TILDEN LECTURE - ORGANOMETALLIC INTERMEDIATES - ULTIMATE REAGENTS

Short-lived intermediates play a central role, through their structure and reactivity, in controlling photochemical reactions of organo-transition metal complexes. Molecules such as Ru(dmpe)2 (dmpe = Me2PCH2CHPMe2) can be studied directly by time-resolved spectroscopy and matrix isolation to reveal key features of reaction mechanisms. Photochemical reductive elimination of H-2 may be complete in picoseconds and re-addition of H-2 in tens of nanoseconds. Excited states of organometallics are more elusive, but sometimes emission and excitation spectra are sufficiently well resolved to estimate the change in geometry in the excited state.