The chemistry of transition metal complexes related to solar energy storage : H₂ production and small molecule (CO₂ and HX; X = Cl, Br) chemistry.

The studies in this thesis have focused on the chemistry of transition metal complexes related to solar energy storage: electrochemical H₂ production, HX splitting and CO₂ activation mediated by transition metal complexes. Transition metal complexes, for example with macrocyclic ligands, can catalyze electrochemical proton reduction, a half reaction of water splitting to H₂/O₂ by electricity generated by sunlight. The strategy for designing efficient molecular catalysts were explored by introducing a Hangman scaffold into metallomacrocyles. The study exhibits synthesis and electrochemistry of metallomacrocyles, and an example of Hangman effect for electrochemical H2 production. Thermodynamically demanding HX splitting to H₂/X₂ by sunlight can be a promising method for solar energy storage. To date, most HX splitting chemistry was studied with metal complexes based on 2"d or 3 rd row transition metals. Hence, the usage of cheaper first row metals is an imperative to discover economically viable catalytic systems. HX chemistry of Ni complexes and photoelimination of H₂ from Ni hydride complexes, and photoactivation of Ni-Cl bonds were studied. CO₂ can be utilized as a carrier of H₂ by the syntheses of liquid fuels from CO₂ and H₂. The challenge of using CO₂ as a precursor for organic molecules is the activation of strong O=CO bonds. The reaction with metal complexes is one of the methods to break or weaken the bonds. The CO₂ chemistry of Ni complexes was explored, and generation of a new binding mode of CO₂ and activation of CO₂ to CO were studied.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2011

Author dc:creator

• Lee, Changhoon, Ph. D. Massachusetts Institute of Technology

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/1721.1/68545

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/68545