The Reactivity Studies of Chromium-Chromium Quintuple Bond

The reactivity of the quintuply bonded dichromium complex (1) stabilized by aminopyridinato ligands have been investigated. The reaction of (1) with alkynes and dienes leads to cycloaddition reactions. Furthermore, the study was extended to various small molecules of group 16 and 17 elements. In the case of group 16, Oxygen leads to the formation of dimeric Cr(V) specie. In contrast, higher homologues undergo addition reactions to give Cr(II) species. For homodiatomic molecules of group 17, insertion of the quintuple bond into the corresponding X-X bond was observed (X = Cl, Br, I). The reaction of (1) with diphenyldisulfide or diphenyldiselenide shows the insertion of the Cr-Cr bond into the S-S or Se-Se bond and the formation of complexes in which the two Cr atoms are joined by two bridging PhS or PhSe groups. Moreover, the reaction of (1) with phosphines ligands is selective and leads to the formation of phosphide-bridged chromium complexes.