posted on 2024-01-04, 09:05authored byMateusz Kowalik, Joanna Masternak, Mateusz Olszewski, Natalia Maciejewska, Katarzyna Kazimierczuk, Jerzy Sitkowski, Aleksandra M. Dąbrowska, Agnieszka Chylewska, Mariusz Makowski
Organometallic half-sandwich complexes [(η5-Cp)IrCl(L)]PF6 (1) and [(η5-Cp)RhCl(L)]PF6 (2) were prepared
using pentamethylcyclopentadienyl
chloride dimers of iridium(III) or rhodium(III) with the 4-amino-N-(2,2′-bipyridin-5-yl)benzenesulfonamide ligand
(L) and ammonium hexafluorophosphate. The crystal structures
of L, 1, and 2 were analyzed
in detail. The coordination reactions of the ligand with the central
ions were confirmed using various spectroscopic techniques. Additionally,
the interactions between sulfaligand, Ir(III), and Rh(III) complexes
with carbonic anhydrase (CA), human serum albumin (HSA), and CT-DNA
were investigated. The iridium(III) complex (1) did not
show any antiproliferative properties against four different cancer
cell lines, i.e., nonsmall cell lung cancer A549, colon cancer HCT-116,
breast cancer MCF7, lymphoblastic leukemia Nalm-6, and a nonmalignant
human embryonic kidney cell line HEK293, due to high binding affinity
to GSH. The sulfonamide ligand (L) and rhodium(III) complex
(2) were further studied. L showed competitive
inhibition toward CA, while complexes 1 and 2, uncompetitive. All compounds interacted with HSA, causing a conformational
change in the protein’s α-helical structure, suggesting
the induction of a more open conformation in HSA, reducing its biological
activity. Both L and 2 were found to induce
cell death through a caspase-dependent pathway. These findings position L and 2 as potential starting compounds for pharmaceutical,
therapeutic, or medicinal research.