Encapsulation of a Metal Complex within a Self-Assembled Nanocage: Synergy Effects, Molecular Structures, and Density Functional Theory Calculations

A novel palladium-based metallacage was self-assembled. This nanocage displayed two complementary effects that operate in synergy for guest encapsulation. Indeed, a metal complex, [Pt­(NO₂)₄]^2–, was hosted inside the cavity, as demonstrated by solution NMR studies. Single-crystal X-ray diffraction shows that the guest adopts two different orientations, depending on the nature of the host–guest interactions involved. A density functional theory computational study is included to rationalize this type of host–guest interaction. These studies pave the way to a better comprehension of chemical interaction and transformation within confined nanospaces

<i>Meso</i>-Helicates with Rigid Angular Tetradentate Ligand: Design, Molecular Structures, and Progress Towards Self-Assembly of Metal–Organic Nanotubes

The self-assembly of two novel metallosupramolecular complexes of the general formulas [L₂M₂(CH₃CN)₄]­[BF₄]₄ (M = Co, <b>1a</b>; M = Ni, <b>1b</b>), where L stands for the tetradentate ligand 3,5-bis­[4-(2,2′-dipyridylamino)­phenylacetylenyl]­toluene, is reported together with their molecular structures ascertained by single-crystal X-ray diffraction studies. Complexes <b>1a</b> and <b>1b</b> are isostructural and show the formation of dinuclear <i>meso</i>-helicates with the two octahedral metal centers displaying respectively Δ and Λ configurations. These <i>meso</i>-helicates display large nanocavities with metal---metal separation distance of >2 nm; furthermore, π–π-stacking occurs among individual units to form one-dimensional (1D) polymers which further autoassemble in another direction through π–π contacts among neighboring chains to generate a two-dimensional (2D) network with regular nanocavities. Our approach might be of interest to prepare metal–organic nanotubes via a bottom-up strategy depending on the assembling functional ligand and the geometry of molecular building block

Gold Compounds Anchored to a Metalated Arene Scaffold: Synthesis, X‑ray Molecular Structures, and Cycloisomerization of Enyne

A novel series of π-complexes of phosphino ligands, [Cp*Ru­(η^<i>6</i>-arene-PAr₂)]­[OTf], has been prepared in which the diarylphosphine unit is attached to a metalated π-arene scaffold. These organometallic phosphino ligands display either an electron-donating methyl group (−PAr₂ = −P­(<i>p</i>-tol)₂) or electron-withdrawing trifluoromethyl group (−PAr₂ = −P­(<i>p</i>-C₆H₄CF₃)₂). This unique class of metallo ligands was converted to heterodinuclear gold complexes upon treatment with [AuCl­(tht)]. The molecular structures of [Cp*Ru­(η⁶-<i>p</i>-CH₃C₆H₄-P­(<i>p</i>-tol)₂-Au-Cl)]­[OTf] and [Cp*Ru­(η^<i>6</i>-C₆H₅-P­(<i>p</i>-C₆H₄CF₃)₂)-Au-Cl]­[OTf] were ascertained by single-crystal X-ray diffraction. A comparative study of these structures with that of [Cp*Ru­(η^<i>6</i>-C₆H₅-PPh₂-Au-Cl)]­[OTf] previously reported revealed important information about the electronic nature of the gold center when it is bonded to a −PPh₂, −P­(<i>p</i>-tol)₂, or −P­(<i>p</i>-C₆H₄CF₃)₂ metallo ligand. DFT computations also shed light on the effect of [Cp*Ru⁺] coordination to [AuCl­(PAr₃)] precatalysts. Several complexes of the family with electron-donating and -withdrawing groups were evaluated toward cycloisomerization reactions of a classical <i>N</i>-tethered 1,6-enyne. These results are presented and discussed