Metal alkylidenes, which are key organometallic intermediates in reactions such as olefination or alkene and alkane metathesis, are typically generated from metal dialkyl compounds [M](CH₂R)₂ that show distinctively deshielded chemical shifts for their α-carbons. Experimental solid-state NMR measurements combined with DFT/ZORA calculations and a chemical shift tensor analysis reveal that this remarkable deshielding originates from an empty metal d-orbital oriented in the M-C_α-C_α' plane, interacting with the C_α p-orbital lying in the same plane. This π-type interaction inscribes some alkylidene character into C_α that favors alkylidene generation via α-H abstraction. The extent of the deshielding and the anisotropy of the alkyl chemical shift tensors distinguishes [M](CH₂R)₂ compounds that form alkylidenes from those that do not, relating the reactivity to molecular orbitals of the respective molecules. The α-carbon chemical shifts and tensor orientations thus predict the reactivity of metal alkyl compounds towards alkylidene generation.

Reported here is the chelate effect as a design principle for tuning heterogeneous catalysts for electrochemical CO₂ reduction. Palladium functionalized with a chelating tris-N-heterocyclic carbene (NHC) ligand (Pd-timtmb^Me ) exhibits a 32-fold increase in activity for electrochemical reduction of CO₂ to C1 products with high Faradaic efficiency (FE_C1 =86 %) compared to the parent unfunctionalized Pd foil (FE=23 %), and with sustained activity relative to a monodentate NHC-ligated Pd electrode (Pd-mimtmb^Me ). The results highlight the contributions of the chelate effect for tailoring and maintaining reactivity at molecular-materials interfaces enabled by surface organometallic chemistry.