Coordination Compounds with Delocalized Ground States. Bisdithiodiketone Complexes of Iron and Cobalt¹

Photochemical reactions of Fe(CO)5 with FcCCH in the presence of S-powder and CS2: Synthesis and characterization of [{μ-SC(H)C(Fc)S}(CO)6Fe2], [μ-SC(O)C(H)C(Fc)S}(CO)6Fe2]; cis-[μ-η1:η2:η1:η1-{C(Fc)C(H)CS2C(H)C(Fc)}(CO)6Fe2] and trans -[μ-η1:η2:η1:η1-{C(Fc)C(H)CS2C(Fc)C(H)}(CO)6Fe2]

“…The IR spectra of 1 and 2 display carbonyl stretching patterns typically observed in the spectra of compounds containing the Fe 2 (CO) 6 groups. The spectrum of compound 1 displays a carbonyl stretching pattern which is identical to that observed for earlier reported [{l-EC(H)@C(R)E 0 }-(CO) 6 Fe 2 ] (E, E 0 = S, Se,Te; R = Ph, Th, C"CCH 3 ) [9][10][11][12][13][14][15][16][17]. Compound 2 shows a band due to the presence of a ketonic carbonyl group at 1655 cm À1 , in addition to the terminal carbonyl bands.…”

Tuning Electronic Properties of Biomimetic [2Fe‐2S] Clusters by Ligand Variations

“…Spectral fits to the Mössbauer data were obtained by using Lorentzian line doublets with isomer shifts δ and quadrupole splittings ∆E Q summarized in Table 2 (the spectrum of 2 is shown in Figure 6 as an example [16] but do not reflect the electronic influences of the peripheral ligand sphere around the iron-sulfur core. In comparison to 2 (∆E Q = 0.86 mm/s) and 3 (∆E Q = 0.83 mm/s), complex 1 (∆E Q = 0.77 mm/s) exhibits a slightly lower quadrupole splitting, even though τ 4 values (that semi-quantify distortions of the coordination polyhedra from a perfect tetrahedron) are very similar for the three clusters reported here.…”

Transition Metal Sulfides and the Origins of Metabolism

“…It was soon discovered that various iron sulfur clusters (e.g., ferredoxins) could be synthesized by self-assembling mechanisms using a variety of reaction schemes (see, for example, Schrauzer et al 1966, Herskovitz et al 1972). There currently exists an enormous body of literature covering the synthesis of model ferredoxins ([Fe n S n (SR) 4 ] −2 , n = 2,4) and rubredoxins ([Fe(SR) 4 ] −2 ), review of which is far beyond the scope of this article (see Hagen et al 1981Hagen et al , 1983 for overviews).…”

“…In the course of an attempt to create biomimetic photosynthetic reaction centers, it was discovered that amino acids could be synthesized via a carbon fixation reaction that appeared to mimic the function of a critical enzyme, pyruvate synthase. The experiment started with gaseous CO 2 bubbled into a solution of tetrahydrofuran, methanol, and water (4:2:1) that contained synthetic iron-sulfur complex [Schrauzer's complex, Fe 2 S 4 C 4 Phenyl 4 ; Schrauzer et al (1966)], sodium hydrosulfite, and sodium bicarbonate. To this solution, Nakajima et al added a 578 CODY thioester, n-octyl thiol phenylacetate, a source of reactive and transferable nitrogen (pyridoxamine dihydrochloride), potassium hydroxide, and zinc acetate.…”