A paramagnetic trigonal paddlewheel complex with iron-dithiolato ligand paddles: {[(C9H18N2S2)Fe(NO)]3Ag2}(BF4)2

Linear and Bent Nitric Oxide Ligand Binding in an Asymmetric Butterfly Complex:

Two synthetic approaches to install metallodithiolate ligands on molybdenum centers using the synthons [Mo₂(CH₃CN)₁₀]⁴⁺ and (N₂S₂)Co(NO) [N₂S₂ = N,N-bis(2-mercaptoethyl)-1,4-diazacycloheptane and NO = nitric oxide], or [Mo(NO)₂(CH₃CN)₄]²⁺ (CH₃CN = acetonitrile) and [(N₂S₂)Co]₂ lead to a bis-nitrosylated, trimetallic dication, CoMoCo'. This unique asymmetric butterfly complex, with S = 1, has a bent NO within the small {Co(NO)}⁸ wing (denoted as Co), reflecting Co^III(NO^-), and is S-bridged to a linear {Mo(NO)}⁶ diamagnetic unit. The latter is further S-bridged to a pentacoordinate (N₂S₂)Co^III(CH₃CN) donor in the larger wing and is the origin of the two unpaired electrons, denoted as Co'. The asymmetry in Mo-Co distances, 3.33 Å in the Co wing and 2.73 Å in the Co' wing, indicated a Mo-Co' bonding interaction. The transfer of NO from (N₂S₂)Co(NO) in the former path is needed to cleave the strong quadruple bond in [Mo≣Mo]⁴⁺, with the energetic cost compensated for via a one-electron bond between Mo and Co', as indicated by natural bonding orbital analysis.

Dioxygen controls the nitrosylation reactions of a protein-bound [4Fe4S] cluster

Iron–sulfur clusters are exceptionally tuneable protein cofactors, and as one of their many roles they are involved in biological responses to nitrosative stress.

Synthesis and characterization of a family of thioether-dithiolate-bridged heteronuclear iron complexes

The thioether-dithiolate-bridged heterotrinuclear complexes [Cp*Fe(μ-1_k³SSS':2_k²SS-tpdt)M(μ-2_k²SS:3_k³SSS'-tpdt)FeCp*][PF₆]₂ (Cp* = η⁵-C₅Me₅; tpdt = S(CH₂CH₂S)₂; 2, M = Co; 3, M = Ni; 4, M = Pd) have been prepared by a reaction of [Cp*Fe(η³-tpdt)] (1) with complexes CoCl₂, NiCl₂(PPh₃)₂, and PdCl₂(PPh₃)₂, respectively. Similarly, treatment of complex 1 with CuCl(PPh₃) or AgPF₆ afforded two heterotrinuclear complexes, [Cp*Fe(μ-1_k³SSS':2_k²SS-tpdt)M(μ-2_k²SS:3_k³SSS'-tpdt)FeCp*][PF₆] (5, M = Cu; 6, M = Ag), while reaction of 1 with the complex AuCl(PPh₃) gave a heterobinuclear complex, [Cp*Fe(μ-1_k³SSS':2_k¹S-tpdt)Au(PPh₃)][PF₆] (7). These complexes have been spectroscopically and crystallographically characterized. An X-ray diffraction analysis showed that complexes 2, 3, 5, and 6 feature a heterometal center binding four sulfur atoms of two tpdt ligands with a cis orientation. However, in the Pd-containing complex 4, two tpdt ligands are arranged in a trans configuration. The μ_eff data and EPR results indicate that complexes 2, 4, 5, 6, and 7 are paramagnetic and only complex 3 is diamagnetic. Electrochemical experiments on these heteronuclear clusters were performed at room temperature. Discrepancy of the redox couples in the CV plots of these complexes indicates different one-electron transfer processes.

Recent Advances in Multinuclear Metal Nitrosyl Complexes

The coordination chemistry of metal nitrosyls has expanded rapidly in the past decades due to major advances of nitric oxide and its metal compounds in biology. This review article highlights advances made in the area of multinuclear metal nitrosyl complexes, including Roussin's salts and their ester derivatives from 2003 to present. The review article focuses on isolated multinuclear metal nitrosyl complexes and is organized into different sections by the number of metal centers and bridging ligands.