The kinetics and mechanism of the reactions of (tmpa)W-(CO)^ and (tmen)W(CO)^ (tmpa = N,N,N',N'-tetramethy1-1,3-diaminopropane and tmen = N,N,N1,N1-tetramethylethylenediamine) with four phosphorus donor ligands (triisopropyl phosphite, triphenyl phosphite, triphenylphosphine and "constrained phosphite", 4-methyl-2,6,7-trioxa-l-phosphabicylo[2.2.2]octane) in xylene have been investigated in detail. These reactions were found to take place by the ring-opening of the bidentate ligand in a reversible step which leads to the formation of a five-coordinate intermediate of the type [(h^-tmpa)W(CO)or [(h^-tmen)W(CO). The intermediate then reacts with one molecule of phosphorus ligand, L, to form a six-coordinate intermediate, which can either expel the bidentate ligand and react with another molecule of L leading to the formation of a new disubstituted tungsten tetracarbonyl or go through a ring-reclosure step to form a seven-coordinate activated com-2 2plex or intermediate of the type [(h -tmpa)W(CO)^(L)] or [(h - tmen)W(CO)^(L)] which then regenerates the substrate through the expulstion of the L molecule. This mechanism is consistent with the observed rate behavior in these systems. For the reaction of (tmpa)W(CO)^ with the "constrained phosphite", an intermediate of the type [(h1-tmpa)W(CO)4P(OCH2)3CCH3] was isolated and identified.
| Identifer | oai:union.ndltd.org:unt.edu/info:ark/67531/metadc330970 |
| Date | 08 1900 |
| Creators | Moradi-Araghi, Ahmad |
| Contributors | Dobson, Gerard R., Desiderato, Robert, Jones, Paul R., Russell, Benny |
| Publisher | North Texas State University |
| Source Sets | University of North Texas |
| Language | English |
| Detected Language | English |
| Type | Thesis or Dissertation |
| Format | vi, 104 leaves : ill., Text |
| Rights | Public, Moradi-Araghi, Ahmad, Copyright, Copyright is held by the author, unless otherwise noted. All rights reserved. |
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