Iridium(III) coordination compounds based on organophosphorus ancillary ligands showing cytotoxicity against breast cancer cells and Fe(III) luminescent sensing

Klaimanee, Ekkapong; Temram, Thitirat; Ratanaphan, Adisorn; Saithong, Saowanit; Sooksawat, Dhassida; Samphao, Anchalee; Yakiyama, Yumi; Sakurai, Hidehiro; Konno, Takumi; Tantirungrotechai, Yuthana; Choojun, Kittisak; Leesakul, Nararak

doi:10.1016/j.saa.2024.125150

Iridium(III) coordination compounds based on organophosphorus ancillary ligands showing cytotoxicity against breast cancer cells and Fe(III) luminescent sensing

Author(s)

Klaimanee, Ekkapong

Temram, Thitirat

Ratanaphan, Adisorn

Saithong, Saowanit

Sooksawat, Dhassida

Samphao, Anchalee

Yakiyama, Yumi

Sakurai, Hidehiro

Konno, Takumi

Tantirungrotechai, Yuthana

Choojun, Kittisak

Leesakul, Nararak

Date Issued

January 15, 2025

Type

Article

DOI

10.1016/j.saa.2024.125150

Abstract

Three phosphorescent iridium(III) complexes consisting bis-diphosphine ligands were prepared and characterized by single-crystal XRD, CHN analysis, spectroscopic techniques, cyclic voltammetry, and DFT. The synthesized complexes were the three monomeric [Ir(ppy)2(L1)Cl] (1), [Ir(ppy)2(L2)]Cl (2) and [Ir(ppy)2(L3)]Cl (3) where L1 = bis-(diphenylphosphino)methane (dppm), L2 = bis-(diphenylphosphino)propane (dppp) and L3 = bis-(diphenylphosphino)benzene (dppbe). Complexes 1–3 gave an absorption band between 240 to 380 nm in both CH2Cl2 and DMSO, which is assigned as a charge transfer transition based on theoretical calculation. They showed a blue-green emission at 460–520 nm in DMSO with an absolute quantum efficiency of 0.013–0.046 at room temperature. The selective photo-induced electron transfer (PET) by Fe³⁺ in DMSO, was studied to obey the Rehm-Weller principle. The 1:1 binding soichiometry between 1–3 and Fe³⁺ was established by Job's plot. The binding constants (Ka) were determined using the Benesi-Hildebrand plot. All the complexes are extremely more potent than cisplatin for in vitro antiproliferative activity towards the human breast cancer cells, HCC1937, MCF-7, and MDA-MB-231. The values of IC50 were in the range of 0.077–0.485 μM, and 1 exhibited the most effective IC50 against MDA-MB-231 cell line, the triple-negative breast cancer cell. Their lipophilicities (log P) were also examined to explain the penetration ability of the studied complexes towards cell barriers, and transport to the molecular target.

Citation

Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy, 325, 2025