title: Oxidatively Locked [Co₂L₃]6+Cylinders Derived from Bis(bidentate) 2-Pyridyl-1,2,3-triazole "Click" Ligands: Synthesis, Stability, and Antimicrobial Studies.
abstract: A small family of [Co₂(Lpytrz)₃]6+cylinders was synthesised from bis(bidentate) 2-pyridyl-1,2,3-triazole "click" ligands (Lpytrz) through an "assembly-followed-by-oxidation" method. The cylinders were characterised using ¹H,13C, and DOSY NMR, IR, and UV-Vis spectroscopies, along with electrospray ionisation mass spectrometry (ESMS). Stability studies were conducted in dimethyl sulfoxide (DMSO) and D₂O. In contrast to similar, previously studied, [Fe₂(Lpytrz)₃]4+helicates the more kinetically inert [Co₂(Lpytrz)₃]6+systems proved stable (over a period of days) when exposed to DMSO and were even more stable in D₂O. The triply stranded [Co₂(Lpytrz)₃]6+systems and the corresponding "free" ligands were tested for antimicrobial activity in vitro against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) microorganisms. Agar-based disk diffusion and Mueller-Hinton broth micro-dilution assays showed that the [Co₂(Lpytrz)₃]6+cylinders were not active against either strain of bacteria. It is presumed that a high charge of the [Co₂(Lpytrz)₃]6+cylinders is preventing them from crossing the bacterial cell membranes, rendering the compounds biologically inactive.
authors.affiliation: Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9016, Otago, New Zealand. roan.vasdev044@gmail.com.
authors.forename: Roan A S
authors.initials: RA
authors.lastname: Vasdev
authors.affiliation: Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9016, Otago, New Zealand. preda458@student.otago.ac.nz.
authors.forename: Dan
authors.initials: D
authors.lastname: Preston
authors.affiliation: Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9016, Otago, New Zealand. synove.scottwell@unsw.edu.au.
authors.forename: Synøve Ø
authors.initials: SØ
authors.lastname: Scottwell
authors.affiliation: Department of Microbiology and Immunology, University of Otago, P.O. Box 56, 720 Cumberland Street, Dunedin 9054, Otago, New Zealand. heather.brooks@otago.ac.nz.
authors.forename: Heather J L
authors.initials: HJ
authors.lastname: Brooks
authors.affiliation: Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9016, Otago, New Zealand. jcrowley@chemistry.otago.ac.nz.
authors.forename: James D
authors.initials: JD
authors.lastname: Crowley
authors.affiliation: Department of Chemistry and Biochemistry, California State University, Long Beach, 1250 Bellflower Boulevard, Long Beach, CA 90840-9507, USA. michael.schramm@csulb.edu.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Schramm
mesh_terms: D000890:Anti-Infective Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D057930:Click Chemistry; D003035:Cobalt / Q000737:chemistry*; D004355:Drug Stability; D008024:Ligands; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D066244:Proton Magnetic Resonance Spectroscopy; D014230:Triazoles / Q000737:chemistry*
chemical_list: D000890:Anti-Infective Agents; D008024:Ligands; D009942:Organometallic Compounds; D014230:Triazoles; D003035:Cobalt
keywords: antimicrobial agents; cobalt(III); cylinders; metallosupramolecular