85575-95-7Relevant articles and documents
Structural diversity in pyridine and polypyridine adducts of ring slipped manganocene: Correlating ligand steric bulk with quantified deviation from ideal hapticity
Cannella, Anthony F.,Dey, Suman Kr,Macmillan, Samantha N.,Lacy, David C.
, p. 5171 - 5180 (2018)
We have synthesized several new manganocene-adduct ([Cp2Mn(L)] = 1-L) complexes using pyridine and polypyridine ligands and report their molecular structures and characterization data. Consistent with other molecules in this class [(ηx-Cp)2MnLn] or [(ηx-Cp)2Mn(L-L)] (n = 1, 2; x = 1, 3, or 5), the manganese-cyclopentadienide interaction deviates from the classical ηx interactions (x = 3 or 5). Such deviations have been ascribed to steric factors and often called non-ideal hapticity. However, there is no quantification of this non-ideal hapticity and thus it is difficult to evaluate the extent of ring slippage or assign hapticity. Furthermore, the hypothesis that non-ideal hapticity in high-spin MnII complexes is induced by steric interactions has not been systematically evaluated. Therefore, we report herein a quantified scale for deviation from ideal hapticity between zero (ideal η5 interaction) and one ( η1 interaction). This quantified deviation from ideal hapticity has an empirical relationship with the ligand's steric properties, which strongly supports the premise that steric interactions cause the deviations in ionic M-Cp interactions.
A Mild Method for Electrochemical Reduction of Heterocyclic N-Oxides
Fukazawa, Yasuaki,Rubtsov, Aleksandr E.,Malkov, Andrei V.
supporting information, p. 3317 - 3319 (2020/05/25)
Deoxygenation of heteroaromatic N-oxides is commonly accomplished using chemical or enzymatic methods. In this work, we report on an expedient protocol for electrochemical reduction of pyridine N-oxide derivatives under mild conditions. A diverse range of mono- and bis N-oxides were converted into the corresponding nitrogen bases in good yields. Importantly, the method is highly selective towards N-oxides and tolerates challenging halo and nitro substituents in the heteroaromatic ring.
Ni(II) complexes with ligands derived from phenylpyridine, active for selective dimerization and trimerization of ethylene
Chandran, Deepak,Lee, Kyeong Mi,Chang, Hyuk Chul,Song, Ga Young,Kim, Il,Lee, Ji-Eun,Suh, Hongsuk
, p. 8 - 13,6 (2020/08/20)
An electrophilic substitution-carbonylation reaction on phenylpyridine based on the concept of 'umpolung' was used to prepare a series of pyridine based carbonyl compounds and bispyridine derivatives. The key intermediate which enhances this reaction is a base aggregate formed by the association of BuLi with lithium 2-dimethylaminoethanolate (LiDMAE) which is stabilized in nonpolar solvents. The presence of polar chelating amides that are used as acyl donors was found to collapse the superbase aggregates liberating nucleophilic 'free' BuLi. These nucleophiles lead a classical nucleophilic reaction to introduce butyl tails on the pre-ligand molecules. Pyridine carbonyl compounds produced by these electrophilic substitution-carbonylation reactions, on treatment with 2,6-diisopropylaniline and (DME)NiBr2 in glacial acetic acid at reflux temperature, gave Ni(II) complexes in good yields in a one pot protocol. These complexes are active toward ethylene, producing selective dimerization and trimerization products.
