It is a subject of exploration whether the phase pure anatase or rutile TiO₂ or the band alignment due to the heterojunctions in the two polymorphs of TiO₂ plays the determining role in efficacy of a photocatalytic reaction. In this work, the phase pure anatase and rutile TiO₂ have been explored for photocatalytic nitroarenes reduction to understand the role of surface structures and band alignment towards the reduction mechanism. The conduction band of synthesized anatase TiO₂ has been found to be more populated with electrons of higher energy than that of synthesized rutile. This has given the anatase an edge towards photocatalytic reduction of nitroarenes over rutile TiO₂. The other factors like adsorption of the reactants and the proton generation did not play any decisive role in catalytic efficacy.

Paramagnetic transition-metal complexes assembled on surfaces are of great interest for potential applications in organic spintronics. The magnetochemical interactions of the spin of the metal centers with both ferromagnetic surfaces and optional axial ligands are yet to be understood. We use a combination of X-ray magnetic circular dichroism (XMCD) and quantum-chemical simulations based on density functional theory (DFT + U) to investigate these metal–organic interfaces with chemically tunable magnetization. The interplay between an optional axial ligand (NO, spin S = 1/2 or NH₃ , S = 0) and Ni and Co ferromagnetic surfaces affecting the spin of Co(II) tetraphenylporphyrin (d⁷, S = 1/2), Fe(II) tetraphenylporphyrin (d⁶, S = 1), Mn(II) tetraphenylporphyrin (d⁵, S = 5/2) and Mn(II) phthalocyanine (d⁵, S = 3/2) is studied. We find that the structural trans effect on the surface rules the molecular spin state, as well as the sign and strength of the exchange interaction with the substrate. We refer to this observation as the surface spin-trans effect.

X‐ray magnetic circular dichroism (XMCD) measurements and density functional theory (DFT)+U calculations reveal an unexpected antiferromagnetic coupling between physisorbed paramagnetic Co‐porphyrin molecules and a Ni surface, separated by a graphene layer. A positive magnetization at the Ni substrate atoms is mediated by graphene and induces a negative one at the Co site, despite only a very small overlap between macrocyclic π and graphene p_z‐orbitals.