An Oxido-Bridged Diiron(II) Complex as Functional Model of Catechol Dioxygenase

作者：Dey Dhananjay; De Abhranil; Yadav Hare Ram; Guin Partha Sarathi; Choudhury Angshuman Roy; Kole Niranjan; Biswas Bhaskar

来源：ChemistrySelect, 2016, 1(9): 1910-1916.

DOI：10.1002/slct.201600575

<jats:title>Abstract</jats:title><jats:p>An oxido‐bridged diiron(II)‐phenanthroline complex, [Fe<jats:sub>2</jats:sub>O(phen)<jats:sub>2</jats:sub>Cl<jats:sub>2</jats:sub>] (<jats:bold>1</jats:bold>) [phen =1,10‐phenanthroline] has been synthesized from an oxido‐bridged diiron(III) precursor in presence of sodium azide and structurally characterized by different spectroscopic tools including single crystal X‐ray diffraction study.From X‐ray crystal structure of <jats:bold>1</jats:bold>, it is revealed that each of the Fe(II) centre is in distorted octahedral geometry with FeN<jats:sub>4</jats:sub>OCl core and the molecule crystallizes in <jats:italic>P</jats:italic>nc2 space group. Bond valence sum (BVS) calculation confirms the existence of iron ions in +2 oxidation state in <jats:bold>1</jats:bold>. The diiron(II) complex has been evaluated as model system for the catechol dioxygenase enzyme by using 3,5<jats:italic>‐</jats:italic>di‐<jats:italic>tert</jats:italic>‐butylcatechol (DTBC) as the substrate in acetonitrile medium, revealing that <jats:bold>1</jats:bold> efficiently mimics the catalytic cycle of catechol dioxygenase. Upon stoichiometric addition of DTBC pretreated with two equivalents of triethylamine (Et<jats:sub>3</jats:sub>N) to the diiron complex, two catecholate‐to‐iron(III) LMCT bands (515 nm and 734 nm) are observed. The in situgenerated catecholate adduct from <jats:bold>1</jats:bold>in acetonitrile solution react with dioxygen to afford exclusively extradiol cleavage products along with a small amount of benzoquinone, which is also discerned from the appearance and decrease in intensity of the electronic spectral bands around (708 nm; 507 nm) nm. Nucleophilic attack by molecular oxygen on catecholate adduct in solution provides substantial evidence for the regioselective extradiol cleavage products.</jats:p>

• 出版日期2016-6-16