Synthesis, structure and reactivity of high-valent early transition metal complexes containing pi coordinated carbocycles and hard pi donor ligands.

Persistent Link:
http://hdl.handle.net/10150/185771
Title:
Synthesis, structure and reactivity of high-valent early transition metal complexes containing pi coordinated carbocycles and hard pi donor ligands.
Author:
Arney, David Sellman Johnson.
Issue Date:
1992
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Ta(DIPP)Cl₄ (1) has been prepared from the reaction of TaCl₅ with 1 equiv of Me₃SiDIPP and is shown to be dimeric. While Ta(DIPP)Cl₄ reacts with Et₂O to form trans-Ta(DIPP)Cl₄(OEt₂) (2), TaCl₅ and Me₃SiDMP react in the presence of Et₂O to provide trans-Ta(DMP)Cl₄(OEt₂) (3) directly. TaCl₅ reacts with 2 equiv of Me₃SiDMP to form the bis phenoxide complex Ta(DMP)₂Cl₃(OEt₂) (6). All of these compounds cyclize 3-hexyne upon their two electron reduction, to form (η⁶-C₆Et₆)Ta(OR)ₓCl₃₋ₓ (OR = DIPP, DMP, x = 1; OR = DMP, x = 2), but do not readily undergo the analogous reaction with 2-butyne. However, (η⁶-C₆Me₆)Ta(DIPP)Cl₂ (10) can be prepared in essentially quantitative yield from the reaction of (η⁶-C₆Me₆)Ta(DIPP)₂Cl (9) with Ta(DIPP)₂Cl₃(OEt₂). The arene ligand in (η⁶-C₆Me₆)Ta(DIPP)Cl₂ (10) is characterized by a folded structure and considerable localization of the π electron density in a 1,4-diene fashion. The thermolysis of (η⁶-C₆Me₆)Ta(DIPP)₂Cl 9 produces free C₆M₆ along with the "tucked in" complex (η¹-C₆Me₅CH₂)Ta(DIPP)₂Cl₂ (11). Compound 11 can be prepared in higher yields from 9 by its thermal decomposition in the presence of Me₃SiCl. Alkylation of tantalum(III) arene complexes affords stable dialkyl (η⁶-C₆Me₆)Ta(DIPP)R₂ and monoalkyl halide species (η⁶-C₆Me₆)Ta(DIPP)RX. The alkyl hydride complexes (η⁶-C₆Me₆)Ta(DIPP)R(H) are also prepared from (η⁶-C₆Me₆)Ta(DIPP)RX and LiBEt₃H. The arene ring in (η⁶-C₆Me₆)Ta(DIPP)Et₂ (18) exhibits a structure consistent with a diene-diyl distortion. The first evidence for the formation of a d¹ arene species is presented in cyclic voltammetry experiments on these compounds. The addition of 4 equiv of LiNHAr to a solution of ZrCl₄(THF)₂ in THF/PY yields Zr(=NAr)(NHAr)₂(PY)₂ (26). Zr(=NAr)(NHAr)(PY)₂ reacts with 1 or 2 equiv of TMSCl in THF/PY to provide Zr(=NAr)(NHAr)Cl(PY)₂ (27) and Zr(=NAr)Cl₂(PY)₃ (28) respectively. MCl₄(THF)₂ (M = Zr or Hf) react with 4 equiv LiNHAr followed by the addition of 2 equiv TMSCl to provide M(=NAr)Cl₂(THF)₂ (24, M = Zr; 25 M = Hf). Both 24 and 25 react with K₂ (C₈H₈) to provide ((η⁸-C₈H₈)M(=NAr))₂ (31, M = Zr; 32, M = Hf). Zr(=NAr)Cl₂(THF)₂ reacts with 1 equiv Li(C₅H₄Me) to provide ((η⁵-C₅H₄Me)Zr(=NAr)Cl)₂ (30). An imprecise structure of this dimeric compound has been determined which exhibits bridging imido functionalities. (η⁵-C₅Me₅)ZrCl₃(THF) reacts with 3 equiv LiNHAr in THF/PY to provide ((η⁵-C₅Me₅)Zr(=NAr)(NHAr)(PY))₂ (33). Compound 33 reacts with 1 equiv TMSCl in THF/PY to provide monomeric (η⁵-C₅Me₅)Zr(=NAr)Cl(PY)₂ (35).
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Dissertations, Academic.; Chemistry, Organic.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Chemistry; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Wigley, David E.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleSynthesis, structure and reactivity of high-valent early transition metal complexes containing pi coordinated carbocycles and hard pi donor ligands.en_US
dc.creatorArney, David Sellman Johnson.en_US
dc.contributor.authorArney, David Sellman Johnson.en_US
dc.date.issued1992en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractTa(DIPP)Cl₄ (1) has been prepared from the reaction of TaCl₅ with 1 equiv of Me₃SiDIPP and is shown to be dimeric. While Ta(DIPP)Cl₄ reacts with Et₂O to form trans-Ta(DIPP)Cl₄(OEt₂) (2), TaCl₅ and Me₃SiDMP react in the presence of Et₂O to provide trans-Ta(DMP)Cl₄(OEt₂) (3) directly. TaCl₅ reacts with 2 equiv of Me₃SiDMP to form the bis phenoxide complex Ta(DMP)₂Cl₃(OEt₂) (6). All of these compounds cyclize 3-hexyne upon their two electron reduction, to form (η⁶-C₆Et₆)Ta(OR)ₓCl₃₋ₓ (OR = DIPP, DMP, x = 1; OR = DMP, x = 2), but do not readily undergo the analogous reaction with 2-butyne. However, (η⁶-C₆Me₆)Ta(DIPP)Cl₂ (10) can be prepared in essentially quantitative yield from the reaction of (η⁶-C₆Me₆)Ta(DIPP)₂Cl (9) with Ta(DIPP)₂Cl₃(OEt₂). The arene ligand in (η⁶-C₆Me₆)Ta(DIPP)Cl₂ (10) is characterized by a folded structure and considerable localization of the π electron density in a 1,4-diene fashion. The thermolysis of (η⁶-C₆Me₆)Ta(DIPP)₂Cl 9 produces free C₆M₆ along with the "tucked in" complex (η¹-C₆Me₅CH₂)Ta(DIPP)₂Cl₂ (11). Compound 11 can be prepared in higher yields from 9 by its thermal decomposition in the presence of Me₃SiCl. Alkylation of tantalum(III) arene complexes affords stable dialkyl (η⁶-C₆Me₆)Ta(DIPP)R₂ and monoalkyl halide species (η⁶-C₆Me₆)Ta(DIPP)RX. The alkyl hydride complexes (η⁶-C₆Me₆)Ta(DIPP)R(H) are also prepared from (η⁶-C₆Me₆)Ta(DIPP)RX and LiBEt₃H. The arene ring in (η⁶-C₆Me₆)Ta(DIPP)Et₂ (18) exhibits a structure consistent with a diene-diyl distortion. The first evidence for the formation of a d¹ arene species is presented in cyclic voltammetry experiments on these compounds. The addition of 4 equiv of LiNHAr to a solution of ZrCl₄(THF)₂ in THF/PY yields Zr(=NAr)(NHAr)₂(PY)₂ (26). Zr(=NAr)(NHAr)(PY)₂ reacts with 1 or 2 equiv of TMSCl in THF/PY to provide Zr(=NAr)(NHAr)Cl(PY)₂ (27) and Zr(=NAr)Cl₂(PY)₃ (28) respectively. MCl₄(THF)₂ (M = Zr or Hf) react with 4 equiv LiNHAr followed by the addition of 2 equiv TMSCl to provide M(=NAr)Cl₂(THF)₂ (24, M = Zr; 25 M = Hf). Both 24 and 25 react with K₂ (C₈H₈) to provide ((η⁸-C₈H₈)M(=NAr))₂ (31, M = Zr; 32, M = Hf). Zr(=NAr)Cl₂(THF)₂ reacts with 1 equiv Li(C₅H₄Me) to provide ((η⁵-C₅H₄Me)Zr(=NAr)Cl)₂ (30). An imprecise structure of this dimeric compound has been determined which exhibits bridging imido functionalities. (η⁵-C₅Me₅)ZrCl₃(THF) reacts with 3 equiv LiNHAr in THF/PY to provide ((η⁵-C₅Me₅)Zr(=NAr)(NHAr)(PY))₂ (33). Compound 33 reacts with 1 equiv TMSCl in THF/PY to provide monomeric (η⁵-C₅Me₅)Zr(=NAr)Cl(PY)₂ (35).en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectDissertations, Academic.en_US
dc.subjectChemistry, Organic.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineChemistryen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorWigley, David E.en_US
dc.contributor.committeememberFeltham, Robert D.en_US
dc.contributor.committeememberEnemark, John H.en_US
dc.contributor.committeememberO'Brien, David F.en_US
dc.contributor.committeememberMash, Eugene A., Jr.en_US
dc.identifier.proquest9220697en_US
dc.identifier.oclc712176806en_US
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