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Bio‐inspired Oxidation of 1‐Aminocarboxylic Acids by a Nonheme Iron(II) Complex: Mimicking the Activity of 1‐Aminocyclopropane‐1‐carboxylic Acid Oxidase
Author(s) -
Rahaman Rubina,
Munshi Sandip,
Paine Tapan Kanti
Publication year - 2018
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201800121
Subject(s) - chemistry , decarboxylation , ligand (biochemistry) , carboxylate , propanoic acid , carboxylic acid , denticity , stereochemistry , substrate (aquarium) , adduct , medicinal chemistry , metal , photochemistry , polymer chemistry , organic chemistry , catalysis , biochemistry , oceanography , receptor , geology
Three new ternary iron(II) complexes, [(Tp Ph2 )Fe II (ACC)] ( 1 ), [(Tp Ph2 )Fe II (ACH)] ( 2 ), and [(Tp Ph2 )Fe II (ADP)] ( 3 ) [Tp Ph2 = hydrotris(3,5‐diphenylpyrazol‐1‐yl)borate, ACC‐H = 1‐aminocyclopropane‐1‐carboxylic acid, ACH‐H = 1‐aminocyclohexane‐1‐carboxylic acid, and ADP‐H = 2‐amino‐2,2‐diphenylacetic acid] were isolated and characterized. X‐ray crystal structures of 1 and 2 reveal that in both the complexes the Tp Ph2 ligand binds to the central iron atom in a facial mode, and the respective 1‐aminocarboxylate monoanion displays bidentate binding mode through one carboxylate oxygen and one amine nitrogen donor. Complex 1 represents a structural model of the enzyme‐substrate adduct of the enzyme, 1‐aminocyclopropane‐1‐carboxylic acid oxidase (ACCO). The iron(II) complexes react with O 2 at ambient temperature to convert the metal coordinated coligands to the corresponding carbonyl compound but in low yields. The yields of the decarboxylated products, however, increase upon increasing the reaction temperature. Isotope labelling experiments and interception studies indicate that the reductive activation of O 2 at the central iron atom concomitant with two‐electron oxidative decarboxylation of the coligand following a pathway very similar to that proposed for the iron(II)‐α‐hydroxy acid complexes of the Tp Ph2 ligand.