CORE Metadata, citation and similar papers at core.ac.uk Provided by Research Commons@Waikato 1 Correspondence to: Professor B K Nicholson Chemistry Department University of Waikato Private Bag 3105 Hamilton New Zealand Email:
[email protected] Fax: 64 7 838 4219 Substituted phenylarsonic acids; structures and spectroscopy. Nicholas C Lloyd, Hugh W. Morgan, Brian K Nicholson* and Ron S. Ronimus School of Science and Engineering, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand. _____________________________________________________________________ Synopsis Spectroscopic data for fifteen substituted phenylarsonic acids are reported, together with the X-ray structures of five examples which form extensive H-bonded networks in the crystals. Pictogram N O O O H H H N H N+ O H O H - O As O H H O As O H H O As N _____________________________________________________________________ 2 Abstract. Full NMR and ESI-MS spectra, and differential scanning calorimeter data are presented for fifteen substituted phenylarsonic acids, including two new fluoro- substituted examples. X-ray crystal structure determinations of five examples (phenylarsonic acid and the 4-fluoro-, 4-fluoro-3-nitro-, 3-amino-4-hydroxy- and 3- amino-4-methoxy- substituted derivatives) were determined and the H-bonding crystal-packing patterns analysed. 1. Introduction. As part of a project to re-investigate the composition and biological activity of the historically-important arsenical remedy for syphilis, Salvarsan, we required a series of substituted arylarsonic acids, RAsO3H2 [1]. There is revived interest in organo-arsenic compounds with the recognition that they are still of pharmaceutical use [2] despite their obvious toxicity, and with a developing understanding of the biological pathways for activity [3].