Using ring strain to inhibit a decomposition path: first synthesis of an Alkyl-BIAN ligand (Alkyl-BIAN = bis(alkyl) acenaphthenequinonediimine)

N-Alkyl imines of acenaphthenequinone are not stable because an isomerization occurs that releases part of the ring strain of the initially formed imine by changing the hybridization of one of the ring carbon atoms from sp2 to sp3; however, if an even more strained ring is present in the alkyl group, the isomerization becomes unfavorable and the compound is stable.