Argentivorous molecules bearing three aromatic side arms: synthesis of triple-armed cyclens and their complexing property towards Ag⁺

Abstract

Triple-armed cyclens bearing three aromatic side-arms were prepared in three steps from (3R,5S)-3,5-dimethyl-1,4,7,10-tetraazacyclododecane-2,6-dione, and the Ag(+)-ion-induced (1)H NMR and UV-vis spectral changes and X-ray structures suggested that the aromatic side-arms cover the Ag(+) incorporated into the ligand cavities like an insectivorous plant (Venus flytrap).

Pentacyclic Nano‐Trefoil

“…The Ag1 atom was four-coordinated to a N 4donor from the cyclen. As we previously reported, [17][18][19][20][21] the four aromatic side arms covered the Ag + ion incorporated in the ligand cavity. The Ag2 atom was in a three-coordinate environment, and was bound to three pyridine nitrogen atoms from three different ligands.…”

Pentacyclic Nano‐Trefoil

“…The Ag1 atom was four‐coordinated to a N 4 ‐donor from the cyclen. As we previously reported, [17–21] the four aromatic side arms covered the Ag + ion incorporated in the ligand cavity. The Ag2 atom was in a three‐coordinate environment, and was bound to three pyridine nitrogen atoms from three different ligands.…”

“…Cyclen is a 12‐membered cyclic polyamine that forms stable complexes with several metal ions [11–22] . Tripier et al.…”

“…In these armed cyclens, the side arms wrap around Ag + to incorporate it in the cyclen via Ag + ‐π interactions between Ag + and the side arms and CH‐π interactions among the side arms. We call these complexes argentivorous molecules, which means silver (argentum) eating (vorous) [17–22] …”

“…[5,6] Cyclen is a 12-membered cyclic polyamine that forms stable complexes with several metal ions. [11][12][13][14][15][16][17][18][19][20][21][22] Tripier et al reported a cyclic dipicolinate and its Pb 2+ and Ba 2+ complexes. [11] They also reported dinuclear Cu 2+ and Zn 2+ complexes of cyclen ligands and their association with phosphate anions.…”