Time-resolved gas-phase kinetic study of the germylene addition reaction, GeH(2) + C(2)D(2).
Time-resolved studies of germylene, GeH(2), generated by laser flash photolysis of 3,4-dimethyl-1-germacyclopent-3-ene, have been carried out to obtain rate coefficients for its bimolecular reaction with C(2)D(2). The reaction was studied in the gas phase, mainly at a total pressure of 1.3 kPa (in SF(6) bath gas) at five temperatures in the range 298-558 K. Pressure variation measurements over the range 0.13-13 kPa (SF(6)) at 298, 397 and 558 K revealed a small pressure dependence but only at 558 K. After correction for this, the second-order rate coefficients gave the Arrhenius equation: log(k infinity/cm3 molecule(-1) s(-)1) = (-10.96 +/- 0.05) + (6.16 +/- 0.37 kJ mol-1)/RT ln 10. Comparison with the reaction of GeH(2) + C(2)H(2) (studied earlier) showed a similar behaviour with almost identical rate coefficients. The lack of a significant isotope effect is consistent with a rate-determining addition process and is explained by irreversible decomposition of the reaction intermediate to give Ge((3)P) + C(2)H(4). This result contrasts with that for GeH(2) + C(2)H(4)/C(2)D(4) and those for the analogous silylene reactions. The underlying reasons for this are discussed.
Reaction of Germylene with Sulfur Dioxide: Gas-Phase Kinetic and Theoretical Studies
Time-resolved studies of germylene, GeH2, generated by laser flash photolysis of 3,4-dimethyl-1-germacyclopent-3-ene at 193 nm, have been carried out to obtain rate constants for its bimolecular reaction with SO2. The reaction was studied in the gas phase, mainly at a total pressure of 10 Torr (in SF6 bath gas) at five temperatures in the range 295–553 K. Pressure variation measurements over the range 1–100 Torr (SF6) at 295, 408, and 553 K revealed no pressure dependence. The second-order rate constants at 10 Torr (SF6 bath gas) fit the Arrhenius equation log(k/cm3 molecule–1 s–1) = (−11.01 ± 0.09) + (4.62 ± 0.65 kJ mol–1)/RT ln 10, where the uncertainties are single standard deviations. The collisional efficiency is 19% at 298 K, and in kinetic terms the reaction resembles that of SiH2 with SO2 quite closely. Quantum chemical calculations at the B3LYP/aug-cc-pvQZ level suggest a mechanism occurring via the initial addition of GeH2 to one O atom of SO2 to form H2GeOSO which, via a 1,3-H shift followed by...
Bodies of Evidence: Burial, Memory and the Recovery of Missing Persons in Cyprus
List of Figures and Maps Acknowledgements Chapter 1. Heirs of Antigone: Disappearances and Political Memory Chapter 2. Suppressed Experiences Chapter 3. Testimonies of Fragmentation, Recollections of Unity Chapter 4. The Missing as a Set of Representations Chapter 5. The Martyrdom of the Missing Chapter 6. L'image Juste, or Juste une Image? Chapter 7. Painting Absences, Describing Losses Chapter 8. Antigone's Doubt, Creon's Dilemma Chapter 9. Power, Complicity, and Public Secrecy Bibliography Appendices Index