Abstract
We report a general method for the preparation and crystallization of highly oxidized metal complexes that are difficult to prepare and handle by more conventional means. This method improves typical bulk electrolysis and crystallization conditions for these reactive species by substituting oxidation-prone organic electrolytes and precipitants with oxidation-resistant compounds. Specifically, we find that CsPF6 is an effective inert electrolyte in acetonitrile, and appears to have general applicability to electrochemical studies in this solvent. Likewise, CCl4 is not only an oxidation-resistant precipitant for crystallization from MeCN but it also enters the lattice. In this way, we synthesized and characterized an Ir(V,V) mono-μ-oxo dimer which only forms at a very high potential (1.9 V vs NHE). This compound, having the highest isolated oxidation state in this redox-active system, cannot be formed chemically. DFT calculations show that the oxidation is centered on the Ir-O-Ir core and facilitated by strong electron-donation from the pyalk (2-(2-pyridinyl)-2-propanolate) ligand. TD-DFT simulations of the UV-visible spectrum reveal that its royal blue color arises from electron excitations with mixed LMCT and Laporte-allowed d-d character. We have also crystallographically characterized a related monomeric Ir(V) complex, similarly prepared by oxidizing a previously reported Ir(IV) compound at 1.7 V, underscoring the general applicability of this method.
| Original language | English |
|---|---|
| Pages (from-to) | 5684-5691 |
| Number of pages | 8 |
| Journal | Inorganic Chemistry |
| Volume | 57 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - May 7 2018 |
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ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry
Cite this
A Dinuclear Iridium(V,V) Oxo-Bridged Complex Characterized Using a Bulk Electrolysis Technique for Crystallizing Highly Oxidizing Compounds. / Shopov, Dimitar Y.; Sharninghausen, Liam S.; Sinha, Shashi Bhushan; Mercado, Brandon Q.; Balcells, David; Brudvig, Gary W; Crabtree, Robert H.
In: Inorganic Chemistry, Vol. 57, No. 9, 07.05.2018, p. 5684-5691.Research output: Contribution to journal › Article
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TY - JOUR
T1 - A Dinuclear Iridium(V,V) Oxo-Bridged Complex Characterized Using a Bulk Electrolysis Technique for Crystallizing Highly Oxidizing Compounds
AU - Shopov, Dimitar Y.
AU - Sharninghausen, Liam S.
AU - Sinha, Shashi Bhushan
AU - Mercado, Brandon Q.
AU - Balcells, David
AU - Brudvig, Gary W
AU - Crabtree, Robert H.
PY - 2018/5/7
Y1 - 2018/5/7
N2 - We report a general method for the preparation and crystallization of highly oxidized metal complexes that are difficult to prepare and handle by more conventional means. This method improves typical bulk electrolysis and crystallization conditions for these reactive species by substituting oxidation-prone organic electrolytes and precipitants with oxidation-resistant compounds. Specifically, we find that CsPF6 is an effective inert electrolyte in acetonitrile, and appears to have general applicability to electrochemical studies in this solvent. Likewise, CCl4 is not only an oxidation-resistant precipitant for crystallization from MeCN but it also enters the lattice. In this way, we synthesized and characterized an Ir(V,V) mono-μ-oxo dimer which only forms at a very high potential (1.9 V vs NHE). This compound, having the highest isolated oxidation state in this redox-active system, cannot be formed chemically. DFT calculations show that the oxidation is centered on the Ir-O-Ir core and facilitated by strong electron-donation from the pyalk (2-(2-pyridinyl)-2-propanolate) ligand. TD-DFT simulations of the UV-visible spectrum reveal that its royal blue color arises from electron excitations with mixed LMCT and Laporte-allowed d-d character. We have also crystallographically characterized a related monomeric Ir(V) complex, similarly prepared by oxidizing a previously reported Ir(IV) compound at 1.7 V, underscoring the general applicability of this method.
AB - We report a general method for the preparation and crystallization of highly oxidized metal complexes that are difficult to prepare and handle by more conventional means. This method improves typical bulk electrolysis and crystallization conditions for these reactive species by substituting oxidation-prone organic electrolytes and precipitants with oxidation-resistant compounds. Specifically, we find that CsPF6 is an effective inert electrolyte in acetonitrile, and appears to have general applicability to electrochemical studies in this solvent. Likewise, CCl4 is not only an oxidation-resistant precipitant for crystallization from MeCN but it also enters the lattice. In this way, we synthesized and characterized an Ir(V,V) mono-μ-oxo dimer which only forms at a very high potential (1.9 V vs NHE). This compound, having the highest isolated oxidation state in this redox-active system, cannot be formed chemically. DFT calculations show that the oxidation is centered on the Ir-O-Ir core and facilitated by strong electron-donation from the pyalk (2-(2-pyridinyl)-2-propanolate) ligand. TD-DFT simulations of the UV-visible spectrum reveal that its royal blue color arises from electron excitations with mixed LMCT and Laporte-allowed d-d character. We have also crystallographically characterized a related monomeric Ir(V) complex, similarly prepared by oxidizing a previously reported Ir(IV) compound at 1.7 V, underscoring the general applicability of this method.
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U2 - 10.1021/acs.inorgchem.8b00757
DO - 10.1021/acs.inorgchem.8b00757
M3 - Article
VL - 57
SP - 5684
EP - 5691
JO - Inorganic Chemistry
JF - Inorganic Chemistry
SN - 0020-1669
IS - 9
ER -