Tri‐ and Tetranuclear Metal‐String Complexes with Metallophilic d(10)–d(10) Interactions

The reaction of 2,6‐F(2)C(6)H(3)SiMe(3) with Ph(2)PLi provided 2,6‐(Ph(2)P)(2)C(6)H(3)SiMe(3) (1), which can be regarded as precursor for the novel anionic tridentate ligand [2,6‐(Ph(2)P)(2)C(6)H(3)](−) (PCP)(−). The reaction of 1 with [AuCl(tht)] (tht=tetrahydrothiophene) afforded 2,6‐(Ph(2)PAuCl)(2)C(6)H(3)SiMe(3) (2). The subsequent reaction of 2 with CsF proceeded with elimination of Me(3)SiF and yielded the neutral tetranuclear complex linear‐[Au(4)Cl(2)(PCP)(2)] (3) comprising a string‐like arrangement of four Au atoms. Upon chloride abstraction from 3 with NaBAr(F) (4) (Ar(F)=3,5‐(CF(3))(2)C(6)H(3)) in the presence of tht, the formation of the dicationic tetranuclear complex linear‐[Au(4)(PCP)(2)(tht)(2)](BAr(F) (4))(2) (4) was observed, in which the string‐like structural motif is retained. Irradiation of 4 with UV light triggered a facile rearrangement in solution giving rise to the dicationic tetranuclear complex cyclo‐[Au(4)(PCP)(2)(tht)(2)](BAr(F) (4)) (5), which comprises a rhomboidal motif of four Au atoms. In 3–5, the Au atoms are associated by a number of significant aurophilic interactions. The atom‐economic and selective reaction of 3 with HgCl(2) yielded the neutral trinuclear bimetallic complex [HgAu(2)Cl(3)(PCP)] (6) comprising significant metallophilic interactions between the Au and Hg atoms. Therefore, 6 may be also regarded as a metallopincer complex [ClHg(AuCAu)] between Hg(II) and the anionic tridentate ligand [2,6‐(Ph(2)PAuCl)(2)C(6)H(3)](−) (AuCAu)(−) containing a central carbanionic binding site and two “gold‐arms” contributing pincer‐type chelation trough metallophilic interactions. Compounds 1–6 were characterized experimentally by multinuclear NMR spectroscopy and X‐ray crystallography and computationally using a set of real‐space bond indicators (RSBIs) derived from electron density (ED) methods including Atoms In Molecules (AIM), the Electron Localizability Indicator (ELI‐D) as well as the Non‐Covalent Interaction (NCI) Index.