title: On reversible bonding of hydrogen molecules on platinum clusters.
abstract: The local reactivity of hydrogenated platinum clusters (Pt clusters) has been studied using the regional density functional theory method. We observed that antibond orbitals constitute the preferable binding site for hydrogen molecules H(2). Those sites are characterized by lowered electronic chemical potential and strong directionality and exhibit electrophilic nature. The platinum-dihydrogen (Pt-H(2)) sigma complexes were formed only by occupation of the lowest electronic chemical potential sites associated with Pt-H antibonds (sigma(PtH) ( *)) in saturated platinum clusters. The formation of sigma complexes caused mutual stabilization with the trans Pt-H bond. Such activated H(2) molecules on Pt clusters in a sense resemble heme-oxygen (heme-O(2)) complex with interaction strength greater than physisorption or hydrogen bonding but below chemisorption strength.
authors.affiliation: Department of Micro Engineering, Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Paweł
authors.initials: P
authors.lastname: Szarek
authors.forename: Kousuke
authors.initials: K
authors.lastname: Urakami
authors.forename: Chenggang
authors.initials: C
authors.lastname: Zhou
authors.forename: Hansong
authors.initials: H
authors.lastname: Cheng
authors.forename: Akitomo
authors.initials: A
authors.lastname: Tachibana