89510-76-9

Upstream product

• 623-27-8 terephthalaldehyde, 
• 53643-43-9 (E)-2-butene-1,4-bis(triphenylphosphonium chloride) 
• 106456-88-6 4-(5,5-dimethyl-1,3-dioxan-2-yl)benzaldehyde 

Downstream Products

• 150465-36-4 1,6-Bis<4-(2-formylvinyl)phenyl>hexa-1,3,5-triene 

Relevant academic research and scientific papers

Intermolecular CH?O hydrogen bonds in formyl-substituted diphenylhexatriene, a [2 + 2] photoreactive organic solid: Crystal structure and IR, NMR spectroscopic evidence

(E,E,E)-1,6-di(4-formylphenyl)-1,3,5-hexatriene (1) undergoes [2 + 2] photocycloaddition in the solid state, while the unsubstituted parent, (E,E,E)-1,6-diphenyl-1,3,5-hexatriene (DPH), is photochemically inert as we reported previously. Although the steering effect of the formyl group for the photoreaction is very clear, the crystal structure of 1 had been unknown. In this study, single crystals of 1 suitable for X-ray diffraction (XRD) analysis were prepared and the crystal structure was investigated. The molecules in crystal are linked through intermolecular CH?O-type hydrogen bonds involving formyl groups to form a 3D structure of π-stacked crystal packing arrangement with intermolecular distance of 3.926 (=b), less than the Schmidt's criteria of 4.2 for the [2 + 2] photoreaction. The existence of CH?O hydrogen bonds is evidenced by FT-IR, 1H and 13C NMR spectroscopic measurements. For the IR peak assignments, ab initio and DFT calculations were performed. The solid-state 1H and 13C NMR spectra were measured using the CRAMPS and CP/MAS techniques, respectively. Owing to the small CH?O angular dependence of the interaction energy (directionality), the CH?O hydrogen bonds are formed in a multiple manner. Thus, although being rather weak, these hydrogen bonds play a decisive role in constructing the [2 + 2] photoreactive crystal structure, without any other stronger intermolecular interactions coexisting.

Solvent-dependent cis-trans one-way photoisomerization of bisformyl-substituted 1,6-diphenyl-1,3,5-hexatriene

Trans, trans, trans -1,6-Bis (p-formylphenyl) -1,3,5-hexatnene underwent stereoselective photoisomerization to give its cis, trans, trans isomer regardless of the solvent polarity. Quantum yields of trans, trans, trans-to-cis, trans, trans isomerization decreased dramatically with decreasing solvent polarity, whereas those of the reverse reaction gradually increased. This led to the cis, trans, trans-to-tran, trans, trans 'one-way' isomerization in nonpolar solvents.

Synthesis and Intramolecular Electron- and Energy-Transfer Reactions of Polyyne- or Polyene-Bridged Diporphyrins

A series of geometrically restricted polyyne- or polyene-bridged diporphyrins 1-7 has been prepared by a convenient, one-pot, double porphyrin cyclization reaction in acceptable yields from the corresponding dialdehydes 1-7CHO.Polyene-bridged diporphyrins 8 and 9 were prepared by a double Horner-Emmons-Wadsworth reaction of formyl-substituted zinc-porphyrin monomer 12 with bis-phosphonate esters 13 and 14, respectively.The diporphyrins 1-9 were transformed into zinc-free-base and zinc-ferric hybrid diporphyrins.Photoinduced intramolecular electron transfer in the zinc-ferric hybrid diporphyrins as well as intramolecular excitation energy transfer in the zinc-free-base hybrid diporphyrins have been studied by picosecond time-resolved fluorescence spectroscopy.Rate constants through the polyene-bridges are larger than those through the polyyne-bridges in both reactions.The distance dependence of the electron-transfer rate was found to be quite small: the attenuation factors were determined to be 0.08 and 0.1 Angstroem-1 for the polyene- and polyyne-bridged diporphyrins, respectively.The distance dependence of the energy-transfer rate was quite similar to that of the electron transfer and was explained better by the Dexter mechanism rather than by the Foerster mechanism.These results clearly demonstarate that the linear ?-conjugated polyyne and polyene spacers enhance through-bond electronic coupling between the donor and acceptor.