Synthesis, crystal structures, and properties of isomers of 3,5-dinitro-(4-methoxyphenyl)aminobenzoy (p-bromophenyl)amide

The syntheses of the pam and ortho isomers of 3,5-dinitro-(4-methoxyphenyl) aminobenzoyl (p-bromophenyl)amide (I and II, respectively) are carried out. The structures and physicochemical properties of these isomers are investi gated. It is found that isomer I exhibits a higher melting temperature (T-m ) and a lower solubility than those for isomer II. The electro nic absorpti on spectra indicate a higher degree of conjugation (resulting in the format ion of quinoid-like structures) for molecule I as compared to molecule II, The physicochemical properties of compounds I and II correlate with their c rystal structures. Crystals of compound I are triclinic; a = 9.851(1), b = 9.884(1), and c = 11.183(2) Angstrom; alpha = 90.45(1)degrees, beta = 115.3 0(1)degrees, and gamma = 90.68(1)degrees; V = 948.2 Angstrom(3): sp. gr. P (1) over bar; and Z = 2. Crystals of compound II are orthorhombic; a = 4.88 4(1), b = 14.561(3), and c = 27.601(6) Angstrom; alpha = beta = gamma = 90 degrees; V = 1962.9(7) Angstrom(3); sp. gr P2(1)2(1)2(1); and Z = 4, In add ition to the usual van der Waals interactions, structure I is characterized by one intramolecular and two weak intermolecular hydrogen bonds that give rise to the centrosymmetric dimer formed by two elongated molecules of com pound I. In structure II, the only intramolecular hydrogen bond is revealed .