Based on the recently proposed super valence bond model, in which superatoms can compose superatomic molecules by sharing valence pairs and nuclei for shell closure, the 23c-14e bi-icosahedral Au(23)((+9)) core of Au(38)(SR)(24) is proved to be a superatomic molecule. Molecular orbital analysis reveals that the Au(23)((+9)) core is an exact analogue of the F(2) molecule in electronic configuration. Chemical bonding analysis by the adaptive natural density partitioning method confirms the superatomic molecule bonding framework of Au(38)(SR)(24) in a straightforward manner.

A highly efficient unbiased global optimization method called dynamic lattice searching (DLS) was proposed. The method starts with a randomly generated local minimum, and finds better solution by a circulation of construction and searching of the dynamic lattice (DL) until the better solution approaches the best solution. The DL is constructed adaptively based on the starting local minimum by searching the possible location sites for an added atom, and the DL searching is implemented by iteratively moving the atom located at the occupied lattice site with the highest energy to the vacant lattice site with the lowest energy. Because the DL can greatly reduce the searching space and the number of the time-consuming local minimization procedures, the proposed DLS method runs at a very high efficiency, especially for the clusters of larger size. The performance of the DLS is investigated in the optimization of Lennard-Jones (LJ) clusters up to 309 atoms, and the structure of the LJ(500) is also predicted. Furthermore, the idea of dynamic lattice can be easily adopted in the optimization of other molecular or atomic clusters. It may be a promising approach to be universally used for structural optimizations in the chemistry field.

The palladium-catalyzed Suzuki−Miyaura coupling reaction is one of the most versatile and powerful tools for constructing synthetically useful unsymmetrical aryl−aryl bonds. In designing a Pd cluster as a candidate for efficient catalysis and mechanistic investigations, it was envisaged to study a case intermediate between, although very different from, the "classic" Pd(0)L n and Pd nanoparticle families of catalysts. In this work, the cluster [Pd 3 Cl(PPh 2 ) 2 (PPh 3 ) 3 ] + [SbF 6 ] − (abbreviated Pd 3 Cl) was synthesized and fully characterized as a remarkably robust framework that is stable up to 170 °C and fully air-stable. Pd 3 Cl was found to catalyze the Suzuki−Miyaura C−C crosscoupling of a variety of aryl bromides and arylboronic acids under ambient aerobic conditions. The reaction proceeds while keeping the integrity of the cluster framework all along the catalytic cycle via the intermediate Pd 3 Ar, as evidenced by mass spectrometry and quick X-ray absorption fine structure. In the absence of the substrate under the reaction conditions, the Pd 3 OH species was detected by mass spectrometry, which strongly favors the "oxo-Pd" pathway for the transmetalation step involving substitution of the Cl ligand by OH followed by binding of the OH ligand with the arylboronic acid. The kinetics of the Suzuki− Miyaura reaction shows a lack of an induction period, consistent with the lack of cluster dissociation. This study may provide new perspectives for the catalytic mechanisms of C−C cross-coupling reactions catalyzed by metal clusters.

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On the basis of the icosahedral and decahedral lattices, the lowest energies of the Lennard-Jones (LJ) clusters containing 562-1000 atoms with the two motifs are obtained by using a greedy search method (GSM). Energy comparison between the decahedra and icosahedra shows that icosahedral structures are predominant. However, most of the icosahedral structures with the central vacancy are more stable than that without the central vacancy. On the other hand, in the range of 562-1000 atoms, there are 41 LJ clusters with the decahedral motif. The number of decahedra increases remarkably compared with the smaller LJ clusters. Consequently, the magic numbers and growth characters of decahedral clusters are also studied, and the results show that the magic numbers of intermediate decahedral clusters occur at 654, 755, 807, 843, 879, 915, and 935.

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A recent experiment reported that a newly crystallized phosphine-protected Au 20 nanocluster [Au 20 (PPhy 2 ) 10 Cl 4 ]Cl 2 [PPhpy 2 = bis(2-pyridyl)phenylphosphine] owns a very stable Au 20 core, but the number of valence electrons of the Au 20 core is 14e, which is not predicted by the superatom model. So we apply the density functional theory to further study this cluster from its molecular orbital and chemical bonding. The results suggest that the Au 20 (+6) core is an analogue of the F 2 molecule based on the super valence bond model, and the 20-center−14-electron Au 20 (+6) core can be taken as a superatomic molecule bonded by two 11center−7-electron superatoms, where the two 11c superatoms share two Au atoms and two electrons to meet an 8-electron closed shell for each. The electronic shell closure enhances the stability of the Au 20 core, besides the PN bridges. Exceptionally, the theoretical HOMO− LUMO gap (1.03 eV) disagrees with the experimental value (2.24 eV), and some possible reasons for this big difference are analyzed in this paper. INTRODUCTIONLigand-protected gold nanoclusters have been widely studied due to their interesting optical, electronic, and charging properties, as well as potential applications in catalysis, biomedicine, and nanoelectronics. 1−5 So far, tremendous advances have been achieved in the synthesis and isolation of thiolate-protected Au nanoparticles (RS−AuNPs). 6−15 Among RS -AuNP s , Au 2 5 (SR) 1 8 , 1 6 − 2 9 Au 3 8 (SR) 2 4 , 1 0 , 3 0 − 3 8 Au 40 (SR) 24 , 36,39,40 Au 102 (SR) 44 , 41−45 and Au 144 (SR) 60 46−48 are more extensively studied. Especially, the crystallization and structural determination of Au 25 , 49,50 Au 36 , 51 Au 38 , 35 and Au 102 52 were breakthroughs in RS−AuNPs research. Theoretical and experimental studies confirm that Au 25 (SR) 18 −combines an icosahedral Au 13 core and six dimeric (−RS− Au−RS−Au−RS−) staple motifs. 19,49,50 Similarly, Au 38 (SR) 24 is also verified to be composed of a face-fused bi-icosahedral Au 23 core and six dimeric and three monomeric (−RS−Au− RS−) staple motifs, 35,53,54 and the bi-icosahedral Au 23 core is proved to be a superatomic molecule consisting of two Au 13 superatoms. 38 In addition, the gold−phosphane clusters are one of few examples of ligand-protected gold clusters whose structures have been characterized, including some small clusters, Au 4−10 , 55−59 Au 11 , 45,60 and Au 13 , 45,61,62 and large ones, [Au 24 (PPh 3 ) 10 (SC 2 H 4 Ph) 5 X 2 ] + , 63 [Au 39 (PPh 3 ) 14 Cl 6 ]-Cl 2 , 64 and Au 55 (PPh 3 ) 2 Cl 6 . 65−68 Recently, Wan et al. 69 isolated a new phosphine-protected Au 20 nanocluster through the reduction of Au(PPhpy 2 )Cl [PPhpy 2 = bis(2-pyridyl)phenylphosphine] by NaBH 4 and determined its structure by single crystal X-ray structural analysis. This new cluster consists of a dicationic cluster [Au 20 (PPhpy 2 ) 10 Cl 4 ] 2+ (A1) and two Cl − , and the dicationic

Using the super valence bond model, a generalized chemical picture for the electronic shells of an Au20 pyramid is given. It is found that Au20 can be viewed to be a superatomic molecule, of which its superatomic 16c-16e core (T) is in D(3)S hybridization bonded with four vertical Au atoms for the molecule-like (TAu4) electronic shell-closure. Based on such a superatom-atom bonding model, TX4 (X = F, Cl, or Br) are predicted to be very stable. Such a superatom-atom T-Au/T-X bonding enriches the scope of chemistry.