In 2-hydroxy aldimine Schiff bases, two types of hydrogen bonds [either N-H···O (keto-amine tautomer) or N···H-O (phenol-imine tautomer)] can exist. It is claimed that the hydrogen-bond type depends neither on the stereochemistry of the molecule nor on the sort of substituent bonded to the N imino atom, but on the kind of aldehyde used. 1 In the solid state, it is also claimed that only an intramolecular N-H···O type hydrogen bond is present in naphthaldimines regardless of the kind of

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... uents, aryl or alkyl. 2 However, our crystallographic studies have shown an intramolecular (N···H-O (phenol-imine tautomer) hydrogen bond, which is in contrast to observations reported in the literature. 2,3 The title ligand was prepared from a mixture of 2hydroxy-1-naphthaldehyde (0.60 g, 3.5 mmol) and 4-