Macropolyhedral Boron-Containing Cluster Chemistry. A Metallathiaborane from S2B17H17: Isolation and Characterisation of [(PMe2Ph)2PtS2B16H16]; A neo-arachno Ten-Vertex Cluster Shape, and the Constitution of the [arachno-B10H15]- Anion

2005 ◽  
Vol 70 (4) ◽  
pp. 430-440 ◽  
Author(s):  
Michael J. Carr ◽  
Michael G. S. Londesborough ◽  
Jonathan Bould ◽  
Ivana Císařová ◽  
Bohumil Štíbr ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Sodium Hydride ◽  
Hydrogen Atoms ◽  
Subsequent Reaction ◽  
Cluster Chemistry ◽  
Cluster Shape ◽  
Open Face

The deprotonation of S2B17H17 with sodium hydride and subsequent reaction with [PtCl2(PMe2Ph)2] gives the new macropolyhedral metallathiaborane [(PMe2Ph)2PtS2B16H16], of which the cluster consists of a conventional eleven-vertex nido {SB10} unit, fused, with two boron atoms in common, with a {PtSB8} unit of unique ten-vertex neo-arachno constitution and geometry. The latter geometry suggests a configuration for the previously structurally uncharacterised [B10H15]- anion; starting from this configuration, DFT calculations of structure and thence of boron nuclear shieldings, which are found very closely to mimic those found experimentally, thence support a fluxional structure for [B10H15]- with three {BHB(bridging)} and two {BH(endo)} hydrogen atoms around a six-membered open face.

scholarly journals 5-Methyl-1,3-phenylene bis[5-(dimethylamino)naphthalene-1-sulfonate]: crystal structure and DFT calculations

2019 ◽  
Vol 75 (7) ◽  
pp. 1079-1083
Author(s):  
Tanwawan Duangthongyou ◽  
Ramida Rattanakam ◽  
Kittipong Chainok ◽  
Songwut Suramitr ◽  
Thawatchai Tuntulani ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Energy Gap ◽  
Rotation Axis ◽  
Three Dimensional ◽  
Hydrogen Atoms ◽  
Lumo Energy ◽  
Compound C ◽  
Dansyl Group ◽  
Weak Hydrogen Bonds ◽  
Homo Lumo

The title compound, C31H30N2S2O6, possesses crystallographically imposed twofold symmetry with the two C atoms of the central benzene ring and the C atom of its methyl substituent lying on the twofold rotation axis. The two dansyl groups are twisted away from the plane of methylphenyl bridging unit in opposite directions. The three-dimensional arrangement in the crystal is mainly stabilized by weak hydrogen bonds between the sulfonyl oxygen atoms and the hydrogen atoms from the N-methyl groups. Stacking of the dansyl group is not observed. From the DFT calculations, the HOMO–LUMO energy gap was found to be 2.99 eV and indicates n→π* and π→π* transitions within the molecule.

Ti-coated BC2N nanotubes as hydrogen storage materials

2013 ◽  
Vol 91 (7) ◽  
pp. 598-604 ◽  
Author(s):  
Seifollah Jalili ◽  
Farzad Molani ◽  
Jeremy Schofield
Keyword(s):  
Dft Calculations ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Molecular Form ◽  
Hydrogen Storage Materials ◽  
Hydrogen Atoms ◽  
Functional Theory ◽  
Adsorption Sites ◽  
Hydrogen Molecules ◽  
Bc2n Nanotubes

Density functional theory (DFT) calculations have been performed to investigate Ti adsorption on BC2N nanotubes and the hydrogen adsorption capacity of Ti-coated structures. Different adsorption sites have been examined for the Ti adatom, and it is found that the most stable structure has a configuration with alternating columns of carbon and boron–nitrogen hexagons. The DFT calculations indicate that an adsorbed Ti atom on a carbon hexagon can bind four hydrogen molecules in molecular form, while Ti atoms on boron–nitride hexagons can adsorb three hydrogen molecules and two hydrogen atoms. Based on the calculations, the gravimetric efficiency corresponding to decoration of 67% of six carbon rings with Ti adatoms is estimated to be 8 wt %. Computation of the charge transfer reveals that the Ti atom on BC2N is in a cationic state. In addition, Ti adsorption has a significant influence on the electronic structure of the nanotubes and allows for the conversion of nanotubes from semiconductors in the pristine state to conductors upon doping. The interactions between the nanotubes, the Ti atom and hydrogen molecules have also been analyzed using Dewar coordination and Kubas interactions.

scholarly journals Isomerisation of nido-[C2B10H12]2− dianions: unprecedented rearrangements and new structural motifs in carborane cluster chemistry

2015 ◽  
Vol 6 (5) ◽  
pp. 3117-3128 ◽  
Author(s):  
David McKay ◽  
Stuart A. Macgregor ◽  
Alan J. Welch
Keyword(s):  
Dft Calculations ◽  
Structural Motifs ◽  
Cluster Chemistry

The formation and isomerisation of nido-[C2B10H12]2− species is investigated through DFT calculations, which reveal novel basket and inverted nido intermediates and unusual inverconversion pathways, including basket collapse and pivoting triangles and diamonds.

Reactions of hydrogen atoms with α-(alkylthio) carbonyl compounds. Time-resolved ESR detection and DFT calculations

2005 ◽  
Vol 31 (7-8) ◽  
pp. 633-641 ◽  
Author(s):  
Pawel Wisniowski ◽  
Krzysztof Bobrowski ◽  
Piotr Filipiak ◽  
Ian Carmichael ◽  
Gordon L Hug
Keyword(s):  
Dft Calculations ◽  
Carbonyl Compounds ◽  
Hydrogen Atoms ◽  
Time Resolved

scholarly journals Reaction of Arylmethyl Isocyanides/Arylmethyl-amines with Xanthate Esters: A Facile and Unexpected Synthesis of Carbamothioates

2019 ◽  
Author(s):  
Narasimhamurthy Rajeev ◽  
Toreshettahally R Swaroop ◽  
Seegehalli M Anil ◽  
Kupalli R Kiran ◽  
Chandru Chandru ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Sodium Hydride ◽  
Unexpected Formation

An unexpected formation of carbamothioates by the reaction of arylmethyl isocyanides with xanthate esters in the presence of sodium hydride is reported. The products thus obtained were compared with carbamothioates obtained by the condensation of the corresponding benzylamines with xanthate esters in the presence of sodium hydride in DMF. A mechanism which is substantiated by DFT calculations to account for the unexpected reactions is proposed.

scholarly journals Heterogeneous Adsorption and Local Ordering of Formate on a Magnetite Surface

2021 ◽  
Author(s):  
Marcus Creutzburg ◽  
Kai Sellschopp ◽  
Steffen Tober ◽  
Elin Grånäs ◽  
Vedran Vonk ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Formic Acid ◽  
Adsorption Mechanism ◽  
Dissociative Adsorption ◽  
Hydrogen Atoms ◽  
Experimental Conditions ◽  
Local Ordering ◽  
Reaction Barriers ◽  
The Stability ◽  
Crucial Ingredient

We report a novel heterogeneous adsorption mechanism of formic acid on the magnetite (111) surface. Our experimental results and DFT calculations give evidence for dissociative adsorption of formic acid in quasi-bidentate and chelating geometries. The latter is induced by the presence of iron vacancies at the surface, making oxygen atoms accessible for hydrogen atoms from dissociated formic acid. DFT calculations predict that both adsorption geometries are energetically favorable under our experimental conditions. The calculations prove that the locally observed (sqrt(3)xsqrt(3)) R30° superstructure consists of formate in a triangular arrangement, adsorbed predominantly in chelating geometry. The results show how defects can stabilize alternative adsorption geometries, which is a crucial ingredient for a detailed atomistic understanding of reaction barriers on magnetite and other oxide surfaces, as well as for the stability of carboxylic acid based nanocomposite materials.

scholarly journals 4-(Dimethylamino)benzohydrazide

IUCrData ◽  
2020 ◽  
Vol 5 (10) ◽  
Author(s):  
Steven P. Kelley ◽  
Valeri V. Mossine ◽  
Thomas P. Mawhinney
Keyword(s):  
Hydrogen Bonding ◽  
Dft Calculations ◽  
Title Compound ◽  
Lattice Energy ◽  
Monoclinic Space Group ◽  
Dispersion Forces ◽  
Hydrogen Atoms ◽  
Space Group ◽  
Hydrogen Bonding Pattern ◽  
Compound C

The title compound, C9H13N3O, crystallizes in the monoclinic space group C2/c and all non-hydrogen atoms are within 0.1 Å of the molecular mean plane. In the crystal, the hydrogen-bonding pattern results in [001] chains built up from fused R 2 2(6) and R 2 2(10) rings; the former consists of N—H...N bonds and the latter N—H...O bonds. Electrostatic and dispersion forces are major contributors to the lattice energy, which was estimated by DFT calculations to be −215.7 kJ mol−1.

scholarly journals Complete σ* intramolecular aromatic hydroxylation mechanism through O2 activation by a Schiff base macrocyclic dicopper(I) complex

2013 ◽  
Vol 9 ◽  
pp. 585-593 ◽  
Author(s):  
Albert Poater ◽  
Miquel Solà
Keyword(s):  
Schiff Base ◽  
Proton Transfer ◽  
Dft Calculations ◽  
Reaction Pathway ◽  
Bond Cleavage ◽  
Bond Formation ◽  
Subsequent Reaction ◽  
O2 Activation ◽  
Aromatic Carbon ◽  
Aromatic Hydroxylation

In this work we analyze the whole molecular mechanism for intramolecular aromatic hydroxylation through O2 activation by a Schiff hexaazamacrocyclic dicopper(I) complex, [CuI 2(bsH2m)]2+. Assisted by DFT calculations, we unravel the reaction pathway for the overall intramolecular aromatic hydroxylation, i.e., from the initial O2 reaction with the dicopper(I) species to first form a CuICuII-superoxo species, the subsequent reaction with the second CuI center to form a μ-η2:η2-peroxo-CuII 2 intermediate, the concerted peroxide O–O bond cleavage and C–O bond formation, followed finally by a proton transfer to an alpha aromatic carbon that immediately yields the product [CuII 2(bsH2m-O)(μ-OH)]2+.

DFT Calculations and Monte Carlo Simulations of the Co-Adsorption of Hydrogen Atoms and Ethylidyne Species on Pt(111)

2001 ◽  
Vol 105 (36) ◽  
pp. 8550-8562 ◽  
Author(s):  
Sergei G. Podkolzin ◽  
Ramchandra M. Watwe ◽  
Qiliang Yan ◽  
Juan J. de Pablo ◽  
James A. Dumesic
Keyword(s):  
Monte Carlo ◽  
Dft Calculations ◽  
Monte Carlo Simulations ◽  
Co Adsorption ◽  
Hydrogen Atoms ◽  
Adsorption Of Hydrogen

Acyl chloride carbon insertion into dicarbaborane cages – new route to tricarbollide cages

2015 ◽  
Vol 87 (2) ◽  
pp. 135-142 ◽  
Author(s):  
Bohumil Štíbr
Keyword(s):  
High Temperature ◽  
Cross Coupling ◽  
Acyl Chloride ◽  
Hydrogen Atoms ◽  
Acyl Chlorides ◽  
High Temperature Reactions ◽  
High Yields ◽  
Open Face

AbstractReactions between the arachno-6,9-C2B8H14 dicarbaborane and acyl chlorides, RCOCl, in the presence of amine bases in CH2Cl2, followed by acidification with conc. H2SO4 at 0 °C, generate in high yields a series of neutral alkyl and aryl tricarbollides of structure 8-R-nido-7,8,9-C3B8H11 (where R=alkyls and aryls). These skeletal alkylcarbonation (SAC) reactions are consistent with an aldol-type condensation between the RCO group and open-face dicarbaborane hydrogen atoms, which is associated with the insertion of the acyl chloride RC unit into the structure under elimination of three extra hydrogen atoms as H2O and HCl. The reactions thus result in an effective cross-coupling between R and the tricarbollide cage. High-temperature reactions between 8-Ar-nido-7,8,9-C3B8H11 (where Ar=Ph, 1-C10H7, and 2-C10H7) compounds and [CpFe(CO)2]2 produced the first types of monoaryl substituted twelve-vertex ferratricarbollide complexes of general constitution [1-(CpFe)-closo-ArC3B8H10] with three different arrangements of cluster carbon vertexes. The Fe-complexation is accompanied by extensive rearrangement of the cluster carbon atoms over the twelve-vertex cage and the complexes isolated can be regarded as ferrocene analogues.

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