Hydrosulfide Oxidation at a Molybdenum Tetrasulfido Complex

Abstract

Hydrogen sulfide (H 2 S) is an important biological signaling molecule and one of three established gasotransmitters. Upon oxidation, H 2 S can form reactive sulfur species (RSS) that play a central role in protein persulfidation. Here we report that a molybdenum tetrasulfide can react directly with hydrosulfide to form polysulfides and oxidize the Mo center. Specifically, [NBu 4 ][TpMoS(S 4 )] reacts with 2 equiv of [NBu 4 ][SH] to form [NBu 4 ][TpMoS 3 ].Trapping experiments with BnBr confirm the formation of polysulfides, as evidenced by the direct trapping of Bn 2 S 2 . This work demonstrates new reaction pathways for H 2 S oxidation and RSS generation from metal-bound polysulfides that will increase our understanding of the potential roles that metals play in signaling processes.

C–H⋯S hydrogen bonding interactions

“…For example, reaction of the molybdenum tetrasulfido complex [NBu 4 ][TpMoS(S 4 )] (Tp = hydrotris(3,5-dimethylpyrazol-1-yl)borate) with HS À results in HS À oxidation to form polysulfides and concomitant formation of a tris(sulfido) Mo complex [NBu 4 ][TpMoS 3 ] byproduct. 35 Upon further inspection of the molecular structure of [NBu 4 ][TpMoS 3 ], we found that the MoQS bond lengths vary by up to 0.019 Å and that the longest MoQS moieties displayed C-HÁ Á ÁS contacts as short as 2.681 Å to the [NBu 4 ] + counterion. Further evidence of a HB Additional evidence for C-HÁ Á ÁS HB interactions is supported by a recent study by Wategaonkar and coworkers using both gasphase vibrational spectroscopy and DFT calculations.…”

Thionitrite (SNO−) and Perthionitrite (SSNO−) are Simple Synthons for Nitrosylated Iron Sulfur Clusters

“…To further expand the connection of S/N crosstalk species with Fe−S building blocks, we next investigated whether polysulfide‐based DNICs, such as 1 , can function as precursors to form biologically‐relevant nitrosylated Fe−S components. Because 1 contains up to four sulfane sulfur equivalents, we expected that these S 0 atoms could be extracted using a mild reducing agent [6, 28] . Addition of one equiv.…”

“…Because 1 contains up to four sulfane sulfur equivalents, we expected that these S 0 atoms could be extracted using a mild reducing agent. [6,28] Addition of one equiv. of PPh 3 to 1 resulted in a new resonance in the 31 P NMR spectrum at 42.08 ppm, which corresponded to S=PPh 3 .…”

Cluster Models of FeMoco with Sulfide and Carbyne Ligands: Effect of Interstitial Atom in Nitrogenase Active Site

“…Targeting a carbyne analog with the same number of BAC donors, compound 5 was treated with BAC; however, no reaction was observed, likely due to a combination of steric constraints and stability of the chelate. 45 generated by sulfur abstraction with 2 PPh3 (see Supporting Information). Adapting the synthetic protocol developed for 2-W, chloride substitution with BAC from 1-Mo allowed the isolation of 2-Mo.…”