title: Preparation and redox studies of α1- and α2-isomers of mono-Ru-substituted Dawson-type phosphotungstates with a DMSO ligand: [α1/α2-P2W17O61Ru(II)(DMSO)](8-).
abstract: Both α1- and α2-isomers of mono-Ru-substituted Dawson-type heteropolytungstates with a DMSO ligand, [α1-P2W17O61Ru(II)(DMSO)](8-) and [α2-P2W17O61Ru(II)(DMSO)](8-), are prepared from the α2-isomer of a monolacunary derivative, [α2-P2W17O61](10-). Reaction of [α2-P2W17O61](10-) with Ru(DMSO)4Cl2 under hydrothermal conditions produces [α2-P2W17O61Ru(II)(DMSO)](8-) as a main product together with [α1-P2W17O61Ru(II)(DMSO)](8-), [PW11O39Ru(II)(DMSO)](5-), and [P2W18O62](6-) as byproducts. By addition of KCl to the reaction mixture, K8[α2-P2W17O61Ru(II)(DMSO)] is isolated in a moderate yield. On the other hand, reaction of [α2-P2W17O61](10-) with Ru2(benzene)2Cl4 under hydrothermal conditions produces an isomeric mixture of [P2W17O61Ru(III)(H2O)](7-) (α1-isomer/α2-isomer ratio: ca. 8/1) as a main product together with [PW11O39Ru(III)(H2O)](4-) and [P2W18O62](6-) as byproducts. By addition of acetone to the reaction mixture, K7[P2W17O61Ru(III)(H2O)] is isolated in a good yield. Reaction of [P2W17O61Ru(III)(H2O)](7-) with DMSO produces [α1-P2W17O61Ru(III)(DMSO)](7-) as a main product and [α2-P2W17O61Ru(III)(DMSO)](7-) as a minor product. By addition of KCl and acetone, the α1-isomer K8[α1-P2W17O61Ru(II)(DMSO)] is isolated in a good yield. Both compounds are fully analyzed by CV, NMR ((1)H, (13)C, (31)P, and (183)W), IR, UV-vis, elemental analysis, mass spectroscopy, and single-crystal structure analysis. Assuming that isomerization does not occur during the reaction of [P2W17O61Ru(III)(H2O)](7-) with DMSO, the isolated [P2W17O61Ru(III)(H2O)](7-) contains the α1-isomer as a main compound with the α2-isomer as a minor compound. Unusual transformation of the α2-isomer of [P2W17O61](10-) to the α1-isomer occurs. Redox behaviors of [α1-P2W17O61Ru(II)(DMSO)](8-) and [α2-P2W17O61Ru(II)(DMSO)](8-) are compared together with Ru(DMSO)-substituted α-Keggin-type heteropolytungstates, [α-XW11O39Ru(DMSO)](n-) (X = Si, Ge, and P).
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University , 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527, Japan.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Ogo
authors.forename: Noriko
authors.initials: N
authors.lastname: Shimizu
authors.forename: Kensuke
authors.initials: K
authors.lastname: Nishiki
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Yasuda
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Mizuta
authors.forename: Tsuneji
authors.initials: T
authors.lastname: Sano
authors.forename: Masahiro
authors.initials: M
authors.lastname: Sadakane