Light activation therapy/photodynamic therapy (PDT) represents a minimally invasive technique for selective delivery or activation of a drug. Photo-activated redox disruption catalysts offer an advantage over existing PDT reagents in treating disease with hypoxic symptoms by targeting the NAD+/NADH balance in cells. The alteration of cellular redox status through changes of the NAD+/NADH concentration has been shown to play an important role in cell death. A series of RuII half-sandwhich complexes of the type Ru(p-cymene)(N'N)X were synthesized where (N'N)= N-tosyl ethylene diamine (TsEn), 2-(N-tosyl)amino pyridine (TsAmpy) and 8-(N-tosyl)quinolamine (TsQuin) and X = Cl or Pyridine with PF6- counter ion. These modified Noyori ligands were found to regioselectively catalyze the transfer hydrogenation of NAD+ to yield NADH in the presence of excess formate. The turnover frequency (TOF) of this catalysis for the aquated chloride complexes increased in the order TsQuin>TsAmpy>TsEn. The pyridine based complexes were inert to hydrolysis at 37oC in dark over more than 48 hours while the chloride adducts proceeded to their corresponding aqua species in the presence of water. When irradiated with UVA light, the pyridine complexes in water at 37oC were found by 1H NMR to photo-decompose rather than photo-disassociate to their aquated form. In the presence of white light irradiation, no change was detected by 1H NMR or UV/Vis spectroscopy.

Development toward ruthenium based light activated redox potential disruption catalysts

247th National Meeting (2014)

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