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You searched for subject:(Methyl Group Transfer). Showing records 1 – 2 of 2 total matches.

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University of Georgia

1. Sanderson, Cynthia Therese. Characterization of benzoyl-substituted group 8 metallocenes as photochemical initiators for the anionic polymerization of vinylic monomers.

Degree: 2014, University of Georgia

This thesis demonstrates that ferrocene, ruthenocene, and their benzoylsubstituted analogs are photoinitiators for the anionic polymerization of ethyl 2- cyanoacrylate and evaluates the effectiveness of these photoinitiators based on the rates of polymerization as determined by attenuated-total-reflectance Fouriertransform infrared spectroscopy (ATR-FTIR). While all of these compounds are effective photoinitiators, the mechanism of photoinitiation depends on which metal is present and whether or not the compound contains electron-withdrawing benzoyl groups. The parent compounds exhibit solvent insensitive ligand field transitions in the visible/near UV region of the spectrum, and resist photoinduced ring loss. Photoinitiation is thereby shown to occur via a photoactive chargetransfer- to-solvent complex between the metallocene and the cyanoacrylate monomer which results in the oxidation of the unsubstituted metallocene and reduction of the electrophilic monomer. In contrast, addition of one or more benzoyl groups to the cyclopentadienyl rings of the metallocene causes the mixing of charge-transfer character (metal-to-ligand) into the ligand field transitions of the parent compound. This charge-transfer character is manifested by an increase in the intensity of the electronic transition, which is accompanied by a shift to lower energy as compared to the transitions of the parent compounds. The nature of this charge transfer character has been studied using resonance Raman spectroscopy, and it is shown that the assignment of metal-toligand charge transfer is accurate for all of the benzoyl-substituted metallocenes studied. In the case of 1,1’-dibenzoylferrocene, this metal-to-ligand charge transfer character is responsible for photoinduced ring loss which occurs upon irradiation into the low-energy electronic transition. This photoreaction has been studied using an on-line photolysis procedure which allows the identification of short-lived photoproducts by mass spectrometry. For the ruthenium containing compounds, addition of a benzoyl group to one or both of the cyclopentadienyl rings causes similar spectral changes as those seen in the case of the iron analogs; however, there is no indication that the primary photochemical reaction is ring loss. Rather, photoinitiation occurs via the same charge-transfer-to-solvent mechanism as seen for the unsubstituted metallocenes. Finally, this manuscript attempts to expand the use of these photoinitiators to another vinylic monomer, methyl methacrylate, which is also susceptible to anionic attack.

Subjects/Keywords: ferrocene; ruthenocene; 1,1\'-dibenzoylferrocene; benzoylruthenocene; 1,1\'-dibenzoylruthenocene; cyanoacrylate; methyl methacrylate; group transfer polymerization; mass spectrometry; resonance Raman spectroscopy; photoinitiated anionic polymerization; attenuated-total-reflectance Fourier-transform infrared spectroscopy

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Sanderson, C. T. (2014). Characterization of benzoyl-substituted group 8 metallocenes as photochemical initiators for the anionic polymerization of vinylic monomers. (Thesis). University of Georgia. Retrieved from http://hdl.handle.net/10724/21968

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Sanderson, Cynthia Therese. “Characterization of benzoyl-substituted group 8 metallocenes as photochemical initiators for the anionic polymerization of vinylic monomers.” 2014. Thesis, University of Georgia. Accessed March 05, 2021. http://hdl.handle.net/10724/21968.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Sanderson, Cynthia Therese. “Characterization of benzoyl-substituted group 8 metallocenes as photochemical initiators for the anionic polymerization of vinylic monomers.” 2014. Web. 05 Mar 2021.

Vancouver:

Sanderson CT. Characterization of benzoyl-substituted group 8 metallocenes as photochemical initiators for the anionic polymerization of vinylic monomers. [Internet] [Thesis]. University of Georgia; 2014. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/10724/21968.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Sanderson CT. Characterization of benzoyl-substituted group 8 metallocenes as photochemical initiators for the anionic polymerization of vinylic monomers. [Thesis]. University of Georgia; 2014. Available from: http://hdl.handle.net/10724/21968

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

2. Remy, Matthew Sean. Group 10 Methyl Transfer Reactions toward Catalyst Development for Oxidative Oligomerization of Methane.

Degree: PhD, Chemistry, 2011, University of Michigan

Abstract Group 10 Methyl Transfer Reactions toward Catalyst Development for Oxidative Oligomerization of Methane by Matthew Sean Remy Chair: Melanie S. Sanford One of the challenges of developing a homogeneous catalyst for oxidative oligomerization of methane (OOM) is promoting a C–C coupling reaction from the product of alkane C–H activation. Heterolytic C–H activation of methane almost exclusively generates a monoalkyl-metal species. In order to make a new C–C bond, it is proposed that a polymethyl intermediate must be generated. Our studies showed that aryl disproportionation is far more favorable than methyl disproportionation. Careful tuning of ancillary ligands at monomethyl-palladium(II) complexes using density functional theory (DFT) calculations facilitated optimization of thermodynamics for methyl disproportionation. This allowed the first observed disproportionation reaction to form a dimethyl-palladium(II) complex. Heating dimethyl complex (tBu-bpy)PdII(CH3)2 (tBu-bpy = 4,4-ditertbutyl-2,2-bipyridine) to 100 °C produced a mixture of methane and ethane over 24 h. One-electron oxidants and 1,4-benzoquinone were found to be effective promoters of ethane formation from (tBu-bpy)PdII(CH3)2 at 25 °C. Mechanistic study of one-electron oxidation uncovered an oxidatively-induced methyl transfer reaction which produced ethane from [(tBu-bpy)PdIV(CH3)3(solvent)]+. Subsequently, one-electron oxidation of complexes of the general formula (tBu-bpy)PdII(CH3)X was developed as an effective method for generation of ethane from monomethyl-palladium(II) complexes. Platinum complexes, (N–N)PtII(CH3)2, similarly undergo one-electron to produce [(N–N)PtIV(CH3)3(solvent)]+. However, these platinum(IV) products are generally stable to reductive elimination of ethane. When the N–N ligand is designed to have steric interactions with axial ligands of platinum(IV), ethane reductive elimination becomes favorable, occurring cleanly over 8.5 hours in acetone and over 1 h in dichloromethane. This document describes experimental evidence for the generation of polymethyl palladium and platinum complexes from model palladium(II) and platinum(II) products of C–H activation subsequent ethane elimination from the polymethyl complexes. In an unrelated project, N-insertion into palladium-carbon bond was observed when palladium(II) complexes of bidentate C–N ligands were reacted with an iminoiodinane oxidant. The reaction was proposed to occur through an imido-palladium(IV) intermediate. Advisors/Committee Members: Sanford, Melaine S. (committee member), Banaszak Holl, Mark M. (committee member), Hollenberg, Paul F. (committee member), Lehnert, Nicolai (committee member).

Subjects/Keywords: One-electron Oxidation of Palladium and Platinum; Methyl Group Transfer; Gas to Liquids; Chemistry; Science

…13 Methyl Transfer at Pd(II) Related to Disproportionation Formation of Dimethyl… …76 Scheme 3.46 Two Concepts for Facilitating Methyl Transfer Between Pd Complexes. . 77… …96 Scheme 4.26 Path 2, Mechanism B: Oxidatively-Induced Methyl Transfer… …x28;solvent)]+ (17OAc).... 102 Scheme 4.36 Methyl Group Scrambling in… …for Methyl Transfer between Platinum Complexes.19… 

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Remy, M. S. (2011). Group 10 Methyl Transfer Reactions toward Catalyst Development for Oxidative Oligomerization of Methane. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/86311

Chicago Manual of Style (16th Edition):

Remy, Matthew Sean. “Group 10 Methyl Transfer Reactions toward Catalyst Development for Oxidative Oligomerization of Methane.” 2011. Doctoral Dissertation, University of Michigan. Accessed March 05, 2021. http://hdl.handle.net/2027.42/86311.

MLA Handbook (7th Edition):

Remy, Matthew Sean. “Group 10 Methyl Transfer Reactions toward Catalyst Development for Oxidative Oligomerization of Methane.” 2011. Web. 05 Mar 2021.

Vancouver:

Remy MS. Group 10 Methyl Transfer Reactions toward Catalyst Development for Oxidative Oligomerization of Methane. [Internet] [Doctoral dissertation]. University of Michigan; 2011. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/2027.42/86311.

Council of Science Editors:

Remy MS. Group 10 Methyl Transfer Reactions toward Catalyst Development for Oxidative Oligomerization of Methane. [Doctoral Dissertation]. University of Michigan; 2011. Available from: http://hdl.handle.net/2027.42/86311

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