Superficially porous materials comprising a coated core having narrow particle size distribution; process for the preparation thereof; and use thereof for chromatographic separations

Abstract

The present invention provides novel chromatographic materials, e.g., for chromatographic separations, processes for its preparation and separations devices containing the chromatographic material; separations devices, chromatographic columns and kits comprising the same; and methods for the preparation thereof. The chromatographic materials of the invention are chromatographic materials comprising having a narrow particle size distribution.

1 . A superficially porous material comprising:
 a substantially nonporous core material comprising a silica core;   a substantially nonporous core coating material disposed on the surface of the substantially nonporous core, wherein the substantially nonporous core coating material comprises a metal oxide; and   one or more layers of a porous shell material disposed on the substantially nonporous core coating material.   
     
     
         2 . The superficially porous material of  claim 1 , comprising more than one layer of the porous shell material wherein each layer is independently selected from an inorganic/organic hybrid material, silica, or mixtures thereof. 
     
     
         3 . The superficially porous material of  claim 2 , wherein the inorganic/organic hybrid material has the formula:
   (SiO 2 ) d /[R 2 ((R) p (R 1 ) q SiO t ) m ]  (I)
   
       wherein,
 R and R 1  are each independently C 1 -C 18  alkoxy, C 1 -C 18  alkyl, C 2 -C 18  alkenyl, C 2 -C 18  alkynyl, C 3 -C 18  cycloalkyl, C 1 -C 18  heterocycloalkyl, C 5 -C 18  aryl, C 5 -C 18  aryloxy, or C 1 -C 18  heteroaryl; 
 R 2  is C 1 -C 18  alkyl, C 2 -C 18  alkenyl, C 2 -C 18  alkynyl, C 3 -C 18  cycloalkyl, C 1 -C 18  heterocycloalkyl, C 5 -C 18  aryl, C 1 -C 18  heteroaryl; or absent; wherein each R 2  is attached to two or more silicon atoms; 
 p and q are each independently 0.0 to 3.0, 
 t is 0.5, 1.0, or 1.5; 
 d is 0 to about 30; 
 m is an integer from 1-20; wherein R, R 1  and R 2  are optionally substituted; provided that: (1) when R 2  is absent, m=1 and 
 
       
         
           
             
               
                 t 
                 = 
                 
                   
                     ( 
                     
                       4 
                       - 
                       
                         ( 
                         
                           p 
                           + 
                           q 
                         
                         ) 
                       
                     
                     ) 
                   
                   2 
                 
               
               , 
             
           
         
       
       when 0<p+q<3; and
 (2) when R 2  is present, m=2-20 and t=(3-(p+q)), when p+q<2. 
 
     
     
         4 . The superficially porous material of  claim 1 , wherein the inorganic/organic hybrid core-coating material has the formula:
   (SiO 2 ) d /[(R) p (R 1 ) q SiO t ]  (II)
   
       wherein,
 R and R 1  are each independently C 1 -C 18  alkoxy, C 1 -C 18  alkyl, C 1 -C 18  alkyl, C 2 -C 18  alkenyl, C 2 -C 18  alkynyl, C 3 -C 18  cycloalkyl, C 1 -C 18  heterocycloalkyl, C 5 -C 18  aryl, C 5 -C 18  aryloxy, or C 1 -C 18  heteroaryl; 
 d is 0 to about 30; 
 p and q are each independently 0.0 to 3.0, provided that when p+q=1 then t=1.5; when p+q=2 then t=1; or when p+q=3 then t=0.5. 
 
     
     
         5 . The superficially porous material of  claim 1 , wherein the inorganic/organic hybrid core-coating material has the formula:
   (SiO 2 ) d /[(R 2 ((R 1 ) r SiO t ) m ]  (III)
   
       wherein,
 R 1  is C 1 -C 18  alkoxy, C 1 -C 18  alkyl, C 1 -C 18  alkyl, C 2 -C 18  alkenyl, C 2 -C 18  alkynyl, C 3 -C 18  cycloalkyl, C 1 -C 18  heterocycloalkyl, C 5 -C 18  aryl, C 5 -C 18  aryloxy, or C 1 -C 18  heteroaryl; 
 R 2  is C 1 -C 18  alkyl, C 2 -C 18  alkenyl, C 2 -C 18  alkynyl, C 3 -C 18  cycloalkyl, C 1 -C 18  heterocycloalkyl, C 5 -C 18  aryl, C 1 -C 18  heteroaryl; or absent; wherein each R 2  is attached to two or more silicon atoms; 
 d is 0 to about 30; 
 r is 0, 1 or 2, provided that when r=0 then t=1.5; when r=1 then t=1; or when r=2, then t=0.5; and 
 m is an integer from 1-20. 
 
     
     
         6 . The superficially porous material of  claim 1 , having improved chemical stability to high pH mobile phases as compared to an unbonded, superficially porous silica particle of the same size. 
     
     
         7 . The superficially porous material of  claim 1 , which has further been surface modified by:
 coating with a polymer;   by coating with a polymer by a combination of organic group and silanol group modification;   a combination of organic group modification and coating with a polymer;   a combination of silanol group modification and coating with a polymer;   formation of an organic covalent bond between the material's organic group and a modifying reagent; or   a combination of organic group modification, silanol group modification and coating with a polymer.   
     
     
         8 . The superficially porous material of  claim 1 , wherein the substantially nonporous core coating material is derived from condensation of one or more polymeric organofunctional metal precursors and/or polymeric metal oxide precursors on a surface of the silica core, or
 application of partially condensed polymeric organofunctional metal precursors, a mixture of two or more polymeric organofunctional metal precursors, or a mixture of one or more polymeric organofunctional metal precursors with a polymeric metal oxide precursor on the surface of the silica core.   
     
     
         9 . The superficially porous material of  claim 1 , comprising more than one layer of porous shell material, wherein each layer of the porous shell material is applied using a polyelectrolyte or a chemically degradable polymer. 
     
     
         10 . The superficially porous material of  claim 1  wherein the initial superficially porous particle contains>90 molar % silica. 
     
     
         11 . The superficially porous material of  claim 1 , wherein the one or more layers of the porous shell material are porous silica. 
     
     
         12 . The superficially porous material of  claim 1 , wherein the one or more layers of the porous shell material are formed in a layer-by-layer process using alternating additions of polyelectrolyte and silica sol. 
     
     
         13 . The superficially porous material of  claim 1 , wherein each of the one or more layers of the porous shell material is independently from 0.05 μm to 5 μm in thickness as measured perpendicular to a surface of the substantially nonporous core material. 
     
     
         14 . The superficially porous material of  claim 1 , wherein each of the one or more layers of the porous shell material is independently from 0.06 μm to 1 μm in thickness as measured perpendicular to a surface of the substantially nonporous core material.