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Structures and Reactions of Diplatinum Complexes

Citation

Darnton, Tania Victoria (2017) Structures and Reactions of Diplatinum Complexes. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/Z9NK3C2J. http://resolver.caltech.edu/CaltechTHESIS:04172017-185314743

Abstract

A d8−d8 complex [Pt2(μ-P2O5(BF2)4]4− (abbreviated Pt(pop-BF2)4−) undergoes two 1e reductions at E1/2 = −1.68 and Ep = −2.46 V (vs Fc+/Fc) producing reduced Pt(pop-B2)5− and superreduced Pt(pop-BF2)6− species, respectively. The EPR spectrum of Pt(pop-BF2)5− and UV−vis spectra of both the reduced and the superreduced complexes, together with TD-DFT calculations, reveal successive filling of the 6pσ orbital accompanied by gradual strengthening of Pt−Pt bonding interactions and, because of 6pσ delocalization, of Pt−P bonds in the course of the two reductions. Both reduction steps proceed without changing either d8 Pt electronic configuration, making the superreduced Pt(pop-BF2)6− a very rare 6p2 σ-bonded binuclear complex. However, the Pt−Pt σ bonding interaction is limited by the relatively long bridging-ligand-imposed Pt−Pt distance accompanied by repulsive electronic congestion. Pt(pop-BF2)4− is predicted to be a very strong photooxidant (potentials of +1.57 and +0.86 V are estimated for the singlet and triplet dσ*pσ excited states, respectively).

Further study of the electronic excited states of Pt(pop-BF2)4- in the presence of luminescence quenchers revealed Stern-Volmer type dynamic quenching of the triplet state by trialkyl and triaryl amines. Quenching of the singlet as well as the triplet was observed in the presence of CoII trisbipyridine complexes, but sample decomposition and the observed presence of simultaneous static and dynamic quenching behaviors hampered quantitative analysis.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:diplatinum pyrophosphito, luminescence, quenching
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Gray, Harry B.
Thesis Committee:
  • Okumura, Mitchio (chair)
  • Rees, Douglas C.
  • Gray, Harry B.
  • Lewis, Nathan Saul
Defense Date:1 August 2016
Non-Caltech Author Email:tdarnton (AT) gmail.com
Record Number:CaltechTHESIS:04172017-185314743
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:04172017-185314743
DOI:10.7907/Z9NK3C2J
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/jacs.6b02559DOIArticle adapted for Chapter 4.
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:10139
Collection:CaltechTHESIS
Deposited By: Tania Darnton
Deposited On:26 May 2017 20:31
Last Modified:02 Jun 2017 22:10

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