“…Three of those structures (wahgob, pijvot, pucnik) have also associated Si···H contacts shorter than 3.39 Å (the van der Waals radii sum), while some additional structures with long H···H distances (> 2.50) obey also the Si···H distance criterion (SiH 4 , pucquz and ekemoy). Finally, structures with Si···Si distances smaller than twice the van der Waals radius for Si (4.38 Å) include those with short H···H and/or Si···H contacts just mentioned plus a handful of additional structures (Si 5 H 10 , histim, libfil, xagkau, wajluo, qahbac, zeqneo, kunzez, qeqsux, riijed, ayejuj, pavmee), all with interaction topology 1 . Conversely, if we search for structures applying a distance criterion for only the H···H contacts, other structures are found (ihosut01, sinkef, volyig, ihadom, ziydoa, zuzbol) with a nearly colinear interaction between two SiH groups ( 3 ) …”
In line with previous work in which we established the factors that enhance attractive CH···HC dihydrogen interactions in alkanes, an extended theoretical analysis of noncovalent intermolecular interactions in group 14 hydrides is presented here. Remarkably, these weak interactions may play a major role in determining the crystal structures adopted by several families of molecules. A combined structural and computational analysis at the MP2 level allowed us to identify and characterize different interactions of the type EH···HE and E···HE (E = Si, Ge, Sn, and Pb), and to find also the most suitable scenario for the establishment of each particular type. The nature of the interactions has been analyzed in terms of natural charges of the atoms involved and a topological analysis of the electron density of several dimers confirms the existence of H···H and H···E attractive contacts. We have observed that the interaction strength increases when descending down the periodic group and that silicon has a marked tendency to establish Si···HSi interactions. A size‐dependent backbone effect that reinforces H···H dihydrogen interactions in polyhedral systems has also been found.
“…Three of those structures (wahgob, pijvot, pucnik) have also associated Si···H contacts shorter than 3.39 Å (the van der Waals radii sum), while some additional structures with long H···H distances (> 2.50) obey also the Si···H distance criterion (SiH 4 , pucquz and ekemoy). Finally, structures with Si···Si distances smaller than twice the van der Waals radius for Si (4.38 Å) include those with short H···H and/or Si···H contacts just mentioned plus a handful of additional structures (Si 5 H 10 , histim, libfil, xagkau, wajluo, qahbac, zeqneo, kunzez, qeqsux, riijed, ayejuj, pavmee), all with interaction topology 1 . Conversely, if we search for structures applying a distance criterion for only the H···H contacts, other structures are found (ihosut01, sinkef, volyig, ihadom, ziydoa, zuzbol) with a nearly colinear interaction between two SiH groups ( 3 ) …”
In line with previous work in which we established the factors that enhance attractive CH···HC dihydrogen interactions in alkanes, an extended theoretical analysis of noncovalent intermolecular interactions in group 14 hydrides is presented here. Remarkably, these weak interactions may play a major role in determining the crystal structures adopted by several families of molecules. A combined structural and computational analysis at the MP2 level allowed us to identify and characterize different interactions of the type EH···HE and E···HE (E = Si, Ge, Sn, and Pb), and to find also the most suitable scenario for the establishment of each particular type. The nature of the interactions has been analyzed in terms of natural charges of the atoms involved and a topological analysis of the electron density of several dimers confirms the existence of H···H and H···E attractive contacts. We have observed that the interaction strength increases when descending down the periodic group and that silicon has a marked tendency to establish Si···HSi interactions. A size‐dependent backbone effect that reinforces H···H dihydrogen interactions in polyhedral systems has also been found.
“…4 The geometry optimization was performed using different combinations of the DFT functionals and basis sets. The results are summarized in The D 5h form of Si 5 Cl 10 at LC-wPBE/6-311G++(3df,3pd) level is 12.6 kJ/mol higher in energy than the optimized structure after zero-point energy correction.…”
Section: Resultsmentioning
confidence: 99%
“…[1][2][3][4][5][6][7][8][9][10][11] For CHS, the attraction to its practical applications is complemented by the interest generated in the structural and bonding features of its precursor, the complex dianion, [Si 6 Cl 12 ·2Cl] 2-, which consists of a planar Si 6 ring (in contrast to neutral Si 6 Cl 12 possessing D 3h symmetry [12][13] ) with two µ 6 coordinated chloride ions forming the apical vertices of a hexagonal bipyramid.…”
We report the detailed computational study of flattening of the puckered Si ring by suppression of the pseudo-Jahn-Teller (PJT) effect through coordination of two Cl anions to the molecule forming an inverse sandwich dianion [SiCl·2Cl] complex. The PJT effect that causes nonplanarity of the SiCl structure (C) results from vibronic coupling of pairs of occupied molecular orbitals (OMOs) and unoccupied molecular orbitals (UMOs). It was shown that filling the intervenient molecular orbitals of puckered SiCl with valent electron pairs of Cl donors suppresses the PJT effect, with the Si ring becoming planar (D) upon complex formation. In this paper, the stabilization energy E(2) associated with donor-acceptor charge transfer (delocalization) was estimated using NBO analysis for all studied inverse sandwich compounds [SiCl·2X] (where X = F, Cl, Br). It was found that the polarizability of the donor ion might significantly affect the stabilization energy value and should be taken into account when choosing the ligands suitable for forming Si-based one-dimensional compounds and other nanoscale materials.
“…The reaction of CPS which is hazardous [40,41] with air was investigated by DSC technique by heating it in a pierced pan at a heating rate of 5°C /min. The DSC curves were evaluated by the kinetic model of two competitive reactions an endothermic (evaporation) and exothermic (reaction with oxygen) one.…”
Section: Safety Analysis Of Cps Handlingmentioning
Si-films were deposited from liquid precursors, especially cyclopentasilane using a high pressure spray deposition system based on an electronically controlled piezo-injector in a inert gas atmosphere. This equipment might be applicable to other liquid precursors and targeted thin Sifilms of importance. The thermal properties and reactivity with oxygen of pure liquid cyclopentasilane and its solutions in toluene are investigated by temperature dependent FTIR-Spectroscopy and Differential Scanning Calorimetry. The homogenous films of silicon in µm range thickness are deposited from pure liquid cyclopentasilane and its solutions in toluene on rigid carbon glass plates and on flexible carbon glass fiber substrates using a high pressure spray deposition system. The morphological and structural properties of the silicon films were investigated. These results and the chemical analysis of the films show that the annealed films are Original Research Article
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