Post‐Metalation Modification of a Macrocyclic Dicobalt(III) Metallohost by Site‐Selective Ligand Exchange for Guest Recognition Control. Issue 34 (19th May 2020)

• Record Type: Journal Article
• Authors: Sakata, Yoko; Okada, Masahiro; Tamiya, Munehiro; Akine, Shigehisa
• Is Part Of: Chemistry. Volume 26:Issue 34(2020)
• Page Start: 7595
• Page End: 7601
• Publication Date: 2020-05-19
• Subjects: cobalt -- ion recognition -- ligand exchange -- macrocycles -- structural conversion; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202001072
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: We propose post‐metalation modification as a useful strategy to control the guest recognition behavior of a metal‐containing macrocyclic host. This is based on the ligand exchange of the axial ligands of a cobalt(III) dinuclear macrocyclic host, [LCo2 X4 ] 2+ (X=axial amine ligand). Four piperidine ligands in [LCo2 (pip)4 ] 2+ (pip=piperidine) were site‐selectively replaced with primary amines. The competitive experiments revealed that the order of the affinity toward the cobalt centers in [LCo2 X4 ] 2+ is primary amine > secondary amine > tertiary amine and that the piperidine‐coordinating complex, [LCo2 (pip)4 ] 2+, was reasonably reactive among the isolable complexes. Indeed, two piperidine ligands at the diagonal positions in [LCo2 (pip)4 ] 2+ were site‐selectively replaced with pyridine or acetate ion. The replacement of piperidine with acetate ion significantly enhanced the recognition ability towards Na + . Abstract : Ligand exchange : Post‐metalation modification based on ligand exchange on the metal centers is a useful strategy to control the guest recognition behavior of a metal‐containing macrocyclic host. The two axial piperidine ligands at diagonal positions in the cobalt(III) dinuclear macrocyclic host, [LCo2 (pip)4 ] 2+ (pip=piperidine), were site‐selectively replaced with acetate ions, which enhanced the Na + recognition ability.