pH-Induced changes in electronic absorption and fluorescence spectra of phenazine derivatives

Spectroscopic Studies on Binding of Porphyrin-Phenazine Conjugate to Four-Stranded Poly(G)

“…The absorption of individual ImPzn dye is characterized by the intense shortwave band at 385 nm (extinction ca. 16,300 M −1 cm −1 ) and the broad longwave shoulder extending to 490 nm [40]. TMPyP 3+ fluorescence spectrum (Fig.…”

Phenazines as chemosensors of solution analytes and as sensitizers in organic photovoltaics

“…A pH sensitive imidazole-fused phenazine 11 was reported by Ryazanova et. al 20 capable of exhibiting reversible optical spectral changes upon pH alterations between pH ranges from 0-14. The UV-visible spectral  max for 11 was centered on 440 nm under neutral pH conditions for these examples while the simple unmodified phenazine peak was at 400 nm in neutral aqueous buffer solutions.…”

“…The UV-visible spectral  max for 11 was centered on 440 nm under neutral pH conditions for these examples while the simple unmodified phenazine peak was at 400 nm in neutral aqueous buffer solutions. 20 This difference could be attributed to a larger -electron system due to fusion…”

“…This is also supported by the fact that if the imidazole acidic hydrogen is replaced by a sugar moiety the observed bathochromic spectral shift at alkaline pH (~12) disappears. 20 Phenazine UV-vis spectrum itself is unaffected by increasing pH of the medium. 11 exhibts a fluorescence emission in the biologically relevant region of 566 nm in aqueous buffer solutions of pH 6 and exhibit fluorescence turn-off behavior under strongly acidic pH.…”

pH-Dependent Complexation between Pyridinyl-Azacrown Ether and Amino-Porphyrin

“…1 Mimicking how natural system uses pH control to regulate the recognition event of binding site and activity, some synthetic molecular systems such as pH-controllable molecular switch have been reported. [2][3][4][5][6] A number of molecular switches have been studied on the basis of the systems whose emission could be modulated by external stimuli such as pH. [7][8][9][10][11][12][13] Porphyrin 14-22 is a well-known luminescent and redox active compound that can accomplish the photoinduced electron transfer upon irradiation and axial coordination on central metal of metalloporphyrin plane.…”