Synthesis of trans-1,2-Difluoroethenediylbis(phosphonic acid) and Other Unsaturated Phosphonic Acids

Abstract

The phosphonic acids (HO)2P(O)CF=CFP(O)(OH)2, CF2=CFCH2CH2P(O)(OH)2, and (HO)2P(O)C=CP-(O)(OH)2(CF2)nCF2 (n = 1,3) have been synthesized for the first time, trans-1,2-Difluoroethenediylbis(phosphonic acid) was prepared from (C2H5O)2P(O)CFBrCFBrP(O)(OC2H5)2, which had been obtained via coupling of the corresponding sulfinate salt, (C2H5O)2P(O)CFBrSO2Na, by adding 30% aqueous hydrogen peroxide to a solution of (C2H5O)2P(O)CFBrSO2Na and iron(II) sulfate. The X-ray crystal structure of the salt [Zn(H2O)6]2+[O(HO)P(O)CF==CFP(O)(OH)O]2- indicates a network of [Zn(H2O)6]2+ dications and the acid dianions linked together with water molecules via hydrogen bonding. The phosphorus, fluorine, and carbon atoms are coplanar. © 1990, American Chemical Society. All rights reserved.