Highly Sensitive Luminescent Metal-Complex Receptors for Anions through Charge-Assisted Amide Hydrogen Bonding

Abstract

Two structurally simple and easily synthesized luminescent anion receptors featured with an amide-type anion binding site and rhenium(I) tricarbonyl pyridine signaling units have been developed, and they display outstanding sensitivity and selectivity toward a variety of anionic species. These complexes are highly emissive in solution. Upon anion binding, the emission intensity was significantly quenched. The sensitivities of these complexes are so high that the emission intensity can be effectively quenched by as much as 10% even in the presence of only 10(-8) M cyanide or fluoride anions. The ability of formation of intramolecular hydrogen bonding between the amide protons and central pyridine is believed to be responsible for the observed high selectivity.

Inorganic photoisomerization: the case study of rhenium(i) complexes

“…Irradiation with UV or visible light is one of the external stimuli that activate the molecular switchable component operating as probe and conformation tuning of bio-molecules, supramolecular machines, memory units and metal ion sensors. [10][11][12][13][14] Most of the photoswitches rely on ring-opening/ closing and isomerization of a pivotal CvC (stilbene) or NvN (azobenzene) bond. Whereas organic photoisomerization is activated by means of UV light, inorganic photoisomerization can also be controlled by the wavelength of irradiation ranging from 450 nm to 300 nm.…”

Self-assembly of [2]Rotaxane Exploiting Reversible Pt(II)- Pyridine Coordinate Bonds

“…Synthetic receptors for anions are based on the amide H-bond donor properties. Particularly, a luminiscent rhenium (I) 2,6-pyridinecarboxamide, N, N´-di-4-pyridylbased receptor has been recently described to bind anions with binding constants as high as 10 4 -10 5 M -1 in CH 2 Cl 2 solution [11]. We were worried that due to the structural resemblance to the binding sites of 2, the triflate anions acting as metal counter ions will inhibit the hydrogen-bonded complex formation between 2 and 3.…”

Sonochemical synthesis of a nano-structured zinc(II) amidic pillar metal–organic framework

“…The N,N′-bis(4-pyridinyl)-1,4-benzenedicarboxamide ligand of bpta is synthesized according to literature method [58]. …”