Optical dissolved oxygen sensor utilizing molybdenum chloride cluster phosphorescence

Abstract

We report on an optical oxygen sensor for aqueous media. The phosphorescent signal from the indicator, K 2 Mo 6 Cl 14 , immobilized in a polymer matrix, is quenched by ground state 3 O 2. Continuous measurements ͑⌬t=10 s͒ over 36 h in oxygen atmospheres ͑0%-21%͒ were obtained with a signal to noise ratio better than 150. Photobleaching was not observed over ϳ13 000 measurements. The senor response at 10, 22, and 37°C water is governed by bimolecular collisional quenching, as evidenced by a linear fit to the Stern-Volmer equation for dissolved oxygen in the range 0 Ͻ ͓O 2 ͔ Ͻ 3 ϫ 10 −4 .

Indicators for optical oxygen sensors

“…Mo clusters were modified to be used for aqueous applications: K 2 Mo 6 Cl 14 clusters were caged in a hydrophobic oxygen polymer matrix, the [(acryloxypropyl)-methylsiloxane-dimethylsiloxane copolymer] [81]. A fiber optic sensor based on the phosphorescence quenching of K 2 Mo 6 Cl 14 clusters has been developed and if showed no photobleaching after more than 13,000 measurements and it gave a linear response in the temperature range between 10 and 37 °C.…”

New Hexanuclear Niobium Cluster Compounds with Pyridine and N‐Methylpyrrolidone Ligands: [Nb6Cl12(Pyr)6][AlCl4]2 and [Nb6Cl12(NMP)6][GaCl4]2

“…Cluster excision and subsequent ligand exchange reactions gives rise to a plethora of new compounds. [2][3][4][5][6][7][8][9][10][11][12][13][14] Recent investigations on early transition metal cluster compounds focus on using them as catalysts, [15,16] luminescent materials, [17,18] sensors, [19] medical X-ray contrast agents, [20,21] or as precursors for elaboration of nano-cluster materials. [22] For all such investigations on possible applications the knowledge about the synthesis, properties, and structures of as many as possible different compounds is essential.…”

Luminescent coordination polymers based on Ca2+ and octahedral cluster anions [{M6Cli8}Cla6]2− (M = Mo, W): synthesis and thermal stability studies

“…Indeed, depending on X and L, some members of this family demonstrate intensive luminescence in the red/near-infrared region with emission lifetimes of hundreds of microseconds and often with significant quantum yields. [11][12][13][14][15][16][17] Due to these properties, materials based on these clusters have been demonstrated to have potential in solar energy harvesting, 18,19 bioimaging, photodynamic therapy, [20][21][22] photo-catalysis, [23][24][25][26][27] oxygen sensing, [28][29][30][31] lighting, [32][33][34] etc.…”