Catalysts based on Amino-Sulfide Ligands for Hydrogenation and Dehydrogenation Processes

Abstract

The present application discloses novel amino-sulfide metal catalysts for organic chemical syntheses including hydrogenation (reduction) of unsaturated compounds or dehydrogenation of substrates. The range of hydrogenation substrate compounds includes esters, lactones, oils and fats, resulting in alcohols, diols, and triols as reaction products. The catalysts of current application can be used to catalyze a hydrogenation reaction under solvent free conditions. The present catalysts also allow the hydrogenation to proceed without added base, and it can be used in place of the conventional reduction methods employing hydrides of the main-group elements. Furthermore, the catalysts of the present application can catalyze a dehydrogenation reaction under homogenous and/or acceptorless conditions. As such, the catalysts provided herein can be useful in substantially reducing cost and improving the environmental profile of manufacturing processes for a variety of chemicals.

What is claimed is: 
     
         1 . A metal complex of Formula II and III
   M(SN) p Z a   II
     M(SNS)Z a   III
   
       wherein:
 each Z is simultaneously or independently a hydrogen or halogen atom, a C 1 -C 6  alkyl, a carbene group, a hydroxyl group, or a C 1 -C 7  alkoxy radical, a nitrosyl (NO) group, CO, CNR (R═Alkyl, Aryl), nitrile, phosphite, phosphinite, or phosphine such as PMe 3  or PPh 3 ; 
 M is a transition metal; preferably from group 6, in which Ru and Os are particularly more preferable; 
 p is equal to 1 or 2, whereas a is equal to 1, 2, or 3; 
 SN and SNS are coordinated ligands of any one of Formulae IA,B: 
 
       
         
           
           
               
               
           
         
       
       where
 SR 1  is a thioether group, which is coordinated to the metal center of the catalyst or pre-catalyst; 
 the dotted lines simultaneously or independently indicate single or double bonds; 
 R 1 , R 2 , R 5 , and R 6  are each independently H, a substituted or unsubstituted linear or branched C 1 -C 20  alkyl (such as a C 1 -C 8  alkyl), a substituted or unsubstituted cyclic C 3 -C 8  alkyl, or a substituted or unsubstituted alkenyl, a substituted or unsubstituted C 5 -C 20  aryl (such as a C 5 -C 14  or C 5 -C 8  aryl), OR or NR 2 ; or when taken together, R 1  and R 2  groups or R 5  and R 6  groups can form a saturated or partially saturated cycle; 
 R 3  and R 4  are each independently H, a substituted or unsubstituted linear, branched or cyclic C 1 -C 8  alkyl or alkenyl, a substituted or unsubstituted C 5 -C 8  aromatic group, ester group; or, when taken together, R 3  and R 4  can form an optionally substituted saturated or partially saturated hetero-aromatic ring; 
 R 5  when taken together with R 4  can form an optionally substituted saturated or partially saturated aromatic ring; 
 R 7  is H, a substituted or unsubstituted linear or branched C 1 -C 8  alkyl (such as a C 1 -C 8  alkyl), a substituted or unsubstituted cyclic C 3 -C 8  alkyl, a substituted or unsubstituted alkenyl, or a substituted or unsubstituted C 5 -C 20  aryl (such as a C 5 -C 14  or C 5 -C 8  aryl); and 
 n, m, and q are simultaneously or independently 0, 1, or 2. 
 
     
     
         2 . The complex of  claim 1 , wherein M is a group 7 metal, a group 8 metal or a group 9 metal. 
     
     
         3 . The metal complex of  claim 2 , wherein M is Ru or Os. 
     
     
         4 . A process for dehydrogenation of a substrate comprising:
 treating the substrate with a catalytic amount of a metal complex of any one of  claims 1 - 3 .   
     
     
         5 . The process of  claim 4 , wherein the substrate comprises at least one alcohol moiety. 
     
     
         6 . The process of  claim 5 , wherein the substrate is a compound of the following Formula: 
       
         
           
           
               
               
           
         
         where R 9  is a substituted or unsubstituted alkyl or a substituted or unsubstituted aryl. 
       
     
     
         7 . The process of  claim 5 , wherein the substrate comprises more than one hydroxyl moiety that undergoes dehydrogenation. 
     
     
         8 . The process of  claim 6 , wherein R 9  comprises an amino group that undergoes dehydrogenation. 
     
     
         9 . The process of  claim 4 , wherein the substrate and product pair of the dehydrogenation reaction is selected from the group consisting of: 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                   Substrate 
                   Product 
                 
                     
                     
                 
                     
                   alcohols 
                   ester 
                 
                     
                   alcohol 
                   aldehyde 
                 
                     
                   alcohol 
                   ketone 
                 
                     
                   diol 
                   lactone 
                 
                     
                   amine + alcohol 
                   amide 
                 
                     
                   amine + alcohol 
                   substituted amine 
                 
                     
                   amine + alcohol 
                   imine 
                 
                     
                   ammonia-borane 
                   aminoboranes 
                 
                     
                   ammonia-borane 
                   borazine 
                 
                     
                   amine 
                   imine 
                 
                     
                   amines 
                   guanidine 
                 
                     
                   alcohol + thiol 
                   thioester 
                 
                     
                   thiol 
                   sulphoxide 
                 
                     
                   alcohol + phosphine 
                   acyl phosphine 
                 
                     
                     
                 
             
                
                
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
           
         
       
     
     
         10 . A process for producing H 2  comprising dehydrogenation of a substrate by treating the substrate with a catalytic amount of a metal complex of any one of  claims 6 - 9 . 
     
     
         11 . The process of  claim 10 , wherein the substrate comprises an alcohol, amine or thiol. 
     
     
         12 . The process of  claim 10 , wherein the substrate is ammonia-borane. 
     
     
         13 . The process of any one of  claims 6 - 12 , wherein the process does not require a hydrogen acceptor. 
     
     
         14 . The process of any one of  claims 6 - 13 , which is a homogeneous process. 
     
     
         15 . A process for hydrogenation of a substrate comprising:
 treating the substrate under a pressure of hydrogen with a catalytic amount of a metal complex of any one of  claims 1 - 3 .   
     
     
         16 . The process of  claim 15 , wherein the substrate comprises at least one ester group. 
     
     
         17 . The process of  claim 16 , wherein the process proceeds according to the following scheme 
       
         
           
           
               
               
           
         
       
     
     
         18 . The process of  claim 15 , wherein the substrate and product pair of the hydrogenation reaction is selected from the group consisting of: 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                   Hydrogenation Substrate 
                   Product 
                 
                     
                     
                 
                     
                   aldehyde 
                   alcohol 
                 
                     
                   ketone 
                   alcohol 
                 
                     
                   ester 
                   alcohol 
                 
                     
                   carboxylic acid 
                   alcohol 
                 
                     
                   ketene 
                   alcohol 
                 
                     
                   enol 
                   alcohol 
                 
                     
                   epoxide 
                   alcohol 
                 
                     
                   aldimine 
                   amine 
                 
                     
                   ketimine 
                   amine 
                 
                     
                   ketene-imine 
                   amine 
                 
                     
                   nitrile 
                   amine 
                 
                     
                   aziridine 
                   amine 
                 
                     
                   nitro 
                   amine 
                 
                     
                   diazo 
                   amine 
                 
                     
                   isocyanide 
                   amine 
                 
                     
                   enamine 
                   amine 
                 
                     
                   lactone 
                   diol 
                 
                     
                   amide 
                   amine + alcohol 
                 
                     
                   aminoboranes 
                   amine-borane 
                 
                     
                   borazine 
                   amine-borane 
                 
                     
                   olefln 
                   alkane 
                 
                     
                   acetylene 
                   alkane 
                 
                     
                   allene 
                   alkane 
                 
                     
                     
                 
             
                
                
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
           
         
       
     
     
         19 . The process of any one of  claims 15 - 18 , which is a solvent-free process.