, and T. N. Durlu

(1)

Crystal Structure and Tautomerism of

1-[N-(4-Iodophenyl)]aminomethylidene-2(1H)naphthalenone H. ¨ Unver

^a

, M. Kabak

^b

, D. M. Zengin

^a

, and T. N. Durlu

^a^;^c

aAnkara University, Faculty of Sciences, Department of Physics, 06100 Tando˜gan, Ankara, Turkey

bAnkara University, Faculty of Sciences, Department of Engineering Physics, 06100 Tando˜gan, Ankara, Turkey

cUniversity of Kırıkkale, Faculty of Art and Science, Department of Physics, Yahs¸ihan Campus, 71450 Kırıkkale, Turkey

Reprint requests to Dr. H. ¨Unver. E-mail: unver@science.ankara.edu.tr Z. Naturforsch.56 b,1003–1008 (2001); received March 28, 2001 Photochromism, Thermochromism, Keto-Enol Tautomerism

1-[N-(4-Iodophenyl)]aminomethylidene-2(1H)naphthalenone (1) (C17H12NOI) has been studied by X-ray analysis, IR,¹H NMR, UV and AM1 semi-empirical quantum mechanical methods. It crystallises in the monoclinic space group P21/n with a = 4.844(3), b = 21.428(2), c = 13.726(2) ˚A,= 93.07(2)(R1 = 0.032 for 4132 reflections [I > 2(I)]). The title compound is not planar and an intramolecular hydrogen bond connects O1 and N1 [2.530(4) ˚A]. Com- plementary IR,¹H NMR and UV measurements in the solution and solid states were carried out. Tautomerism and conformations of the title compound were also investigated by AM1 semi-empirical quantum mechanical calculations and the results are compared with the X-ray data.