Indole Schiff Base Complex: Synthesis and Optical Binding Investigation with Biogenic Amines

Area of Science:

• Analytical Chemistry
• Materials Science
• Food Science

Background:

• Biogenic amines are key indicators of food quality and freshness, produced by bacterial action.
• Elevated levels of biogenic amines are linked to adverse health effects.
• Existing detection methods using salphen base complexes show limited fluorescence enhancement.

Purpose of the Study:

• To synthesize and characterize a novel Zn(II) Schiff base complex with an indole sidechain.
• To enhance fluorescence properties for improved biogenic amine detection.
• To investigate the binding behavior of the complex with specific biogenic amines (phenylethylamine and cadaverine).

Main Methods:

• Synthesis and structural verification of the Zn(II) indole Schiff base complex using spectroscopic techniques.
• Analysis of binding interactions with biogenic amines via UV-Vis and fluorescence spectroscopy.
• Job's plot analysis to determine binding stoichiometry.

Main Results:

• The synthesized Zn(II) indole Schiff base complex demonstrated stronger binding with phenylethylamine (K_b = 8.21 × 10⁴ M^-1) than cadaverine (K_b = 2.51 × 10⁴ M^-1).
• Binding with phenylethylamine resulted in higher fluorescence enhancement (54%) compared to cadaverine (51%).
• Job's plot analysis confirmed a 1:1 binding ratio between the complex and the biogenic amines.

Conclusions:

• The novel Zn(II) indole Schiff base complex exhibits promising sensing capabilities for biogenic amines.
• The complex's enhanced fluorescence properties make it suitable for developing sensitive detection materials.
• Future applications include the development of solid-state fluorescence sensors for real-time food spoilage monitoring in the food industry.