Structural and dynamical aspects of alkylammonium salts of a silicodecatungstate as heterogeneous epoxidation catalystsElectronic supplementary information (ESI) available: Powder XRD analyses of C3 (Fig. S1) and C5 (Fig. S2), space filling models of the crystal structure of alkylammonium salts (Fig. S3), powder XRD analyses of C3 (Fig. S4) and C5 (Fig. S5) immersed in EtOAc, intensities of the signals of 13C-CPMASNMR spectra as a function of contact times (Fig. S6-S10). See DOI: 10.1039/c2dt304

The structural and dynamical aspects of alkylammonium salts of a silicodecatungstate [(CH 3 ) 4 N] 4 [-SiW 10 O 34 (H 2 O) 2 ] [ C1 ], [(n-C 3 H 7 ) 4 N] 4 [-SiW 10 O 34 (H 2 O) 2 ] [ C3 ], [(n-C 4 H 9 ) 4 N] 4 [-SiW 10 O 34 (H 2 O) 2 ] [ C4 ], and [(n-C 5 H 11 ) 4 N] 4 [-SiW 10 O 34 (H 2 O) 2 ] [ C5 ] were investigated. The results of sorption isotherms, XRD analyses, and solid-state NMR spectroscopy show that facile sorption of solvent molecules, flexibility of structures, and high mobility of alkylammonium cations are crucial to the uniform distribution of reactant and oxidant molecules throughout the bulk solid, which are related to the high catalytic activities for epoxidation of alkenes. Facile sorption of solvents, structural flexibility, and mobility of cations are crucial to the high catalytic activities of alkylammonium silicodecatungstates.