THE CHEMISTRY OF MIXED ALKYL ARYLOXIDE COMPOUNDS OF ZIRCONIUM(IV)

ANNE KATHRYN MCMULLEN, Purdue University

Abstract

A series of mono- and bisaryloxides of zirconium(IV) were prepared by addition of 2,6-di-tertbutylphenol to the tetraalkyls: Zr(OAr')(CH(,2)Ph-(chi))(,2), ((chi) = H, 4F, 3F, 4Me); Zr(OAr')(,2)Me(,2)Me(,2) and Zr(OAr')(,2) (CH(,2)SiMe(,3))(,2). Zr(OAr')(CH(,2)Ph)(,3) was found to contain an unusual multisite interaction between the aryl ring of one benzyl ligand and the zirconium. The thermal cyclometallation of Zr(OAr')(,2)(CH(,2)Ph-(chi))(,2) was studied. The reaction is first order with a small substituted effect. Activation parameters were obtained for Zr(OAr')(,2)(CH(,2)Ph)(,2). The mechanism involves a concerted four centered pathway. Mono-, bis- and tris-(eta)('2)-iminoacyl compounds were prepared by the insertion of isocyanides: Zr(OAr')(,2)(((eta)('2)-xyNCCH(,2)Ph)(CH(,2)Ph); Zr(OAr')(,2)((eta)('2)-RNCCH(,2)Ph)(,2), (R = Bu('t)(,2), xy, Ph); Zr(OAr')(,2)((eta)('2)-RNCMe)(,2) (R = Bu('t), xy, Ph-(chi); (chi) = H, 3F, 4Cl, 30Me, 40Me, 4NMe(,2)); Zr(OAr')((eta)('2)-xyNCCH(,2)Ph)(,2)(CH(,2)Ph); and Zr(OAr')((eta)('2)RNCCH(,2)Ph)(,3), (R = Bu('t), xy). The Zr(OAr')(,2)((eta)('2)-R'NCR)(,2) thermally coupled to form enediamide complexes, Zr(OAr')(,2)(R'NC(R)C(R)NR'). The enediamides are fluxional through a ligand inversion. Kinetic studies of the intramolecular coupling reaction were carried out. It is first order with a small substituent effect and favored by electron withdrawing groups. CO reacts with Zr(OAr')(,2)((eta)('2)-xyNCCH(,2)Ph)(CH(,2)Ph) to form an enamidolate, Zr(OAr')(,2)(OC(CH(,2)Ph)C(CH(,2)Ph)Nxy). Addition of CO to Zr(OAr')(,2)R(,2) in the presence of pyridine results in (alpha),(alpha)-disubstituted-2,6-pyridine-dimethoxide, Zr(OAr')(,2)(OCH(R)pyCH(R)O)(py).

Degree

Ph.D.

Subject Area

Chemistry

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