Ph3C

Ph3C denotes the triphenylmethyl group, a bulky aryl-substituted tertiary carbon fragment widely used in organic synthesis. The moiety consists of a central carbon bound to three phenyl rings. Depending on the reaction context, the central carbon can carry a positive charge (trityl cation, Ph3C+), a radical (Ph3C•), or a negative charge (trityl anion, Ph3C−). The three phenyl rings delocalize charge and spin, giving unusual stability to all three species relative to simple carbenium/carb anions or radicals.

In practice, the neutral triphenylmethyl group is most familiar as a leaving or protecting group. Trityl groups, installed as protection for alcohols (trityl ethers) or carboxyl groups (trityl esters), are popular because they are bulky and acid-labile. The trityl cation, Ph3C+, is a strong electrophile used in certain alkylation and addition reactions, while the trityl radical Ph3C• is a persistent radical employed in polymerization and radical chemistry. The trityl anion Ph3C− is a strong nucleophile/base that can initiate deprotonation or act as a nucleophile under appropriate conditions.

Historically, the triphenylmethyl motif was developed in mid-20th-century organic chemistry and remains a staple in protecting-group strategies and in studies of stabilized carbanions, radicals, and cations. The term Ph3C is often encountered in the literature shorthand for this moiety, sometimes explicitly as Ph3CCl or derivatives used to introduce the trityl group.

See also: trityl group, triphenylmethane, trityl chloride, trityl protecting groups.