Crystal structure and tautomerism of 1-[N-(4-iodophenyl)]aminomethylidene-2(1H)naphthalenone

1-[N-(4-Iodophenyl)]aminomethylidene-2(1H)naphthalenone (1) (C17H12NOI) has been studied by X-ray analysis, IR, H-1 NMR, UV and AM1 semi-empirical qua ntum mechanical methods. It crystallises in the monoclinic space group P2(1 )/n with a=4.844(3), b=21.428(2), C=13.726(2) Angstrom, beta =93.07(2)degre es (R1=0.032 for 4132 reflections [I>2 sigma (I)]). The title compound is n ot planar and an intramolecular hydrogen bond connects O1 and N1 [2.530(4) Angstrom]. Complementary IR, H-1 NMR and UV measurements in the solution an d solid states were carried out. Tautomerism and conformations of the title compound were also investigated by AM1 semi-empirical quantum mechanical c alculations and the results are compared with the X-ray data.