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:

New luminescent iridium (III) complexes
containing NCN cyclometallated ligands:
synthesis, photophysical properties and
emission tuning

BRULATTI, PIERPAOLO (2010) New luminescent iridium (III) complexes
containing NCN cyclometallated ligands:
synthesis, photophysical properties and
emission tuning.
Doctoral thesis, Durham University.



The luminescence properties of cyclometallated iridium(III) complexes render them of interest, for example, as phosphorescent dopants in organic light-emitting devices (OLEDs), as photoactive units in solar energy conversion, and as biosensors. The vast majority comprise three bidentate ligands, archetypal examples being Ir(ppy)3 and [Ir(ppy)2(bpy)]+ (ppy = 2-phenylpyridine; bpy = 2,2'- bipyridine).

The work described here explores the chemistry of iridium(III) complexes that contain a terdentate cyclometallating ligand. Most of the complexes studied have
the general formula Ir(N^C^N)(N^C)X, where N^C^N represents a terdentate ligand based on 1,3-di(2-pyridyl)benzene; N^C a bidentate ligand such as ppy; and X is a monodentate ligand such as chloride, cyanide, thiocyanate or an acetylide.
The synthetic methodology developed involves reaction of the N^CH^N proligand with iridium(III) chloride to give a dimer of the form [Ir(N^C^N)Cl(-Cl)]2, which is cleaved upon treatment with a bidentate N^CH ligand. The one remaining chloride ligand can then be exchanged for other monodentate ligands through silvercatalysed metathesis.

Most of these complexes are highly luminescent, with quantum yields in degassed dichloromethane at room temperature between 0.2 and 0.9. The effect of substituents in both the aryl and pyridyl rings of the terdentate and bidentate ligands has been investigated, together with the influence of X. The emission energy has been shown to vary over a very wide range, from the blue to red regions (max = 456 to 667 nm). The trends have been partially rationalised using time-dependent density functional theory and cyclic voltammetry. Some complexes have been incorporated into multi-layer OLEDs that display unusually
high efficiency, particularly for the red-emitting devices.

Selected rhodium(III) analogues have been prepared, together with related iridium(III) complexes incorporating bidentate N^N (bpy) ligands. A preliminary investigation into the utility of these complexes for the construction of multimetallic assemblies has been made, through the introduction of bridging ligands into
position X.

Item Type:Thesis (Doctoral)
Award:Doctor of Philosophy
Keywords:cyclometallated iridium(III) complexes; OLEDs; terdentate cyclometallating ligand; emission tuning
Faculty and Department:Faculty of Science > Chemistry, Department of
Thesis Date:2010
Copyright:Copyright of this thesis is held by the author
Deposited On:18 Oct 2010 12:48

Social bookmarking: del.icio.usConnoteaBibSonomyCiteULikeFacebookTwitter