Multipoint Recognition of Ditopic Aromatic Guest Molecules via Ag−π Interactions within a Dimetal Macrocycle

Abstract

A macrocyclic host molecule possessing a nanocavity with two Ag(I) centers for guest binding and four anthracene walls has been developed. This dimetal-macrocycle forms stable inclusion complexes with ditopic aromatic guest molecules, [2.2]paracyclophane, and ferrocene, in solution and/or in the solid state through Ag-π interactions within the nanocavity. The binding constants for the inclusion complexes were found to range roughly from 10(4) to 10(9) M(-1). Electrochemical measurement revealed that the oxidized form of the included cationic ferrocene was less stabilized due to the direct binding to the cationic two Ag(I) centers.

Molecular recognition by multiple metal coordination inside wavy-stacked macrocycles

“…In this study, we create a rigid macrocyclic ligand hexapap H 6 1 , and embed the metals in its cavity 11–16 with their labile coordination sites directed toward the center of the pore. The complexation of H 6 1 with Zn II produces a hexanuclear complex, Zn-hexapap [ 1 Zn 6 X n ] (X = exchangeable labile ligands).…”

Triggered Exchange of Anionic for Neutral Guests inside a Cationic Coordination Cage

“…15 The addition of halide anions triggers a mechanical process, a compression of the double cage along the Pd 4 -axis, that prepares the central cavity for the subsequent inclusion of the guest. Vice versa, the neutral guest kinetically stabilizes the halide anions in the outer pockets.…”

Host‐Guest Interactions by Metal‐to‐Metal Dative Bonding: Recognition of Ruthenocene by a Metallo‐Host

“…The stability constant of the complexation of [Ag 1 (Et 2 O)]SbF 6 with RuCp 2 ( K a = [[Ag 1 (RuCp 2 )] + ]/([RuCp 2 ][[Ag 1 X] + ]) M –1 ) was estimated to be over 10 4 in CD 2 Cl 2 at 300 K (see Supporting Information). This value is as large as those of reported examples for non‐substituted metallocene in non‐polar organic solvents,8,13 suggesting high availability of metal‐to‐metal dative bonding for trapping RuCp 2 . As reported by Sano, RuCp 2 reacts with solvated Ag I to form an unidentified insoluble matter 7i.…”

“…A metallo‐host, [Ag 1 (Et 2 O)]SbF 6 , was prepared by metal complexation of 1 and AgSbF 6 in CHCl 3 /acetone and subsequent recrystallization by ether vapor diffusion 8. The 1 H NMR spectrum of [Ag 1 (Et 2 O)]SbF 6 showed broad signals in the aromatic region in CD 2 Cl 2 probably due to the exchange of coordinating solvent molecules (Figure 2a).…”

“…In this study, a mononuclear Ag I complex ([Ag 1 (Et 2 O)]SbF 6 ) of 2,9‐bis(9‐anthracenyl)‐1,10‐phenanthroline ( 1 ) was prepared as a metallo‐host possessing a coordinatively labile site of Ag I ion as a guest binding site (Figure 2),8 and NMR and X‐ray analyses demonstrated that this metallo‐host can effectively bind RuCp 2 by Ru–Ag type dative bonding to form a host‐guest complex [Ag 1 (RuCp 2 )]SbF 6 both in solution and in the solid state (Figure 1c).…”