10.1021/om049251x.s001 Tomoaki Tanase Tomoaki Tanase Eri Goto Eri Goto Hiroe Takenaka Hiroe Takenaka Takashi Horiuchi Takashi Horiuchi Yasuhiro Yamamoto Yasuhiro Yamamoto Junpei Kuwabara Junpei Kuwabara Kohtaro Osakada Kohtaro Osakada Cage-Type Hexanuclear Platinum(0) Clusters with Diphosphine and Isocyanide Ligands Encapsulating Two Mercury(0) Atoms American Chemical Society 2005 Hg 2 Pt 6 antiprismatic cluster core PtCl 2 Isocyanide Ligands Encapsulating NH 4 PF 6 2.7930 Å D 3 symmetry PtHgPt trinuclear aliphatic isocyanide t RNC D 3 diphosphine ligands methylene chains trinuclear structure EHMO Hg 2 Pt 6 clusters triplatinum planes mercury atom DFT methods Pt 3 Hg 2 Pt 3 cluster frameworks n PPh 2 equivalent diphosphine ligand 8 b dimercury axis 2005-01-17 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Cage_Type_Hexanuclear_Platinum_0_Clusters_with_Diphosphine_and_Isocyanide_Ligands_Encapsulating_Two_Mercury_0_Atoms/3304543 Reduction of a mixture containing [PtCl<sub>2</sub>(cod)], aromatic isocyanide (RNC; R = 2,6-xylyl (Xyl), 2,4,6-mesityl (Mes)), diphosphine (Ph<sub>2</sub>P(CH<sub>2</sub>)<i><sub>n</sub></i>PPh<sub>2</sub>; <i>n</i> = 5 (dpppn), <i>n</i> = 6 (dpphx)), and NH<sub>4</sub>PF<sub>6</sub> by sodium amalgam (<1%) afforded trigonal-antiprismatic hexanuclear platinum(0) clusters encapsulating two mercury(0) atoms, [Hg<sub>2</sub>Pt<sub>6</sub>(μ-RNC)<sub>6</sub>(μ-diphos)<sub>3</sub>] (diphos = dpphx, R = Xyl (<b>6a</b>); diphos = dpppn, R = Xyl (<b>8a</b>), Mes (<b>8b</b>)). Complexes <b>6a</b> and <b>8a</b> were characterized by X-ray crystallographic analyses to demonstrate that two triangular platinum(0) units, {Pt<sub>3</sub>(μ-RNC)<sub>3</sub>}, are connected by three diphosphine ligands with long methylene chains to form a closed cage of the cluster-based metallocryptand, in which two mercury(0) atoms are incarcerated with a notably short Hg−Hg distance. In complex <b>8a</b> (<i>n</i> = 5), the centroids of the two Pt(0) triangles are linearly arranged with respect to the Hg−Hg axis to form a pseudo-<i>D</i><sub>3</sub>-symmetrical Hg<sub>2</sub>Pt<sub>6</sub> antiprismatic cluster core (average Pt−Pt = 2.6719 Å, average Pt−Hg = 2.9417 Å, and Hg−Hg = 2.8424(2) Å). In contrast, in complex <b>6a</b> (<i>n</i> = 6) the two triplatinum planes glide away from the dimercury axis to lose the <i>D</i><sub>3</sub> symmetry (average Pt−Pt = 2.639 Å, average Pt−Hg = 2.923 Å, and Hg−Hg = 2.826(2) Å). The electronic structures of the Pt<sub>3</sub>Hg<sub>2</sub>Pt<sub>3</sub> cluster frameworks are discussed on the basis of molecular orbital calculations with EHMO and DFT methods. Hg<sub>2</sub>Pt<sub>6</sub> clusters with an incomplete open-cage structure, [Hg<sub>2</sub>Pt<sub>6</sub>(μ-RNC)<sub>6</sub>(RNC)<sub>2</sub>(μ-diphos)<sub>2</sub>] (diphos = dpphx, R = Xyl (<b>7a</b>); diphos = dpppn, R = Mes (<b>9b</b>)), were also isolated as minor products and were transformed into the closed-cage clusters <b>6a</b> and <b>8b</b> by treatment with an equivalent diphosphine ligand. By using dppb (<i>n</i> = 4), an open-cage mixed-metal cluster with a single mercury atom, [HgPt<sub>6</sub>(μ-RNC)<sub>6</sub>(RNC)<sub>2</sub>(μ-dppb)<sub>2</sub>] (R = Xyl (<b>10a</b>), Mes (<b>10b</b>)), was obtained as the sole product. When the aliphatic isocyanide <i>t-</i>BuNC was used in the reduction with dpphx, the Hg<sub>2</sub>Pt<sub>6</sub> mixed-metal cluster was not produced, and instead, the PtHgPt trinuclear complex [HgPt<sub>2</sub>(μ-dpphx)<sub>3</sub>] (<b>11</b>) was obtained in a low yield and was characterized by X-ray crystallography to demonstrate the linear trinuclear structure with a considerable attractive Pt−Hg interaction (average Pt−Hg = 2.7930 Å and Pt−Hg−Pt = 179.591(3)°). The electronic structures of <b>11</b> are also discussed.