Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Synthesis and characterization of the tetrameric, tri-titanium(IV)-substituted Wells-Dawson-substructure polyoxotungstate, [(P2W15Ti3O60.5)(4)](36-) : the significance of ultracentrifugation molecular weight measurements in detecting aggregated, anhydride forms of polyoxoanions
Autore:
Nomiya, K; Arai, Y; Shimizu, Y; Takahashi, M; Takayama, T; Weiner, H; Nagata, T; Widegren, JA; Finke, RG;
Indirizzi:
Kanagawa Univ, Fac Sci, Dept Mat Sci, Kanagawa 2591293, Japan Kanagawa Univ Kanagawa Japan 2591293 pt Mat Sci, Kanagawa 2591293, Japan Kanagawa Univ, Fac Engn, Dept Appl Chem, Yokohama, Kanagawa 2218686, JapanKanagawa Univ Yokohama Kanagawa Japan 2218686 ma, Kanagawa 2218686, Japan Colorado State Univ, Dept Chem, Ft Collins, CO 80523 USA Colorado State Univ Ft Collins CO USA 80523 hem, Ft Collins, CO 80523 USA
Titolo Testata:
INORGANICA CHIMICA ACTA
, volume: 300, anno: 2000,
pagine: 285 - 304
SICI:
0020-1693(20000430)300:<285:SACOTT>2.0.ZU;2-3
Fonte:
ISI
Lingua:
ENG
Soggetto:
METAL-OXIDE ANALOGS; SUPPORTED ORGANOMETALLIC COMPLEX; ALL-INORGANIC COMPOSITION; SOLVENT SOLUBLE FORMS; TRISUBSTITUTED HETEROPOLYTUNGSTATES; W-183 NMR; CATALYST PRECURSORS; STRUCTURAL CHARACTERIZATION; TRANSITION-METALS; SODIUM SALT;
Keywords:
polyoxotungstate; Wells-Dawson-type polyoxoanions; tri-titanium(IV) substituted polyoxoanions; Ti-O-Ti anhydride forms of Ti(IV); substituted polyoxoanions; ultracentrifugation solution molecular weight measurements;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
76
Recensione:
Indirizzi per estratti:
Indirizzo: Nomiya, K Kanagawa Univ, Fac Sci, Dept Mat Sci, Kanagawa 2591293, Japan Kanagawa Univ Kanagawa Japan 2591293 , Kanagawa 2591293, Japan
Citazione:
K. Nomiya et al., "Synthesis and characterization of the tetrameric, tri-titanium(IV)-substituted Wells-Dawson-substructure polyoxotungstate, [(P2W15Ti3O60.5)(4)](36-) : the significance of ultracentrifugation molecular weight measurements in detecting aggregated, anhydride forms of polyoxoanions", INORG CHIM, 300, 2000, pp. 285-304

Abstract

The preparation and crystallization of a tetrameric form of the tri-Ti-IV-substituted Wells-Dawson-substructure (i.e. [P2W18O62](6-) -type) heteropolyoxoanion, [(P2W15Ti3O60.5)(4)](36 -), as its water-soluble potassium salt,are described. This compound has been prepared by a direct reaction of Na-12[P2W15O56]. 18H(2)O with 30% aqueous Ti-IV(SO4)(2) solution. The compoundwith a formula of {K28H8[P2W15Ti3O60.5](4)}. 0.8KCl . 56H(2)O (1) was obtained in 38% yield as an analytically pure, colorless, powdered solid. The crystallization of 1 was achieved in the presence of KCI in pH 2.0 water to form {K28H8[P2W15Ti3O60.5](4)}. 46H(2)O (2). The KCl significantly aids thecrystallization of 1, but does not enter into the final composition of crystalline 2. The mixed tetrabutylammonium plus potassium salt {(Bu4N)(17)H11K8[P2W15Ti3O60.5](4)} (3) was successfully prepared as an analytically purewhite powder from the reaction of 1 in pH 2.0 water with solid (Bu4N)Br; the resultant 3 is acetonitrile- and DMSO-soluble, but water-insoluble. Compositional and structural characterization of 1-3 was accomplished by complete elemental analyses, TG/DTA, FT-IR, W-Vis spectroscopy, and solution P-31and W-183 NMR spectroscopies, including solid-state GHD/MAS P-31 NMR spectroscopy in the case of 2. We also report a scaled-up, 10-12 g preparation of the trimeric {(BU4N)(15)H-17[P2W15Ti3O61.3](3)} (4) (i.e. the tri-Ti-O-Tianhydride-bridged {[P2W15Ti3O61]-O-[P2W15Ti3O61]-O-[P2W15Ti3O61]}(32-)) and its partial deprotonation and partial Ti-O-Ti cleavage with Bu4N+OH- to the primarily dimeric {(Bu4N)(9)H-3[P2W15Ti3Osimilar to 62]n} (5) (n = 1-2) (i.e. the primarily mono-Ti-O-Ti anhydride-bridged {[P2W15Ti3O61]}(22-)). Most importantly, each of the tri-titanium-substituted Wells-Dawson-type polyoxoanions 1-5 are shown, by solution molecular weight experiments plus appropriate control experiments, to exist in aggregated, Ti-O-Ti anhydride forms, with the parent compounds 1, 2 and 3 all existing as tetramers,[(P2W15Ti3O60.5)(4)](36-). This finding of only Ti-O-Ti-bridged, anhydride forms oftri-Ti(IV) substituted Wells-Dawson polyoxoanions is important in that it corrects several previous, erroneous reports in the literature claiming, without molecular weight evidence, that the monomeric '[P2W15Ti3O62](12-)' exists. Monomeric '[P2W15Ti3O62](12 -)' however, still unknown. (C) 2000 Elsevier Science S.A. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/12/20 alle ore 10:29:10