Alkyl chain regulation: distinctive odd–even effects of mechano-luminescence and room-temperature phosphorescence in alkyl substituted carbazole amide derivatives

A series of carbazole amide derivatives with different lengths from methyl to octyl (CAC- N , N = 1–8). Compounds with even-numbered alkyl chains exhibit mechanoluminescence (ML) property, however, no ML is observed in the odd-numbered counterparts.