isomerized

Isomerized is the past participle of the verb isomerize, meaning that a molecule has undergone isomerization—a rearrangement that produces one or more isomers. Isomers share the same molecular formula but differ in atomic connectivity (structural or constitutional isomers) or in the spatial arrangement of atoms (stereoisomers). When a molecule is described as isomerized, it exists as a different isomer from its original form.

Isomerization can yield structural isomers or stereochemical isomers. Structural isomerization changes how atoms are connected, producing compounds with different connectivity. Stereochemical isomerization preserves connectivity but changes spatial arrangement, such as cis-trans (geometric) isomerization, enantiomerization, or diastereomerization. Tautomerization is often discussed separately, though it is a related form of isomerization involving proton and electron shifts.

Isomerization can occur by thermal, photochemical, or catalytic means. Thermal isomerization uses heat to overcome energy barriers; photochemical isomerization uses light to promote electronic transitions; catalysts—acids, bases, or metal complexes—facilitate rearrangements at milder conditions. In biology, enzymes called isomerases catalyze specific steps, such as trans-retinal to all-trans forms during vision or cis-trans isomerizations of signaling molecules.

Applications include refining and chemical synthesis, where isomerization alters reactivity or physical properties like boiling points; pharmaceuticals, where different isomers can have distinct biological activity; and materials science, where stereochemistry influences material properties. Isomerized forms may be stabilized or interconverted as part of controlling function, reactivity, and behavior.