Photooxidative Generation of Dodecaborate-Based Weakly Coordinating Anions
Abstract
Redox-active proanions of the type B_(12)(OCH_2Ar)_(12) [Ar = C_6F_5 (1), 4-CF_3C_6H_4 (2), 3,5-(CF_3)_2C_6H_3 (3)] are introduced in the context of an experimental and computational study of the visible-light-initiated polymerization of a family of styrenes. Neutral, air-stable proanions 1–3 were found to initiate styrene polymerization through single-electron oxidation under blue-light irradiation, resulting in polymers with number-average molecular weights (M_n) ranging from ∼6 to 100 kDa. Shorter polymer products were observed in the majority of experiments, except in the case of monomers containing 4-X (X = F, Cl, Br) substituents on the styrene monomer when polymerized in the presence of 1 in CH_2Cl_2. Only under these specific conditions are longer polymers (>100 kDa) observed, strongly supporting the formulation that reaction conditions significantly modulate the degree of ion pairing between the dodecaborate anion and cationic chain end. This also suggests that 1–3 behave as weakly coordinating anions (WCA) upon one-electron reduction because no incorporation of the cluster-based photoinitiators is observed in the polymeric products analyzed. Overall, this work is a conceptual realization of a single reagent that can serve as a strong photooxidant, subsequently forming a WCA.
Additional Information
© 2019 American Chemical Society. Received: March 30, 2019; Published: June 25, 2019. Special Issue: Celebrating the Year of the Periodic Table: Emerging Investigators in Inorganic Chemistry. The authors acknowledge Aayush Gupta (UIC) for preliminary computational work. M.S.M. was supported by NSF Bridge-to-Doctorate (Grant HRD-1400789) and Predoctoral Fellowship (Grant DGE-0707424) and the UCLA Christopher S. Foote Fellowship. H.B.G. was supported by the NSF (Grants CHE-1305124 and CHE-1763429). A.N.A. was supported by NSF CAREER Award CHE-1351968. Research pertaining to synthesis of the cluster compounds performed at UCLA was supported as part of the Synthetic Control Across Length-scales for Advancing Rechargeables (SCALAR) and Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award DE-SC0019381. A.M.S. thanks 3M for a Non-Tenured Faculty Award, the Alfred P. Sloan Foundation for a Fellowship in Chemistry, and the Research Corporation for Science Advancement (RCSA) for a Cottrell Scholar Award. M.D.S. acknowledges a Dr. Raymond and Dorothy Wilson Research Fellowship (UCLA). A.I.W. acknowledges the University of California, Los Angeles, Graduate Division, for a Dissertation Year Fellowship. The authors declare the following competing financial interest(s): UCLA holds patents on materials used in this work, from which A.M.S. may receive royalty payments.Attached Files
Supplemental Material - ic9b00935_si_001.pdf
Supplemental Material - ic9b00935_si_002.mov
Supplemental Material - ic9b00935_si_003.mov
Files
| Name | Size | Download all |
|---|---|---|
|
md5:cedd39bdfe5baabfb277668b3714184a
|
31.8 MB | Preview Download |
|
md5:3e206f9f054da7586f965e9d2926c210
|
2.0 MB | Download |
|
md5:db7081808921bf22b94f55fc07520177
|
1.7 MB | Download |
Additional details
- Eprint ID
- 96698
- Resolver ID
- CaltechAUTHORS:20190625-112728745
- HRD-1400789
- NSF
- DGE-0707424
- NSF Graduate Research Fellowship
- UCLA
- CHE-1305124
- NSF
- CHE-1763429
- NSF
- CHE-1351968
- NSF
- DE-SC0019381
- Department of Energy (DOE)
- 3M
- Alfred P. Sloan Foundation
- Cottrell Scholar of Research Corporation
- Created
-
2019-06-25Created from EPrint's datestamp field
- Updated
-
2021-11-16Created from EPrint's last_modified field