Two heterometallic photocatalysts were designed and probed for water reduction. Both [(bpy)2RuIINiII(L1)](ClO4)2 (1) and [(bpy)2RuIINiII(L2)2RuII(bpy)2](ClO4)2 (2) can generate the low‐valent precursor involved in hydride formation prior to dihydrogen generation. However, while the bimetallic [RuIINiII] (1) requires the presence of an external photosensitizer to trigger catalytic activity, the trimetallic [RuIINiIIRuII] (2) displays significant coupling between the catalytic and light‐harvesting units to promote intramolecular multielectron transfer and perform photocatalysis at the Ni center. A concerted experimental and theoretical effort proposes mechanisms to explain why 1 is unable to achieve self‐supported catalysis, while 2 is fully photocatalytic.

Two heterometallic photocatalysts were designed and probed for water reduction. Both [(bpy)2RuIINiII(L1)](ClO4)2 (1) and [(bpy)2RuIINiII(L2)2RuII(bpy)2](ClO4)2 (2) can generate the low‐valent precursor involved in hydride formation prior to dihydrogen generation. However, while the bimetallic [RuIINiII] (1) requires the presence of an external photosensitizer to trigger catalytic activity, the trimetallic [RuIINiIIRuII] (2) displays significant coupling between the catalytic and light‐harvesting units to promote intramolecular multielectron transfer and perform photocatalysis at the Ni center. A concerted experimental and theoretical effort proposes mechanisms to explain why 1 is unable to achieve self‐supported catalysis, while 2 is fully photocatalytic.

Three new metallosurfactants containing 3d 4 manganese(III) ions, namely, [Mn III (L NO2-N2O2 )Cl(MeOH)] (1), [Mn III (L N2O2 )(H 2 O)(MeOH)]Cl (2), and [Mn III (L N2O3 )] (3), bound to three distinct phenylenediamine-bridged phenolate-rich ligands were designed, deposited as Langmuir−Blodgett monolayer films on gold electrodes, and probed for directional electron transfer in Au|LB|Au junctions. All three Mn III metallosurfactants promote current rectification, and we compare the behavior of these metallosurfactants with that of our previously studied 3d 1 V�O IV , 3d 3 Cr III , and 3d 5 Fe III species in similar environments through a rigorous effort. Based on the analysis of electrochemical, spectroscopic, microscopic, and DFT results, we propose distinct mechanisms by which electronic configurations and ligand frameworks influence and modulate the energy gap between the electrode Fermi levels and the molecular orbitals responsible for electron transport. Our previous work characterized distinct mechanisms, i.e., electron transport through below-Fermi for V IV Obased SOMOs and above-Fermi for Fe III -based SOMOs and ligand-based HOMOs for the Cr III species. These Mn III species show electron transport similar to Fe III ; however, low current capacities suggest that film quality is an important factor to be considered.