87221-87-2

Upstream product

• 1020-31-1 3,5-Di-tert-butylcatechol 
• 3383-21-9 3,5-di-tert-butyl-o-benzoquinone 

Relevant academic research and scientific papers

A novel pentadentate redox-active ligand and its iron(III) complexes: Electronic structures and O2 reactivity

A novel redox-active ligand, H4Ph2SLAP (1) which was designed to be potentially pentadentate with an O,N,S,N,O donor set is described. Treatment of 1 with two equivalents of potassium hydride gave access to octametallic precursor complex [H2Ph2SL APK2(thf)]4 (2), which reacted with FeCl 3 to yield iron(III) complex [H2Ph2SL APFeCl] (3). Employing Fe[N(SiMe3)2] 3 for a direct reaction with 1 led to ligand rearrangement through C-S bond cleavage and thiolate formation, finally yielding [HLAPFe] (5). Upon exposure to O2, 3 and 5 are oxidized through formal hydrogen-atom abstraction from the ligand NH units to form [ Ph2SLSQFeCl] (4) and [LSQFe] (6) featuring two or one coordinated iminosemiquinone moieties, respectively. Moessbauer measurements demonstrated that the iron centers remain in their +III oxidation states. Compounds 3 and 5 were tested with respect to their potential as models for the catechol dioxygenase. Thus, they were treated with 3,5-di-tert-butyl- catechol, triethylamine and O2. It turned out that the iron-catecholate complexes react with O2 in dichloromethane at ambient conditions through C-C bond cleavage mainly forming extradiol cleavage products. Intradiol products are only side products and quinone formation becomes negligible. This observation has been rationalized by a dissociation of two donor functions upon coordination of the catecholate. A radical convention: A novel pentadentate O,N,S,N,O ligand system, LH4, which is redox active, has been developed, so that its iron(III) complex (H2LFeCl) reacts with O2. H atoms are abstracted from the NH units present so that the ligand is converted into a diradical, featuring two iminosemiquinonato moieties that clamp a high-spin iron(III) center. The complex proved capable of mimicking catechol dioxygenase reactivity, and mediates extradiol cleavage with remarkable selectivity.

Intradiol Oxygenation of 3,5-Di-t-butylcatechol Catalyzed by Iron(III) Salts

3,5-Di-t-butylcatechol is oxygenated by Fe(III) salts without addition of ligands in THF/water, DMF, or DMF/aqueous borate buffer to give intradiol cleavage products.Intermediate formation of semiquinonatoiron(II) and catecholatoiron(III) complexes is indicated by electronic, Moessbauer, ESR spectroscopy.

INTRA- AND EXTRADIOL OXYGENATIONS OF 3,5-DI-TERT-BUTYLCATECHOL CATALYZED BY BIPYRIDINEPYRIDINEIRON(III) COMPLEX

Iron(III) complex coordinated by 2,2'-bipyridine and pyridine catalyzes oxygenation of 3,5-di-t-butylcatechol with molecular oxygen to give intra- and extradiol fission products as well as oxidation to give 3,5-di-t-butyl-1,2-benzoquinone.Structures and reactivities of the products have indicated that the oxygenation proceeds by the Hamilton process rather than the dioxetane process.