Coordination-Induced σ-Hole Chalcogen Bonding Involving Anionic Sulfur Donors of Dithiocarbamate-Type Ligands: Electrophilicity of Anions in Group 10 Metal Complexes

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Abstract Coordination-induced electrophilic activation of anionic ligands inverts the conventional reactivity of coordination compounds. Here, we report experimental and theoretical evidence for σ-hole chalcogen bond (ChB) donation from anionic dithiocarbamate-type sulfur centers. Isomorphous Group 10 metal complexes bearing a fluorosulfonamide-modified dithiocarbamate ligand, Ni (1), Pd (2), and Pt (3), were prepared and structurally characterized. In the solid state, all three engage in bifurcated S···F contacts, in which two coordinated S atoms interact with a single F of a neighboring molecule. MEP, QTAIM, EDA, and NBO calculations reveal a localized σ-hole between the S atoms within the {MNS3} plane, weakly positive on the 0.002 au isodensity surface, and donation from fluorine lone pairs into the σ*(C–S) orbitals, the hallmark of ChB. Electron-density (ED) and electrostatic-potential (ESP) profiles along the S···F bond paths (ED minimum nearer sulfur, ESP minimum nearer fluorine; separation 0.16–0.19 Å) assign the anionic sulfur as the ChB donor. Although the σ-hole becomes less positive from Ni to Pt, the S···F contacts contract systematically, driven by cooperative dispersion, correlation, and orbital contributions. Together with the reported halogen bond donation from anionic PtIV-bound iodides, this finding indicates that coordination-induced electrophilicity of anionic ligands extends beyond a single ligand/NCI system, offering a design principle for supramolecular engineering.

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