Photocleavage of the 1,3-dimethyluracil cyclobutane dimer sensitized by (1,10-phenanthroline) tricarbonylrhenium(I) chloride. Self inhibition by the monomer

The complex Re(o-phan) (CO)(3)Cl is used as a photolyase model. The phospho rescence of the complex is quenched by the 1,3-dimethyluracil cyclobutane d imer with k(q)=5.4 X 10(7) M-1 s(-1). The quenching is accompanied by the c leavage of the dimer. However, this sensitized photolysis cannot be driven very far because the regenerated monomer quenches the triplet of the comple x more efficiently (k(q) = 1.2 X 10(9)). The sensitized monomerization is t hus limited by self inhibition. (C) 2000 Elsevier Science S.A. All rights r eserved.