6‑Diphenylphosphinoacenaphth-5-yl-mercurials as Ligands for d¹⁰ Metals. Observation of Closed-Shell Interactions of the Type Hg(II)···M; M = Hg(II), Ag(I), Au(I)

The salt metathesis reaction of ArLi with HgCl₂ produced Ar₂Hg (1, Ar = 6-Ph₂P-Ace-5), which underwent complex formation with d¹⁰-configurated transition metal chlorides and triflates to give the complexes 1·HgCl₂, 1·Hg­(O₃SCF₃)₂, 1·AgCl, 1·Ag­(O₃SCF₃), [1·Ag­(NCMe)₂]­(O₃SCF₃), 1·AuCl, and [1·Au]­(O₃SCF₃) comprising significant metallophilic interactions between Hg­(II) and Hg­(II), Ag­(I), and Au­(I), respectively. The transmetalation reaction of ArSnBu₃ with HgCl₂ afforded ArHgCl (2) that also forms a complex with additional HgCl₂, namely, 2·HgCl₂, which however lacks metallophilic interactions. Compounds 2 and 1·HgCl₂ possess the same elemental composition and can be interconverted in solution by choice of the solvent. In the presence of tetrahydrothiophene (tht), the complexes 1·AuCl and [1·Au]­(O₃SCF₃) underwent rearrangement into the Au­(III) cation [cis-Ar₂Au]⁺ ([3]⁺, which was isolated as Cl^– and (O₃SCF₃)⁻ salts) and elemental Hg. The reaction of 1·Hg­(O₃SCF₃)₂ with ArH produced the complex ArHg­(ArH)­(O₃SCF₃) (4). The metallophilic interactions are theoretically analyzed by a set of real-space bonding indicators derived from the atoms-in-molecules (AIM) and electron localizability indicator (ELI) space-partitioning schemes.