- Library Home /
- Search Collections /
- Open Collections /
- Browse Collections /
- UBC Theses and Dissertations /
- Iron(II) coordination compounds with improved octahedral...
Open Collections
UBC Theses and Dissertations
UBC Theses and Dissertations
Iron(II) coordination compounds with improved octahedral character and photophysical properties for solar energy harvesting Overney-Ragan, Tobias
Abstract
A series of novel Fe(II) coordination complexes were synthesized and investigated for enhanced structural and photophysical properties. Spacer sulfur atoms were introduced in a terpyridine ligand motif, and a near-perfect octahedral coordination environment resulted in the stabilization of the spin-crossover transition between LS and HS in the crystallographic state. Two nonequal Fe(II) centers were contained within the unit cell of the homoleptic complex Fe(TPS)₂, with bond lengths unambiguously attributed to different spin-states on the nonequal Fe(II) centers within the same crystal at 100 K, and a gradual increase to LS character at higher temperatures. Two pincer-type ligands were synthesized in an effort to improve the excited-state lifetime decay pathway in Fe(II) complexes. Both ligand motifs incorporated a coordinating amido bridging moiety, which resulted in panchromatic light absorption, with charge-transfer bands in the far-vis and NIR regions. Furthermore, computational calculations confirmed that both complexes’ HOMOs are composed of contributions from both metal and ligand orbitals, as opposed to metal-centered as in most classical complexes. A pincer ligand with flanking NHCs was successful in raising the ⁵MC energy to a noncompetitive height with respect to the ³MLCT state, resulting in deactivation of the excited state via the ³MC state. When the NHCs were substituted for pyridines in the second ligand framework, the decay pathway proceeded through the ³MLCT to the ³MC and ⁵MC states. In both cases, the excited state ³MLCT decays were more than an order of magnitude larger than those in the prototypical comparison complex, Fe(tpy)₂.
Item Metadata
Title |
Iron(II) coordination compounds with improved octahedral character and photophysical properties for solar energy harvesting
|
Creator | |
Supervisor | |
Publisher |
University of British Columbia
|
Date Issued |
2022
|
Description |
A series of novel Fe(II) coordination complexes were synthesized and investigated for enhanced structural and photophysical properties. Spacer sulfur atoms were introduced in a terpyridine ligand motif, and a near-perfect octahedral coordination environment resulted in the stabilization of the spin-crossover transition between LS and HS in the crystallographic state. Two nonequal Fe(II) centers were contained within the unit cell of the homoleptic complex Fe(TPS)₂, with bond lengths unambiguously attributed to different spin-states on the nonequal Fe(II) centers within the same crystal at 100 K, and a gradual increase to LS character at higher temperatures.
Two pincer-type ligands were synthesized in an effort to improve the excited-state lifetime decay pathway in Fe(II) complexes. Both ligand motifs incorporated a coordinating amido bridging moiety, which resulted in panchromatic light absorption, with charge-transfer bands in the far-vis and NIR regions. Furthermore, computational calculations confirmed that both complexes’ HOMOs are composed of contributions from both metal and ligand orbitals, as opposed to metal-centered as in most classical complexes. A pincer ligand with flanking NHCs was successful in raising the ⁵MC energy to a noncompetitive height with respect to the ³MLCT state, resulting in deactivation of the excited state via the ³MC state. When the NHCs were substituted for pyridines in the second ligand framework, the decay pathway proceeded through the ³MLCT to the ³MC and ⁵MC states. In both cases, the excited state ³MLCT decays were more than an order of magnitude larger than those in the prototypical comparison complex, Fe(tpy)₂.
|
Genre | |
Type | |
Language |
eng
|
Date Available |
2023-09-30
|
Provider |
Vancouver : University of British Columbia Library
|
Rights |
Attribution-NonCommercial-NoDerivatives 4.0 International
|
DOI |
10.14288/1.0417566
|
URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
|
Graduation Date |
2022-11
|
Campus | |
Scholarly Level |
Graduate
|
Rights URI | |
Aggregated Source Repository |
DSpace
|
Item Media
Item Citations and Data
Rights
Attribution-NonCommercial-NoDerivatives 4.0 International