1. Synthesis, characterization, kinetic investigation and biological evaluation of Re(I) di- and tricarbonyl complexes with tertiary phosphine ligands.
- Author
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Gantsho, Verity Lindy, Dotou, Mazzarine, Jakubaszek, Marta, Goud, Bruno, Gasser, Gilles, Visser, Hendrik Gideon, and Schutte-Smith, Marietjie
- Subjects
LIGANDS (Chemistry) ,HELA cells ,CHEMICAL bond lengths ,EPITHELIAL cells ,CERVICAL cancer - Abstract
Rhenium(I) di- and tri-carbonyl complexes of the form fac-[Re(CO)
3 (L,L′-Bid)X] and [Re(CO)2 (L,L′-Bid)X2 ], where X = aqua (H2 O), methanol (CH3 OH), triphenylphosphine (PPh3 ), 1,3,5-triaza-7-phosphaadamantane (PTA), tricyclohexylphosphine (PCy3 ) and L,L′-Bid = O,O′ bidentate ligands (tropolone = TropH and 3-hydroxyflavone = FlavH) and N,O bidentate ligands (8-hydroxyquinoline = QuinH, 5,7-chloro-8-hydroxyquinoline = diCl-QuinH and quinoline-2,4-dicarboxylic acid = QuinH2 ), were synthesized and unambiguously characterized by1 H-,13 C-and31 P-NMR, IR, UV/Vis and micro-analysis. The crystal structures of four complexes, namely fac-[Re(CO)3 (QuinH)(H2 O)]·H2 O (5), fac-[Re(CO)3 (Quin)(PPh3 )] (11), fac-[Re(CO)3 (diCl-Quin)(PPh3 )] (12) and [Re(CO)2 (Trop)(PPh3 )2 ]·2C6 H5 CH3 (20) were obtained. Re–P bonding distances for 11 and 12 are 2.4948(8) and 2.4908(8) Å, respectively, indicating the effect of the electron-withdrawing substituents of the diCl-Quin− ligand. The second-order rate constants for the substitutions of methanol at 25.1 °C in fac-[Re(CO)3 (L,L′-Bid)(CH3 OH)] (L,L′-Bid = Trop, Flav and QuinH) type complexes by different entering phosphine ligands (PPh3 , PCy3 , and PTA) varied between 7.23(7) × 10−5 and 1.32(3) × 10−3 M−1 s−1 and were found to depend on the coordinated bidentate ligand (in general k1 (QuinH) < k1 (Trop) < k1 (Flav)). The toxicity of fac-[Re(CO)3 (QuinH)(PTA)], fac-[Re(CO)3 (Trop)(PTA)], fac-[Re(CO)3 (Trop)(PPh3 )] and fac-[Re(CO)3 (Flav)(PPh3 )] on the cervical cancer HeLa and epithelial RPE-1 cell lines was then evaluated. Complex fac-[Re(CO)3 (Flav)(PPh3 )] (16) and fac-[Re(CO)3 (Trop)(PPh3 )] (13) displayed the highest cytotoxicity with IC50 values of 12.21 ± 0.17 μM and 13.35 ± 0.94 μM, respectively in HeLa cells. Interestingly, a small selectivity towards cancer over non-cancerous cells was observed for these compounds (IC50 = 18.41 ± 3.16 μM and >25 μM in RPE-1 cells). [ABSTRACT FROM AUTHOR]- Published
- 2020
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