An Organotin Vanadate with Sodalite Topology and Catalytic Versatility in Oxidative Transformations

Abstract

The new coordination polymer formulated as [Et 3 SnVO 3 ] (1) has been synthesized and shown by a combined single-crystal and synchrotron powder X-ray diffraction structural analysis, supported by solid-state NMR, to possess a three-dimensional network structure with the sodalite topology, formed by tetravanadate polyanions, [V 4 O 12 ] 4À , that are linked by Et 3 Sn + spacers. The catalytic versatility of compound 1 for liquid phase organic reactions was demonstrated by applying it for the epoxidation of olefins, the oxidative dehydrogenation of alcohols, and the oxidation of benzyl alcohol to benzaldehyde and benzoic acid, using tert-butyl hydroperoxide (TBHP) as oxidant. Compound 1 acts a solid reservoir for soluble, catalytically active species, which promote high selectivities to the epoxide and carbonyl (aldehyde/ketone/acid) products. The epoxidation activity compares favorably with those reported for other organotin molybdate, tungstate and vanadate coordination polymers, and is superior to that displayed by the starting materials used for its synthesis (Et 3 SnBr and NH 4 VO 3 ) and the metavanadate NBu 4 VO 3 .[a] Dr.

Facile One-Pot Preparation of Organotin-Oxometalate Polymers for Efficient Synthesis of Dimethyl Carbonate from CO2

“…However, when a physical mixture of Bu 3 SnCl and Na 2 MoO 4 ·2H 2 O was used as a catalyst, the DMC yield and TON were very low, suggesting that the integration of [MoO 4 ] 2– and [Bu 3 Sn] + groups could improve the catalytic activity remarkably and a good synergistic effect was likely to appear between the two groups. , In terms of the DMC yield, the performance of the catalysts followed the order ( n Bu 3 Sn) 2 MoO 4 > ( n Pr 3 Sn) 2 MoO 4 > (Et 3 Sn) 2 MoO 4 > (Me 3 Sn) 2 MoO 4 > (Cy 3 Sn) 2 MoO 4 > (Ph 3 Sn) 2 MoO 4 ·2H 2 O (Table , entries 6–11), indicating that the catalytic activity increased with the increased size of the R coordination group. The active result was also consistent with the sequence of Lewis acidic-basic sites, and ( n Bu 3 Sn) 2 MoO 4 with the largest acidic-basic amount displayed the highest activity, indicating that more acidic-basic sites were conducive to improving the catalytic performance, as several studies have revealed that the acidic-basic sites played a vital role in the catalytic activity. , However, for (Cy 3 Sn) 2 MoO 4 and [(Ph 3 Sn) 2 MoO 4 ]·2H 2 O catalysts (Table , entries 10 and 11), the decrease in activity mainly resulted from the serious steric hindrance of the ring group, which reduced the interactions of the active center of the catalyst with the reactants. , These results suggest that the catalytic performance was strongly affected by the nature of the Sn-bound R coordination group.…”

“…25,26 However, for (Cy 11), the decrease in activity mainly resulted from the serious steric hindrance of the ring group, which reduced the interactions of the active center of the catalyst with the reactants. 43,44 These results suggest that the catalytic performance was strongly affected by the nature of the Sn-bound R coordination group.…”