Investigating the antiplasmodial activity of substituted cyclopentadienyl rhodium and iridium complexes of 2-(2-pyridyl)benzimidazole

Transition Metal Complexes as Antimalarial Agents: A Review

“…Structure of complexes 199-207. [194,195] against Dd2, 0.25 μM against 3D7, 1.23 μM against NF54 strains). The antitubercular activity of 199-204 was determined against the 3D7, Dd2, and NF54 strains.…”

“…[60] In addition, Fe(II) (40, 42) complexes of ART showed impressive antimalarial activity against the CQ-resistant strain Dd2. Interestingly, Rh(III) (152,154), and Ir(III) (193)(194)(195) complexes of ART-based ligand (L46) showed even better antimalarial activity than ART against sensitive as well as resistant strains of P. Falciparum (Table 13). The Ru(II) (142 a-d), Rh(III) (143 a-d), and Ir(III) (176 a-d) complexes having 2-phenyl benzimidazole derivatives (L45a-L45d) showed a massively improved antimalarial activity over the respective ligands L45a-L45d.…”

Targets, Mechanisms and Cytotoxicity of Half-Sandwich Ir(III) Complexes Are Modulated by Structural Modifications on the Benzazole Ancillary Ligand

“…were mounted on a glass fiber and transferred to a Bruker X8 APEX II CCD-based diffractometer equipped with a graphitemonochromated Mo Kα radiation source (λ = 0.71073 Å). The highly redundant data sets were integrated using SAINT [47] and corrected for Lorentz and polarization effects. The absorption correction was based on the function fitting to the empirical transmission surface as sampled by multiple equivalent measurements with the program SADABS [52].…”

“…than cisplatin, ACC25 with the general formula [Ir(η :κ -C5Me4CH2py)(phpy)]PF6 (C5Me4CH2py = 2-[ (2,3,4,5-tetramethylcyclopentadienyl)methyl] pyridine and phpy=2phenylpyridine) that is unambiguously localized in the mitochondria [43] as well as another family of nonfluorescent half-sandwich iridium complexes able to generate ROS and disrupt mitochondrial membrane potential [8]. On this basis and considering the wide range of pharmacological properties exhibited by benzimidazole and its derivatives [44][45][46][47], we have prepared four series of neutral and cationic half-sandwich Ir(III)-Cp* complexes bearing eight different arylbenzazole ligands (Figure 1A) according to the notation n[Z,X-Y] (Figure 1B Such a diversity has allowed us to modify three different structural parameters, i.e., heteroatom in benzazole (X), the donor atom in the aryl ring (Z), the global charge of the complex and the metallacycle size and geometry (5-membered for series A and B, and 6-membered for series C and D). Moreover, in solution, the chloride leaving group (Y) is replaced with H2O or DMSO molecules, depending on their water solubility, leading to aqua or DMSO-adducts Hence, this study highlights the strong dependence of the chemical and biological behavior of iridium half-sandwich complexes on the nature and position of the atom or group of atoms in the X, Y and Z positions and to prove that small differences in the structure can cause critical changes in their properties.…”

Antiplasmodial activity, structure–activity relationship and studies on the action of novel benzimidazole derivatives

“…Furthermore, the obtaining of derivatives related to the antiallergic drug astemizole 31 – 33 or lerisetron 34 , showed congeners with good IC 50 values, from 47 nM to 1.7 μM against NF54 and K1 strains; moreover, derivatives related to some natural products, as carvacrol, showed activity values of 0.48 – 1.76 μg/mL 35 . Ferroquine, a ferrocenyl-chloroquine in phase 2b studies, led to Baartzes et al to the obtaining and evaluation of ferrocenyl and neutral and cationic iridium (III) and rhodium (III) aminoquinoline-benzimidazole hybrids 36 , 37 and 2(2-pyridyl)benzimidazole 38 . In the same sense, iridium(III), rhodium(III) and ruthenium (II) BZ-complexes were also tested against Pf 39 .…”