We modeled the interaction between tin(II) porphyrin (SnPor) and platinum (Pt) by density functional theory. Our calculations indicate that Pt binds strongly on SnPor and that SnPor enhances the catalytic property of Pt for reduction reactions. This enhancement is attributed to the partial negative charge on Pt, the low electron density at Pt and the localization of frontier electrons oil Pt. Of note, the electron affinity of SnPor-Pt is low (0.13 eV). In the SnPor-Pt-1 state, SnPor stabilizes the extra negative charge while a very loose HOMO electron localizes on Pt - suggesting that SnPor-Pt can also be used for ligand-to-metal charge transfer. (c) 2006 Elsevier B.V. All rights reserved.