The Preparation and Crystal Structures of the 1 : 1 Adducts of 5-Nitrosalicylic Acid and 2-Chloro-3,5- dinitrobenzoic Acid with Triphenylphosphine Oxide

Abstract

The (1 : 1) adducts of 5-nitrosalicylic acid (5-nsa) and 2-chloro-3,5-dinitrobenzoic acid (cdnba) with triphenylphosphine oxide (tppo), [(5-nsa)(tppo)] (1) and [(cdnba)(tppo)] (2), have been prepared and their structures determined by X-ray diffraction and reffned to residuals R 0·045 (1) and 0·043 (2) for 2540 and 3265 observed reflections respectively. Crystals of both adducts are monoclinic, space group P2₁/c (1) and P2₁/a (2), with 4 dimer units in cells of dimensions a 16·217(1), b 7·6807(8), c 19·697(4) Å, β 113·357(8)° [for (1)] and a 16·009(5), b 8·687(1), c 17·640(5) Å, β 90·30(1)^o [for (2)]. In both examples, the two molecules comprising the asymmetric unit are linked by a single hydrogen bond between the proton of the carboxylic acid and the phosphoryl oxygen of tppo [O- - -O, 2·524(3) Å (1); 2·72(3) Å (2)], while, in each case, the additional functional groups of the acid are not involved in any other intermolecular hydrogen-bonding interactions.