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Triruthenium and Triosmium Carbonyl Cluster Complexes Containing Deprotonated Di(2-pyridyl)amine in Unusual Coordination Modes

“…Therefore, although tentative proposals can be provided, the explanation for the different chemical behavior of Hdpa with analogous ruthenium and osmium clusters remains unknown. In a few instances, differences in the reactions of these clusters with some heterocyclic ligands have also been observed …”

Triruthenium and Triosmium Carbonyl Cluster Complexes Containing Bridging Ligands Derived from 2-Amino-7,8-benzoquinoline

“…Compounds 1 and 2 are unique, not only because they are the first polynuclear derivatives of H 2 abq but also because of their structures. Metalated heterocyclic ligands tend to occupy axial positions in trinuclear clusters; ,− in other words, they are positioned on one side of the metal triangle. However, the particular structure of the abq ligand and its coordination through three atoms (two nitrogens and one carbon) forces the occupation of both axial and equatorial positions in complex 1 and a completely new type of structure for complex 2 .…”

“…No metalations of 2-aminopyridines and 2-aminoquinolines have hitherto been reported, but the metalation of pyridine 8,12 and quinoline 8f,13,14 rings by triruthenium and triosmium clusters has been reported on a few occasions. It is noteworthy that pyridines behave similarly to triruthenium and triosmium carbonyls,8f but this is not the case for quinolines, which behave as pyridines with ruthenium, giving cyclometalated 48-electron species containing μ-η 2 - N,C ligands, but give unsaturated cyclometalated 46-electron triosmium derivatives containing μ 3 -η 2 - N,C ligands 14b. Di(2-pyridyl)amine also gives different products when treated with analogous ruthenium and osmium carbonyls, since it behaves as a “normal” Hapy ligand with osmium but gives a cyclometalated product with ruthenium 2a…”