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Chlorophyll and bacteriochlorophyll derivatives possessing a trifluoroacetyl group at the 3-position were synthesized as new colorimetric sensors for amine detection. α-Amino alcohol formation of t...

Zinc complexes of 31-epimerically pure 32,32,32-trifluoro-bacteriopheophorbide-d methyl ester were prepared and their self-aggregation was examined in 1% (v/v) dichloromethane and hexane by visible and circular dichroism spectroscopies. Both the synthetic 31-trifluoromethylated diastereomers gave amorphous self-aggregates in the nonpolar organic solvent, while the corresponding nonfluorinated compounds possessing the 31-methyl group formed well-ordered and large oligomers similar to in vivo aggregates of bacteriochlorophyll-d in a chlorosome, a main light-harvesting antenna of green photosynthetic bacteria. The difference is ascribed to steric factor of the 3-CF3 group, which was supported by optical properties of other synthetic zinc 31-hydroxy-131-oxo-chlorins possessing trifluoromethyl or secondary/tertiary substituents at the 31-position in the nonpolar organic solvent.

Chlorophyll derivative possessing a trifluoroacetyl group at the 3-position was synthesized as a new chemosensor for alcohols and amines. Intense Qy peak of the trifluoroacetyl-chlorin (701 nm in CHCl3) showed blue shifts to 667 nm in MeOH and 665 nm in n-BuNH2 due to the formation of the corresponding hemiacetal and hemiaminal with visible color changes. Thermodynamic parameters for the complexation between trifluoroacetyl-chlorin and n-BuNH2 in CDCl3 were determined to be ΔH = −48 kJ mol−1 and ΔS = −147 J K−1 mol−1. Ratiometric fluorescence sensing of n-BuNH2 in THF was also demonstrated.

Chlorophyll and bacteriochlorophyll derivatives possessing a trifluoroacetyl group at the 3-position were synthesized as new colorimetric sensors for amine detection. α-Amino alcohol formation of t...

The 3-acetyl groups of synthetic methyl pyropheophorbides were rotated around the 3–3 1 bond and the rotational conformers were obtained in a dichloromethane solution of 20-bromo- and methyl-substituted compounds, based on their electronic and vibrational absorption spectra. Such a rotational deviation of the 3-acetyl group from the cyclic tetrapyrrole plane induced less π-conjugation to affect the redmost Q y band, which has been observed in natural photosynthetic antenna systems, bacteriochlorophyll- a molecules in oligopeptides.

3-Trifluoroacetylchlorin possessing an ω-aminoalkyl chain at the 17-propionate residue was prepared to realize a chlorophyll-based supramolecule acting as a thermochromic switch. A THF solution of the synthetic sensor molecule appeared brown, while the solution color became purple at lower temperature due to the conversion of the trifluoroacetyl group to its α-amino alcohol adduct form in a molecule.