Session: COMP Poster Session:

The theoretically inspired development of two heterometallic photocatalysts, [(bpy)₂Ru^IINi^II(L_^ox)](ClO₄)₂ (1) and [(bpy)₂Ru^IINi^II(dmg)₂Ru^II(bpy)₂](ClO₄)₂ (2) for water reduction is described. Detailed DFT analysis predicts that both can generate the low-valent precursor involved in hydride formation prior to dihydrogen generation. The computational study further demonstrates that the bimetallic complex requires the presence of an external photosensitizer to trigger catalytic activity. On the other hand, the trimetallic catalyst displays significant coupling between the catalytic and light-harvesting units to promote intramolecular multielectron transfer and perform photocatalysis at the Ni center. All the theoretical predictions have been supported by the experiments demonstrating that complex 1 is unable to achieve self-supported catalysis. However, dihydrogen generation by 1 has been reported in presence of the external photosensitizer, [Ru^II(bpy)₃]²⁺, with a TON_24h of 59 under irradiation with blue light. The trimetallic [Ru^IINi^IIRu^II] (2) is fully photocatalytic (TON_24h = 49) even in the absence of an external photosensitizer under the identical experimental conditions.

Shivnath Mazumder

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