| Autor: |
Tanuhadi E; Fakultät für Chemie, Institut für Biophysikalische Chemie, Universität Wien, 1090 Wien, Austria., Al-Sayed E; Fakultät für Chemie, Institut für Biophysikalische Chemie, Universität Wien, 1090 Wien, Austria., Roller A; Fakultät für Chemie, Zentrum für Röntgenstrukturanalyse, Universität Wien, 1090 Wien, Austria., Čipčić-Paljetak H; Center for Translational and Clinical Research, Croatian Center of Excellence for Reproductive and Regenerative Medicine, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia., Verbanac D; Faculty of Pharmacy and Biochemistry, University of Zagreb, 10000 Zagreb, Croatia., Rompel A; Fakultät für Chemie, Institut für Biophysikalische Chemie, Universität Wien, 1090 Wien, Austria. |
| Abstrakt: |
We report on a family of five new 4f- and 4d-doped sandwich-type germanotungstates with the general formula [( n -C 4 H 9 ) 4 N] l / m H 2 [(M(H 2 O) 3 )(γ-GeW 10 O 35 ) 2 ]·3(CH 3 ) 2 CO [M(H 2 O) 3 (GeW 10 ) 2 ] (M = Ce III , Nd III , Gd III , Er III , l = 7; Zr IV , m = 6), which have been synthesized at room temperature in an acetone-water mixture. Among the compound series, [Zr(H 2 O) 3 (GeW 10 ) 2 ] 8 - , which has been obtained in the presence of 30% H 2 O 2 , represents the first example of a 4d-substituted germanotungstate incorporating the intact dilacunary [γ-Ge IV W 10 O 36 ] 8- building block. All compounds were characterized thoroughly in the solid state by single-crystal and powder X-ray diffraction (XRD), IR spectroscopy, thermogravimetric analysis (TGA), and elemental analysis and in solution by NMR and UV-vis spectroscopy. The phosphoesterase activity of [Ce(H 2 O) 3 (GeW 10 ) 2 ] 9- and [Zr(H 2 O) 3 (GeW 10 ) 2 ] 8- toward the model substrates 4-nitrophenyl phosphate (NPP) and O , O -dimethyl O -(4-nitrophenyl) phosphate (DMNP) was monitored with 1 H- and 31 P-NMR spectroscopy revealing an acceleration of the hydrolytic reaction by an order of magnitude ( k corr = 3.44 (±0.30) × 10 -4 min -1 for [Ce(H 2 O) 3 (GeW 10 ) 2 ] 9- and k corr = 5.36 (±0.05) × 10 -4 min -1 for [Zr(H 2 O) 3 (GeW 10 ) 2 ] 8- ) as compared to the uncatalyzed reaction ( k uncat = 2.60 (±0.10) × 10 -5 min -1 ). [Ce(H 2 O) 3 (GeW 10 ) 2 ] 9- demonstrated improved antibacterial activity toward Moraxella catarrhalis (MIC 32 μg/mL), compared to the unsubstituted [GeW 10 O 36 ] 8- POM (MIC 64 μg/mL). |
