Facile CO₂ Cycloaddition to Epoxides by Using a Tetracarbonyl Metal Selenotungstate Derivate [{Mn(CO)₃}₄(Se₂W₁₁O₄₃)]⁸–

A novel polyoxometalate cluster, i.e., Na 1.5 H 4.5 [(CH 3 ) 4 N] 2 {[Mn(CO) 3 ] 4 (Se 2 W 11 O 43 )}·9H 2 O ( 1 ), has been successfully synthesized under moderately acidic conditions. Compound 1 contains four electron-donating {Mn(CO) 3 } + organometallic entities, which are grafted over an unprecedented heteropolytungstate electron-acceptor group. Compound 1 was further structurally characterized by various physicochemical techniques like elemental analyses, inductively coupled plasma (ICP) analyses, IR and UV–vis spectroscopy, electrochemistry, and single-crystal X-ray diffraction, and so on. The polyoxoanion of 1 comprises a novel {Se 2 W 11 } fragment, which is obtained from molecular assembly of rare {SeW 3 } and {SeW 8 } species. Evaluation of the data from solution-state IR spectrum showed excellent agreement with the solid state IR spectrum, indicating the intact clusters in the CH 3 CN/Na 2 SO 4 solvent. Also, negative electrospray ionization mass spectrometry (ESI-MS) was an alternative tool to verify the stability of 1 in the mixed solvent. Additionally, the resulting hybrid can act as a catalyst for cyclic carbonate formation from the reactants epoxides and CO 2 under modest reaction conditions in conjunction with a 1-ethyl-1-methylpyrrolidinium bromide ( 2 ). The good activity can be substantiated due to the cooperative influence of polyoxoanion and Br – ions. Complex 1 can also be easily recycled and reused three times without obvious decrease of catalytic activity.