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Updated: Jun 21, 2026

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
Published on: June 10, 2021
DNA-binding geometry dependent energy transfer from 4',6-diamidino-2-phenylindole to cationic porphyrins
Biao Jin1, Kil Sik Min, Sung Wook Han
1Department of Chemistry, Yeungnam University, Gyeongsan City, Gyeongbuk, 712-749, Republic of Korea.
Abstract:
The circular and linear dichroism (CD and LD) spectral properties of the meso-tetrakis(N-methylpyridinium-4-yl)porphyrin (TMPyP)-DNA complex at a [porphyrin]/[DNA] ratio below 0.015 showed that TMPyP intercalates between DNA base pairs. Contrarily, when cis-bis(N-methylpyridinium-4-yl)porphyrin (BMPyP) is associated with DNA, no CD spectrum was induced and a bisignate LD spectrum was observed. These spectral properties of both the TMPyP and BMPyP were essentially retained when the minor groove of the DNA was saturated with 4',6-diamidino-2-phenylindole (DAPI). The fluorescence of the DNA-bound DAPI was effectively quenched by BMPyP and TMPyP. The quenching by BMPyP can be described through a pure static mechanism while TMPyP quenching produced an upward bending curve in the Stern-Volmer plot. Quenching efficiency was by far greater than predicted by the "sphere of action model", suggesting that the DNA provides some additional processes for an effective energy transfer.
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