scholarly journals Characterization of a strong covalent Th3+–Th3+ bond inside an Ih(7)-C80 fullerene cage

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jiaxin Zhuang ◽  
Roser Morales-Martínez ◽  
Jiangwei Zhang ◽  
Yaofeng Wang ◽  
Yang-Rong Yao ◽  
...  
Keyword(s):  
Density Functional ◽  
Arc Discharge ◽  
Fullerene Cage ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
Metal Metal ◽  
Fundamental Understanding ◽  
Metal Bonds ◽  
Discharge Method

AbstractThe nature of the actinide-actinide bonds is of fundamental importance to understand the electronic structure of the 5f elements. It has attracted considerable theoretical attention, but little is known experimentally as the synthesis of these chemical bonds remains extremely challenging. Herein, we report a strong covalent Th-Th bond formed between two rarely accessible Th3+ ions, stabilized inside a fullerene cage nanocontainer as Th2@Ih(7)-C80. This compound is synthesized using the arc-discharge method and fully characterized using several techniques. The single-crystal X-Ray diffraction analysis determines that the two Th atoms are separated by 3.816 Å. Both experimental and quantum-chemical results show that the two Th atoms have formal charges of +3 and confirm the presence of a strong covalent Th-Th bond inside Ih(7)-C80. Moreover, density functional theory and ab initio multireference calculations suggest that the overlap between the 7s/6d hybrid thorium orbitals is so large that the bond still exists at Th-Th separations larger than 6 Å. This work demonstrates the authenticity of covalent actinide metal-metal bonds in a stable compound and deepens our fundamental understanding of f element metal bonds.

scholarly journals Metal-Rich Metallaboranes: Synthesis, Structures and Bonding of Bi- and Trimetallic Open-Faced Cobaltaboranes

Inorganics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 28
Author(s):  
Kriti Pathak ◽  
Chandan Nandi ◽  
Jean-François Halet ◽  
Sundargopal Ghosh
Keyword(s):  
Electronic Structures ◽  
Density Functional ◽  
Room Temperature ◽  
Electron Pair ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Cluster 2 ◽  
Cobalt Center

Synthesis, isolation, and structural characterization of unique metal rich diamagnetic cobaltaborane clusters are reported. They were obtained from reactions of monoborane as well as modified borohydride reagents with cobalt sources. For example, the reaction of [Cp*CoCl]2 with [LiBH4·THF] and subsequent photolysis with excess [BH3·THF] (THF = tetrahydrofuran) at room temperature afforded the 11-vertex tricobaltaborane nido-[(Cp*Co)3B8H10] (1, Cp* = η5-C5Me5). The reaction of Li[BH2S3] with the dicobaltaoctaborane(12) [(Cp*Co)2B6H10] yielded the 10-vertex nido-2,4-[(Cp*Co)2B8H12] cluster (2), extending the library of dicobaltadecaborane(14) analogues. Although cluster 1 adopts a classical 11-vertex-nido-geometry with one cobalt center and four boron atoms forming the open pentagonal face, it disobeys the Polyhedral Skeletal Electron Pair Theory (PSEPT). Compound 2 adopts a perfectly symmetrical 10-vertex-nido framework with a plane of symmetry bisecting the basal boron plane resulting in two {CoB3} units bridged at the base by two boron atoms and possesses the expected electron count. Both compounds were characterized in solution by multinuclear NMR and IR spectroscopies and by mass spectrometry. Single-crystal X-ray diffraction analyses confirmed the structures of the compounds. Additionally, density functional theory (DFT) calculations were performed in order to study and interpret the nature of bonding and electronic structures of these complexes.

scholarly journals Preparation of Zirconium Oxide Powder Using Zirconium Carboxylate Precursors

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Mohammed H. Al-Hazmi ◽  
YongMan Choi ◽  
Allen W. Apblett
Keyword(s):  
Dft Calculations ◽  
Density Functional ◽  
Dissociative Adsorption ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
Experimental Findings ◽  
Periodic Dft Calculations ◽  
Good Agreement

Zirconia was prepared at low temperatures (<450°C) using single several source precursors based on zirconium carboxylates where the R groups were systematically varied. The combination of density functional theory (DFT) calculations and extensive characterization of the precursors (i.e., X-ray diffraction, thermal gravimetric analysis, infrared spectroscopy, and scanning electron microscopy) indicated that the carboxylic acid complexes may link the zirconium metal with a cis bidentate configuration. Periodic DFT calculations were performed to examine the interaction between monoclinic ZrO2 and propanoic acid. Dissociative adsorption takes place through the cis bidentate structure with an adsorption energy of −1.43 eV. Calculated vibrational frequencies using the optimized structure are in good agreement with experimental findings.

Arc Discharge Synthesis of Oxides and Carbides of Tungsten and Aluminum

2013 ◽  
Vol 8 (2) ◽  
pp. 95-101
Author(s):  
Alexey Zaikovsky ◽  
Aleksandr Fedoseev ◽  
Salavat Sakhapov ◽  
Anton Evtushenko ◽  
Marina Serebriakova ◽  
...  
Keyword(s):  
Arc Discharge ◽  
Experimental Investigations ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthesis Of Nanoparticles ◽  
Synthesized Materials ◽  
Discharge Method

Experimental investigations of the possibility of arc discharge method for synthesis of nanoparticles of oxides and carbides of tungsten and aluminum have been presented. The method is based on anode atomization of composed graphite – aluminum and graphite – WO3 electrodes. The transmitted electron microscopy, thermal gravimetric analysis and X-ray diffraction were applied for the characterization of morphology and properties of synthesized materials. It was experimentally shown the arc discharge method allows to syntheses the nanoparticles of oxides and carbides of tungsten and aluminum

X-ray characterization of tripyridinium bis[tetrabromidoferrate(III)] bromide asymmetric unit in solution by Debye function analysis

2016 ◽  
Vol 30 (24) ◽  
pp. 1650174
Author(s):  
F. Baniasadi ◽  
N. Sahraei ◽  
M. B. Fathi ◽  
M. M. Tehranchi ◽  
N. Safari ◽  
...  
Keyword(s):  
Density Functional ◽  
Function Analysis ◽  
Dilute Solution ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
Debye Function ◽  
Functional Theory ◽  
X Ray ◽  
Diluted Solution

Abundant asymmetric unit of the [FeBr4]2[py.H]3Br magnetic molecule in the acetonitrile solvent was characterized via Debye function analysis (DFA) of the X-ray powder diffraction pattern from dilute solution. A diluted solution of the material in acetonitrile solvent has been prepared to reduce, as far as possible, the interaction between the molecular units. The X-ray diffraction from the sample was measured and Debye function simulations of three out of ten chemically plausible molecular units were observed to suitably comply with the experimental results. These three configurations were further optimized with first-principles method in the framework of density functional theory (DFT) and the most stable structure according to the calculated total energy is presented.

scholarly journals Hydrosilyation of CO2 using a silatrane hydride: structural characterization of a silyl formate compound

2021 ◽  
Vol 99 (2) ◽  
pp. 259-267
Author(s):  
Serge Ruccolo ◽  
Erika Amemiya ◽  
Daniel G. Shlian ◽  
Gerard Parkin
Keyword(s):  
Molecular Structure ◽  
Density Functional Theory ◽  
Oxygen Atom ◽  
Structural Characterization ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray

The silatrane hydride compound, [N(CH2CH2O)3]SiH, reacts with CO2 in the presence of the [tris(2-pyridylthio)methyl]zinc hydride complex, [Tptm]ZnH, to afford the silyl formate and methoxide derivatives, [N(CH2CH2O)3]SiO2CH and [N(CH2CH2O)3]SiOCH3. The molecular structure of [N(CH2CH2O)3]SiO2CH has been determined by X-ray diffraction, thereby demonstrating that the formate ligand adopts a distal conformation in which the uncoordinated oxygen atom resides with a trans-like disposition relative to silicon. Density functional theory calculations indicate that the atrane motif of [N(CH2CH2O)3]SiO2CH is flexible, such that the energy of the molecule changes relatively little as the Si···N distance varies over the range 2.0–3.0 Å.

scholarly journals Identification of a uranium–rhodium triple bond in a heterometallic cluster

2019 ◽  
Vol 116 (36) ◽  
pp. 17654-17658 ◽  
Author(s):  
Genfeng Feng ◽  
Mingxing Zhang ◽  
Penglong Wang ◽  
Shuao Wang ◽  
Laurent Maron ◽  
...  
Keyword(s):  
Triple Bond ◽  
Covalent Bond ◽  
Small Molecule Activation ◽  
X Ray Diffraction ◽  
Multiple Bonds ◽  
Uranium Metal ◽  
Heterometallic Cluster ◽  
Metal Metal ◽  
Metal Bonds

The chemistry of d-block metal–metal multiple bonds has been extensively investigated in the past 5 decades. However, the synthesis and characterization of species with f-block metal–metal multiple bonds are significantly more challenging and such species remain extremely rare. Here, we report the identification of a uranium–rhodium triple bond in a heterometallic cluster, which was synthesized under routine conditions. The uranium–rhodium triple-bond length of 2.31 Å in this cluster is only 3% longer than the sum of the covalent triple-bond radii of uranium and rhodium (2.24 Å). Computational studies reveal that the nature of this uranium–rhodium triple bond is 1 covalent bond with 2 rhodium-to-uranium dative bonds. This heterometallic cluster represents a species with f-block metal–metal triple bond structurally authenticated by X-ray diffraction. These studies not only demonstrate the authenticity of the uranium–metal triple bond, but also provide a possibility for the synthesis of other f-block metal–metal multiple bonds. We expect that this work may further our understanding of the bonding between uranium and transition metals, which may help to design new d-f heterometallic catalysts with uranium–metal bonds for small-molecule activation and to promote the utilization of abundant depleted uranium resources.

scholarly journals Experimental and theoretical characterization of the Zn—Zn bond in [Zn2(η5-C5Me5)2]

2007 ◽  
Vol 63 (6) ◽  
pp. 862-868 ◽  
Author(s):  
Juan F. Van der Maelen ◽  
Enrique Gutiérrez-Puebla ◽  
Ángeles Monge ◽  
Santiago García-Granda ◽  
Irene Resa ◽  
...  
Keyword(s):  
Electron Density ◽  
Density Functional ◽  
Topological Analysis ◽  
Open Shell ◽  
Synchrotron Diffraction ◽  
Functional Theory ◽  
Metal Metal ◽  
Moller Plesset ◽  
Experimental Electron Density

The existence and characterization of a bond between the Zn atoms in the recently synthesized complex [Zn2(η5-C5Me5)2], as well as between Zn and ligand C atoms is firmly based on neutron diffraction and low-temperature X-ray synchrotron diffraction experiments. The multipolar analysis of the experimental electron density and its topological analysis by means of the `Atoms in Molecules' (AIM) approach reveals details of the Zn—Zn bond, such as its open-shell intermediate character (the results are consistent with a typical metal–metal single bond), as well as many other topological properties of the compound. Experimental results are also compared with theoretical ab initio calculations of the DFT (density functional theory) and MP2 (Møller-Plesset perturbation theory) electron densities, giving a coherent view of the bonding in the complex. For instance, charges calculated from the AIM approach applied to the atomic basin of each Zn atom are, on average, +0.72 e from both the experimental and the theoretical electron density, showing a moderate charge transfer from the metal, confirmed by the calculated topological indexes.

scholarly journals Polymerization Isomerism in Co-M (M = Cu, Ag, Au) Carbonyl Clusters: Synthesis, Structures and Computational Investigation

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1529
Author(s):  
Cristiana Cesari ◽  
Beatrice Berti ◽  
Francesco Calcagno ◽  
Cristina Femoni ◽  
Marco Garavelli ◽  
...  
Keyword(s):  
Solid State ◽  
Density Functional ◽  
Molecular Structures ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
Cluster Chemistry ◽  
Molecular Weights ◽  
Crystallization Conditions

The reaction of [Co(CO)4]− (1) with M(I) compounds (M = Cu, Ag, Au) was reinvestigated unraveling an unprecedented case of polymerization isomerism. Thus, as previously reported, the trinuclear clusters [M{Co(CO)4}2]− (M = Cu, 2; Ag, 3; Au, 4) were obtained by reacting 1 with M(I) in a 2:1 molar ratio. Their molecular structures were corroborated by single-crystal X-ray diffraction (SC-XRD) on isomorphous [NEt4][M{Co(CO)4}2] salts. [NEt4](3)represented the first structural characterization of 3. More interestingly, changing the crystallization conditions of solutions of 3, the hexanuclear cluster [Ag2{Co(CO)4}4]2− (5) was obtained in the solid state instead of 3. Its molecular structure was determined by SC-XRD as Na2(5)·C4H6O2, [PPN]2(5)·C5H12 (PPN = N(PPh3)2]+), [NBu4]2(5) and [NMe4]2(5) salts. 5 may be viewed as a dimer of 3 and, thus, it represents a rare case of polymerization isomerism (that is, two compounds having the same elemental composition but different molecular weights) in cluster chemistry. The phenomenon was further studied in solution by IR and ESI-MS measurements and theoretically investigated by computational methods. Both experimental evidence and density functional theory (DFT) calculations clearly pointed out that the dimerization process occurs in the solid state only in the case of Ag, whereas Cu and Au related species exist only as monomers.

Predicting bond dissociation energy and bond length for bimetallic diatomic molecules: a challenge for electronic structure theory

2017 ◽  
Vol 19 (8) ◽  
pp. 5839-5854 ◽  
Author(s):  
Junwei Lucas Bao ◽  
Xin Zhang ◽  
Xuefei Xu ◽  
Donald G. Truhlar
Keyword(s):  
Density Functional Theory ◽  
Active Sites ◽  
Density Functional ◽  
Electronic Structure Theory ◽  
Structure Theory ◽  
Strongly Correlated ◽  
Functional Theory ◽  
Metal Metal ◽  
Catalytically Active ◽  
Metal Bonds

We test the accuracy of Kohn–Sham density functional theory for strongly correlated metal–metal bonds that occur in catalytically active sites and intermediates and examine the orbitals and configurations involved to analyze the results.

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