Bifunctional Metal-Organic Layer with Organic Dyes and Iron Centers for Synergistic Photoredox Catalysis

Here we report the design of a bifunctional metal-organic layer (MOL), Hf-EY-Fe, by bridging eosin Y (EY)-capped Hf-6 secondary building units (SBUs) with Fe-TPY (TPY = 4'-(4-carboxypheny1)[2,2':6',2 ''-terpyridine]-5,5 ''-dicarboxylate) ligands. With the organic dye EY as an efficient photosensitizer and TPY-Fe(OTf)(2) as the catalytic center, Hf-EY-Fe efficiently catalyzes aminotrifluoromethylation, hydroxytrifluoromethylation, and chlorotrifluoromethylation of alkenes. Hf-EY-Fe also catalyzes the synthesis of CF3-substituted derivatives of large bioactive molecules such as rotenone, estrone, and adapalene with sizes of up to 2.2 nm. The proximity between EY and iron centers and their site isolation in Hf-EY-Fe enhance catalytic activity while inhibiting their mutual deactivation, leading to high turnover numbers of up to 1840 and good recyclability of the MOL catalyst.

Automated summary

A bifunctional metal-organic layer, Hf-EY-Fe, designed by bridging EY-capped Hf-6 SBUs with Fe-TPY ligands, efficiently catalyzes various reactions on alkenes and synthesis of CF3-substituted derivatives of large bioactive molecules. The proximity between EY and iron centers in Hf-EY-Fe enhances catalytic activity and inhibits mutual deactivation, resulting in high turnover numbers and good recyclability of the MOL catalyst.