Spectroscopic Studies and Crystal Structure of 4-(2-Hydroxy-3-Methoxybenzylideneamino)-N-(5-Methylisoxazol-3-yl) Benzenesulfonamide

Abstract

Schiff base 4-[(2-hydroxy-3-methoxybenzylideneamino)-N-(5-methylisoxazol-3-yl)benzene-sulfonamide has been synthesized from the reaction of 4-amino-N-(5-methylisoxazol-3-yl)benzenesulfonamide(sulfamethoxazole) with 2-hydroxy-3-methoxybenzaldehyde. It has been characterized by elemental analysis, MS, IR, 1H NMR, 13C NMR, HETCOR and UV–Visible techniques. The structure of it also has been examined crystallographically. For the compound exist as dominant form of enol-imines in both the solid state and the solutions. It crystallizes in the monoclinic space group P21/c with a = 8.2694(7), b = 8.3453(5), c = 26.260(2) A, β = 97.142(7) °, V = 1798.1(2) A3, D x = 1.431 g cm−3, R 1 = 0.0529 and wR 2 = 0.1370 [I > 2σ(I)], respectively. The tautomerism in the Schiff base ligands plays an important role for distinguishing their photochromic and thermochromic characteristics. Both phenomena is associated with a proton transfer (enol-imine, O–H···N, keto-amine, O···H–N).