21899-24-1Relevant articles and documents
MnO2 mediated sequential oxidation/olefination of alkyl-substituted heteroarenes with alcohols
Zhang, Chunyan,Li, Zehua,Fang, Yanchen,Jiang, Shaohua,Wang, Maorong,Zhang, Guoying
supporting information, (2020/02/15)
A practical and efficient ligand-free MnO2 mediated sequential oxidation and olefination has been developed for the facile synthesis of a broad range of unsaturated N-heteroazaarenes from simple alkyl-substituted heteroarenes and alcohols. The procedure tolerates a series of functional groups, such as methoxyl, chloro, bromo, iodo, vinyl, phenolic and hetero groups, providing the olefination products in moderate to good yields.The protocol could be conducted at mild conditions and used environmentally friendly air as the clear oxidant.
Nickel-catalysed direct α-olefination of alkyl substituted N-heteroarenes with alcohols
Das, Jagadish,Vellakkaran, Mari,Banerjee, Debasis
supporting information, p. 7530 - 7533 (2019/07/04)
Catalytic α-olefination of alkylheteroarenes with primary alcohols via dehydrogenative coupling is presented. A simple nickel catalyst system stabilised by readily available nitrogen ligands enables a series of interesting E-configured vinylarenes (confirmed by X-ray crystal-structure analysis) to be synthesised in good to excellent yields with olefin/alkane selectivity of >20:1. Hydrogen and water are generated as byproducts and quantitative determination of H2 was performed.
Synthesis, structural features, absorption spectra, redox behaviour and luminescence Properties of ruthenium(II) rack-type dinuclear complexes with ditopic, hydrazone-based ligands
Stadler, Adrian-Mihail,Puntoriero, Fausto,Campagna, Sebastiano,Kyritsakas, Nathalie,Welter, Richard,Lehn, Jean-Marie
, p. 3997 - 4009 (2007/10/03)
The isomeric bis(tridentate) hydrazone ligand strands 1a-c react with [Ru(terpy)Cl3] (terpy = 2,2':6'.2"-terpyridine) to give dinuclear rack-type compounds 2a-c, which were characterised by several techniques, including X-ray crystallography and NMR methods. The absorption spectra, redox behaviour and luminescence properties (both in fluid solution at room temperature and in rigid matrix at 77 K) of the ligand strands 1a-c and of the metal complexes 2a-c have been studied. Compounds 1a-c exhibit absorption spectra dominated by intense π-π* bands, which, in the case of 1b and 1c, extend within the visible region, while the absorption spectra of the rack-type complexes 2a-c show intense bands both the in the UV region, due to spin-allowed ligand-centred (LC) transitions, and in the visible, due to spin-allowed metal-to-ligand charge-transfer (MLCT) transitions. The energy position of these bands strongly depends on the ligand strand: in the case of 2a. the lowest energy MLCT band is around 470 nm, while in 2b and 2c, it lies beyond 600 nm. Ligands 1a-c undergo oxidation processes that involve orbitals based mainly on the CH3-N-N= fragments. The complexes 2a-c undergo reversible metal-centred oxidalion, while reductions involve the hydrazone-based ligands: in 2b and 2c, the bridging ligand is reduced twice and in 2a once before reduction of the peripheral terpy ligands takes place. Ligands 1a-c exhibit luminescence from the lowest-lying 1π-π* level. Only for complex 2a does emission occur; this may be attributed to a 3MLCT state involving the bridging ligand. Taken together, the results clearly indicate that the structural variations introduced translate into interesting differences in the spectroscopic, luminescence and redox properties of the ligand strands as well as of the rack-type metal complexes.
