Gold(I) Metallo‐Tweezers for the Recognition of Functionalized Polycyclic Aromatic Hydrocarbons by Combined π–π Stacking and H‐Bonding

Abstract

Two gold(I)-based metallo-tweezers with bis(Au-NHC) pincers and a carbazole connector have been obtained and used for the recognition of polycyclic aromatic hydrocarbons (PAHs). In the case of the tweezer with pyrene-NHC ligands, the presence of the pyrene fragment and the N-H bond in the carbazole linker enable the receptor to show significant enhanced binding abilities toward PAHs functionalized with H-bonding groups, through combined π-π stacking and H-bonding.

Chemically Tunable Formation of Different Discrete, Oligomeric, and Polymeric Self‐Assembled Structures from Digold Metallotweezers

“…Amongt he noncovalent intermo-lecular interactions, attractive metallophilic interactions, [4] especially those observed for Au I ,h ave been increasingly utilized as ad esign element to synthesize functional high-dimensional systems. [10] In the first example, a gold(I) metallotweezer with ab is-alkynyl linker and terminal pyrene-functionalized N-heterocyclic carbene ligands( 1 in Scheme 1) was able to dimerize in the presence of "naked" M + ions (M = Cu, Tl, Ag) as ac onsequence of p-stacking and metallophilic interactions. [6] Gold alkynyl complexes [7] have recently been regarded as an interesting typeo fo rganometallic-based metalloligandsd ue to their potentialb inding abilitiest hrough the alkynyl ligandsa nd by aurophilic/metallophilic interactions.…”

“…[8] In this context,w er ecently becamei nterested in the preparation of digold(I) metallotweezers containing bis-alkynyl linkers for the recognition of metal cations [9] and polycyclic aromatic hydrocarbons. [10] In the first example, a gold(I) metallotweezer with ab is-alkynyl linker and terminal pyrene-functionalized N-heterocyclic carbene ligands( 1 in Scheme 1) was able to dimerize in the presence of "naked" M + ions (M = Cu, Tl, Ag) as ac onsequence of p-stacking and metallophilic interactions. Such dimerization resulted in encapsulation of the metal cation inside the cavity of the dimer,g iving rise to discrete self-aggregated duplex structures showingmetallophilic interactions between M + and the surrounding four Au atoms of the structure( 2).…”

The Complex Coordination Landscape of a Digold(I) U‐Shaped Metalloligand

“…Under these circumstances we found that the molecule may self‐aggregate, but the process is reversible and may also give rise to more complex structures, such as oligomers and polymers . On the other hand, V‐shaped metallotweezers do not self‐aggregate because the arms of the tweezer diverge from the connector, therefore reducing the self‐complementarity character of the molecule, and allowing the system to be used as receptor of PAHs, such as pyrene, as shown in Scheme . All these findings allowed us to slowly unravel the complex supramolecular landscape of this new class of metallotweezers.…”

“…By incorporating gold–alkynyl units in the core of molecular tweezers, we were recently able to prepare a series of di‐gold metallotweezers for the recognition of naked metal cations and polycyclic aromatic hydrocarbons (PAHs) . The recognition properties of this type of metallotweezers are highly dependent on the nature of the rigid connector, and on the ancillary ligands that constitute the arms of the tweezer (Scheme ).…”

A Rigid Trigonal‐Prismatic Hexagold Metallocage That Behaves as a Coronene Trap

“…By using rigid bis(alkynyl) connectors combined with a pyrene‐imidazolylidene ligand, we recently described a series of digold metallo‐tweezers, which we used for the recognition of bare metal cations and polycyclic aromatic hydrocarbons . Based on these previous results, we assumed that we could obtain a new interesting family of metallorganic cages by replacing the mono‐NHC ligand by poly‐NHC ligands connected by extended conjugated π‐systems.…”