Polycationic Ru(II) luminophores: syntheses, photophysics, and application in electrostatically driven sensitization of lanthanide luminescence

Knighton, Richard C., Beames, Joseph M. and Pope, Simon J. A. ORCID: https://orcid.org/0000-0001-9110-9711 2023. Polycationic Ru(II) luminophores: syntheses, photophysics, and application in electrostatically driven sensitization of lanthanide luminescence. Inorganic Chemistry 62 (48) , pp. 19446-19456. 10.1021/acs.inorgchem.3c02352

Preview

PDF - Published Version Available under License Creative Commons Attribution. Download (2MB) | Preview

Abstract

A series of photoluminescent Ru(II) polypyridine complexes have been synthesized in a manner that varies the extent of the cationic charge. Two ligand systems (L1 and L2), based upon 2,2′-bipyridine (bipy) mono- or difunctionalized at the 5- or 5,5′-positions using N-methylimidazolium groups, were utilized. The resulting Ru(II) species therefore carried +3, +4, +6, and +8 complex moieties based on a [Ru(bipy)3]2+ core. Tetra-cationic [Ru(bipy)2(L2)][PF6]4 was characterized using XRD, revealing H-bonding interactions between two of the counteranions and the cationic unit. The ground-state features of the complexes were found to closely resemble those of the parent unfunctionalized [Ru(bipy)3]2+ complex. In contrast, the excited state properties produce a variation in emission maxima, including a bathochromic 44 nm shift of the 3MLCT band for the tetra-cationic complex; interestingly, further increases in overall charge to +6 and +8 produced a hypsochromic shift in the 3MLCT band. Supporting DFT calculations suggest that the trend in emission behavior may, in part, be due to the precise nature of the LUMO and its localization. The utility of a photoactive polycationic Ru(II) complex was then demonstrated through the sensitization of a polyanionic Yb(III) complex in free solution. The study shows that electrostatically driven ion pairing is sufficient to facilitate energy transfer between the 3MLCT donor state of the Ru(II) complex and the accepting 2F5/2 excited state of Yb(III).

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Chemistry
Publisher:	American Chemical Society
ISSN:	0020-1669
Funders:	Leverhulme Trust (RPG-2021- 003)
Date of First Compliant Deposit:	21 November 2023
Date of Acceptance:	3 November 2023
Last Modified:	23 Jan 2024 14:55
URI:	https://orca.cardiff.ac.uk/id/eprint/164125

Actions (repository staff only)

Edit Item