title: Multimetallic and Mixed Environment Iridium(III) Complexes: A Modular Approach to Luminescence Tuning Using a Host Platform.
abstract: Mononuclear and trinuclear bis-cyclometallated IrIIIcomplexes of the host ligands tris(4-[4'-methyl-2,2'-bipyridyl]methyl)cyclotriguaiacylene (L1) and tris(4-(4'-methyl-2,2'- bipyridyl)carboxy)cyclotriguaiacylene (L2) have been prepared. Complexes [{Ir(ppy)2}3(L1)](PF6)3(1.1), [{Ir(ppy)2}(L1)](PF6)3(1.2), [{Ir(ppy)2}3(L2)](PF6)3(2.1) and [{Ir(ppy)2}(L2)](PF6)3(2.2) (where ppy=phenylpyridinato) showed distinct photophysical properties depending on the L ligand. Complexes featuring the L1 ligand were comparatively blue-shifted in solution, with longer lifetimes and higher quantum yields. The mixed bis-cyclometallated IrIIIcomplexes [{Ir(ppy)2}{Ir(dFppy)2}2(L1)](PF6)3(1.3), [{Ir(ppy)2}{Ir(dFppy)2}2(L2)](PF6)3(2.3), [{Ir(ppy)2}2{Ir(dFppy)2}(L1)](PF6)3(1.4) and [{Ir(ppy)2}2{Ir(dFppy)2}(L2)](PF6)3(2.4) (where dFppy=2,4-difluorophenylpyrinato) were also synthesised. Steady-state and time-resolved spectroscopy, along with electrochemical investigations, show that the Ir(III) chromophores within these mixed Ir-environment species behave as isolated centres, with no energy transfer or electronic communication between them.
authors.affiliation: School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK.
authors.forename: Victoria E
authors.identifier: http://orcid.org/0000-0001-5270-4534
authors.initials: VE
authors.lastname: Pritchard
authors.affiliation: Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St. Andrews, St Andrews, Fife, KY16 9ST, UK.
authors.forename: Diego
authors.initials: D
authors.lastname: Rota Martir
authors.affiliation: Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St. Andrews, St Andrews, Fife, KY16 9ST, UK.
authors.forename: Eli
authors.identifier: http://orcid.org/0000-0001-7183-6022
authors.initials: E
authors.lastname: Zysman-Colman
authors.affiliation: School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK.
authors.forename: Michaele J
authors.identifier: http://orcid.org/0000-0001-6586-7981
authors.initials: MJ
authors.lastname: Hardie
keywords: cyclometallated; cyclotriveratrylene; iridium; luminescence; trinuclear complexes