Comprehensive iron-selenium-thiolate cluster chemistry

Journal Article · Wed Sep 04 00:00:00 EDT 1991 · Inorganic Chemistry; (United States)

OSTI ID:7273740

Yu, Shibao; Holm, R H ^[1]; Papaefthymiou, G C ^[2]

---

1. Harvard Univ., Cambridge, MA (United States)
2. Massachusetts Inst. of Tech., Cambridge (United States)

Reconstitution of apoferredoxins and other proteins with iron salts and selenide has resulted in the incorporation of Fe{sub n}Se{sub n} clusters in proteins whose native clusters are Fe{sub n}S{sub n} (n = 2,4). These nonnative clusters have proven useful in interpreting certain electronic features of native cluster, and tend to occur in high-spin' forms (S {ge} 1/2). These observations have prompted investigation of a comprehensive set of Fe-Se-SR clusters. Reaction of (Et{sub 4}N){sub 2}(Fe(SEt){sub 4}) with 1 equiv of elemental Se in acetonitrile affords (Et{sub 4}N){sub 2}(Fe{sub 2}Se{sub 2}(SEt){sub 4}) (1, 55%). Ligand substitution of 1 with 4 equiv of PhSH gives (Et{sub 4}N){sub 2}(Fe{sub 2}Se{sub 2}(SPh){sub 4}) (2, 72%). Reaction of (Et{sub 4}N){sub 2}(Fe(SEt){sub 4}) with 1.4 equiv of elemental Se in acetone gives (Et{sub 4}N){sub 3}(Fe{sub 3}Se{sub 4}(SEt){sub 4}) (3, 67%), which with PhSH is converted to (Et{sub 4}N){sub 3}(Fe{sub 3}Se{sub 4}(SPh){sub 4}) (4, 66%). The reaction system FeCl{sub 3}/Se/4NaSEt in ethanol assembles (Et{sub 4}N){sub 2}(Fe{sub 4}Se{sub 4}(SEt){sub 4}) (5, 66%). The (Fe{sub 4}({mu}{sub 3}-Se){sub 4}){sup 2+} core has the familiar cubane stereochemistry with a compressed tetragonal distortion from cubic symmetry. Reduction of 3 with Zn in acetonitrile or 5 with sodium acenaphthylenide in THF/acetonitrile gives (Et{sub 4}N){sub 3}(Fe{sub 4}Se{sub 4}(SEt){sub 4}) (6, 56-68%). The reaction system FeCl{sub 3}/Na{sub 2}Se{sub 2}/3NaSEt assembles (Et{sub 4}N){sub 4}(Fe{sub 6}Se{sub 9}(SEt){sub 2}) (7, 68%). Of all properties, isotropic shifts most readily distinguish Fe-S and Fe-Se clusters of the same nuclearity. Comparison of the structures of (Fe{sub 4}Q{sub 4}){sup 2+} structures (Q = S, Se) provides strong evidence that a compressed tetragonal geometry is the intrinsically preferred structure of this oxidation state.

• OSTI ID: 7273740
• Journal Information: Inorganic Chemistry; (United States), Vol. 30:18; ISSN 0020-1669
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
59 BASIC BIOLOGICAL SCIENCES
METALLOPROTEINS
CHEMICAL PREPARATION
CRYSTAL STRUCTURE
ABSORPTION SPECTROSCOPY
BOND ANGLE
BOND LENGTHS
ELECTROCHEMISTRY
ELECTRON SPIN RESONANCE
FERREDOXIN
GROUND STATES
IRON SELENIDES
MONOCLINIC LATTICES
NMR SPECTRA
ORTHORHOMBIC LATTICES
PROTEINS
SOLID CLUSTERS
TEMPERATURE RANGE 0000-0013 K
THIOLS
ULTRAVIOLET SPECTRA
X-RAY DIFFRACTION
CHALCOGENIDES
CHEMISTRY
COHERENT SCATTERING
CRYSTAL LATTICES
DIFFRACTION
DIMENSIONS
ENERGY LEVELS
IRON COMPOUNDS
LENGTH
MAGNETIC RESONANCE
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
RESONANCE
SCATTERING
SELENIDES
SELENIUM COMPOUNDS
SPECTRA
SPECTROSCOPY
SYNTHESIS
TEMPERATURE RANGE
TRANSITION ELEMENT COMPOUNDS
400201* - Chemical & Physicochemical Properties
550200 - Biochemistry