Metal-ligand redox interaction in the multielectron chemistry of porphyrinogen coordination compounds

Metal complexes of the macrocycle porphyrinogen (calix[4]pyrrole) are studied with an emphasis on the redox activity ("non-innocence") of the ligand (Chapter I). Porphyrinogen complexes of spherical, redox-inert metal dications exist in three oxidation states, dianionic, neutral, and dicationic, characterized structurally by zero, one, and two direct bonds between adjacent pyrroles, respectively. All three are isolated on the preparative scale, and interconverted electrochemically (Chapter II). Each carbon-carbon bond functions as a reservoir of two redox equivalents. The neutral oxidation state exhibits an optical intervalence charge transfer transition, characteristic of ligand-based two-electron mixed valency (Chapter III). Dianionic zinc porphyrinogen reacts with carbon dioxide, and neutral zirconium(IV) porphyrinogen with dioxygen. Two zirconium porphyrinogen units can carry a water molecule as an oxo bridging the metals and two protons on the ligands (Chapter IV). Iron porphyrinogen has three available oxidation states, a dianion, a monoanion, and a dication. The interconversion of the latter two is a selective three-electron transformation, preparatively and electrochemically (Chapter V). complex are largely decoupled from each other and can be chosen independently (Chapter IX).

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• Bachmann, Julien

Advisor dc:contributor.advisor

• Daniel G. Nocera.

• Chemistry.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/35314

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/35314