Synthesis, structural characterization and conversion of dinuclear iron-sulfur clusters containing the disulfide ligand: [Cp*Fe(μ-η2:η2-bdt)(cis-μ-η1:η1-S2)FeCp*], [Cp*Fe(μ-S(C6H4S2))(cis-μ-η1:η1-S2)FeCp*], and [{Cp*Fe(bdt)}2(trans-μ-η1:η1-S2)]

Cyclic iron tetra N-heterocyclic carbenes: synthesis, properties, reactivity, and catalysis

Cyclic iron tetracarbenes are an emerging class of macrocyclic iron N-heterocyclic carbene (NHC) complexes. They can be considered as an organometallic compound class inspired by their heme analogs, however, their electronic properties differ, e.g. due to the very strong σ-donation of the four combined NHCs in equatorial coordination. The ligand framework of iron tetracarbenes can be readily modified, allowing fine-tuning of the structural and electronic properties of the complexes. The properties of iron tetracarbene complexes are discussed quantitatively and correlations are established. The electronic nature of the tetracarbene ligand allows the isolation of uncommon iron(III) and iron(IV) species and reveals a unique reactivity. Iron tetracarbenes are successfully applied in C-H activation, CO₂ reduction, aziridination and epoxidation catalysis and mechanisms as well as decomposition pathways are described. This review will help researchers evaluate the structural and electronic properties of their complexes and target their catalyst properties through ligand design.

Biomimetic catalytic oxidative coupling of thiols using thiolate-bridged dinuclear metal complexes containing iron in water under mild conditions

A green approach to disulfides via aerobic oxidative coupling of thiols was developed with a thiolate-bridged heteronuclear complex in water.

Synthesis and reactivity of thiolate-bridged multi-iron complexes supported by cyclic (alkyl)(amino)carbene

The combined utilization of Me₂-cAAC (Me₂-cAAC = :C(CH₂)(CMe₂)₂N-2,6-ⁱPr₂C₆H₃) and thiolates as supporting ligands enables the access of unprecedented carbene coordinated thiolate-bridged diiron(ii) complexes [(Me₂-cAAC)Fe(μ-SR)(Br)]₂ (R = Me, 3; R = Et, 4). The coordination environment of each tetrahedral iron(ii) center in complexes 3 and 4 is composed of one terminal bromide atom, one carbene carbon atom and two thiolate sulfur atoms, which is similar to the carbide-containing sulfur-rich environment of iron centers in the belt region of the FeMo-cofactor. Interestingly, when NaSCPh₃ was chosen as the thiolate ligand, C-S bond homolysis occurred to form a rare [3 : 1] site-differentiated cubane-type cluster [(Me₂-cAAC)Fe₄S₄(Br)₃][Me₂-cAACH] (5). Furthermore, complexes 3 and 4 exhibit good exchange reactivity toward the azide anion to give novel thiolate-bridged diiron complexes with two azido ligands in a trans arrangement.

Migratory insertion and hydrogenation of a bridging azide in a thiolate-bridged dicobalt reaction platform

A novel well-defined thiolate-bridged dicobalt azido complex is converted to a rare sulfilimide-bridged dicobalt complex via nitrogen atom migratory insertion into the Co-S bond upon thermolysis. Intriguingly, the homolytic cleavage of hydrogen is achieved by this azide under mild conditions to furnish a partially hydrogenated azido complex.