Phosphorescent Osmium (II) complexes and uses thereof

Abstract

There is disclosed herein phosphorescent compounds, uses thereof, and devices including organic light emitting diode (OLEDs) including such compounds. Compounds of interest include: wherein A is Os or Ru The anionic chelating chromophores N{circumflex over ( )}N, which are formed by connecting one pentagonal ring structure containing at least two nitrogen atoms to a hexagonal pyridine type of fragment via a direct carbon-carbon linkage. L is a neutral donor ligand; the typical example includes carbonyl, pyridine, phosphine, arsine and isocyanide; two neutral L's can also combine to produce the so-called chelating ligand such as 2,2′-bipyridine, 1,10-phenanthroline and N-heterocyclic carbene (NHC) ligand, or bidentate phosphorous ligands such as 1,2-bis(diphenylphosphino)ethane, 1,2-bis(diphenylphosphino)benzene. L can occupy either cis or trans orientation. When L occupies the trans position, the preferred structure contains both the hexagonal fragment of NAN as well as its pentagonal fragment located at the trans position respect to their counterparts of the second NAN chromophore. When L occupies the cis position, the preferred structure consists of the pentagonal unit of N{circumflex over ( )}N chromophores residing opposite to the L. X 1 , X 2 and X 3 independently are C or N; when X 2 is N, R, is omitted, when X 3 is N, R 2 is omitted, R 1 is H, C1-C8 alkyl, C1-C8 substituted phenyl or C1-C4 perfluoroalkyl, R 2 is H, F or cyano substituent, X 4 is either C or N; X 4 may locate at any position of the hexagonal ring, when X 4 is N and R 3 and R 4 are not linked to X 4 , R 3 is H, methyl or C1-C3 small alkyl, R 4 is H, methyl or C1-C3 small alkyl, or R 3 and R 4 together form an additional conjugated unit with structure

1 . A compound of structure III:  
       
         
           
           
               
               
           
         
         wherein:  
         the anionic chelating chromophores N{circumflex over ( )}N, are formed by connecting a pentagonal ring structure containing at least two nitrogen atoms to a hexagonal pyridine type of fragment via a direct carbon-carbon linkage;  
         A is Os or Ru;  
         L stands for a neutral donor ligand;  
         L can occupy either cis or trans orientation;  
         X 1 , X 2  and X 3  are independently C or N;  
         when X 2  is N, R 1  is omitted;  
         when X 3  is N, R 2  is omitted;  
         R 1  is H, C1-C8 alkyl, C1-C8 substituted phenyl or C1-C4 perfluoroalkyl;  
         R 2  is H, F and/or a cyano substituent;  
         X 4  of the hexagonal fragment is either C or N;  
         X 4  may locate at any position of the hexagonal ring, when X 4  is N and R 3  and R 4  are not linked to X 4 ; and  
         R 3  is H, methyl or C 1 -C 3  small alkyl;  
         R 4  is H, methyl or C 1 -C 3  small alkyl, or;  
         R 3  and R 4  together form the additional conjugated unit with structure  
       
     
     
         2 . The compound of  claim 1  wherein A is Os.  
     
     
         3 . The compound of  claim 1  wherein A is Ru.  
     
     
         4 . The compound of  claim 1  wherein X 1  is C.  
     
     
         5 . The compound of  claim 1  wherein X 1  is N.  
     
     
         6 . The compound of  claim 1  wherein X 2  is C.  
     
     
         7 . The compound of  claim 1  wherein X 2  is N.  
     
     
         8 . The compound of  claim 1  wherein X 3  is C.  
     
     
         9 . The compound of  claim 1  wherein X 3  is N.  
     
     
         10 . The compound of  claim 1  wherein R 2  is a fluoro and cyano substituent.  
     
     
         11 . The compound of  claim 1  wherein “L” is carbonyl and the remaining substituents are selected to provide structure 1a, 1b, or 1c:  
       
         
           
           
               
               
           
         
       
     
     
         12 . A method of making a compound of structure I, comprising a condensation reaction of a bidentate chelating ligand of general formula  
       
         
           
           
               
               
           
         
         with osmium metal reagent Os 3 (CO) 12  in the substantial absence of solvent media or in the presence of a high boiling polar organic solvent at elevated temperature.  
       
     
     
         13 . The compound of  claim 2  wherein substituents are selected to provide structure 3a, 3b, or 3c;  
       
         
           
           
               
               
           
         
         wherein examples of R 1 , R 2  and H are as previously defined in formula (1a), (1b) and (1c) in  claim 11 .  
       
     
     
         14 . The compound of  claim 2  wherein substituents are selected to provide structures 4a, 4b or 4c:  
       
         
           
           
               
               
           
         
         wherein R 1 , R 2  and H are as previously defined in formula (1a), (1b) and (1c) in  claim 11 , the phosphine donor ligand is selected from PPh 3 , PPh 2 Me, PPhMe 2 , PMe 3 , PPh 2 (C 2 F 5 ), PPh(C 2 F 5 ) 2 , PPh 2 Et, PPhEt 2 , PEt 3 , PPh 2 (CH═CH 2 ) and PPh(CH═CH 2 ) 2 , the phosphite ligand is selected from P(OPh) 3 , P(OMe) 3  and P(OEt) 3 , the arsine ligand is selected from AsPh 3  and AsMe 3 .  
       
     
     
         15 . A method of making a compound of  claim 14  comprising a condensation reaction of a bidentate chelating ligand of general formula  
       
         
           
           
               
               
           
         
         with osmium carbonyl reagent Os 3 (CO) 12  in the presence of a high boiling polar organic solvent at elevated temperature, followed by treatment of resulting reaction mixture with a freshly sublimed decarbonylation reagent Me 3 NO or Et 3 NO, and the phosphine donor ligand.  
       
     
     
         16 . The compound of  claim 2  wherein substituents are selected to provide structures 5a, 5b or 5c:  
       
         
           
           
               
               
           
         
         wherein examples of R 1 , R 2  and H are as previously defined in formula (1a), (1b) and (1c) in  claim 1 , chelating diphosphine ligand R 3   2 P{circumflex over ( )}PR 3   2  are selected from 1,2-bis(dimethylphosphino)ethane, 1,2-bis(diphenylphosphino)ethane, 1,2-bis(diphenylphosphino)benzene, 1,2-bis(diethoxylphosphino)benzene, cis-1,2-bis(diphenylphosphino)ethylene, bis(dipentafluoroethylphosphino)ethane 1,2-bis(dipentafluorophenylphosphino)ethane, 1,3-bis(dimethylphosphino)propane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(dimethylphosphino)butane and 1,4-bis(diphenylphosphino)butane, for which the carbon spacer linking the phosphorous donor group is considerably lengthened to increase the chelating bite angle at the Os(II) metal center.  
       
     
     
         17 . The compound of  claim 1  in which the 2-pyridyl unit of the pyrazolate, triazolate and tetrazolate ligands is further modified to add an aromatic heterocycle molecule and to replace the pyrazolate fragment of the anionic ligand by an imidiazolate or an indazolate unit.  
     
     
         18 . The compound of  claim 17  wherein the aromatic hetercycle molecule is selected from:  
       
         
           
           
               
               
           
         
       
     
     
         19 . The compound of  claim 17  wherein the aromatic heterocycle molecule is selected from pyrazine, pyrimidine, pyridazine, quinoline and isoquinoline.  
     
     
         20 . A light-emitting device, comprising; 
 a pair of electrodes,    a substrate,    one or more organic layers deposited on said substrate,    at least one organic layer including a functional phosphorescent component,    said functional phosphorescent component include a compound of structure III.    
     
     
         21 . The light-emitting device of  claim 20  wherein the compound of structure III is placed in a substantially non-ionic environment.  
     
     
         22 . The light-emitting device of  claim 20  wherein the phosphorescent component includes a compound of structure I.  
     
     
         23 . The light-emitting device of  claim 20  wherein the phosphorescent component includes a compound of structure II.  
     
     
         24 . The light-emitting device of  claim 20  where said device is either an organic light emitting diode, or a polymer light-emitting diode, or a functional layer made of small moles or a functional layer made of polymers, or a composite material made of small moles and polymer molecules.  
     
     
         25 . The light-emitting device of  claim 24  where said small moles include oligomers.  
     
     
         26 . The light-emitting device of  claim 20  where said organic layer include a second phosphorescent material.  
     
     
         27 . A light-emitting device comprising an anode and a cathode, a hole transport layer, an electron transport layer, and wherein at least one of said hole transport layer and said electron transport layer comprises an active material of structure III.  
     
     
         28 . The light-emitting device of  claim 26  wherein the compound of structure III is located in a substantially non-ionic environment.  
     
     
         29 . The light-emitting device of  claim 26  further including a hole injection promotion layer adjacent to at least one of said hole transport layer.  
     
     
         30 . The light-emitting device of  claim 26  further including an electron injection promotion layer adjacent to at least one of said electron transport layer.  
     
     
         31 . The light-emitting device of  claim 29 , wherein said electron injection promotion layer is LiF.  
     
     
         32 . The light-emitting device of  claim 28 , wherein said hole injection promotion layer is [Poly(ethylene dioxythiophene:polystryrene sulfonate)] (PEDOT-PSS).  
     
     
         33 . The light-emitting device of  claim 20  wherein the organic layers are deposited by using a dry deposition method or a wet thin film processing method.  
     
     
         34 . The light-emitting device of  claim 27  wherein the layers are deposited by using a dry deposition method or a wet thin film processing method.  
     
     
         35 . The light-emitting device of  claim 20  where the dry deposition method is selected of the group of thermal deposition and sputtering deposition and PECVD deposition and MOCVD deposition.  
     
     
         36 . The light-emitting device of  claim 20  where the wet thin film processing method is selected of the group of Langmuir-Blodgett, screen printing, and ink-jet printing, and solution dipping and, spin-coating.