Robust cuprous phenanthroline sensitizer for solar hydrogen photocatalysis.

The Cu(I) metal-to-ligand charge-transfer complex, [Cu(dsbtmp)2](+) (dsbtmp = 2,9-di(sec-butyl)-3,4,7,8-tetramethyl-1,10-phenanthroline), exhibits outstanding stability as a visible-light-absorbing photosensitizer in hydrogen-evolving homogeneous photocatalysis. In concert with the Co(dmgH)2(py)Cl water reduction catalyst and N,N-dimethyl-p-toluidine sacrificial donor in 1:1 H2O:CH3CN, this Cu(I) sensitizer remains active even after 5 days of visible-light-pumped (λex = 452 ± 10 nm) hydrogen evolution catalysis. Deuteration studies illustrate that the hydrogen produced from this composition does indeed originate from aqueous protons.