title: Intercluster compound between a tetrakis{triphenylphosphinegold(I)}oxonium cation and a keggin polyoxometalate (POM): formation during the course of carboxylate elimination of a monomeric triphenylphosphinegold(I) carboxylate in the presence of POMs.
abstract: The preparation and structural characterization of a novel intercluster compound, [{Au(PPh(3))}(4)(μ(4)-O)](3)[α-PW(12)O(40)](2)·4EtOH (1), constructed between a tetrakis{triphenylphosphinegold(I)}oxonium cation and a saturated α-Keggin polyoxometalate (POM) are described. The tetragold(I) cluster oxonium cation was formed during the course of carboxylate elimination of a monomeric phosphinegold(I) carboxylate complex, i.e., [Au((R,S)-pyrrld)(PPh(3))] [(R,S)-Hpyrrld = (R,S)-2-pyrrolidone-5-carboxylic acid], in the presence of the free acid form of a Keggin POM, H(3)[α-PW(12)O(40)]·7H(2)O. The liquid-liquid diffusion between the upper water/EtOH phase containing the Keggin POM and the lower CH(2)Cl(2) phase containing the monomeric gold(I) complex gave a pure crystalline sample of 1 in good yield (42.1%, 0.242 g scale). Complex 1 was formed by ionic interaction between the tetragold(I) cluster cation and the Keggin POM anion. As a matter of fact, the POM anion in 1 can be exchanged with the BF(4)(-) anion using an anion-exchange resin (Amberlyst A-27) in BF(4)(-) form. By using other Keggin POMs, such as H(4)[α-SiW(12)O(40)]·10H(2)O and H(3)[α-PMo(12)O(40)]·14H(2)O, the same tetragold(I) cluster cation was also formed, i.e., in the forms of [{Au(PPh(3))}(4)(μ(4)-O)](2)[α-SiW(12)O(40)]·2H(2)O (2) and [{Au(PPh(3))}(4)(μ(4)-O)](3)[α-PMo(12)O(40)](2)·3EtOH (3). Compounds 1-3, as dimethyl sulfoxide-soluble, EtOH- and Et(2)O-insoluble dark-yellowish white solids, were characterized by complete elemental analysis, thermogravimetric and differential thermal analyses, Fourier transform IR, X-ray crystallography, and solid-state (CPMAS (31)P and (29)Si) and solution ((31)P{(1)H} and (1)H) NMR spectroscopy. The molecular structures of 1 and 2 were successfully determined. The tetragold(I) cluster cation was composed of four PPh(3)Au(I) units bridged by a central μ(4)-oxygen atom in the geometry of a trigonal pyramid or distorted tetrahedron.
authors.affiliation: Department of Materials Science, Faculty of Science, Kanagawa University, Hiratsuka, Kanagawa 259-1293, Japan. nomiya@kanagawa-u.ac.jp
authors.forename: Kenji
authors.initials: K
authors.lastname: Nomiya
authors.forename: Takuya
authors.initials: T
authors.lastname: Yoshida
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Sakai
authors.forename: Arisa
authors.initials: A
authors.lastname: Nanba
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Tsuruta
mesh_terms: D002264:Carboxylic Acids / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006046:Gold / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D050607:Organogold Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010720:Phosphines / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014414:Tungsten / Q000737:chemistry*; D017973:Tungsten Compounds / Q000737:chemistry*; D000099294:Polyoxometalates
chemical_list: D002264:Carboxylic Acids; D006046:Gold; D050607:Organogold Compounds; D010720:Phosphines; D014414:Tungsten; D017973:Tungsten Compounds; C102296:polyoxometalate I; D000099294:Polyoxometalates