A luminescent pH sensor based on a sol–gel film functionalized with a luminescent organometallic complex

Abstract

A rhenium(I) tricarbonyl complex with a 3-(pyridin-2-yl)pyrazole chromophoric ligand and a functionalized organosilane spectator ligand, [Re(py-pzH)(CO) 3 (L 1 )](CF 3 SO 3 ) (1) [where py-pzH~3-(pyridin-2-yl)pyrazole, L 1 ~3-N-(pyridin-4-ylmethylene)aminopropyltriethoxysilane], as well as its analog, [Re(py-pzH)(CO) 3 (py)](CF 3 SO 3 ) (2) (where py~pyridine) have been synthesized. The room temperature MLCT luminescence properties of 1 and 2 (l max at 484 and 489 nm, respectively) were found to be sensitive to the protonation±deprotonation status of the 3-(pyridin-2-yl)pyrazole ligand. Spectro¯uorometric pH titration of 2 in aqueous media revealed an excited state pK a of 7.05. Sol±gel material formed from hydrolysis of 1 was successfully spin-coated onto glass microscope slides. The result was a sol±gel based luminescent pH sensor capable of responding over a wide pH range from pH 2.3 to 12 in air. The applicability of the principle of direct perturbation of electronic factors of sensor molecules in the development of luminescent chemical sensing materials is demonstrated.

Rhenium(I) tricarbonyl complexes with bispyridine ligands attached to sulfur-rich core: Syntheses, structures and properties

“…Considerable efforts have been devoted to the design and synthesis of transition-metal polypyridine complexes, largely due to their potential applications such as efficient photocatalysts for CO 2 reduction [1-6], materials for molecular electronics and photonics [7][8][9][10][11][12][13][14][15][16][17][18], and sensitizers for solar energy conversion [19][20][21][22][23][24][25][26][27][28]. In the dye-sensitized solar cells (DSSCs) based on Ru II polypyridyl dyes, carboxylic acid pendants are key to the attachment of dyes to the semiconductor surface [29].…”

Molecular and Electronic Structure in the Metal-to-Ligand Charge Transfer Excited States of fac-[Re(4,4‘-X2bpy)(CO)3(4-Etpy)]+* (X = CH3, H, Co2Et). Application of Density Functional Theory and Time-Resolved Infrared Spectroscopy

“…MLCT excited states based on rhenium(I) also hold potential for such applications. The sensitivity of their photophysical properties to the environment makes them ideal candidates as sensors of local microscopic environmental conditions, such as polarity, pH, CO 2 , and O 2 . − …”

Synthesis of 1H-Pyrazol-5-yl-pyridin-2-yl-[1,2,4]triazinyl Soft-Lewis Basic Complexants via Metal and Oxidant Free [3 + 2] Dipolar Cycloaddition of Terminal Ethynyl Pyridines with Tosylhydrazides

“…Dipolar cycloaddition reactions incorporating 4-methylsulfononhydrazides are widely employed for the production of pyrazoles, 1,2,3-triazoles, and other heteroarenes . This versatile heterocycle exists in natural products, biologically active compounds, materials, and has been utilized as a ligand for C–C bond-forming transformations . Hydrazide dipoles can also be used in cross-coupling reactions .…”