Argentivorous Molecules with Chromophores in Side Arms: Silver Ion-Induced Turn On and Turn Off of Fluorescence

Abstract

The synthesis of argentivorous molecules (L1 and L2 ) having two chromophores (4-(anthracen-9-yl)­benzyl or 4-(pyren-1-yl)­benzyl groups) and two benzyl groups and the fluorescence properties of their silver complexes in a solution and the solid state are reported. A crystallographic approach for the Ag+ complexes with L1 and L2 revealed that the observed fluorescence changes stem from the excimer formation and extinction of fluorescent. Furthermore, binding stabilities of L1 and L2 toward Ag+ ions were estimated by the Ag+-induced UV–vis and PL spectral changes.

Bis-Argentivorous Molecules Bridged by Phenyl and 4,4′-Biphenyl Groups: Structural and Dynamic Behavior of Silver Complexes

“…Maier et al reported that the strength of the intermolecular Ag + –π interaction in solution was −1.34 to −2.63 kcal/mol . In addition, the structures of tetra-armed cyclen/Ag + complexes in the data previously reported showed only two types of conformers: Δ­( δδδδ ) and Λ­( λλλλ ) forms. − ,,,,− Therefore, we performed DFT calculations (B3LYP/6-31G*) of the Λ­( λλλλ ) form and its side arm rotated isomer, Δ­( λλλλ ) form, to investigate whether the silver­(I) complex with 1,4,7,10-tetrabenzyl-1,4,7,10-tetraazacyclododecane forms not only stable Δ­( δδδδ ) and Λ­( λλλλ ) but also Δ­( λλλλ ) and Λ­( δδδδ ) forms (Figure S17). As a result, the energy difference between Λ­( λλλλ ) and Δ­( λλλλ ) forms was about 8.6 kJ/mol, and the relative amounts of each isomer would be 2.1 × 10 6 :1 (=Λ­( λλλλ ):Δ­( λλλλ )) (Table S1).…”

Argentivorous molecules with chromophores: dependence of their fluorescence intensities on the distance between a donor and an acceptor

“…Synthesis of new tetra-armed cyclens with anthracene units (L 2 and L 3 ) Tetra-armed cyclens (L 2 and L 3 , Fig. 1) were prepared by reductive amination of 1,7-dibenzyl-1,4,7,10-tetraazacyclododecane (1, 1,7-dibenzylcyclen) 25 with the corresponding anthracenyl benzaldehydes (5 and 6) in the presence of NaBH(OAc) 3 . 9-Bromomethylanthracene (2) 26 and 2-(anthracen-9-yl)ethyl-4methyl benzenesulfonate (3) 27 were prepared according to the procedure described in the literature.…”

“…This result indicates that the resonance is inhibited by the orthogonality between the phenyl group and anthracene, as shown by the X-ray crystallographic analysis reported previously. 25…”

“…In addition, the fluorescence on-off behaviors via structurefunction relationships based on single-crystal X-ray analysis were determined. 25 This result stimulated our curiosity regarding (i) different PET effects according to the length of the linker existing between the cyclen nitrogen and fluorophore and (ii) fluorescence change for the silver(I) complexation of cyclen hosts. Hence, we synthesized new fluorescent tetraarmed cyclens (L 2 and L 3 ) with different linker lengths between the cyclen and anthracene units.…”

“…Mp: 203.0-204.0 °C (dec.). Synthesis of 1,7-bis(4′-(9″-anthrylethoxy)benzyl)-4,10-bis benzyl-1,4,7,10-tetraazacyclo dodecane (L 3 ) 1,7-Dibenzylcyclen 25 (1, 0.176 g, 0.5 mmol), 4-(9′-anthrylethoxy)benzaldehyde (6, 0.653 g, 2.0 mmol), and NaBH(OAc) 3 (0.424 g, 2.0 mmol) were added to 1,2-dichloroethane (6 mL) under a nitrogen atmosphere. The mixture was stirred for 7 days at room temperature.…”