Luminescent Cyclometallated Iridium (III) Complexes Having Acetylide Ligands

Abstract

The present invention relates to phosphorescent (triplet-emitting) organometallic materials. The phosphorescent materials of the present invention comprise Ir(III)cyclometallated alkynyl complexes for use as triplet light-emitting materials. The Ir(III)cyclometallated alkynyl complexes comprise at least one cyclometallating ligand and at least one alkynyl ligand bonded to the iridium. Also provided is an organic light emitting device comprising an anode, a cathode and an emissive layer between the anode and the cathode, wherein the emissive layer comprises a Ir(III)cyclometallated alkynyl complex as a triplet emitting material.

1 . A compound having the formula I: 
       
         
           
           
               
               
           
         
         wherein: 
         X 1 ̂X 2  is a substituted or unsubstituted bidentate cyclometallated aromatic ligand; 
         X 1  and X 2  are independently selected from C and N; 
         Z is an acetylide ligand having the structure:
 —C≡C—R 1 , —C≡C—(C≡C) x —R 1 , or —C≡C-(A-C≡C) y —R 1 , 
 
         each R 1  is independently selected from the group consisting of H, alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, heteroaryl, Si(R 2 ) 3 , M(L) z , and a heterocyclic group, each of which may be substituted or unsubstituted; 
         each x is independently selected from 0-5; 
         each y is independently selected from 0-5; 
         each R 2  is independently selected from H, alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, heteroaryl, and a heterocyclic group; 
         M is a metal atom; 
         L is a mono-, bi- or tridentate ligand; 
         z is 0-5; 
         A is aryl or heteroaryl; 
         Y is a monodentate ancillary ligand; 
         a is 1, 2, 3, or 4; 
         b is 0, 1, 2, or 3; 
         n is 1 or 2; 
         the sum of a+b+n is 4 or 5; and 
         Cat is an optional cation the charge of which provides a net neutral charge for formula I. 
       
     
     
         2 . The compound of  claim 1 , wherein n is 2, a is 1 and b is 1. 
     
     
         3 . The compound of  claim 1 , wherein n is 2, a is 2. 
     
     
         4 . The compound of  claim 1 , having the formula II: 
       
         
           
           
               
               
           
         
         wherein 
         ĈN is a substituted or unsubstituted cyclometallated ligand; 
         each R 1  is independently selected from the group consisting of H, alkyl, cycloalkyl, alkenyl, cycloalkenyl, awl, heteroaryl, Si(R 2 ) 3 , M(L) z , and a heterocyclic group, each of which may be substituted or unsubstituted; 
         each R 2  is independently selected from H, alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, heteroaryl, and a heterocyclic group; 
         M is a metal atom; 
         L is a mono-, bi- or tridentate ligand; 
         z is 0-5; 
         Y is a monodentate ancillary ligand; and 
         Cat is an optional cation the charge of which provides a net neutral charge for formula II. 
       
     
     
         5 . The compound of  claims 1  or  2 , wherein each R 1  is independently selected from: 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         wherein each X is independently selected from C(R′) d , N(R′) e , S, O, SO, SO 2  and Si(R′) d ; 
         d is 1 or 2; 
         e is 0 or 1; 
         n is 1 to 5; 
         each R is independently selected from H, halo, CN, alkyl, cycloalkyl, alkenyl, aryl, aralkyl, heteroaryl; OR′, NR′ 2 , CO 2 R′, COR′, CONR′ 2 , and Si(R′) 3 ; 
         each R′ is independently selected from H, alkyl, cycloalkyl, alkenyl, aryl, aralkyl, and heteroaryl; 
         M is a metal atom; L is a mono-, bi- or tridentate ligand; and 
         j is 0 to 5. 
       
     
     
         6 . The compound of  claim 2 , wherein Y has the formula —C═N—R 3 ; and R 3  is selected from the group consisting of alkyl, cycloalkyl, alkenyl, aryl, aralkyl, and heteroaryl. 
     
     
         7 . The compound of  claim 1 , having the formula III: 
       
         
           
           
               
               
           
         
         wherein 
         ĈN is a substituted or unsubstituted cyclometallated ligand; 
         R 1a  and R 1b  are independently selected from the group consisting of 
         H, alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, heteroaryl, Si(R 2 ) 3 , M(L) z , and a heterocyclic group, each of which may be substituted or unsubstituted; 
         each R 2  is independently selected from H, alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, heteroaryl, and a heterocyclic group; 
         M is a metal atom; 
         L is a mono-, bi- or tridentate ligand; 
         z is 0-5; and 
         Cat is an optional cation the charge of which provides a net neutral charge for formula III. 
       
     
     
         8 . The compound of  claim 1 , wherein the triplet energy of the acetylide ligand Z is lower than that of the ĈN cyclometallating ligands. 
     
     
         9 . The compound of  claim 1  having the structure selected from the group consisting of: 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
       
     
     
         10 . An organic light emitting device comprising an anode, a cathode and an emissive layer between the anode and the cathode, wherein the emissive layer comprises the compound of the  claim 1 .