Synthesis, DNA binding mode, singlet oxygen photogeneration and DNA photocleavage activity of ruthenium compounds with porphyrin–imidazo[4,5‐f]phenanthroline conjugated ligand

Abstract

Using 1,10‐phenanothroline‐5,6‐dione and 10,20‐bis(4‐methylphenyl)porphyrin copper as starting materials, a conjugated porphyrin–imidazo[4,5‐f]‐1,10‐phenanothroline ligand (Por 1) was prepared. Subsequently, the copper complex of Por 1 was reacted with Ru(1,10‐phenanothroline)2Cl2 to yield ruthenium compound Por 2. After removal of copper metal under acid condition, the free base porphyrin of Por 2 (Por 3) was prepared. The structure of these compounds was confirmed using UV–visible, 1H NMR, mass and infrared spectroscopies and elemental analysis. Through UV–visible, fluorescence and circular dichroism analyses, the interaction modes between Por 1–3 and calf thymus DNA were investigated. Por 1 interacted with DNA via outside groove face, but Por 2 and Por 3 showed intercalative interaction with DNA. Binding constants between Por 1–3 and DNA were 7.79 × 105, 1.29 × 106 and 1.32 × 106 M−1, respectively. With 5,10,15,20‐tetraphenylporphyrin (H2TPP) as a control, the singlet oxygen (1O2) generation of Por 1–3 was measured using the 1,3‐diphenylisobenzofuran method. The 1O2 generation rate of Por 1–3 followed the order: Por 3 >Por 1 >H2TPPP >Por 2. Por 1 and Por 3 showed better 1O2 quantum yields than Por 2, which were almost threefold higher than that of H2TPP. The DNA cleavage ability of Por 1–3 was analyzed using gel electrophoresis. Por 3 showed higher DNA photocleavage activity, with more than 50% photocleavage rate at 20 μM. These results suggest that amphipathic (hydrophilic/lipophilic) Por 3 with conjugated Por 1 ligand is a potential photosensitizer in cancer therapy.

Rational design of iridium–porphyrin conjugates for novel synergistic photodynamic and photothermal therapy anticancer agents

“…Recent promising metal-porphyrin conjugates include: porphyrinoid-Pt(II) conjugates; 52 metal-organic frameworks with porphyrin ligands; 53 a porphyrin-Ru complex conjugate; 54 and a combination of cationic Cu-porphyrin with Schiff base Cu complexes. 55 These covalent porphyrin-transition metal conjugates, used for PDT only, are structurally very different from the molecules reported herein for PDT and PTT.…”

Small-Molecule Porphyrin-Based Organic Nanoparticles with Remarkable Photothermal Conversion Efficiency for in Vivo Photoacoustic Imaging and Photothermal Therapy

“…Porphyrin derivatives were widely used for fluorescence imaging, PDT, − and PTT because of their large extinction coefficients, good biocompatibility, and minor adverse effects on organisms. , However, the absorption maxima of many porphyrin derivatives are generally below 700 nm, and they always showed deficient photostability in NIR treatment which limits their long-term use. , One of the efficient ways to overcome these problems is to redshift the Q band absorption to near 800 nm through enhancing their π-conjugated system. Diketopyrrolopyrrole (DPP) derivatives − were extensively used in electronic devices and fluorescence probes because of their high molar absorption coefficient and photostability, planar and conjugated structure, and unique optical properties .…”

Carbon Dots @ Platinum Porphyrin Composite as Theranostic Nanoagent for Efficient Photodynamic Cancer Therapy

“…Because photosensitizers are typically harmless without light, tumor treatment can be precisely targeted by selective illumination, thus limiting damage to surrounding healthy tissues [ 7 – 9 ]. Activatable photosensitizers, such as porphyrin and phthalocyanines derivatives, have been demonstrated to possess simultaneous cancer imaging and therapy capabilities, and some of these photosensitizers have been approved for clinical use [ 10 , 11 ]. However, many of them are limited because of poor water solubility, prolonged cutaneous photosensitivity, inadequate selectivity, and their inability to be absorbed in the region (> 700 nm) where the skin is most transparent, which are encountered in clinical applications of numerous traditional chemicals.…”