Isolation of C1 through C4 derivatives from CO using heteroleptic uranium(iii) metallocene aryloxide complexes

The conversion of C1 feedstock molecules such as CO into commodity chemicals is a desirable, but challenging, endeavour. When the U(iii) complex, [(C₅Me₅)₂U(O-2,6- ^t Bu₂-4-MeC₆H₂)], is exposed to 1 atm of CO, only coordination is observed by IR spectroscopy as well as X-ray crystallography, unveiling a rare structurally characterized f element carbonyl. However, using [(C₅Me₅)₂(MesO)U (THF)], Mes = 2,4,6-Me₃C₆H₂, reaction with CO forms the bridging ethynediolate species, [{(C₅Me₅)₂(MesO)U}₂(μ₂-OCCO)]. While ethynediolate complexes are known, their reactivity has not been reported in much detail to afford further functionalization. For example, addition of more CO to the ethynediolate complex with heating forms a ketene carboxylate, [{(C₅Me₅)₂(MesO)U}₂(μ ₂:κ ²:η ¹-C₃O₃)], which can be further reacted with CO₂ to yield a ketene dicarboxylate complex, [{(C₅Me₅)₂(MesO)U}₂(μ ₂:κ ²:κ ²-C₄O₅)]. Since the ethynediolate showed reactivity with more CO, we explored its reactivity further. A [2 + 2] cycloaddition is observed with diphenylketene to yield [{(C₅Me₅)₂U}₂(OC(CPh₂)C([double bond, length as m-dash]O)CO)] with concomitant formation of [(C₅Me₅)₂U(OMes)₂]. Surprisingly, reaction with SO₂ shows rare S-O bond cleavage to yield the unusual [(O₂CC(O)(SO)]^2- bridging ligand between two U(iv) centres. All complexes have been characterized using spectroscopic and structural methods, and the reaction of the ethynediolate with CO to form the ketene carboxylate has been investigated computationally as well as the reaction with SO₂.

Exploring the reactivity of homoleptic organozincs towards SO2: Synthesis and structure of a homologous series of organozinc sulfinates

Studies on the reactivity of zinc alkyl compounds towards SO2 are relatively less explored than either the oxygenation or hydrolysis reactions. We report on environmentally friendly and efficient syntheses of...

Towards Extended Zinc Ethylsulfinate Networks by Stepwise Insertion of Sulfur Dioxide into Zn-C Bonds

The ability to utilize polluting gases in efficient metal-mediated transformations is one of the most pressing challenges of modern chemistry. Despite numerous studies on the insertion of SO₂ into M-C bonds, the chemical reaction of SO₂ with organozinc compounds remains little explored. To fill this gap, we report here the systematic study of the reaction of Et₂ Zn towards SO₂ as well as the influence of Lewis bases on the reaction course. Whereas the equimolar reaction provided a novel example of a structurally characterized organozinc ethylsulfinate compound of general formula [(EtSO₂ )ZnEt]_n , the utilization of an excess of SO₂ led to the formation of the zinc(II) bis(ethylsulfinate) compound [(EtSO₂ )₂ Zn]_n . Moreover, we have discovered that the presence of N-donor Lewis bases represents an efficient tool for the preparation of extended zinc ethylsulfinates, which in turn led to the formation of 1D [(EtSO₂ ZnEt)₂ (hmta)]_n and 2D [((EtSO₂ )₂ Zn)₂ (DABCO)]_n ⋅solv (in which solv=THF or toluene, hmta= hexamethylenetetramine, and DABCO=1,4-diazabicyclo[2.2.2]octane) coordination polymers, respectively. The results of DFT calculations on the reactivity of SO₂ towards selected Zn-C reactive species as well as the role of an N-donor Lewis base on the stabilization of the transition states complement the discussion.

SO2 and SO3 reactions with [(C5Me5)2Sm-O-Sm(C5Me5)2]: a DFT investigation and comparison with CO2 reactivity

Samarocene oxide [Cp*₂Sm-O-SmCp*₂] with Cp* = C₅Me₅, often seen as an undesirable product resulting from the oxidation of samarocene, has been reported to react with organic and inorganic anhydrides.