title: Structural characterization of 1,3-propanedithiols that feature carboxylic acids: Homologues of mercury chelating agents.
abstract: The molecular structures of a series of 1,3-propanedithiols that contain carboxylic acid groups, namelyrac- andmeso-2,4-dimercaptoglutaric acid (H4DMGA) and 2-carboxy-1,3-propanedithiol (H3DMCP), have been determined by X-ray diffraction. Each compound exhibits two centrosymmetric intermolecular hydrogen bonding interactions between pairs of carboxylic acid groups, which result in a dimeric structure for H3DMCP and a polymeric tape-like structure forrac- andmeso-H4DMGA. Significantly, the hydrogen bonding motifs observed forrac- andmeso-H4DMGA are very different to those observed for the 1,2-dithiol,rac-2,3-dimercaptosuccinic acid (rac-H4DMSA), in which the two oxygen atoms of each carboxylic acid group hydrogen bond to two different carboxylic acid groups, thereby resulting in a hydrogen bonded sheet-like structure rather than a tape. Density functional theory calculations indicate that 1,3-dithiolate coordination to mercury results in larger S-Hg-S bond angles than does 1,2-dithiolate coordination, but these angles are far from linear. As such, κ2-S2coordination of these dithiolate ligands is expected to be associated with mercury coordination numbers of greater than two.In vivostudies demonstrate that bothrac-H4DMGA and H3DMCP reduce the renal burden of mercury in rats, although the compounds are not as effective as either 2,3-dimercaptopropane-1-sulfonic acid (H3DMPS) ormeso-H4DMSA.
authors.affiliation: Department of Chemistry, Columbia University, New York, NY 10027, USA.
authors.forename: Wesley
authors.initials: W
authors.lastname: Sattler
authors.forename: Joshua H
authors.initials: JH
authors.lastname: Palmer
authors.forename: Christy C
authors.initials: CC
authors.lastname: Bridges
authors.forename: Lucy
authors.initials: L
authors.lastname: Joshee
authors.forename: Rudolfs K
authors.initials: RK
authors.lastname: Zalups
authors.forename: Gerard
authors.initials: G
authors.lastname: Parkin
keywords: Chelating agent; Mercury; Thiolate