Crystal and molecular structure of 2-(2′-methylaminophenyl)-4H-3,1-benzoxazine-4-one

Abstract

A planar structure for molecules of 2-(2′-methylaminophenyl)-4H-3,1-benzoxazine-4-one was found by x-ray structural analysis. Shortening of the N-Ph bond and lengthening of the distance between amino- and azine-N atoms in comparison to the tosyl analog was demonstrated to lead to a bathochromic shift of the absorption spectrum and a hypsochromic displacement of the luminescence spectrum. As a result, the Stokes shift of 2-(2′-methylaminophenyl)-4H-3,1-benzoxazine-4-one is smaller than that of 2-(2′-tosylaminophenyl)-4H-3,1-benzoxazine-4-one. In the crystal, molecules of 2-(2′-methylaminophenyl)-4H-3,1-benzoxazine-4-one are stacked with intermolecular interaction energy between molecules in the stack of −12.5 and −14.2 kcal/mole. The stacks are joined into layers parallel to (010).