STRUCTURAL CHEMISTRY OF SULFONATED FLUOROBENZYLPHOSPHONATE SALTS .1..

A study of the salts of 4-fluoro-3-sulfobenzylphosphonic acid has resu lted in the synthesis of two new compounds with unusual layered struct ures. The crystal structures of these salts and the parent acid have b een determined by single crystal X-ray methods. Crystal data: 4-F-3-SO 3H-C6H3CH2PO3H2 . H2O: triclinic, space group P (1) over bar, Z=2, a=8 .475(2), b=11.814(2), c=5.519(1) Angstrom, alpha=93.58(1)degrees, beta =90.47(1)degrees, gamma=88.73(1)degrees, V=551.4(2) Angstrom(3), R(F)= 0.037 for 1519 observations (1> 3(sigma(I)) and 182 variables, [Ni(NH3 )(2)(H2O)(4)](3)(4-F-3-SO3-C6H3CH2PO3)(2) . 4H(2)O: triclinic, space g roup P (1) over bar, Z=1, a=12.998(3), 6=13.050(2), c=6.217(4) Angstro m, alpha=92.68(2)degrees, beta=93.52(3)degrees, gamma= 79.40(2)degrees , V=1033.9(7) Angstrom(3), R(F)=0.037 for 2689 observations (1> 3 sigm a(I)(1)) and 511 variables; Na-3(4-F-3-SO3-C6H3CH2PO3). 8.5H(2)O: mono clinic, C2/c, Z=8, a=25.636(4), b=6.218(4), c=24.136(2) Angstrom, beta =98.33(1)degrees, V=3807(3) Angstrom(3), R(F)=0.047 for 2262 observati ons (I> 3 sigma(I)) and 254 variables. The parent acid monohydrate cry stallizes in layers with the acidic groups directed to the faces of th e layer. The water molecules are in between the layers hydrogen-bonded to the sulfonate oxygen atoms. The nickel salt contains three indepen dent cations, each of which is hexacoordinated to a mixture of water a nd ammonia molecules. Thus, there is no direct coordination of the nic kel by either the sulfonate or phosphonate oxygen atoms. The structure has alternating layers, the first formed by the anions and one of the nickel complexes, and the second by the other two complexes and the f ree water molecules. The sodium salt also has the anions arranged in l ayers but with an interpenetrating three-dimensional network of ionic and hydrogen bonds involving the cations and water molecules. The sodi um ions are coordinated to a mixture of sulfonate oxygen atoms and bri dging water molecules in irregular six-fold environments. These struct ures are discussed in terms of the coordination behavior of the difunc tional anions in the context of known monofunctional phosphonate and s ulfonate compounds.