THE PREPARATION AND CRYSTAL-STRUCTURES OF THE 1 1 ADDUCTS OF 5-NITROSALICYLIC ACID AND 2-CHLORO-3,5-DINITROBENZOIC ACID WITH TRIPHENYLPHOSPHINE OXIDE/

The (1:1) adducts of 5-nitrosalicylic acid (cdnba) with triphenylphosp hine oxide (tppo), [(5-nsa)(tppo)] (1) and [(cdnba)(tppo)] (2), have b een prepared and their structures determined by X-ray diffraction and refined to residuals R 0.045 (1) and 0.043 (2) for 2540 and 3265 obser ved reflections respectively. Crystals of both adducts are monoclinic, space group P2(1)/c (1) and P2(1)/a (2), with 4 dimer units in cells of dimensions a 16.217(1), b 7.6807(8), c 19.697(4) Angstrom, beta 113 .357(8)degrees [for (1)] and a 16.009(5), b 8.687(1), c 17.640(5) Angs trom, beta 90.30(1)degrees [for (2)]. In both examples, the two molecu les comprising the asymmetric unit are linked by a single hydrogen bon d between the proton of the carboxylic acid and the phosphoryl oxygen of tppo [O---O, 2.524(3) Angstrom (1); 2.572(3) Angstrom (2)], while, in each case, the additional functional groups of the acid are not inv olved in any other intermolecular hydrogen-bonding interactions.