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

A superficially porous material comprising superficially porous particles, wherein the superficially porous particles comprise an inorganic/organic hybrid core and one or more layers of a porous shell material surrounding the inorganic/organic hybrid core wherein the inorganic/organic hybrid core has a pore volume of less than 0.10 cc/g;

• and
• wherein the inorganic/organic hybrid core has the formula:
• (SiO2)d/[R2((R)p(R1)qSiOt)m] (I)
• wherein,
• R and R1 are each independently C1-C18 alkoxy, C1-C18 alkyl, C2-C18 alkenyl, C2-C18 alkynyl, C3-C18 cycloalkyl, C1-C18 heterocycloalkyl, C5-C18 aryl, C5-C18 aryloxy, or C1-C18 heteroaryl;
• R2 is C1-C18 alkyl, C2-C18 alkenyl, C2-C18 alkynyl, C3-C18 cycloalkyl, C1-C18 heterocycloalkyl, C5-C18 aryl, C1-C18 heteroaryl, wherein R2 is attached to two or more silicon atoms;
• R, R1 and R2 are optionally substituted;
• p and q are each independently 0.0 to 2.0,
• t is 0.5, 1.0, or 1.5;
• d is 0 to about 30;
• and
• m=2-20,
• t
• =
• (
• 3
• -
• (
• p
• +
• q
• )
• )
• 2
• ,
• and p+q≤2.