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Figure-eight Octaphyrin Bis-Ge(IV) Complexes: Synthesis, Structures, Aromaticity, and Chiroptical Properties
- Source :
- Chemistry, an Asian journal. 15(9)
- Publication Year :
- 2020
-
Abstract
- Highly twisted structures of expanded porphyrin provide a prominent basis to unravel the relationship between aromaticity and chirality. Here we report the synthesis of bis-Ge(IV) complexes of [38]octaphyrin that display rigid figure-eight structures. Two bis-Ge(IV) [38]octaphyrin isomers with respect to the stereochemistry of the axial hydroxy groups on the germanium ions were obtained and found to be aromatic. Upon oxidation with MnO2 , these [38]octaphyrin complexes were converted to a single syn-type isomer of [36]octaphyrin with retained figure-eight conformation. The enantiomers have been successfully separated by HPLC equipped with a chiral stationary phase. While aromatic [38]octaphyrin Ge(IV) complexes showed quite large molar circular dichroism of up to Δϵ=1500 M-1 cm-1 with a dissymmetry factor gabs of 0.035, weakly antiaromatic [36]octaphyrin Ge(IV) complexes underscored moderate values; Δϵ=540 M-1 cm-1 with gabs of 0.023. Thus, the figure-eight octaphyrin scaffold has been proved to be an attractive platform for novel chiroptical materials with tunable aromaticity.
- Subjects :
- Circular dichroism
010405 organic chemistry
Organic Chemistry
chemistry.chemical_element
Aromaticity
Germanium
General Chemistry
010402 general chemistry
01 natural sciences
Biochemistry
Porphyrin
0104 chemical sciences
Ion
chemistry.chemical_compound
Crystallography
chemistry
Enantiomer
Chirality (chemistry)
Antiaromaticity
Subjects
Details
- ISSN :
- 1861471X
- Volume :
- 15
- Issue :
- 9
- Database :
- OpenAIRE
- Journal :
- Chemistry, an Asian journal
- Accession number :
- edsair.doi.dedup.....c4bc3eed5e66b595ae35944d2004abcf