Reactions of group iii metal atom with ethylene and carbon dioxide molecules: a matrix isolation study

TLDR: In this article, the reactions of Al, Ga and In atoms with C2H4 and CO2 have been investigated by matrix isolation infrared spectroscopy, showing that metal-carbon interactions and the relative IR intensities are more sensitive to finer differences in the metal-ethylene bonding and vary continuously from one metal to the other.

Abstract: The reactions of Al, Ga and In atoms with C2H4 and CO2 have been investigated by matrix isolation infrared spectroscopy. Reactions with ethylene yield a series of C2v symmetry π complexes with comparable geometries. The C-C bond is similarly weakened (- 30 % in C=C force constant) in the complexes of the three metals. The strengthes of the metal-carbon interactions and the relative IR intensities are more sensitive to finer differences in the metal-ethylene bonding and vary continuously from one metal to the other. Reactions with CO2, on the other hand reveal large variation of reactivity from one group III metal atom to the other. Only Al and Ga atoms form complexes in the ground state and both AlCO2 and GaCO2 have two isomeric froms, one of C2v and one of CS or C1 symmetry. The most stable configuration is nevertheless not the same for AlCO2 (CS symmetry) as for GaCO2 (C2v).