Excellent correlation between substituent constants and pyridinium N-methyl chemical shifts
作者:Sha Huang、Jesse C.S. Wong、Adam K.C. Leung、Yee Man Chan、Lili Wong、Myrien R. Fernendez、Amanda K. Miller、Weiming Wu
DOI:10.1016/j.tetlet.2009.06.081
日期:2009.9
Substituents on the pyridinium ring of N-methylpyridinium derivatives, especially those on the 2- or 4-position, have a large effect on the 1H and 13C NMR chemical shifts of the N-methyl group. Reasonable correlations between the chemical shift changes and the resonance substituentconstants are observed. The dual substituent parameter approach provides an excellent correlation when a combination of
Synthesis and properties of aza analogs of merocyanine dyes based on N-substituted 2- and 4-aminopyridinium salts
作者:I. A. Borisova、A. A. Zubarev、L. A. Rodinovskaya、A. M. Shestopalov
DOI:10.1007/s11172-018-2054-2
日期:2018.1
A series of aza analogs of the merocyanine dyes based on 1-N-alkyl-2- and 1-N-alkyl-4-aminopyridinium salts and ethoxymethylidenemalononitrile was synthesized. Their physico-chemical properties were studied.
intercalates were studied by X-ray analysis, electrochemistry, UV/Vis absorptionspectra, TGA, IR spectra, SHG, and were completed by DFT calculations. The synthesis of tripodal tris(pyridin-4-yl)amine is given for the first time. The HOMO–LUMO gap, the position of the longest-wavelength absorption maxima, and the dipole moment of aminopyridines can easily be tuned by attaching/removing pyridin-4-yl electron
Novel co-crystals with π-hole interactions between iodide anions and quinoid rings involving charge transfer
作者:Valentina Milašinović、Krešimir Molčanov
DOI:10.1039/d1ce01156a
日期:——
contacts between iodide anions and the quinoid rings have been structurally characterised. Sandwich-like groups I−⋯quinone⋯I− are present in all of them; competition of this motif with halogen bonding has been described for the first time. The black colour of the crystals indicates chargetransfer from the iodide to the quinoid ring, which is interpreted as n → π*. Intermolecular interactions were analysed
六种新型四溴醌与有机阳离子的碘化物盐的共晶体在碘化物阴离子和醌环之间显示出短接触的结构特征。三明治状的基团 I − ⋯quinone⋯I −都存在于其中;首次描述了该基序与卤素键的竞争。晶体的黑色表示电荷从碘化物转移到醌型环,这被解释为 n → π*。使用 Hirshfeld 表面和 Voronoi-Dirichlet 多面体分析分子间相互作用。
One-Dimensional π-Stacks of Pancake-Bonded 5,6-Dichloro-2,3-dicyanosemiquinone Radical Anions
of stacking), stacks of pancake-bonded dimers, isolated pancake-bonded dimers, and mixed stacks comprising DDQ radicals and aromatic cations. General features of pancake bonding of DDQ radicals are defined: parallel ring planes, offset along the carbonyl···carbonyl axis by 2.05–2.15 Å, and interplanar separations of 2.90–2.95 Å (for pancake-bonded dimers) or 3.08–3.24 Å (for regular stacks of equidistant