These functional groups form cross-links in the self-assembly of [2 + 3] (“two plus three”) or [4 + 4] (“four plus four”) molecular organic cages. These functional groups hold together Vitrimax resins, since polymers containing them act as self-healing vitrimers. DHFR reduces this functional group in folic acid. 2D COFs (“two D coffs”) mostly use boronates or this functional group as linkers. Two of these groups bridge the salicylates in a salen ligand. Decarboxylases (-5[1])and aldolases use this functional group to link (*) PLP to a lysine (10[1])residue. (10[2])Beta-lactams are formed by the [2 + 2] (-5[1])cycloaddition of (10[1])ketenes to this functional (10[1])group. Sodium cyanoborohydride reduces this functional group, which forms after dehydration when ammonia attacks a carbonyl. For 10 points, name this functional group in which carbon (10[1])is double-bonded to (10[1]0[4])nitrogen. ■END■