135366-32-4

Upstream product

• 66749-96-0 4-(1,4,7,10-tetraoxa-13-aza-cyclopentadec-13-yl)-benzaldehyde 
• 135366-31-3 4-(4,7,10,13-tetraoxa-1-azacyclopentadecyl)benzoic acid 
• 504-24-5 4-aminopyridine 

Downstream Products

• 135366-35-7 fac-(bpy)Re(CO)3(NC₅H₄NHCOC₆H₄NC₁₀H₂₀O₄)PF₆ 

Relevant academic research and scientific papers

Cation-controlled photophysics in a Re(I) fluoroionophore

Alkali and alkaline earth metal cations have a profound effect on the photophysics of the dir (Re) → π* (bpy) metal-to-ligand charge-transfer (MLCT) excited state in crown ether substituted complex 1. The unique cation-induced effects arise because of the influence of the "crowned" cation on the energy of the ligand-to-ligand charge-transfer (LLCT) excited state that is formed by charge transfer from the donor nitrogen to the electron-deficient metal center in the MLCT state (bpy)ReI-A → hv (bpy?-)MLCTReII-A →kic (bpy?-)LLCTReIA?+ (where bpy = 2,2′-bipyridine and A = the amine donor). In the absence of cations, the energy of the LLCT state lies below the MLCT state. As a result, kic is large and the LLCT state provides a path for rapid radiationless decay of the MLCT state. However, due to the ion-dipole interaction between the cation and the donor nitrogen in cation-crown complexes (1···Mn+), the energy of the LLCT state is higher than that of the MLCT state. Under these conditions, the MLCT state decays primarily by "normal" radiative and nonradiative decay paths. As a result, the MLCT emission yield is larger for the 1···Mn+ complexes compared to that for 1. Emission quantum yield and lifetime data for the 1···Mn+ complexes are interpreted by a kinetic model in which the rate-determining step for excited-state decay involves dissociation of the cation from the macrocycle. The crown-substituted complex 1 provides a paradigm for a MLCT-based cation sensor.