title: Hydrogen-bonded assemblies of two-electron reduced mixed-valence [XMo12O40] (X = P and Si) with p-phenylenediamines.
abstract: Hydrogen-bonded assemblies of the two-electron reduced mixed-valence Keggin clusters [PMo(12)O(40)](5-) and [SiMo(12)O(40)](6-) were obtained by the one-pot electron-transfer reactions between p-phenylenediamine (PPD) or 2,3,5,6-tetramethyl-PPD (TMPPD) (donors) and H(+)(3)[PMo(12)O(40)](3-) or H(+)(4)[SiMo(12)O(40)](4-) (acceptors) in CH(3)CN. The redox states of the [PMo(12)O(40)](5-) and [SiMo(12)O(40)](6-) clusters were confirmed by the redox titrations and electronic absorption measurements. In (HPPD(+))(3)(H(+))(2)[PMo(12)O(40)](5-)(CH(3)CN)(3-6) (1), the N-H ~ O hydrogen-bonded interactions between the monoprotonated HPPD(+) (or diprotonated H2PPD(2+)) and the [PMo(12)O(40)](5-) resulted in a windmill-like assembly and hydrophilic one-dimensional channels are formed with a cross-sectional area of 0.065 nm(2), and these are filled by the CH(3)CN molecules. Also, the CH(3)CN molecules in salt 1 were removed by immersing the single crystals of 1 into H(2)O, CH(3)OH, and C(2)H(5)OH solvents. In the compound, (HTMPPD(+))(6)[SiMo(12)O(40)](6-)(CH(3)CN)(6) (2), the N-H ~ O hydrogen-bonded interactions between the monoprotonated HTMPPD(+) molecules and the [SiMo(12)O(40)](6-) formed a "Saturn-ring"-like assembly. Each Saturn-ring was arranged into an hexagonally packed array via hydrogen-bonded and π-stacking interactions of HTMPPD(+), while the CH(3)CN solvent present in salt 2 are only found in the zero-dimensional isolated cavities.
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials (IMRAS), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan. akuta@tagen.tohoku.ac.jp
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Akutagawa
authors.forename: Fumito
authors.initials: F
authors.lastname: Kudo
authors.forename: Ryo
authors.initials: R
authors.lastname: Tsunashima
authors.forename: Shin-ichiro
authors.initials: S
authors.lastname: Noro
authors.forename: Leroy
authors.initials: L
authors.lastname: Cronin
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Nakamura