Process for preparing transition metal-carbene complexes

Abstract

Process for preparing cyclometallated transition metal-carbene complexes comprising at least one carbene ligand, which comprises reacting a ligand precursor with a base, an auxiliary reagent and a metal complex comprising at least one metal M 1 (route A) or reacting the ligand precursor with a basic auxiliary reagent and a metal complex comprising at least one metal M 1 (route B). The present invention further relates to the use of an auxiliary reagent selected from among salts comprising at least one metal selected from the group consisting of Ag, Hg, Sb, Mg, B and Al together with a base in a process for preparing cyclometallated metal complexes.

1 . A process for preparing cyclometallated carbene complexes of the general formula (I) comprising at least one carbene ligand 
       
         
           
           
               
               
           
         
         where the symbols have the following meanings: 
         M 1  is a metal atom selected from the group consisting of Ir, Co, Rh, Ni, Pd, Pt, Fe, Ru, Os, Cr, Mo, W, Mn, Tc, Re, Cu and Au in any oxidation state possible for the respective metal atom; 
         carbene is a carbene ligand of the general formula (II) 
       
       
         
           
           
               
               
           
         
         L is a monoanionic or dianionic ligand which may be monodentate or bidentate; 
         K is an uncharged monodentate or bidentate ligand; 
         n is the number of carbene ligands, with n being at least 1, and the carbene ligands in the complex of the formula I being able to be identical or different in the case of n>1; 
         m is the number of ligands L, with m being able to be 0 or ≧1 and the ligands L being able to be identical or different in the case of m>1; 
         o is the number of ligands K, with o being able to be 0 or ≧1 and the ligands K being able to be identical or different in the case of o>1; 
         where the sum n+m+o is dependent on the oxidation state and coordination number of the metal atom used and on the denticity of the ligands carbene, L and K and also on the charge on the ligands carbene and L, with the proviso that n is at least 1; 
         where the symbols in the carbene ligand of the general formula II have the following meanings: 
         Do 1  is a donor atom selected from the group consisting of O and S; 
         Do 2  is a donor atom selected from the group consisting of C, N, P, O and S; 
         r is 0; 
         s is 2 when Do 2  is C, is 1 when Do 2  is N or P and is 0 when Do 2  is O or S; 
         X is a spacer selected from the group consisting of silylene, alkylene, arylene, heteroarylene, alkynylene, alkenylene, NR 13 , PR 14 , BR 15 , O, S, SO, SO 2 , CO, CO—O, O—CO and (CR 16 R 17 ) w , where one or more nonadjacent (CR 16 R 17 ) groups can be replaced by NR 13 , PR 14 , BR 15 , O, S, SO, SO 2 , CO, CO—O, O—CO; 
         w is from 2 to 10; 
         R 13 , R 14 , R 15 , R 16 , R 17  are each H, alkyl, aryl, heteroaryl, alkenyl, alkynyl; 
         p is 0 or 1; 
         q is 0 or 1; 
         Y 1 , Y 2  are each, independently of one another, hydrogen or a carbon-comprising group selected from the group consisting of alkyl, aryl, heteroaryl, alkynyl and alkenyl groups;
 or 
 
         Y 1  and Y 2  together form a bridge between the donor atom Do 1  and the nitrogen atom N which has at least two atoms, of which at least one is a carbon atom, 
         R 1 , R 2  are each, independently of one another, hydrogen or an alkyl, aryl, heteroaryl, alkynyl or alkenyl radical,
 or 
 R 1  and R 2  together form a bridge having a total of from three to five atoms, of which one or two atoms can be heteroatoms, and the remaining atoms are carbon atoms, so that the group 
 
       
       
         
           
           
               
               
           
         
         
           forms a five- to seven-membered ring which may optionally have, in addition to the existing double bond, one further double bond or in the case of a six- or seven-membered ring two further double bonds and may optionally be substituted by alkyl or aryl groups and/or groups having a donor or acceptor action and may optionally comprise at least one heteroatom; 
         
         with Y 1  and R 1  also being able to be joined to one another via a bridge which can have the following meanings: 
         alkylene, arylene, heteroarylene, alkynylene, alkenylene, NR 18 , PR 19 , BR 20 , O, S, SO, SO 2 , SiR 30 R 31 , CO, CO—O, O—CO and (CR 21 R 22 ) x , where one or more nonadjacent (CR 21 R 22 ) groups may be replaced by NR 18 , PR 19 , BR 20 , O, S, SO, SO 2 , SiR 30 R 31 , CO, CO—O, O—CO, where 
         x is from 2 to 10; 
         and 
         R 18 , R 19 , R 20 , R 21 , R 22 , R 30 , R 31  are each H, alkyl, aryl, heteroaryl, alkenyl, alkynyl; 
         R 3  is hydrogen or an alkyl, aryl, heteroaryl, alkynyl or alkenyl radical; 
         which comprises reaction of a ligand precursor of the general formula (III) 
       
       
         
           
           
               
               
           
         
         where 
         Q −  is a monoanionic counterion, 
         and 
         G is H when Do 2 =C and
 is H or a free electron pair when Do 2 =N, S, O or P; 
 
         and 
         the further symbols in the ligand precursor of the formula III have the meanings given in respect of the ligand of the formula II, 
         wherein 
         the reaction comprises the use of a base and an auxiliary reagent selected from among salts of Ag, Hg, Sb, Mg, B and Al (route A) or the use of a basic auxiliary reagent comprising at least one metal selected from the group consisting of Ag, Hg, Sb, Mg, B and Al (route B) and the ligand precursor of the general formula III is 
         (A) reacted with the base, a metal complex comprising at least one metal M 1  and the auxiliary reagent (route A), 
         or 
         (B) reacted with the basic auxiliary reagent to give a protected carbene and the protected carbene is subsequently reacted with a metal complex comprising at least one metal M1 (route B); 
         to give a cyclometallated carbene complex of the formula I. 
       
     
     
         2 - 11 . (canceled) 
     
     
         12 . The process according to  claim 1 , wherein the group 
       
         
           
           
               
               
           
         
       
       is the structure 
       
         
           
           
               
               
           
         
         where the symbols have the following meanings: 
         Z is CH or N, where from 0 to 3 of the symbols Z can be N; 
         R 12  is an alkyl, aryl, heteroaryl, alkynyl, alkenyl radical, or 2 radicals R 12  together form a fused-on ring which may optionally comprise at least one heteroatom, or R 12  is a radical having a donor or acceptor action; 
         with the group of the structure 
       
       
         
           
           
               
               
           
         
         also being able to be linked via the aromatic basic skeleton or via one of the radicals R 12  to Y 1  via a bridge which can have the following meanings: 
         alkylene, arylene, heteroarylene, alkynylene, alkenylene, NR 18 , PR 19 , BR 20 , O, S, SO, SO 2 , SiR 30 R 31 , CO, CO—O, O—CO and (CR 21 R 22 ) x , where one or more nonadjacent (CR 21 R 22 ) groups may be replaced by NR 18 , PR 19 , BR 20 , O, S, SO, SO 2 , SiR 30 R 31 , CO, CO—O, O—CO, where 
         x is from 2 to 10; 
         and 
         R 18 , R 19 , R 20 , R 21 , R 22 , R 30 , R 31  are each H, alkyl, aryl, heteroaryl, alkenyl, alkynyl; 
         t is from 0 to 4, where, when t is >1, the radicals R 12  can be identical or different. 
       
     
     
         13 . The process according to  claim 1 , wherein
 (A) the ratio of metal complex comprising at least one metal M 1 , ligand precursor of the formula III, base and auxiliary reagent is 1:1-10:0.5-15 per metal atom M 1  and number of carbene ligands n (route A);   
       or
 (B) the ratio of metal complex comprising at least one metal M 1 , ligand precursor of the formula III and basic auxiliary reagent is 1:1-10:0.05-5 per metal atom M 1  and number of carbene ligands n (route B). 
 
     
     
         14 . The process according to  claim 1 , wherein the process is carried out in a solvent. 
     
     
         15 . The process according to  claim 1 , wherein the process is carried out at a temperature of 60 to 200° C. 
     
     
         16 . The process according to  claim 1 , wherein Ir is used as metal M 1 . 
     
     
         17 . The process according to  claim 1 , wherein the auxiliary reagent used in route A and the basic auxiliary reagent in route B comprises Ag. 
     
     
         18 . The process according to  claim 1 , wherein route A is used and KHMDS, NaHMDS, LiHMDS, KO t Bu, NaO t Bu, LiO t Bu, NaH, KOAc, NaOAc, LiOAc, NEt 3 , BuLi, RMgHal, where R is alkyl, aryl, alkenyl, KOH, NaOH, LiOH, Cs 2 CO 3 , K 2 CO 3 , Na 2 CO 3 , Li 2 CO 3 , pyridine and/or DBU is used as base in route A. 
     
     
         19 . The process according to  claim 1 , wherein route A is used and AgBF 4 , AgNO 3 , AgSbF 6 , AgPF 6 , AgAsF 6 , AgSCN, AgOCN, Ag 2 SO 4 , AgClO 4 , Ag(COOCF 3 ), and Ag(OTf) is used as auxiliary reagent in route A. 
     
     
         20 . The process according to  claim 1 , wherein route B is used and Ag 2 O, Ag 2 Co 3 , AgOAc and/or Ag 2 S is used as basic auxiliary reagent in route B. 
     
     
         21 . A method for preparing a cyclometallated carbene complex, wherein said method comprises the use of an auxiliary reagent selected from salts comprising at least one metal selected from the group consisting of Ag, Hg, Sb, Mg, B and Al together with a base.