Crystal structures of two new divalent transition-metal salts of carb-oxy-benzene-sulfonate anions.

Hexa-aqua-nickel(II) bis-(3-carb-oxy-4-hy-droxy-benzene-sulfonate) dihydrate, [Ni(H2O)6][C6H3(CO2H)(OH)SO3]2·2H2O, (I), crystallizes in the triclinic space group P with the nickel(II) aqua complexes on centers of inversion. The carboxyl-ate group is protonated and neither it nor the sulfonate group is involved in direct coordination to the metal ions. The structure consists of alternating layers of inorganic cations and organic anions linked by O-H⋯O hydrogen bonds that also include non-coordinated water mol-ecules of crystallization. The first-row divalent transition-metal salts of this anion are reported as both dihydrates and tetra-hydrates, with two distinct structures for the dihydrates that are both layered but differ in the hydrogen-bonding pattern. Compound (I) represents the second known example of one of these structures. Hexa-aqua-cobalt(II) bis-(3-carb-oxy-benzene-sulfonate) dihydrate, [Co(H2O)6][C6H4(CO2H)SO3]2·2H2O, (II), also crystallizes in triclinic P with the cobalt(II) aqua complexes on centers of inversion. The structure is also built of alternating layers of complex cations and organic anions without direct coordination to the metal by the protonated carboxyl-ate or unprotonated sulfonate groups. A robust O-H⋯O hydrogen-bonding network involving primarily the coordin-ated and non-coordinated water mol-ecules and sulfonate groups directs the packing. This is the first reported example of a divalent transition-metal salt of the 3-carb-oxy-benzene-sulfonate anion.

The low-temperature triclinic crystal structure of silver 3-sulfo-benzoic acid.

Poly[(µ4-3-carboxybenzenesulfonato)silver(I)], Ag(O3SC6H4CO2H) or [Ag(C7H5O5S)] n , has been found to undergo a reversible phase transition from monoclinic to triclinic between 160 and 150 K. The low-temperature triclinic structure (space group P ) has been determined at 100 K. In contrast to the reported room temperature monoclinic structure, in which the nearly equivalent carboxyl-ate C-O distances indicate that the acidic hydrogen is randomly distributed between the O atoms, at 100 K the C-O (protonated) and C=O (unprotonated) bonds are clearly resolved, resulting in the reduction in symmetry from C2/c to P .

From Glucose to Polymers: A Continuous Chemoenzymatic Process.

Efforts to synthesize degradable polymers from renewable resources are deterred by technical and economic challenges; especially, the conversion of natural building blocks into polymerizable monomers is inefficient, requiring multistep synthesis and chromatographic purification. Herein we report a chemoenzymatic process to address these challenges. An enzymatic reaction system was designed that allows for regioselective functional group transformation, efficiently converting glucose into a polymerizable monomer in quantitative yield, thus removing the need for chromatographic purification. With this key success, we further designed a continuous, three-step process, which enabled the synthesis of a sugar polymer, sugar poly(orthoester), directly from glucose in high yield (73 % from glucose). This work may provide a proof-of-concept in developing technically and economically viable approaches to address the many issues associated with current petroleum-based polymers.