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Papers by John Harrod
Journal of Organometallic Chemistry, 1976
ABSTRACT
ChemInform, 2000
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Coordination Chemistry Reviews, 2000
Organometallics, 2000
ABSTRACT A kinetic study of the photochemical reaction of [Cp2Zr(mu-SiH2Ph)](2)(2+)2[BBun(C6F5)(4... more ABSTRACT A kinetic study of the photochemical reaction of [Cp2Zr(mu-SiH2Ph)](2)(2+)2[BBun(C6F5)(4-n)](-) (1) with PhCH2SiH3 to give the analogous PhCH2SiH2 complex 2 was carried out using a combination of NMR and EPR spectroscopy to follow the rates of disappearance of reactants and the appearance of intermediates and products. The paramagnetic intermediate [Cp2ZrIII](+)[BBun(C6F5)(4-n)](-) (3) is produced with a quantum efficiency of 0.96 +/- 0.16 on irradiation of 1 with light having lambda < 450 nm. The rate law and analysis of intermediates supports a Zr(IV)/Zr(III) redox mechanism in which the rate-determining step is photodecomposition of 1 to generate 3 and silyl radicals by homolytic dissociation. In the presence of excess PhCH2SiH3 3 reacts rapidly to give products.
Acs Symposium Series, 1988
... Auteur(s) / Author(s). HARROD JF (1) ; Affiliation(s) du ou des auteurs / Author(s) Affiliati... more ... Auteur(s) / Author(s). HARROD JF (1) ; Affiliation(s) du ou des auteurs / Author(s) Affiliation(s). (1) McGill univ., dep. ... Anglais Editeur / Publisher. Oxford University Press, Cary, NC, ETATS-UNIS (1974) (Revue) Mots-clés anglais / English Keywords. Mass spectrometry. ; ...
Journal of Organometallic Chemistry, 1995
ABSTRACT
Organometallics, 1997
The thermal decomposition of dibutylzirconocene (1) at room temperature affords paramagnetic buty... more The thermal decomposition of dibutylzirconocene (1) at room temperature affords paramagnetic butylzirconocene(III) (11), zirconocene(III) hydride (12), the diamagnetic butenylzirconocene(IV) hydride dimer 5a, and the 1,1-bis(cyclopentadienyl)-2-methyl-3-(zirconocenyl hydride)-1-zirconacyclobutane(IV) dimer 9. Initially, decomposition furnishes crotylzirconocene(IV) hydride (3a), followed by 1,1-bis(cyclopentadienyl)-2-ethyl-1-zirconacyclopropane(IV) (2a) and 1,1-bis(cyclopentadienyl)-3,4-diethyl-1-zirconacyclopentane(IV) (4a), listed in the order of appearance. This order suggests that the primary decomposition reaction is a γ-H abstraction, which leads to the formation of 1,1-bis(cyclopentadienyl)-2methyl-1-zirconacyclobutane(IV) (6a). The latter was not observed experimentally but is postulated on the basis of secondary products. Reactions leading to the above compounds are discussed from mechanistic and thermochemical points of view. The reported compounds have been characterized by either EPR or multidimensional, multinuclear NMR spectroscopy. Compound 3a has also been synthesized independently from zirconocene chloride hydride and crotylmagnesium bromide and undergoes the same rearrangements into 2a and then 4a. The allyl analog 3b, synthesized from zirconocene chloride hydride and allylmagnesium bromide, exhibits the same behavior and rearranges into 1,1-bis(cyclopentadienyl)-3,4dimethyl-1-zirconacyclopentane (4b).
Syn Reactiv Inorg Metal Org C, 1980
Inorg Chem Commun, 1999
The titanocene(III) complexes Cp2TiX(PMe3) (X=F, Cl, Br, I, Me, SMe) are readily synthesized by c... more The titanocene(III) complexes Cp2TiX(PMe3) (X=F, Cl, Br, I, Me, SMe) are readily synthesized by comproportionation reactions of Cp2Ti(PMe3)2 and Cp2TiX2. The products are characterized by EPR spectroscopy.
Journal of Organometallic Chemistry, 1976
ABSTRACT
ChemInform, 2000
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Coordination Chemistry Reviews, 2000
Organometallics, 2000
ABSTRACT A kinetic study of the photochemical reaction of [Cp2Zr(mu-SiH2Ph)](2)(2+)2[BBun(C6F5)(4... more ABSTRACT A kinetic study of the photochemical reaction of [Cp2Zr(mu-SiH2Ph)](2)(2+)2[BBun(C6F5)(4-n)](-) (1) with PhCH2SiH3 to give the analogous PhCH2SiH2 complex 2 was carried out using a combination of NMR and EPR spectroscopy to follow the rates of disappearance of reactants and the appearance of intermediates and products. The paramagnetic intermediate [Cp2ZrIII](+)[BBun(C6F5)(4-n)](-) (3) is produced with a quantum efficiency of 0.96 +/- 0.16 on irradiation of 1 with light having lambda < 450 nm. The rate law and analysis of intermediates supports a Zr(IV)/Zr(III) redox mechanism in which the rate-determining step is photodecomposition of 1 to generate 3 and silyl radicals by homolytic dissociation. In the presence of excess PhCH2SiH3 3 reacts rapidly to give products.
Acs Symposium Series, 1988
... Auteur(s) / Author(s). HARROD JF (1) ; Affiliation(s) du ou des auteurs / Author(s) Affiliati... more ... Auteur(s) / Author(s). HARROD JF (1) ; Affiliation(s) du ou des auteurs / Author(s) Affiliation(s). (1) McGill univ., dep. ... Anglais Editeur / Publisher. Oxford University Press, Cary, NC, ETATS-UNIS (1974) (Revue) Mots-clés anglais / English Keywords. Mass spectrometry. ; ...
Journal of Organometallic Chemistry, 1995
ABSTRACT
Organometallics, 1997
The thermal decomposition of dibutylzirconocene (1) at room temperature affords paramagnetic buty... more The thermal decomposition of dibutylzirconocene (1) at room temperature affords paramagnetic butylzirconocene(III) (11), zirconocene(III) hydride (12), the diamagnetic butenylzirconocene(IV) hydride dimer 5a, and the 1,1-bis(cyclopentadienyl)-2-methyl-3-(zirconocenyl hydride)-1-zirconacyclobutane(IV) dimer 9. Initially, decomposition furnishes crotylzirconocene(IV) hydride (3a), followed by 1,1-bis(cyclopentadienyl)-2-ethyl-1-zirconacyclopropane(IV) (2a) and 1,1-bis(cyclopentadienyl)-3,4-diethyl-1-zirconacyclopentane(IV) (4a), listed in the order of appearance. This order suggests that the primary decomposition reaction is a γ-H abstraction, which leads to the formation of 1,1-bis(cyclopentadienyl)-2methyl-1-zirconacyclobutane(IV) (6a). The latter was not observed experimentally but is postulated on the basis of secondary products. Reactions leading to the above compounds are discussed from mechanistic and thermochemical points of view. The reported compounds have been characterized by either EPR or multidimensional, multinuclear NMR spectroscopy. Compound 3a has also been synthesized independently from zirconocene chloride hydride and crotylmagnesium bromide and undergoes the same rearrangements into 2a and then 4a. The allyl analog 3b, synthesized from zirconocene chloride hydride and allylmagnesium bromide, exhibits the same behavior and rearranges into 1,1-bis(cyclopentadienyl)-3,4dimethyl-1-zirconacyclopentane (4b).
Syn Reactiv Inorg Metal Org C, 1980
Inorg Chem Commun, 1999
The titanocene(III) complexes Cp2TiX(PMe3) (X=F, Cl, Br, I, Me, SMe) are readily synthesized by c... more The titanocene(III) complexes Cp2TiX(PMe3) (X=F, Cl, Br, I, Me, SMe) are readily synthesized by comproportionation reactions of Cp2Ti(PMe3)2 and Cp2TiX2. The products are characterized by EPR spectroscopy.