Pulsed laser kinetic studies of liquids under high pressure
Abstract
A high pressure apparatus constructed for measuring the rates of reactions in liquids under pressures ranging from 1 to 2000 atm has been used to measure the complexation kinetics of molybdenum hexacarbonyl reacting with 2,2-bipyridine, 4,4'-dimethyl 2-2'-bipyridine and 4,4'-diphenyl 2-2'-bipyridine in toluene. Pentacarbonyl reaction intermediates are created by a 10 nsec flash of frequency tripled Nd:YAG laser light. Measured activation volumes for chelate ligand ring closure indicate a change in mechanism from associative interchange to dissociative interchange as steric hindrance increases. A similar high pressure kinetics study of molybdenum carbonyl complexation by several substituted phenanthrolines is now well advanced that indicates that with the more rigid phenanthroline ligands steric effects from bulky substituents have less effect on the ring closure mechanism than in the case of the bipyridine ligands. An experimental concentration dependence of the fluorescence quantum yield of cresyl violet has been harmonized with previously published contradictory reports. Fluorescence of cresyl violet in various solvents and in micellar systems has also been systematically explored.
- Publication:
-
Unknown
- Pub Date:
- November 1991
- Bibcode:
- 1991plks.rept.....E
- Keywords:
-
- Chemical Reactions;
- Complex Compounds;
- Pressure Effects;
- Pulsed Lasers;
- Pyridines;
- Reaction Kinetics;
- Azines;
- Carbonyl Compounds;
- Fluorescence;
- High Pressure;
- Irradiation;
- Molybdenum Compounds;
- Neodymium Lasers;
- Lasers and Masers