between steric and electronic factors mediates the ideal positioning of oxidant and substrate in the rate-determining transition state that affects the reactivity of high-valent reaction intermediates.
A Mononuclear Nonheme Iron(IV)-Oxo Complex of a Substituted N4Py Ligand: Effect of Ligand Field on Oxygen Atom Transfer and C-H Bond Cleavage Reactivity
Singh, Reena,Ganguly, Gaurab,Malinkin, Sergey O.,Demeshko, Serhiy,Meyer, Franc,Nordlander, Ebbe,Paine, Tapan Kanti
, p. 1862 - 1876 (2019/01/25)
A mononuclear iron(II) complex [FeII(N4PyMe2)(OTf)](OTf)(1), supported by a new pentadentate ligand, bis(6-methylpyridin-2-yl)-N,N-bis((pyridin-2-yl)methyl)methanamine (N4PyMe2), has been isolated and characterized. Introduction of methyl groups in the 6-position of two pyridine rings makes the N4PyMe2 a weaker field ligand compared to the parent N4Py ligand. Complex 1 is high-spin in the solid state and converts to [FeII(N4PyMe2)(CH3CN)](OTf)2 (1a) in acetonitrile solution. The iron(II) complex in acetonitrile displays temperature-dependent spin-crossover behavior over a wide range of temperature. In its reaction with m-CPBA or oxone in acetonitrile at -10 °C, the iron(II) complex converts to an iron(IV)-oxo species, [FeIV(O)(N4PyMe2)]2+ (2). Complex 2 exhibits the M?ssbauer parameters δ = 0.05 mm/s and ΔEQ = 0.62 mm/s, typical of N-ligated S = 1 iron(IV)-oxo species. The iron(IV)-oxo complex has a half-life of only 14 min at 25 °C and is reactive toward oxygen-atom-transfer and hydrogen-atom-transfer (HAT) reactions. Compared to the parent complex [FeIV(O)(N4Py)]2+, 2 is more reactive in oxidizing thioanisole and oxygenates the C-H bonds of aliphatic substrates including that of cyclohexane. The enhanced reactivity of 2 toward cyclohexane results from the involvement of the S = 2 transition state in the HAT pathway and a lower triplet-quintet splitting compared to [FeIV(O)(N4Py)]2+, as supported by DFT calculations. The second-order rate constants for HAT by 2 is well correlated with the C-H bond dissociation energies of aliphatic substrates. Surprisingly, the slope of this correlation is different from that of [FeIV(O)(N4Py)]2+, and 2 is more reactive only in the case of strong C-H bonds (>86 kcal/mol), but less reactive in the case of weaker C-H bonds. Using oxone as the oxidant, the iron(II) complex displays catalytic oxidations of substrates with low activity but with good selectivity.
Catalytic and regiospecific extradiol cleavage of catechol by a biomimetic iron complex
Chatterjee, Sayanti,Sheet, Debobrata,Paine, Tapan Kanti
supporting information, p. 10251 - 10253 (2013/10/22)
An iron(iii)-catecholate complex of a facial tridentate ligand reacts with dioxygen in the presence of ammonium acetate-acetic acid buffer to cleave the aromatic C-C bond of 3,5-di-tert-butylcatechol regiospecifically resulting in the formation of an extradiol product with multiple turnovers.
Efficient Synthesis of a Porphyrin - N-Tripod Conjugate with Covalently Linked Proximal Ligand: Toward New-Generation Active-Site Models of Cytochrome c Oxidase
Collman, James P.,Zhong, Min,Wang, Zhong,Rapta, Miroslav,Rose, Eric
, p. 2121 - 2124 (2008/02/09)
Matrix Presented A new-generation cytochrome c oxidase active-site model compound (4) featuring both a trisimidazolyl moiety and a proximal base has been designed and efficiently synthesized. During this study, a facile method based on the chemistry of a
Preparation of substituted tris(2-pyridyl)methanol derivatives as mimics of the metal binding site of carbonic anhydrase
Hannon, Michael J.,Mayers, Paul C.,Taylor, Paul C.
, p. 8509 - 8512 (2007/10/03)
A series of novel mono-substituted and symmetrically tri-substituted tris(2-pyridyl)methanols have been prepared in a one-step reaction from the corresponding 2-bromopyridines. Metal complexes of these compounds and their further functionalised derivative
