Manipulating Reduction Potentials in an Artificial Safranin Cofactor

Tetrahedron Lett. 2012 Mar 7;53(10):1201-1203. doi: 10.1016/j.tetlet.2011.12.028. Epub 2011 Dec 14.


Safranines hold great promise as artificial flavin-like electron transfer cofactors with tunable properties. We report the design and chemical synthesis of the p-methoxy derivative of safranine O using a new synthetic route based on the Ulmann condensation. Spectroelectrochemical comparison of the purified parent safranine and this derivative demonstrates that the modification increases its two-electron reduction potential by 125 mV, or 5.75 kcal/mol. This modification also causes redshifts in the absorbance and fluorescence spectra of the cofactor, suggesting that it may find future utility in arrayed sensor applications.