1. Ion and Neutral Thermochemistry from the Gas to Solution Phase an overview Tomas Baer University of North Carolina Chapel Hill, NC Mesilla Workshop on Organometallic Chemistry - 2006

2. Ion and Neutral thermochemistry – Gas Phase ML 2 ML + L M + 2L ML 2 + ML + + L M + + 2L Known IE(M) Lichtenberger Yang Yang Sztáray Armentrout Baer Sztáray Derived

3. Ionization Energy Measurements IE ad  H ion  Electron Energy IE ad ? Uncertainty = 0.10eV (10 kJ/mol) IE ad  Electron Energy IE ad Uncertainty = 0.01eV (1 kJ/mol) Molecular beam cooling – laser ionizationRoom Temperature PES

4. Thermal energy and Breakdown Diagram EoEo Photon energy (hv) E o -hv P+P+ D+D+ E o ± 10 meV (1 kJ/mol) hv E o -hv P(E) E o P + AB + Fractional Abundance Known thermal energy distribution TPEPICO experiment No worries about FC factors

5. Dissociation Onset Measurements Collisional Dissociation - Armentrout Collision energy (eV) AB + A + + B  H dis E0E0 E 0 ± 50 meV (5 kJ/mol) A + signal AB + + M  A + + B + M Again, no worries about FC factors. But there are other worries such as dissociation rate constants.

6. (C 6 H 6 ) 2 Cr Breakdown diagram BzCrBz +  CrBz + + Bz  Cr + + 2 Bz Li and Baer, J. Phys. Chem. A. 106 9820-9826 (2002) BzCrBz BzCrBz + CrBz + + Bz E int (Bz) + E trans hvhv

7. Energy partitioning in dissociation E0E0 E E-E 0 EiEi PEt 3 +  HPEt 2 + + C 2 H 4 Need only product vibrational frequencies. No adjustable parameters involved.

8. (C 6 H 6 ) 2 Cr Energetics Measured IE (laser spectrosc.) Kurikawa et al. (1999) Organometallics18, 1430 4s 3d 3d 3d 3d 3d Cr Measured IE (laser spectrosc.) D.S. Yang (unpublished) 5.465eV

9. Solvation Effects in neutral organometallic complexes ML n ML n-1 + L ML n-1 SML n-1  S + L  S SML n-1 ML n-1 + L ML n (g) fHofHo BE[M-L(g)] ML n  S BE[M-L(s)] SE(SML n-1 + L ) BE[M-S(g)] Gas Phase Solution Phase photoacoustic calorimetry Ted Burkey & Joe Grabowski transient IR spectroscopy Eric Weitz CID, PEPICO, PES Baer/Sztáray/Armentrout Lichtenberger/Yang Theory: Chris Cramer; Tom Ziegler; Mu-Hyun Baik SE(ML n )