We use cookies to ensure that we give you the best experience on our website. By continuing to browse this repository, you give consent for essential cookies to be used. You can read more about our Privacy and Cookie Policy.

Durham e-Theses
You are in:

Synthesis and luminescence of iridium and rhodium complexes incorporating NCN-coordinating terdentate ligands

Whittle, Victoria Louise (2008) Synthesis and luminescence of iridium and rhodium complexes incorporating NCN-coordinating terdentate ligands. Doctoral thesis, Durham University.



The luminescent properties of transition metal complexes containing polypyridyl and cyclometalating ligands make them potential candidates for a range of applications; for example, as triplet-harvesting agents in organic light-emitting devices (OLEDs), owing to the potentially high quantum yields of triplet emission; in solar cells, converting light to electrical energy; and as sensors and probes in biological systems. The synthesis of a series of [M(NCN)(X^X^X)]’^n^+’ and [M(NCN)(X^X)C1](^n+) coordinated complexes (where M = Ir or Rh; X = heterocyclic N or cyclometalated aryl C; and n = 0-2) bearing pyridyl and pyrazolyl-based NCN-coordinating ligands (cyclometalating through the central phenyl ring) is reported, alongside their photophysical and electrochemical properties. Whilst luminescence was generally observed from the pyridyl-based iridium(III) complexes at ambient temperature, the charge-neutral Rh(III) complex [Rh(NCN)(NC)Cl] was the only complex amongst those containing a rhodium centre to be emissive under these conditions. Similarly, the pyrazolyl Ir(III) complexes exhibit lower luminescence intensities than their pyridyl analogues, owing to the poorer Ti-accepting ability of the pyrazole rings which results in a blue-shift in the emission profile and more ligand-based character. In addition to the synthesis of these complexes, a sequential cross-coupling - bromination - cross-coupling strategy has been developed for the linear stepwise expansion of an [Ir(NCN)(NNC)(^+) coordinated complex, incorporating a pendant bromophenyl group on the central pyridyl ring of the NNC ligand, via in situ palladium- catalysed Suzuki cross-coupling reactions with aryl boronic acids. This strategy has-been further extended to the controlled synthesis of linear multimetallic assemblies using boronic acid appended Ir(III) and Ru(II) complexes. A heterometallic trinuclear [Ir-ɸ-Ir- ɸ (_2)-Ru](^4+) assembly was prepared, where the phenylene bridges between the metal centres do not contribute to the excited state of the trimetallic system, and efficient energy-transfer occurs to the lower energy ruthenium terminus. The emissive and energy-channelling properties of such multimetallic assemblies can be tailored by the careful choice of the constituent "building blocks”.

Item Type:Thesis (Doctoral)
Award:Doctor of Philosophy
Thesis Date:2008
Copyright:Copyright of this thesis is held by the author
Deposited On:08 Sep 2011 18:25

Social bookmarking: del.icio.usConnoteaBibSonomyCiteULikeFacebookTwitter