The M(CO)$\sb{\rm 6-x}$(PF$\sb3$)$\sb{\rm x}$ complexes where M is Cr, Mo and W and x is 0 to 6 are known. The reactivity of both isomeric forms of the complexes x = 2 and 3 with $\sp{13}$CO and PF$\sb3$ were studied under purely thermal and under photolytic conditions. The results for the thermal reactions in which the samples were in the gas phase are: for chromium and tungsten (100 and 140$\sp\circ$C respectively) the complexes isomerize exclusively via an intramolecular process as there is no C-13 incorporation and only a steady state equilibrium is attained between the isomers. For the molybdenum complexes (100$\sp\circ$C), the reaction is principally an intermolecular process. When starting with either fac- or mer-Mo(PF$\sb3$)$\sb3$(CO)$\sb3$, the intermediate is rigid; stereoselective C-13 incorporation in the Mo(PF$\sb3$)$\sb2$($\sp{13}$CO)(CO)$\sb3$ produced is observed. When starting with either cis- or trans-Mo (PF$\sb3$)$\sb2$(CO)$\sb4$, it appears that the intermediate (Mo(PF$\sb3$)(CO)$\sb4$) will rearrange to place the vacancy cis to the phosphine. In condensed state thermal reactions, for molybdenum complexes, the products obtained result from $\sp{12}$CO and PF$\sb3$ release which remain trapped in the lattice and are reattached. The degree of C-13 incorporation is reduced due to small amount of sample that is volatilized and the small solubility of CO in the complexes at elevated temperatures. Photolytic reactions of the Cr, Mo and W complexes at 100$\sp\circ$C with $\sp{13}$CO present reveal a large degree of product scrambling. When the samples were photolyzed while dissolved in methylcyclohexane, the reaction speed was reduced but is primarily nonselective. Photolytic reactions either neat or in MeCH with PF$\sb3$ present, yielded highly substituted products (x $>$ 3). Finally, procedures to prepare the fac-Mo (PF$\sb3$)$\sb3$(CO)$\sb3$ / isomer in large relative yields are discussed. These reactions were studied with packed column gas chromatography and infrared spectroscopy. / Source: Dissertation Abstracts International, Volume: 51-04, Section: B, page: 1810. / Major Professor: Ronald J. Clark. / Thesis (Ph.D.)--The Florida State University, 1990.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_78247 |
| Contributors | Berger Barnard, Tomas Gabriel., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 163 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
Page generated in 0.002 seconds