Off-campus UMass Amherst users: To download dissertations, please use the following link to log into our proxy server with your UMass Amherst user name and password.
Non-UMass Amherst users, please click the view more button below to purchase a copy of this dissertation from Proquest.
(Some titles may also be available free of charge in our Open Access Dissertation Collection, so please check there first.)
SYNTHESIS, REACTIVITY, AND SPECTROSCOPIC PROPERTIES OF GROUP 4B METALLOCENE CARBONYL, PHOSPHINE, AND ACETYLENE COMPLEXES
Abstract
The metal carbonyl complexes, Cp(,2)M(CO)(,2) (M = Zr, Hf) and (C(,5)Me(,5))(,2)M(CO)(,2) (M = Ti, Zr, Hf) were prepared in good yield under mild conditions via the reductive carbonylation of the corresponding metallocene dichloride compound using activated magnesium metal as a reducing agent. Cp(,2)M(CO)(,2) and (C(,5)Me(,5))(,2)M(CO)(,2) (M = Ti, Zr, Hf) are photoactive. The photolysis of Cp(,2)Ti(CO)(,2) with PF(,3) results in the formation of Cp(,2)Ti(PF(,3))(,2) in high yield, while the irradiation of Cp(,2)Ti(CO)(,2) with PF(,2)N(Me)PF(,2) and PEt(,3) in aliphatic solvents yields the monocarbonylphosphine complexes Cp(,2)Ti(CO){PF(,2)N(Me)PF(,2)} and Cp(,2)Ti(CO)(PEt(,3)). The thermolysis of Cp(,2)Ti(CO)(,2) with PF(,2)N(Me)PF(,2) (pentane), PEt(,3), and PPh(,3) (hexane) was found to produce the respective monocarbonyl-phosphine complexes in good yield. The photochemical reaction of Cp(,2)M(CO)(,2) (M = Zr, Hf) with PF(,3), PMe(,3), and PPh(,3) led to the mono-substituted products Cp(,2)M(CO)(PR(,3)) (M = Zr, Hf) (R = F, Me, Ph). In the case of Cp(,2)Zr(CO)(,2) with PF(,3), the disubstituted product Cp(,2)Zr(PF(,3))(,2) could also be isolated. The titanocene monocarbonyl-phosphine complex Cp(,2)Ti(CO)(PEt(,3)) was found to be very reactive with pi-acceptor ligands (L) at room temperature or below resulting in the formation of the monocarbonyl complex Cp(,2)Ti(CO)(L), L = CO, PF(,3), PF(,2)N(Me)PF(,2), P(OPh)(,3), PhC(TBOND)CPh, Ph(,f)C(TBOND)CPh(,f), Ph(,f)C(TBOND)CPh, and MeOOCC(H)=C(H)COOMe. Cp(,2)Ti(CO)(PPh(,3)) exhibited similar reactivity as did Cp(,2)Ti(CO)(PEt(,3)), while Cp(,2)Ti(CO)(PF(,3)) proved to be less reactive. Both the thermal and photochemical reactions of Cp(,2)Ti(CO)(,2) with Ph(,f)C(TBOND)CPh(,f) and PhC(TBOND)CPh led to the formation of a novel 1,4-dititanacyclohexadiene complex, {Cp(,2)Ti(RC(TBOND)CR)}(,2) (R = Ph(,f), Ph), as the major product. The monocarbonyl-pi-acetylene complex Cp(,2)Ti(CO)(h('2)-RC(TBOND)CR) is postulated as a reaction intermediate to this dititanacycle. The thermolysis of Cp(,2)M(CO)(,2) (M = Zr, Hf) with two equivalents of RC(TBOND)CR (R = Ph, Ph(,f), Et) led to exclusive formation of the respective metallacyclopentadienes Cp(,2)M(RC(TBOND)CR)(,2) in very good yield. The photolysis of Cp(,2)M(CO)(,2) (M = Zr, Hf) with RC(TBOND)CR (R = Ph, Et) also resulted in exclusive formation of the respective metallacyclopentadiene Cp(,2)M(RC(TBOND)CR)(,2). When Cp(,2)Zr(CO)(,2) was thermolyzed with MeC(TBOND)CMe in a closed system, a novel complex containing tetramethylcyclopentadienone ligands was formed. A similar reaction with PhC(TBOND)CPh gave tetracyclone as the major product.
Subject Area
Chemistry
Recommended Citation
SIKORA, DAVID JOHN, "SYNTHESIS, REACTIVITY, AND SPECTROSCOPIC PROPERTIES OF GROUP 4B METALLOCENE CARBONYL, PHOSPHINE, AND ACETYLENE COMPLEXES" (1982). Doctoral Dissertations Available from Proquest. AAI8229610.
https://scholarworks.umass.edu/dissertations/AAI8229610