Phosphorescent Side-Chain Functionalized Poly(norbornene)s Containing Iridium Complexes

Abstract

Norbornenes containing phosphorescent iridium complexes based on Ir(ppy)3 and Ir(ppy)2(bpy)(PF6) were synthesized and copolymerized with alkylnorbornenes via ring-opening metathesis polymerization in nonpolar solvents using ruthenium initiators. The luminescent properties of the resulting polymers both in solution and in the solid state were tested. The polymers were found to retain the optical properties of the phosphorescent small molecule analogues with emission maxima in the yellow/green, quantum yields from 0.23 to 0.24 for Ir(ppy)2(bpy)(PF6) analogues, 0.02 to 0.03 for mer-Ir(ppy)3 analogues, and 0.20 to 0.24 for fac-Ir(ppy)3 analogues, and lifetimes of 0.41 to 0.55 μs for Ir(ppy)2(bpy)(PF6) analogues, 0.22 to 0.62 μs for mer-Ir(ppy)3 analogues, and 1.28 to 1.48 μs for fac-Ir(ppy)3 analogues. By combining the phosphorescent properties of these emissive molecules with the solution processability and ease of synthesis of polynorbornene backbones, these materials might be highly useful in the field of light-emitting devices and emissive display technology.

Recent Developments in the Application of Phosphorescent Iridium(III) Complex Systems

“…V) The most widely utilized method to access polymers containing phosphorescent Ir III complexes is the (co)polymerization, [33,[134][135][136][137][138][139][140][141][142][143][144][145][146][147][148] or (co)condensation, [36,[93][94][95]119,120, of suitably functionalized complexes. Weck and co-workers used the ring-opening metathesis polymerization (ROMP) of functionalized exo-norbornene [134,136] or cyclooctene monomers [135] to synthesize homo-and copolymers equipped with Ir III emitters.…”

“…Weck and co-workers used the ring-opening metathesis polymerization (ROMP) of functionalized exo-norbornene [134,136] or cyclooctene monomers [135] to synthesize homo-and copolymers equipped with Ir III emitters. A first proof of the feasibility was gained by polymerizing norbornenes bearing tris-cyclometallated (facial and meridional) complexes as well as charged bis-cyclometallated iridium(III) bipyridine complexes and by performing copolymerizations with alkyl-functionalized norbornene.…”

“…A first proof of the feasibility was gained by polymerizing norbornenes bearing tris-cyclometallated (facial and meridional) complexes as well as charged bis-cyclometallated iridium(III) bipyridine complexes and by performing copolymerizations with alkyl-functionalized norbornene. [134] They demonstrated the copolymerization of a cyclooctene-functionalized triscyclometallated Ir III complex with a carbazole-functionalized cyclooctene. [135] Further on, norbornenes bearing various heteroleptic tris-cyclometallated Ir III complexes were copolymerized with a (bis-carbazole-fluorene)-norbornene derivative.…”

Solution‐Processable Carbazole‐Based Conjugated Dendritic Hosts for Power‐Efficient Blue‐Electrophosphorescent Devices

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Phosphorescent polymer light-emitting diodes (PPLEDs), in which the triplet emitters are dispersed into the polymeric hosts via physical blending [1][2][3][4][5][6] or chemical bonding, [7][8][9][10][11][12] have attracted much attention because of their low-cost preparation from solution either by spin-coating or via inkjet printing as well as the capability to harness both the singlet and triplet excitons to realize theoretical 100% internal quantum efficiency. [13][14][15] For solid-state lighting applications, the development of power-efficient blue, green and red PPLEDs is essential.

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Polymers that Contain Ligated Metals in their Side Chain: Building a Foundation for Functional Materials in Opto‐Electronic Applications with an Emphasis on Lanthanide Ions

“…A number of groups have studied the solution behavior of polymers that contain Ir III complexes. Schubert studied a variety of backbones [27][28][29][30][31] that contained Ir III complexes including poly(ethylene glycol) (PEG), polystyrene (PS), and poly(e-caprolactone) (PCL), Weck reported a number of poly(norbornenes) that contained Ir III complexed with bipyridine and phenyl-pyridine ligands, [32,33] while Tew reported block copolymers based on PS and terpy-modified acrylamides that contained Ir III confined to one block. [34] Much of this work has focused on establishing synthetic methods to produce a variety of new metal-containing polymers that are well characterized.…”