The formation of weak noncovalent interactions in organic reactions is key to understanding organometallic chemistry, but difficult to measure. Nanosecond FTIR has allowed us to probe the formation of weak ligand complexes, in particular we have studied the ligand exchange between M(CO)5 (where M = W, Mo, Cr) complexes and aromatic and aliphatic ligands. Temperature dependent measurements suggest a dissociative mechanism for ligand exchange. DFT calculations are used to understand both energies and vibrational frequencies in experimental data. Jeong and Lee describe a Pauson-Khand reaction where an enyne diester is reacted with an Mo(CO)6 metal center to produce an ester cyclopentenone.  This reaction requires both the coordination of a double and triple bond to the metal center.  Nanosecond FTIR measurements show that the addition of the alkyne happens on a nanosecond timescale, followed by the addition of the alkene on a microsecond timescale.

Nanosecond FTIR in probing solvent ligand systems and a metal-mediated Pauson-Khand reaction

243rd National Meeting (2012)

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