Double σ-Aromaticity in a Surface-Deposited Cluster: Pd₄ on TiO₂ (110)

Abstract

ABSTRACT:We report the presence of -aromaticity in a surface deposited cluster, Pd 4 on TiO 2 (110). In the gas phase, Pd 4 adopts a tetrahedral structure. However, surface binding promotes a flat, -aromatic cluster. This is the first time aromaticity is found in surface deposited clusters. Systems of this type emerge as a promising class of catalyst, and so realization of aromaticity in them may help to rationalize their reactivity and catalytic properties, as a function of cluster size and composition.Surface-deposited clusters composed of only a few atoms gain popularity as a new class of potent heterogeneous catalysts.

Pure and Zn-doped Pt clusters go flat and upright on MgO(100)

“…This situation is analogous to that in Pd clusters. 6,13 With an additional electron being added to make an anion, there is a chance to further use more 6s-and also 6p-AOs on Pt in the valence set. Indeed, the Natural Bond Order 65 analysis performed at the UTPPSh/ aug-cc-pVTZ level of theory shows for the trapezoidal clusters 6p-AOs are close enough in energy to the 5d-AOs, and so they mix, making it impossible to uncover their isolated contributions to the MOs.…”

“…The catalytic properties of such nanometer and subnanometer clusters can be outstanding, but depend strongly and nonlinearly on cluster size and composition, [1][2][3][4][5][6][7] and also on the nature of the support. 6,[8][9][10][11][12][13] The electronic structure of clusters is reminiscent of molecules, in that important chemical-physical properties can be understood from a molecular orbital (MO) picture, wherein the MOs will be well-separated in energy, rather than having continuous energy bands. 14,15 The support plays the role of a ligand in very small (o1 nm) clusters, capable of actively modifying cluster structures, charge, and other properties (see e.g.…”

α-d-Glucopyranose Adsorption on a Pd30 Cluster Supported on Boron Nitride Nanotube

“…The adsorption geometry of the supported Pd 30 cluster can be analyzed considering the matching-points of the interacting (111) Pd plane with the BNNT. For other supported metallic systems, it was already shown that complementary symmetries, characterizing cluster faces and support surfaces, are significant driving forces, which leads to effective interactions between them [40]. This criterion has been also employed to understand the growth mechanism of h-BN nanosheets on low Miller-index planes of different metals, driving at the conclusion that negligible lattice mismatches give raise to stronger adsorption [19].…”

Optical, Electrical, and Catalytic Properties of Metal Nanoclusters Investigated by ab initio Molecular Dynamics Simulation: A Mini Review

“…The weak Pd−H energy allows the chemisorbed H atoms to react with other adsorbates or two H atoms reacts together to form H 2 molecule (19,20). Small Pd nanoclusters deposited on solid supporting surfaces, such as MgO (21) or TiO 2 (22,23), were also theoretically studied since it was believed to be responsible for the majority of catalytic activity. The behavior characteristic to the clusters comes from a large fraction of surface atoms and the discrete nature of electronic states, which makes the electronic state of the cluster quite different from those of the bulk structure (24,25).Metal clusters with an appropriate size would be an excellent representation of the metal nanoparticles (26).…”