title: Application of Hectorite-Coated Silica Gel Particles as a Packing Material for Chromatographic Resolution.
abstract: A new type of clay column particles was prepared, in which a hectorite layer (∼0.1 µm thickness) covered uniformly the surface of amorphous silica particles with an average radius of 5 µm (ref. Okada et al., The Journal of Physical Chemistry C, 116, 21864-21869 (2012)). The hectorite layer was fully ion-exchanged with Δ-[Ru(phen)3](2+) (phen = 1,10-phenanthroline) ions by being immersed in a methanol solution of Δ-[Ru(phen)3](ClO4)2 (1 mM). The modified silica gel particles thus prepared were packed into a stainless steel tube (4 mm (i.d.) × 25 cm) as a high-performance liquid chromatography column. Optical resolution was achieved when the racemic mixtures of several metal complexes or organic molecules were eluted with methanol. In the case of tris(acetylacetonato)ruthenium(III) ([Ru(acac)3]), for example, the Λ- and Δ-enantiomers gave an elution volume of 2.6 and 3.0 mL, respectively, with the separation factor of 1.2. The total elution volume (5 mL) was nearly one-tenth for the previously reported column of the same size (RU-1 (Shiseido Co., Ltd.)) packed with the spray-dried particles of synthetic hectorite (average radius 5 µm) ion-exchanged by the same Ru(II) complexes.
authors.affiliation: Department of Chemistry and Material Engineering, Shinshu University, Wakasato 4-17-1, Nagano 380-8553, Japan tomohiko@shinshu-u.ac.jp.
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Okada
authors.affiliation: Department of Chemistry and Material Engineering, Shinshu University, Wakasato 4-17-1, Nagano 380-8553, Japan.
authors.forename: Aisaku
authors.initials: A
authors.lastname: Kumasaki
authors.affiliation: Department of Chemistry and Material Engineering, Shinshu University, Wakasato 4-17-1, Nagano 380-8553, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Shimizu
authors.affiliation: Department of Chemistry, Toho University, Funabashi 274-8510, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Yamagishi
authors.affiliation: Department of Chemistry, Graduate School of Science and Engineering, Ehime University, Matsuyama 790-8577, Japan.
authors.forename: Hisako
authors.initials: H
authors.lastname: Sato