Equilibrium data are reported for the reaction CpMo(CO)3H + 3MeCN ⇋ Mo(CO)3(MeCN)3 + CpH. Over the temperature range 43-82°C, ΔH = -11.2 kcal/mol, ΔS = -51.3 cal/(mol°C). Calorimetric data for the enthalpies of displacement of C5R5H by nitriles are reported: Cr, R = Me, -0.7 ± 0.7 kcal/mol, M = W, R = H, -5.6 ± 0.7, R = Me, -5.4 ± 0.7 kcal/mol. The enthalpy of reaction of Na+(indenyl)- with (p-xylene)Mo(CO)3 forming Na+Mo(CO)3(indenyl)- is -17.3 ± 0.2 kcal/mol, approximately 10 kcal/mol less than the corresponding reaction of Na+C5H5-. The heat of reaction of (indenyl) W(CO)3H with EtCN forming W(CO)3(EtCN)3, -20.0 ± 0.8 kcal/mol, is approximately 14 kcal/mol more exothermic than the corresponding reaction of the cyclopentadienyl complex, also in keeping with a reduced M-indenyl ground-state bond energy. Synthetic strategies to the (C5R5)M(CO)3H complexes are summarized.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry