Ligand variation in molybdenum imido alkylidene complexes : a synthetic, structural, and catalytic study

Chapter 1. A general introduction is given. Chapter 2. The biscarboxylate species, Mo(NR)(CHCMe 2Ph)(O 2CPh3)2 (R = 2,6-i-Pr2C6H3, 2,6- Me2C6H3, 2-t-BuC 6H4, or 1 -adamantyl) are compared to newly synthesized bis(terphenylcarboxylate) species, Mo(NR)(CHCMe 2Ph)(O 2CTer)2 (Ter = 2,6-diphenyl-4- methylphenyl or 2,6-diphenyl-4-methoxyphenyl). Preparation of bis(terphenylcarboxylate) species was accomplished through protonolysis of Mo(NR)(CHCMe2R')(Me2Pyr)2 with two equivalents of TerCO2H and one of them was characterized through X-ray crystallography. Photolysis experiments of many of the biscarboxylate complexes led to rate constants for the converstion of anti to syn species, which are much slower than bisalkoxide species. Trimethylphosphine adducts of selected triphenylacetate complexes have been isolated and studied in solution. Protonolysis of Mo(NAr)(CHCMe 2R')(Me 2Pyr)2 (Ar = 2,6-i-Pr 2C6H3) with one equivalent of TerCO2H led to the isolation of a handful of monocarboxylate species, Mo(NAr)(CHCMe 2Ph)(O 2CAr')(Me2Pyr). An X-ray structure of one of them was also characterized. Several of the bis(triphenylacetate) complexes and all of the monocarboxylates are active initiators for the regioselective polymerization of diethyl dipropargylmalonate (DEPDM). In the case of the latter compounds, activity towards olefins is also observed and briefly mentioned.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2012

Author dc:creator

• Lichtscheidl, Alejandro G. (Alejandro Gaston)

Advisor dc:contributor.advisor

• Richard R. Schrock.

• Chemistry.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/73363

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/73363