Cavity-Containing [Fe2L3]4+ Helicates: An Examination of Host-Guest Chemistry and Cytotoxicity
Open Access
- 7 July 2021
- journal article
- research article
- Published by Frontiers Media SA in Frontiers in Chemistry
Abstract
Two new di(2,2′-bipyridine) ligands, 2,6-bis([2,2′-bipyridin]-5-ylethynyl)pyridine (L1) and bis(4-([2,2′-bipyridin]-5-ylethynyl)phenyl)methane (L2) were synthesized and used to generate two metallosupramolecular [Fe2(L)3](BF4)4 cylinders. The ligands and cylinders were characterized using elemental analysis, electrospray ionization mass spectrometry, UV-vis, 1H-, 13C and DOSY nuclear magnetic resonance (NMR) spectroscopies. The molecular structures of the [Fe2(L)3](BF4)4 cylinders were confirmed using X-ray crystallography. Both the [Fe2(L1)3](BF4)4 and [Fe2(L2)3](BF4)4 complexes crystallized as racemic (rac) mixtures of the ΔΔ (P) and ΛΛ (M) helicates. However, 1H NMR spectra showed that in solution the larger [Fe2(L2)3](BF4)4 was a mixture of the rac-ΔΔ/ΛΛ and meso-ΔΛ isomers. The host-guest chemistry of the helicates, which both feature a central cavity, was examined with several small drug molecules. However, none of the potential guests were found to bind within the helicates. In vitro cytotoxicity assays demonstrated that both helicates were active against four cancer cell lines. The smaller [Fe2(L1)3](BF4)4 system displayed low μM activity against the HCT116 (IC50 = 7.1 ± 0.5 μM) and NCI-H460 (IC50 = 4.9 ± 0.4 μM) cancer cells. While the antiproliferative effects against all the cell lines examined were less than the well-known anticancer drug cisplatin, their modes of action would be expected to be very different.Keywords
Funding Information
- Marsden Fund
- MacDiarmid Institute for Advanced Materials and Nanotechnology
This publication has 103 references indexed in Scilit:
- [Fe2L3]4+ Cylinders Derived from Bis(bidentate) 2-Pyridyl-1,2,3-triazole “Click” Ligands: Synthesis, Structures and Exploration of Biological ActivityMolecules, 2013
- Anion-Dependent Formation of Helicates versus Mesocates of Triple-Stranded M2L3 (M = Fe2+, Cu2+) ComplexesInorganic Chemistry, 2011
- Nickel(ii) and iron(ii) triple helicates assembled from expanded quaterpyridines incorporating flexible linkagesDalton Transactions, 2011
- Antimicrobial activity of an iron triple helicateInternational Journal of Antimicrobial Agents, 2009
- Supramolecular Iron Cylinder with Unprecedented DNA Binding Is a Potent Cytostatic and Apoptotic Agent without Exhibiting GenotoxicityCell Chemical Biology, 2008
- DNA binding of dinuclear iron(II) metallosupramolecular cylinders. DNA unwinding and sequence preferenceNucleic Acids Research, 2008
- Recognition of DNA Three‐Way Junctions by Metallosupramolecular Cylinders: Gel Electrophoresis StudiesChemistry – A European Journal, 2007
- DNA Three-Way Junction with a Dinuclear Iron(II) Supramolecular Helicate at the Center: A NMR Structural StudyInorganic Chemistry, 2007
- Interaction between a DNA oligonucleotide and a dinuclear iron(II) supramolecular cylinder; an NMR and molecular dynamics studyJBIC Journal of Biological Inorganic Chemistry, 2002
- Intramolecular DNA Coiling Mediated by a Metallo-Supramolecular CylinderAngewandte Chemie, 2001