Pirkle-type Chiral Stationary Phases

The Pirkle-Concept Chiral Stationary Phases generally fall into three classes: π-electron acceptor/π-electron donors, the π-electron acceptors and the π-electron donors. With Pirkle Phases, chiral recognition occurs at binding sites. Major binding sites are classified as π-basic or π-acidic aromatic rings, acidic sites, basic sites, and steric interaction sites. Aromatic rings are potential sites for π-π interactions. Acidic sites supply hydrogens for potential intermolecular hydrogen bonds-the hydrogen is often an amido proton (N-H) from an amide, carbamate, urea, or amine. Basic sites, such as π-electrons, sulfinyl or phosphinyl oxygens, and hydroxy or ether oxygens, may also be involved in hydrogen bond formation. Steric interactions may also occur between large groups.

The latest and most revolutionary addition to the Pirkle-Concept series is the π-electron acceptor/π-electron donor phase. This concept is an innovative incorporation of both π-acceptor and π-donor characteristics, resulting in a phase that can be used for a wide variety of compound groups.