A. V. D. Lee, P. Richez, C. Tapiero
May 31, 2005
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Influential Citations
9
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Journal
Journal of Molecular Structure
Abstract
Abstract The crystal structure of nitarsone, 4-nitrophenylarsonic acid, a substitute for nifursol and dimetridazole in the prevention and treatment of turkey histomoniasis desease, has been determined from synchrotron X-ray powder diffraction data. Nitarsone crystallizes in the monoclinic space group P 2 1 / n with unit cell parameters a =7.46413(5), b =25.68543(17), c =4.657388(32) A, β =105.4670(5)°. The structure was solved using simulated annealing techniques by treating the molecule as a rigid body for which the configuration resulting from an energy minimization was used in slightly adapted form. Structure refinement treated the NO 2 and the AsO(OH) 2 groups as free groups, leading to final confidence factors R p =0.059 and R wp =0.071. The crystal structure contains 4 molecules per unit cell that are hydrogen bonded to form infinite chains of dimers running along the c -axis. Nitarsone's low toxicity when compared with inorganic sources of arsenic is explained by the existence of a partial double C–As bond (1.866(5) A) which confers greater stability so that under physiological conditions nitarsone is not converted to mineral-like As V or III.