1,2 chemiluminescent dioxetanes of improved performance

A compound of the formula ##STR8## wherein T is spiroadamantyl, unsubstituted or substituted at one or both bridgehead carbons, said substituents being independently selected from the group consisting of a hydroxyl group, F, Cl, an unsubstituted straight or branched chain alkyl group of 1-6 carbon atoms, an alkyl group of 1-6 carbon atoms mono- di- or tri-substituted with a hydroxy or 1-3 halogen atoms, a phenyl group, a cyano group and an amide group;

• Wherein X is phenyl or naphthyl, bearing 1-3 electron active substituents, each said electron active substituent being independently selected from the group consisting of Cl, F, alkoxy, aryloxy, trialkylammonium, alkylamido, arylamido, arylcarbamoyl, alkylcarbamoyl, cyano, nitro, ester, alkyl-or arylsulfonamido, trifluoromethyl, aryl, alkyl, trialkyl-triaryl-or alkylarylsilyl, alkyl- or arylamidosulfonyl, alkyl- or arylsulfonyl and alkyl- or arylthioether, wherein, in each case, each alkyl or aryl moiety is comprised of 1-12 carbon atoms;
• Wherein Z is an enzyme cleavable moiety, H or E.sub.3 Si, wherein each E is independently H, alkyl, aryl or aralkyl of 1-12 carbon atoms, and
• Wherein R is alkyl, aryl, aralkyl or cycloalkyl, of 1-20 carbon atoms, which may contain 1-2 heteroatoms selected from the group consisting of P, N, S and O, wherein R bears at least one halogen substitutent.