Magic Numbers in Silicon Dioxide-Based Clusters

Xu, Can; Wang, Wenning; Zhang, Wingham; Zhuang, Jun; Liu, Lei; Kong, Qingyu; Zhao, Li; Long, Yingcai; Fan, Kangnian; Qian, Shixiong; Li, Yufen

doi:10.1021/jp002695w

Cited by 41 publications

(36 citation statements)

References 18 publications

(33 reference statements)

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“…5 A comparison of Figures 1a to d indicates that not only the intensity of the magic number cluster sequence varies with samples, but also the abundance distribution in the mass spectrum shows some dependence on sample properties and/or experimental conditions. We found that, in general, n ϭ 4 and 8 are magic numbers, but the intensity of the n ϭ 5 cluster,…”

Section: Mass Spectrometric Resultsmentioning

confidence: 92%

“…[1][2][3][4][5] A 308 nm XeCl excimer laser was used for the generation of silica clusters, and time-of-flight (TOF) mass spectrometry was employed for studying the abundance distribution of the clusters. The mass spectrometric measurement was concentrated in the negative ion channel, because for the silica clusters rich information has only been observed in the negative ion mass spectra.…”

Section: Methodsmentioning

confidence: 99%

“…Taking all isomers obtained in our calculation into consideration, the much lower energies of the cage isomers of (SiO 2 ) 4 Ϫ suggest that the magic number cluster n ϭ 4 will most probably take the cage-like structures. The bonding characteristics in the isomers of the neutral and anionic magic number clusters have been analyzed in our previous article 5 and will not be repeated here.…”

Section: O 2 H 3 ]mentioning

confidence: 99%

“…[1][2][3][4] The phenomenon that has attracted our particular interest is the first observation of magic number silica-containing clusters [(SiO 2 ) n O 2 H 3 ] Ϫ (n ϭ 4,8), which has been reported in our previous artricle. 5 In the XeCl excimer laser ablation mass spectra, several silica-containing cluster sequences are produced, but only the [(SiO 2 ) n O 2 H 3 ]…”

Section: Introductionmentioning

confidence: 99%

“…5 In the present article, calculation results using the density functional theory will be reported with emphasis on the n ϭ 8 silica clusters to account for the appearance of the second magic number cluster in the mass spectra. In our calculation, genetic algorithm (GA) was used as supplementary means to help searching for the isomer structures.…”

Section: Introductionmentioning

confidence: 99%

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Magic number silicon dioxide‐based clusters: Laser ablation‐mass spectrometric and density functional theory studies

Kong¹,

Zhao²,

Wang³

et al. 2005

J Comput Chem

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The magic number silica clusters [(SiO(2))(n)O(2)H(3)](-) with n = 4 and 8 have been observed in the XeCl excimer laser (308 nm) ablation of various porous siliceous materials. The structural origin of the magic number clusters has been studied by the density functional theoretical calculation at the B3LYP/6-31G** level, with a genetic algorithm as a supplementary tool for global structure searching. The DFT results of the first magic number cluster are parallel to the corresponding Hartree-Fock results previously reported with only small differences in the structural parameters. Theoretical calculation predicts that the first magic number cluster (SiO(2))(4)O(2)H(4) and its anion [(SiO(2))(4)O(2)H(3)](-) will most probably take pseudotetrahedral cage-like structures. To study the structural properties of the second magic number cluster, geometries of the bare cluster (SiO(2))(8), the neutral complex cluster (SiO(2))(8)O(2)H(4), and the anionic cluster [(SiO(2))(8)O(2)H(3)](-) are fully optimized at the B3LYP/6-31G** level, and the corresponding vibrational frequencies are calculated. The DFT calculations predict that the ground state of the bare silica octamer (SiO(2))(8) has a linear chain structure, whereas the second magic number complex cluster (SiO(2))(8)O(2)H(4) and its anion [(SiO(2))(8)O(2)H(3)](-) are most probably a mixture of cubic cage-like structural isomers with an O atom inside the cage and several quasi-bicage isomers with high intercage interactions. The stabilization of these structures can also be attributed to the active participation of the group of atoms 2O and 4H (3H for the anion) in chemical bonding during cluster formation. Our theoretical calculation gives preliminary structural interpretation of the presence of the first and second magic number clusters and the absence of higher magic numbers.

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Section: Mass Spectrometric Resultsmentioning

confidence: 92%

Section: Methodsmentioning

confidence: 99%

Section: O 2 H 3 ]mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Magic number silicon dioxide‐based clusters: Laser ablation‐mass spectrometric and density functional theory studies

Kong¹,

Zhao²,

Wang³

et al. 2005

J Comput Chem

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Structural Preferences of Single‐Walled Silica Nanostructures: Nanospheres and Chemically Stable Nanotubes

Linnolahti

Kinnunen

Pakkanen

2005

Chemistry A European J

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Structural preferences of single-walled and coordinatively saturated spherical and tubular nanostructures of silica have been determined by ab initio calculations. Two families of spherical (SiO2)n clusters derived from Platonic solids and Archimedean polyhedra are depicted, with n ranging from 4-120. The analogue of a truncated icosidodecahedron, Ih-symmetric Si120O240, is favored in energy, closely followed by the Ih-symmetric Si60O120-truncated icosahedron. The silica nanotubes derived from spherical clusters are capped by Si2O2 rings, whereas the tubular section consists of single oxygen bridges. Periodic studies performed with open-ended silica nanotubes and the alpha-quartz polymorph of silica, along with a comparisons to fullerenes and carbon nanotubes, suggest that tubes with diameters of approximately 1 nm should be chemically stable.

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Silica‐immobilized acid ionic liquid: An efficient catalyst for pentanal self‐condensation

Wang

Yang

et al. 2020

J of Chemical Tech & Biotech

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BACKGROUND: Pentanal self-condensation to 2-propyl-2-heptenal is an important process of carbon chain extension for the industrial manufacture of 2-propylheptanol, which is an important plasticizer alcohol. The existing industrial processes all use liquid alkali catalysts, so they suffer from problems such as difficult recovery and high costs for treatment of alkalicontaining wastewater. In the present work, three immobilized acid ionic liquids were prepared separately with SiO 2 , MCM-41, and SBA-15 as support for pentanal self-condensation. RESULTS: The structures of the as-prepared immobilized acid ionic liquids were confirmed with the help of FT-IR, TG, SEM-EDS, and N 2 adsorption-desorption techniques. The characterization and activity evaluation results indicate that there are positive correlations among the number of hydroxyl groups on the support surface, ionic liquid loading, and the catalytic activity. Among the three immobilized acid ionic liquids, silica-immobilized acid ionic liquids (SiO 2-IL-SO 3 H) showed an extraordinary catalytic performance for pentanal self-condensation because of its higher ionic liquid loading. The yield and selectivity of 2-propyl-2-heptenal could respectively reach 73.9% and 91.5% under suitable reaction conditions and a high turnover number (TON) of 179.1 was obtained. CONCLUSION: Pyridine adsorption infrared spectroscopy and density functional theory (DFT) simulation were employed to investigate the structure and acidity of SiO 2-IL-SO 3 H. The optimized structures were obtained, and the calculation results indicate that the acidity of SiO 2-IL-SO 3 H is higher than the corresponding homogeneous ionic liquid system, which may be the main reason for its excellent catalytic performance and catalytic efficiency.

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Magic Numbers in Silicon Dioxide-Based Clusters

Cited by 41 publications

References 18 publications

Magic number silicon dioxide‐based clusters: Laser ablation‐mass spectrometric and density functional theory studies

Magic number silicon dioxide‐based clusters: Laser ablation‐mass spectrometric and density functional theory studies

Structural Preferences of Single‐Walled Silica Nanostructures: Nanospheres and Chemically Stable Nanotubes

Silica‐immobilized acid ionic liquid: An efficient catalyst for pentanal self‐condensation

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