A density functional study of intra- and interring haptotropic η2,η2 rearrangements in rhodium, ruthenium, and osmium naphthalene complexes

Abstract

The density functional theory method was used to perform quantum chemical modeling of the mechanisms of η 2 ,η 2 intraring (Intra HR) and η 2 ,η 2 interring (Inter HR) haptotropic rearrangements for η 2 complexes of naphthalene with rhodium, ruthenium, and osmium. The structure of transition states and intermediates was studied, and the energy parameters of haptotropic rearrangements in these complexes were determined. We used the PBE functional, the TZV2p three exponential basis set for valence electrons, and the SBK JC relativistic pseudopotential for core electrons. η 2 ,η 2 Intra HR was found to occur inside the aro matic ring of η 2 naphthalene complexes without going outside it through intermediates and transition states with η n structures (n = 1, 2). Inter HR occurred as metal replacements on the periphery of the naphthalene ligand through intermediates and transition states with η n structures (n = 1, 2, 3) from one ring into another. The calculated activation barriers for η 2 ,η 2 Intra HR and η 2 ,η 2 Inter HR in the complexes studied closely agree with their experimental values.

Influence of Ion Pairing in Inter-Ring Haptotropic Rearrangements in Cationic Cyclopentadienyl Complexes of Ruthenium with Naphthalene: A DFT Investigation

“…Thermally induced intramolecular η 6 :η 6 -IRHR processes have been investigated experimentally (for labeled complexes) and theoretically. Since the pioneering semiempirical work of Albright et al, DFT investigations have been performed mostly for chromium tricarbonyl complexes of PAL − and only to some extent for molybdenum and tungsten . On the other hand, it is quite strange and intriguing that η 6 :η 6 -IRHR in synthetically available and very stable PAL complexes of the iron triad (Fe, Ru, Os), which are important from a synthetic practical point of view, have been virtually not investigated. − The influence of photochemical activation on such rearrangements has been poorly and not thoroughly investigated, although many thermally induced reactions have photochemical analogues − which might be quite complex and possibly involve not only the lowest triplet state .…”