Enhanced Luminescent Iridium(III) Complexes Bearing Aryltriazole Cyclometallated Ligands

Abstract

Herein we report the synthesis of 4-aryl-1-benzyl-1H-1,2,3-triazoles (atl), made via "Click chemistry" and their incorporation as cyclometallating ligands into new heteroleptic iridium(III) complexes containing diimine (N(^)N) ancillary ligands 2,2'-bipyridine (bpy) and 4,4'-di-tert-butyl-2,2'-bipyridine (dtBubpy). Depending on decoration, these complexes emit from the yellow to sky blue in acetonitrile (ACN) solution at room temperature (RT). Their emission energies are slightly blue-shifted and their photoluminescent quantum efficiencies are markedly higher (between 25 and 80%) than analogous (C(^)N)(2)Ir(N(^)N)(+) type complexes, where C(^)N is a decorated 2-phenylpyridinato ligand. This increased brilliance is in part due to the presence of the benzyl groups, which act to sterically shield the iridium metal center. X-ray crystallographic analyses of two of the atl complexes corroborate this assertion. Their electrochemistry is reversible, thus making these complexes amenable for inclusion in light-emitting electrochemical cells (LEECs). A parallel computational investigation supports the experimental findings and demonstrates that for all complexes included in this study, the highest occupied molecular orbital (HOMO) is located on both the aryl fragment of the atl ligands and the iridium metal while the lowest unoccupied molecular orbital (LUMO) is located essentially exclusively on the ancillary ligand.

Exploring the self-assembly and energy transfer of dynamic supramolecular iridium-porphyrin systems

“…360 nm) compared to 1 due to presence of the electron-withdrawing fluorine atoms on the C^N ligands, which stabilize the highest occupied molecular orbital (HOMO) and consequently increase the band gap. 25 The energy levels of the frontier orbitals of 1 and 2 are given in Figure S78. and ZnTPP-pyridine after mathematical subtraction of the absorption of free ZnTPP.…”

Towards Water Soluble Mitochondria-Targeting Theranostic Osmium(II) Triazole-Based Complexes

“…We, and others, have paid particular attention to the use of copper-catalysed coupling of alkynes and azides to form 1,2,3-triazole-based ligands [7][8][9][10] and have investigated the photophysical properties of their resultant complexes. A significant number of reports have appeared detailing the photophysical and photochemical properties of triazole-based complexes of Re(I), Ru(II) and Ir(III) [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. Examples of triazole-containing complexes of osmium(II)…”

Visible‐Light‐Mediated Decarboxylative Radical Additions to Vinyl Boronic Esters: Rapid Access to γ‐Amino Boronic Esters

“…Although initial attempts demonstrated that A could promote the desired reaction, it was found that optimum yields were obtained when using the more reducing photocatalyst Ir[dF(Me)ppy] 2 (dtbbpy)PF 6 ( E ) 17. We were delighted to discover that simple cycloalkane carboxylic acids of various ring sizes and acyclic secondary carboxylic acids reacted to give the corresponding alkyl boronic esters in moderate to good yields ( 31 – 35 ).…”