Ascorbic acid intake and oxalate synthesis.

In humans, approximately 60 mg of ascorbic acid (AA) breaks down in the body each day and has to be replaced by a dietary intake of 70 mg in women and 90 mg in men to maintain optimal health and AA homeostasis. The breakdown of AA is non-enzymatic and results in oxalate formation. The exact amount of oxalate formed has been difficult to ascertain primarily due to the limited availability of healthy human tissue for such research and the difficulty in measuring AA and its breakdown products.

Platinum(II) diimine complexes with halide/pseudohalide ligands and dangling trialkylamine or ammonium groups.

A series of platinum(II) complexes with the formulas Pt(diimine)(pip(2)NCNH(2))(L)(2+) [pip(2)NCNH(2)(+) = 2,6-bis(piperidiniummethyl)phenyl cation; L = Cl, Br, I, NCS, OCN, and NO(2); diimine = 1,10-phenanthroline (phen), 5-nitro-1,10-phenanthroline (NO(2)phen), and 5,5'-ditrifluoromethyl-2,2'-bipyridine (dtfmbpy)] were prepared by the treatment of Pt(pip(2)NCN)Cl with a silver(I) salt followed by the addition of the diimine and halide/pseudohalide under acidic conditions. Crystallographic data as well as (1)H NMR spectra establish that the metal center is bonded to a bidentate phenanthroline and a monodentate halide/pseudohalide. The pip(2)NCNH(2)(+) ligand with protonated piperidyl groups is monodentate and bonded to the platinum through the phenyl ring.