14969-34-7Relevant academic research and scientific papers
Experimental and theoretical insights into molecular and solid-state properties of isomeric Bis(salicylaldehydes)
Durka, Krzysztof,Górski, Bartosz,B?ocki, Krzysztof,Urban, Mateusz,Wo?niak, Krzysztof,Barbasiewicz, Micha?,Luliński, Sergiusz
, p. 8674 - 8689 (2019)
A series of five bis(salicylaldehydes), including four isomeric compounds based on a benzene scaffold and a closely related naphthalene derivative, were investigated in order to elucidate the impact of resonance effects and intramolecular hydrogen bonds (HBs) on the macroscopic properties of these systems. Density functional theory (DFT) computations revealed important differences between isomers on the molecular level, which was reflected in different charge distributions, aromatic C-C bond orders, and aromaticity characters. The consequences of these features were evidenced by the UV-vis absorption spectra: for 1,3-diformyl-4,6-dihydroxybenzene (2), the longest wavelength absorption band is observed at 285 nm, while its isomers 1,4-diformyl-2,5-dihydroxybenzene (1), 1,4-diformyl-2,3-dihydroxybenzene (3), and 1,2-diformyl-3,6-dihydroxybenzene (4) are characterized by absorption in the visible range (379-407 nm). The specificity of 2 results from simultaneous lowering and elevation of HOMO and LUMO energy levels, respectively. We have found that the HOMO/LUMO energy variations follow trends observed in isomeric dihydroxybenzenes (HOMO) and phthalaldehydes (LUMO), and these effects operate separately to some extent. Furthermore, theoretical calculations indicate that the UV-vis spectral properties of bis(salicylaldehydes) are directly transferable to the corresponding bis(salicylaldimines) and their boron complexes. Finally, the influence of structural and molecular stabilization effects was analyzed by means of X-ray structural analysis and periodic DFT computations.
Liquid crystalline bis(N-salicylideneaniline)s: Synthesis and thermal behavior of constitutional isomers
Hiremath, Uma S.
, p. 3419 - 3423 (2013/07/04)
The first examples of mesogenic bis(N-salicylideneaniline)s (BSANs), wherein two lipophilic (half-disk shaped) entities are interlinked through the dihydroxydiformylbenzene core, were synthesized and characterized. In particular, three constitutional (positional) isomeric BSANs were prepared by the facile twofold condensation of 3,4,5-tris(alkoxy)anilines with 2,3-dihydroxyterephthalaldehyde, 4,6-dihydroxyisophthalaldehyde, and 2,5-dihydroxyterephthalaldehyde and their structures were established by elemental analyses, FT-IR, 1H NMR, and 13C NMR. Proton NMR experiments demonstrated their existence in enol-imine (OH) form solely. Polarizing optical microscopic, differential scanning calorimetric, and powder X-ray diffraction studies evidenced the occurrence of columnar mesomorphism in two sets of isomers.
Microwave-assisted Vilsmeier-Haack formylation of aromatic substrates
Ghosh, Kumaresh,Adhikari, Suman
experimental part, p. 959 - 961 (2009/12/24)
A microwave-assisted Vilsmeier-Haack formylation reaction has been studied on various amines, phenols and polynuclear hydrocarbons under solvent free condition that rapidly affords higher yield of products compared to traditional thermal condition.
Conjugated macrocycles related to the porphyrins. Part 18: Synthesis and spectroscopic characterization of electron-rich benzi- and oxybenziporphyrins: Influence of steric and electronic factors on porphyrinoid aromaticity
Richter, Daniel T,Lash, Timothy D
, p. 3657 - 3671 (2007/10/03)
Although 4,6-dihydroxyisophthalaldehydes failed to condense with tripyrranes to produce porphyrinoid products, the related dimethoxydialdehydes reacted with tripyrrane 9 to give, following oxidation with aqueous ferric chloride solution, nonaromatic dimet
