Cis/trans Fluorescent Recognition by Naphthalimide Dyes ⊂ CB [7] Assembly

Area of Science:

• Supramolecular Chemistry
• Analytical Chemistry
• Organic Chemistry

Background:

• Cis/trans isomerism is crucial in chemistry and biology.
• Developing selective recognition methods for isomers remains a challenge.
• Fluorescent probes offer sensitive detection capabilities.

Purpose of the Study:

• To develop a novel fluorescent probe for distinguishing cis/trans isomers.
• To utilize the host-guest complex of naphthalimide dye and cucurbit[7]uril (CB[7]) for isomer recognition.
• To differentiate between maleic acid (MA) and fumaric acid (FA) based on their isomeric forms.

Main Methods:

• Formation of a 1:1 assembly between naphthalimide dye and cucurbit[7]uril (CB[7]).
• Utilizing the naphthalimide dye⊂CB[7] assembly as a fluorescent probe.
• Employing fluorescence titration to analyze the interaction with maleic acid (MA) and fumaric acid (FA).

Main Results:

• The naphthalimide dye⊂CB[7] assembly showed selective binding with maleic acid (MA) due to its cis configuration.
• Titration with MA resulted in a significant decrease in fluorescence intensity, nearly quenching at 1.5 equivalents.
• Fumaric acid (FA), with its trans configuration, exhibited weak and unstable interactions, leading to inconspicuous changes in fluorescence intensity.

Conclusions:

• The developed fluorescent probe based on naphthalimide dye and CB[7] can effectively distinguish between cis (MA) and trans (FA) isomers.
• The distinct binding affinities are attributed to the spatial arrangement of carboxyl groups in the isomers.
• This method provides a sensitive and selective approach for isomer recognition.