title: Crystal structure of ammonium isosaccharate and aqueous solubility of ammonium and sodium isosaccharates.
abstract: Ammonium isosaccharate, C6H15NO6.H2O (NH4-ISA), has been synthesized and its crystal structure solved by single-crystal X-ray diffraction methods. NH4-ISA crystallizes in the monoclinic space group P2(1) (#4) with cell parameters a=8.6470(12)A, b=5.0207(7)A, c=9.8193(14)A, beta=91.643(3) degrees , V=426.12(10)A3, Z=2. The structure was refined by full-matrix least-squares on F2 yielding final R-values (all data) R1=0.0485 and Rw2=0.1104. The structure consists of alternating (NH4)+ and (C6H11O6)- layers parallel to the ab plane. An extended network of O-H...O intermolecular (ISA)...(ISA) hydrogen bonds links the (ISA)- anions within the ab plane, while the 3-D connectivity along the c-axis is provided only by (ISA-)...(NH4+)...(ISA-) hydrogen bonds. The aqueous solubility (Si, [ML(-1)]) of NH4- and Na-ISA has been shown to be pH independent at ambient conditions within the range 4.5<pH<10 with S(NH4-ISA)=4.035 and S(Na-ISA)=1.731, respectively, which values are about two orders of magnitude higher than that of the Ca-ISA analogue.
authors.affiliation: Sandia National Laboratories, PO Box 5800, MS 0779, Albuquerque, NM 87185-0779, USA.
authors.forename: Ranko P
authors.initials: RP
authors.lastname: Bontchev
authors.forename: Robert C
authors.initials: RC
authors.lastname: Moore
mesh_terms: D003460:Crystallization; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D015394:Molecular Structure; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012995:Solubility; D013400:Sugar Acids / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D000644:Quaternary Ammonium Compounds; D013400:Sugar Acids; C492894:isosaccharinic acid; D014867:Water