Probing the Mechanism for 2,4'-Dihydroxyacetophenone Dioxygenase Using Biomimetic Iron Complexes
| Autor: | Amitava Adhikary, William W. Brennessel, Jia Li, Ferman A. Chavez, Atanu Banerjee, Aramice Y.S. Malkhasian, Timothy A. Jackson, Adedamola A. Opalade, Monika A. Molenda |
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| Rok vydání: | 2021 |
| Předmět: |
Models
Molecular Denticity Molecular Structure 010405 organic chemistry Ligand Protonation 010402 general chemistry 01 natural sciences 0104 chemical sciences Dioxygenases Inorganic Chemistry Trigonal bipyramidal molecular geometry chemistry.chemical_compound Crystallography chemistry Dioxygenase Biomimetic Materials Octahedral molecular geometry Alcaligenes Physical and Theoretical Chemistry Trifluoromethanesulfonate Phosphine Density Functional Theory Iron Compounds |
| Zdroj: | Inorganic chemistry. 60(10) |
| ISSN: | 1520-510X |
| Popis: | In this study, we report the synthesis and characterization of [Fe(T1Et4iPrIP)(2-OH-AP)(OTf)](OTf) (2), [Fe(T1Et4iPrIP)(2-O-AP)](OTf) (3), and [Fe(T1Et4iPrIP)(DMF)3](OTf)3 (4) (T1Et4iPrIP = tris(1-ethyl-4-isopropyl-imidazolyl)phosphine; 2-OH-AP = 2-hydroxyacetophenone, and 2-O-AP- = monodeprotonated 2-hydroxyacetophenone). Both 2 and 3 serve as model complexes for the enzyme-substrate adduct for the nonheme enzyme 2,4'-dihydroacetophenone (DHAP) dioxygenase or DAD, while 4 serves as a model for the ferric form of DAD. Complexes 2-4 have been characterized by X-ray crystallography which reveals T1Et4iPrIP to bind iron in a tridentate fashion. Complex 2 additionally contains a bidentate 2-OH-AP ligand and a monodentate triflate ligand yielding distorted octahedral geometry, while 3 possesses a bidentate 2-O-AP- ligand and exhibits distorted trigonal bipyramidal geometry (τ = 0.56). Complex 4 displays distorted octahedral geometry with 3 DMF ligands completing the ligand set. The UV-vis spectrum of 2 matches more closely to the DAD-substrate spectrum than 3, and therefore, it is believed that the substrate for DAD is bound in the protonated form. TD-DFT studies indicate that visible absorption bands for 2 and 3 are due to MLCT bands. Complexes 2 and 3 are capable of oxidizing the coordinated substrate mimics in a stoichiometric and catalytic fashion in the presence of O2. Complex 4 does not convert 2-OH-AP to products under the same catalytic conditions; however, it becomes anaerobically reduced in the presence of 2 equiv 2-OH-AP to 2. |
| Databáze: | OpenAIRE |
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