eprintid: 9905 rev_number: 4 userid: 6 dir: disk0/00/00/99/05 datestamp: 2011-11-10 20:07:11 lastmod: 2016-11-15 13:52:35 status_changed: 2011-11-10 20:07:11 type: thesis_degree metadata_visibility: show contact_email: jaw27@pitt.edu item_issues_count: 0 eprint_status: archive creators_name: Wei, Jianjun creators_email: jaw27@pitt.edu creators_id: JAW27 title: Heterogeneous Electron Transfer of Supramolecular Assemblies ispublished: unpub divisions: sch_as_chemistry full_text_status: public keywords: Cytochrome c; Electron transfer; Porphyrins; Electrochemistry; Self-assembled Monolayers abstract: Heterogeneous electron transfer of protein, porphyrins through self-assembled monolayer (SAM) at gold electrodes was studied. The SAM was characterized by electrochemistry, thickness measurement, contact angle, scanning tunneling microscopy (STM) and others. The electron transfer rate constants of cytochrome c immobilized on a SAM by directly ¡°wiring¡± its heme through a variety of nitrogen ligands (pyridine, imidazole or nitrilE) were measured by cyclic voltammetry. The electron transfer mechanism was explored by changing the distance between the electrode and protein, the composition of the SAM chains, the type of cytochrome c (horse heart cytochrome, rat cytochrome c and its mutants), and the conditions of electrolyte solutions. The results were compared to those of cytochrome c electrostatically adsorbed at carboxylic acid terminated SAMs, distinguishing the electron transfer mechanism and electron transfer pathways. A unified theoretical model, i.e. a gradual transition of the mechanism from a friction controlled reaction at short distance to tunneling controlled reaction at long distance, was applied to these ¡°heme-wired¡± systems. In a study of photo-induced electron transfer of porphyrins through SAMs with chiral structure, an asymmetrical effect on the efficiency of electron transfer through these chiral chain structures was found. Induced circular dichroism of porphyrin aggregates, orbital angular momentum interaction in electronic coupling, are proposed as possible mechanisms for the asymmetry of electronic tunneling. date: 2005-02-01 date_type: completed institution: University of Pittsburgh refereed: TRUE etdcommittee_type: committee_chair etdcommittee_type: committee_member etdcommittee_type: committee_member etdcommittee_type: committee_member etdcommittee_name: Waldeck, David H etdcommittee_name: Armitage, Bruce A etdcommittee_name: Walker, Gilbert etdcommittee_name: Amemiya, Shigeru etdcommittee_email: dave@pitt.edu etdcommittee_email: army@andrew.cmu.edu etdcommittee_email: gilbertw@pitt.edu etdcommittee_email: amemiya@pitt.edu etdcommittee_id: DAVE etdcommittee_id: etdcommittee_id: GILBERTW etdcommittee_id: AMEMIYA etd_defense_date: 2004-11-23 etd_approval_date: 2005-02-01 etd_submission_date: 2004-12-01 etd_access_restriction: immediate etd_patent_pending: FALSE assigned_doi: doi:10.5195/pitt.etd.2011.9905 thesis_type: dissertation degree: PhD committee: David H. Waldeck (dave@pitt.edu) - Committee Chair committee: Bruce A. Armitage (army@andrew.cmu.edu) - Committee Member committee: Gilbert Walker (gilbertw@pitt.edu) - Committee Member committee: Shigeru Amemiya (amemiya@pitt.edu) - Committee Member etdurn: etd-12012004-172612 other_id: http://etd.library.pitt.edu/ETD/available/etd-12012004-172612/ other_id: etd-12012004-172612 citation: Wei, Jianjun (2005) Heterogeneous Electron Transfer of Supramolecular Assemblies. Doctoral Dissertation, University of Pittsburgh. (Unpublished) document_url: http://d-scholarship-dev.library.pitt.edu/9905/1/WeiJianjun12042004thesis.pdf