Date of Award
1991
Degree Type
Dissertation
Degree Name
Doctor of Philosophy
Abstract
The work presented in this thesis concerns the synthesis and characterization of a series of novel phosphine-carbonyl complexes of cobalt. Chapters 2 and 3 outline mononuclear and homodinuclear cobalt complexes, chapters 4 and 5 discuss heterobimetallic complexes (CoM(CO){dollar}\sb{lcub}\rm n{rcub}{dollar}({dollar}\mu{dollar}-dppm){dollar}\sb2{dollar}) (M = Rh,n = 3; M = Mn or Re, n = 5), and finally chapters 6 and 7 discuss complexes containing the {dollar}\mu{dollar}-PPh{dollar}\sb2{dollar} group and the complex ((CO){dollar}\sb2{dollar}({dollar}\eta\sp1{dollar}-dppm) Co({dollar}\mu{dollar}-dppm)BH{dollar}\sb2{dollar}), respectively.;Introduction of CO into Co(II)/phosphine/NaBH{dollar}\sb4{dollar} reaction systems, previously shown to produce a number of interesting complexes, has provided a novel approach to the synthesis of phosphine-carbonyl complexes of cobalt. A number of complexes were isolated including the previously known (CoH(CO) (PPh{dollar}\sb3)\sb3{dollar}) and also (Co(CO) (PP){dollar}\sb2{dollar}) {dollar}\sp+{dollar} (PP = dppm or dppe). In addition isomers of {dollar}\{lcub}{dollar}Co(CO){dollar}\sb2{dollar}(dppm){dollar}\{rcub}\sb2{dollar}, were prepared by this method. By introduction of RhCl{dollar}\sb3\cdot{dollar} (H{dollar}\sb2{dollar}O){dollar}\sb{lcub}\rm n{rcub}{dollar} into the reaction system, the heterobimetallic complex (CoRh(CO){dollar}\sb3(\mu{dollar}-dppm){dollar}\sb2{dollar}) was isolated. Complexes (M(CO) (dppm){dollar}\sb2{dollar}) (Co(CO){dollar}\sb4{dollar}), isolated for M = Co, and observed by {dollar}\sp{lcub}31{rcub}{dollar}P and {dollar}\sp{lcub}13{rcub}{dollar}C in the case of M = Rh, were observed to lose CO in the formation of complexes (CoM(CO){dollar}\sb{lcub}\rm n{rcub}(\mu{dollar}-dppm){dollar}\sb2{dollar}) (M = Co, n = 4; M = Rh, n = 3). Similarly the (Co(CO)(dppm){dollar}\sb2{dollar}) {dollar}\sp+{dollar} cation reacted with other metal carbonyl anions (M(CO){dollar}\sb5{dollar}) {dollar}\sp-{dollar} (M = Mn or Re) to give the complexes ((CO){dollar}\sb2{dollar} ({dollar}\eta\sp1{dollar}-dppm) Co({dollar}\mu{dollar}-dppm)M(CO){dollar}\sb4{dollar}) and (CoM(CO){dollar}\sb5(\mu{dollar}-dppm){dollar}\sb2{dollar}).;The fluxionality of (CoM(CO){dollar}\sb{lcub}\rm n{rcub}(\mu{dollar}-dppm){dollar}\sb2{dollar}) (M = Co, n = 4; M = Rh, n = 3; M = Mn, n = 5) and protonated derivatives (Co{dollar}\sb2(\mu{dollar}-H) (CO){dollar}\sb4(\mu{dollar}-dppm){dollar}\sb2{dollar}) {dollar}\sp+{dollar} and (CoRh({dollar}\mu{dollar}-H) (CO){dollar}\sb3(\mu{dollar}-dppm){dollar}\sb2{dollar}) {dollar}\sp+{dollar} was investigated by variable temperature {dollar}\sp1{dollar}H, {dollar}\sp{lcub}13{rcub}{dollar}C and {dollar}\sp{lcub}31{rcub}{dollar}P NMR and four types of fluxionality were observed.;The reactivity of complexes (CoM(CO){dollar}\sb{lcub}\rm n{rcub}(\mu{dollar}-dppm){dollar}\sb2{dollar}) (M = Co, n = 4; M = Rh, n = 3) was investigated with a range of inorganic oxidizing agents and complexes (CoM ({dollar}\mu{dollar}-X) ({dollar}\mu{dollar}-CO)({dollar}\mu{dollar}-dppm){dollar}\sb2{dollar}(CO){dollar}\sb2{dollar}) {dollar}\sp{lcub}\rm n+{rcub}{dollar} (M = Co or Rh; X = Cl, n = 1; X = Br, n = 1; X = I, n = 1; X = S, n = 0) and (CoRh({dollar}\mu{dollar}-H) (CO){dollar}\sb{lcub}\rm n{rcub}{dollar}({dollar}\mu{dollar}-dppm){dollar}\sb2{dollar}) {dollar}\sp+{dollar} (M = Co, n = 4; M = Rh, n = 3) were characterized. The reactivity of (CoM(CO){dollar}\sb{lcub}\rm n{rcub}{dollar}({dollar}\mu{dollar}-dppm){dollar}\sb2{dollar}) towards olefins was demonstrated to be limited.;Surprising results from the Co(II)/dppm/NaBH{dollar}\sb4{dollar}/CO reaction systems were the isolation of complexes (Co{dollar}\sb2{dollar}({dollar}\mu{dollar}-H) ({dollar}\mu{dollar}-PPh{dollar}\sb2{dollar}) ({dollar}\mu{dollar}-dppm){dollar}\sb{lcub}\rm n{rcub}{dollar}(CO){dollar}\sb{lcub}\rm 6-2n{rcub}{dollar}) (n = 1 or 2) and (Ni{dollar}\sb2{dollar}({dollar}\mu{dollar}-PPh{dollar}\sb2{dollar}) ({dollar}\mu{dollar}-dppm){dollar}\sb2{dollar}(CO){dollar}\sb2{dollar}) {dollar}\sp+{dollar}, resulting from the cleavage of a P-C bond in dppm under very mild conditions, and the isolation of ((CO){dollar}\sb2{dollar}({dollar}\eta\sp1{dollar}-dppm) Co({dollar}\mu{dollar}-dppm) BH{dollar}\sb2{dollar}) containing the first structurally characterized simple metal-BH{dollar}\sb2{dollar} linkage.
Recommended Citation
Elliot, David J., "Homo- And Hetero-dinuclear Complexes Of Cobalt" (1991). Digitized Theses. 2057.
https://ir.lib.uwo.ca/digitizedtheses/2057