Crystal Structures of 2-Aminotropone, N,N’-Di(tropon-2-yl)piperazine, and 5-(4-Ethoxyphenylazo)tropolone

Crystal structures of 2-aminotropone (1), N,N’-di(tropon-2-yl)piperazine (2), and 5-(4-ethoxyphenylazo)tropolone (3) have been elucidated by X-crystallographic analysis. 2-Aminotropone (1) contains three crystallographically independent molecules in the crystal lattice. The NH2 groups of 2-aminotropone unit of 1 participate in the N-H···O intermolecular hydrogen bonds. Two tropone units of N,N’-di(tropon-2-yl)piperazine (2) have an anti orientation to the piperazine ring. The crystal packing of 2 is consolidated by π···π, C-H···π, and C-H···O interactions. 5-(4-Ethoxyphenylazo)tropolone (3) forms O-H···O hydrogen bond dimmers about inversion centres, involving the OH group and an intermolecular carbonyl O acceptor.