Synthesis and characterisation of helicate and mesocate forms of a double-stranded diruthenium(II) complex of a di(terpyridine) ligand
Date
2019
Authors
Flint, K.L.
Collins, J.G.
Bradley, S.J.
Smith, T.A.
Sumby, C.J.
Keene, F.R.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
Australian Journal of Chemistry, 2019; 72(10):762-768
Statement of Responsibility
Kate L. Flint, J. Grant Collins, Siobhan J. Bradley, Trevor A. Smith, Christopher J. Sumby and F. Richard Keene
Conference Name
DOI
Abstract
A diruthenium(ii) complex involving the di(terpyridine) ligand 1,2-bis{5-(5″-methyl-2,2′:6′,2″-terpyridinyl)}ethane was synthesised by heating an equimolar ratio of RuCl₃ and the ligand under reflux conditions in ethylene glycol for 3 days, realising double-stranded helicate and mesocate forms which were chromatographically separated. The two species were obtained in relatively low yield (each ~7–9 %) from the reaction mixture. X-Ray structural studies revealed differences in the cavity sizes of the two structures, with the helicate structure having a significantly smaller cavity. Furthermore, the helicate and mesocate forms pack with notably different arrangements of the structures with the helicate having large solvent and anion filled pores. 1D/2D NMR studies revealed rigidity in the mesocate structure relative to that of the helicate, such that the –CH₂CH₂– signal was split in the former and appeared as a singlet in the latter. In a manner analogous to the behaviour of the parent [Ru(tpy)₂]²⁺ coordination moiety (tpy = 2,2′:6′,2″-terpyridine), photophysical studies indicated that both the helicate and mesocate forms were non-emissive at ~610 nm at room temperature, but at 77 K in n-butyronitrile, both isomers showed emission at ~610 nm (λex 472 nm). However, the temporal emission characteristics were very different: time-resolved studies showed the emission of the helicate species decayed with a dominant emission lifetime of ~10 μs (similar to the emissive properties of free [Ru(tpy)₂]²⁺ under the same conditions), whereas for the mesocate the emission lifetime was at least three orders of magnitude lower (~4 ns).
School/Discipline
Dissertation Note
Provenance
Description
Access Status
Rights
Journal compilation © CSIRO 2019