Isolation of a monomeric SiO compound 3 as a stable donor-acceptor complex with two different ligands -a σ-donating ligand (pyridine, dimethylaminopyridine, N-heterocyclic carbene) and a donor-acceptor ligand (iminophosphorane)-is presented. The SiO complex 3 is soluble in ordinary organic solvents and is stable at room temperature in solution and in the solid state. Of particular interest, 3 remains reactive and can be used as a stable and soluble unimolecular SiO reagent.

The donor-stabilized sila-β-lactone 1 reacts with CO via a remarkable reversible [2+2]-cycloaddition reaction to form the spiro-cyclic silicon carbonate derivative 2. Furthermore, photolysis of 2 under pressure of CO affords the first persistent SiO -CO cycloadduct 3, presenting a Si O -like structure, which is stabilized by a Lewis donor-acceptor type ligand. As predicted by theoretical calculations, in marked contrast to the thermodynamically stable SiO dimer, the SiO -CO mixed cycloadduct 3 is labile and readily releases CO .

Isolation of a monomeric SiO2 compound 3 as a stable donor–acceptor complex with two different ligands —a σ‐donating ligand (pyridine, dimethylaminopyridine, N‐heterocyclic carbene) and a donor–acceptor ligand (iminophosphorane)—is presented. The SiO2 complex 3 is soluble in ordinary organic solvents and is stable at room temperature in solution and in the solid state. Of particular interest, 3 remains reactive and can be used as a stable and soluble unimolecular SiO2 reagent.

The donor-stabilized sila--lactone 1 reacts with CO 2 via a remarkable reversible [2+2]-cycloaddition reaction to form the spiro-cyclic silicon carbonate derivative 2. Furthermore, photolysis of 2 under pressure of CO 2 affords the first persistent SiO 2-CO 2cycloadduct 3, presenting a Si 2 O 4-like structure, which is stabilized by a Lewis donor-acceptor type ligand. As predicted by theoretical calculations, in marked contrast to the thermodynamically stable SiO 2-dimer, the SiO 2-CO 2 mixed cycloadduct 3 is labile and readily releases CO 2. Although carbon dioxide (CO 2) and silicon dioxide (SiO 2) are two archetypal group-14 oxides with great basic and applied significance in chemistry, their physical and chemical properties are completely different. CO 2 is a thermodynamically stable molecule held together by C=O double bonds, which exists in the gas phase under ambient conditions. The activation of this highly stable molecule, in order to use it as renewable carbon source, [1,2] as well as its capture and its storage [3] are particularly important issues in current chemistry. In marked contrast, monomeric SiO 2 is a very unstable molecule and forms extremely stable 3D-network structures constituted only by Si-O -bonds. Found in nature in many different forms, such as sand or quartz, silica (SiO 2) n is the