Synthesis of Boron-Fused 1,4-Dithiin via Cobalt-Mediated Disulfuration of Alkyne at the o-Carborane-9,12-dithiolate Unit

Abstract

We present the first synthesis and characterization of a series of boron-fused 1,4-dithiin compounds through the reactions of newly established boron-substituted 16e half-sandwich complex Cp*Co(9,12-S 2 C 2 B 10 H 10 ) with alkynes. The generated C 2 S 2 B 2 ring in these 1,4-dithiin species is a stable structural motif with electron-negative sulfur atoms, as evidenced by theoretical calculation and its solid-state self-assembly. Single-crystal X-ray analysis indicates that C carb −H•••S hydrogen bonding is involved in the self-assemblies of these compounds, which serves as a compatible interaction with stronger C carb −HAll new compounds are characterized by NMR, mass spectroscopy, and X-ray structural analysis.

Effect of Nature of Substituents on Coordination Properties of Mono- and Disubstituted Derivatives of Boron Cluster Anions [BnHn]2– (n = 10, 12) and Carboranes with exo-Polyhedral B–X Bonds (X = N, O, S, Hal)

“…Similar cobalt(III) complex with cyclopentadienyl ligand [Cp*Co{9,12-S2C2B10H10}] was isolated and structurally characterized [152]. This complex is built similarly to the previously discussed rhodium(III) and iridium(III) complexes (see Figure 31).…”

“…It was found that [Cp*Ir{9,10-S2C2B10H10}] reacts with phosphine ligands L (L = Ph3P, Me2PhP, MePh2P, Ph2PCH2PPh2) in dichloromethane at room temperature to give complexes [Cp*Ir(L){9,10-S2C2B10H10}]. At the same time, the reaction of [Cp*Ir{9,10-S2C2B10H10}] with dppe leads to the formation of a corresponding dimeric complex [Cp*Ir(Ph2PCH2){9,10-S2C2B10H10}]2 (Figure32b), where CH…HB, CH…B, CH…S, CH…HC, and BH…π intermolecular interactions are observed[151].Similar cobalt(III) complex with cyclopentadienyl ligand [Cp*Co{9,12-S2C2B10H10}] was isolated and structurally characterized[152]. This complex is built similarly to the previously discussed rhodium(III) and iridium(III) complexes (see Figure31).…”

Electronic Effect-Guided, Palladium-Catalyzed Regioselective B–H Activation and Multistep Diarylation of o-Carboranes with Aryl Iodides

“…Huge steric hindrance arisen from o-methylphenyl and o-carboranyl groups can even block the formation of corresponding diarylated ocarbobane derivatives. (3) The preference of arylation/diarylation at B(4)/B (5) sites in o-carbobanes was identified by more positive NPA charge distribution on B(4)/B(5)−Hs in it. Further mechanism and energy calculations verify the regioselectivity results predicted by NBO theory well and hint the regioselectivity of B−H activation here is strikingly affected by electronic effect.…”

“…o -Carboranes, with two adjacent B–H vertices in carboranes replaced by C–H units, have potential applications in many a field such as boron neutron capture therapy and drug development. − Therefore, the functionalization of o -carboranes has become the focus in carborane area for decades. − …”

Sulfur-Centered Reactivity of Oxidized Iron-Thiolate Complex toward Unsaturated Hydrocarbon Addition

“…The formation of the thiyl radicals is attributed to the existence of the noninnocent sulfur ligands like dithiolenes, which have the ability to delocalize electron density. Similarly, Yan and co-workers adopted [S 2 C 2 (B 10 H 10 )] 2– unit to synthesize Co complexes, which also exhibit sulfur-centered addition of alkynes and can release the alkyne disulfurated products . Unexpectedly, Goh utilized soft thioether-dithiolate tpdt (tpdt = S­(CH 2 CH 2 S – ) 2 ) tridentate ligand to generate the half-sandwich ruthenium complex, which displayed sulfur-based alkylation by electrophilic attack of alkylation agent .…”