Synthetic analogs of the active sites of iron-sulfur proteins. XI. Synthesis and properties of complexes containing the iron sulfide (Fe2S2) core and the structures of bis[o-xylyl-.alpha.,.alpha.'-dithiolato-.mu.-sulfido-ferrate(III)] and bis[p-tolylthiolato-.mu.-sulfido-ferrate(III)] dianions

Abstract

Das aus Bis(oz‐mercapto)‐o‐xylol (I) und FeCl3 darstellbare" Dianion (II) entspricht in seiner Elektronenstruktur den aktiven Bestandteilen der P?anzenferredoxine und Ferredoxinproteine (spektroskopische und magnetische Daten).

Spin-adapted density matrix renormalization group algorithms for quantum chemistry

“…Figure 3. We constructed the geometry (see supplementary information 58 ) by replacing p-toluene groups with methyl groups in the crystal structure of the [Fe 2 S 2 (S-p-tol) 4 ] 2− complex synthesized by Mayerle et al 53 To determine the active space, first we carried out an UBP86/SVP calculation 54 on the high spin state of the molecule (S z = 10). Next, the doubly occupied and singly occupied alpha valence molecular orbitals were localized by using the Pipek-Mezey localization scheme.…”

Identification of the iron-sulfur center in trimethylamine dehydrogenase.

“…These analogues have been independently prepared and studied (8)(9)(10)(11) Enzyme Preparation. TMADH was isolated from bacterium W3A1 and purified as described previously (1).…”

“…The blue shift of the band maximum (444-425 nm) upon passing from aqueous to the aproticaqueous solvent is indicative of a change in protein structure and chromophore environment. Previous studies (4-7) have utilized as extruding reagent benzenethiol, whose complexes I and II in reaction 2 possess in this range intense bands from which core structures may be identified and quantitated (5,11 isolated as its crystalline tetraphenylarsonium salt. As for a number of lower molecular weight Fe-S* proteins (5,6), an 80% HMPA/H20 solvent medium whose aqueous component was buffered to pH 8.5 has proven adequate for solubilization and stabilization of TMADH prior to execution of the core extrusion reactions [2].…”

Synthetic analogs of active sites of iron-sulfur proteins: bis (o-xylyldithiolato) ferrate (III) monoanion, a structurally unconstrained model for the rubredoxin Fe-S4 unit.

“…Thus [Fe4S4(SR)4]2-(1) and [Fe2S2(S2-o-xyl)2]2- (2), whose precise structures have been determined (10)(11)(12), have been shown to be synthetic analogs of the active sites of HPred and 4-and 8-Fe Fdo0, and 2-Fe FdNO proteins, respectively.…”

“…For Ho = 80 kOe this (25,27,28). These internal fields are reduced from the usual saturation value of about -500 kOe (31) (12,16,23,24) and represent influences of protein tertiary structure and active site environment which are not yet interpretable (23,24).…”