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Free keywords:
carbon dioxide;
IR spectroscopy;
magnesium;
mass spectrometry;
structure elucidation
Abstract:
A magnesium complex incorporating a novel metal-CO2 binding motif is spectroscopically identified. Here we show with the help of infrared photodissociation spectroscopy that the complex exists solely in the [ClMg(η2-O2C)]− form. This bidentate double oxygen metal–CO2 coordination has previously not been observed in neutral nor in charged unimetallic complexes. The antisymmetric CO2 stretching mode in [ClMg(η2-O2C)]− is found at 1128 cm−1, which is considerably redshifted from the corresponding mode in bare CO2 at 2349 cm−1, suggesting that the CO2 moiety has a considerable negative charge (∼1.8 e−
). We also employed electronic structure calculations and kinetic analysis to support the interpretation of the experimental results.