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81.
Organic–inorganic hybrid material of formula (C4H3SC2H4NH3)2[PbI4] was synthesized and studied by X-ray diffraction, Infrared absorption, Raman scattering, UV–Visible absorption and photoluminescence measurements. The molecule crystallizes as an organic–inorganic two-dimensional (2D) structure built up from infinite PbI6 octahedra surrounded by organic cations. Such a structure may be regarded as quantum wells system in which the inorganic layers act as semiconductor wells and the organic cations act as insulator barriers. Room temperature IR and Raman spectra were recorded in the 520–3500 and 10–3500 cm−1 frequency range, respectively. Optical absorption measurements performed on thin films of (C4H3SC2H4NH3)2[PbI4] revealed three distinct bands at 2.4, 2.66 and 3.25 eV. We also report DFT calculations of the electric dipole moments (μ), polarizability (α), the static first hyperpolarizability (β) and HOMO–LUMO analysis of the title compound investigated by GAUSSIAN 09 package. The calculated static first Hyperpolarizability is equal to 11.46 × 10−31 esu. 相似文献
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83.
Dr. Christopher J. Heard Prof. Roy L. Johnston Prof. Dr. J. Christian Schön 《Chemphyschem》2015,16(7):1461-1469
The energy landscapes of sub‐nanometre bimetallic coinage metal clusters are explored with the Threshold Algorithm coupled with the Birmingham Cluster Genetic Algorithm. Global and energetically low‐lying minima along with their permutational isomers are located for the Cu${_4 }$ Ag${_4 }$ cluster with the Gupta potential and density functional theory (DFT). Statistical tools are employed to map the connectivity of the energy landscape and the growth of structural basins, while the thermodynamics of interconversion are probed, based on probability flows between minima. Asymmetric statistical weights are found for pathways across dividing states between stable geometries, while basin volumes are observed to grow independently of the depth of the minimum. The DFT landscape is found to exhibit significantly more frustration than that of the Gupta potential, including several open, pseudo‐planar geometries which are energetically competitive with the global minimum. The differences in local minima and their transition barriers between the two levels of theory indicate the importance of explicit electronic structure for even simple, closed shell clusters. 相似文献
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85.
《Comptes Rendus Chimie》2015,18(4):391-398
1,2-bis(2′-aminophenoxy)-4-methylbenzene provides a Schiff base by reaction with 2-pyridinecarboxaldehyde. The stereochemical rigidity of ortho-aminophenyl diamines causes this latter, as well as the corresponding nitro precursors, be chiral. The chiral conformation of the diamine precursor is maintained in the octahedral zinc(II) and cobalt(II) complexes prepared from the Schiff base. The crystal structures of [ZnL(NO3)(H2O)]NO3 and CoLCl2 complexes exhibit non-planar cis-α configurations with both enantiomers (Δ and Λ). This implies that in the Schiff base ligand the two α-diimine systems shape an octahedral cavity having the same chirality of the precursory diamine. 相似文献
86.
Inversion twinning in a second polymorph of the hydrochloride salt of the recreational drug ethylone
T. Stanley Cameron J. Stuart Grossert Chad R. Maheux Idralyn Q. Alarcon Catherine R. Copeland Anthony Linden 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(4):266-270
A second polymorph of the hydrochloride salt of the recreational drug ethylone, C12H16NO3+·Cl−, is reported [systematic name: (±)‐2‐ethylammonio‐1‐(3,4‐methylenedioxyphenyl)propane‐1‐one chloride]. This polymorph, denoted form (A), appears in crystallizations performed above 308 K. The originally reported form (B) [Wood et al. (2015). Acta Cryst. C 71 , 32–38] crystallizes preferentially at room temperature. The conformations of the cations in the two forms differ by a 180° rotation about the C—C bond linking the side chain to the aromatic ring. Hydrogen bonding links the cations and anions in both forms into similar extended chains in which any one chain contains only a single enantiomer of the chiral cation, but the packing of the ions is different. In form (A), the aromatic rings of adjacent chains interleave, but pack equally well if neighbouring chains contain the same or opposite enantiomorph of the cation. The consequence of this is then near perfect inversion twinning in the structure. In form (B), neighbouring chains are always inverted, leading to a centrosymmetric space group. The question as to why the polymorphs crystallize at slightly different temperatures has been examined by density functional theory (DFT) and lattice energy calculations and a consideration of packing compactness. The free energy (ΔG) of the crystal lattice for polymorph (A) lies some 52 kJ mol−1 above that of polymorph (B). 相似文献
87.
Zakieh Yousefi Hossein Eshtiagh‐Hosseini Alireza Salimi Janet Soleimannejad 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(5):386-393
In the title compound, [Cu(C7H3N2O4)(C4H5N2)(H2O)], (I), pyridine‐2,6‐dicarboxylate (pydc2−), 2‐aminopyrimidine and aqua ligands coordinate the CuII centre through two N atoms, two carboxylate O atoms and one water O atom, respectively, to give a nominally distorted square‐pyramidal coordination geometry, a common arrangement for copper complexes containing the pydc2− ligand. Because of the presence of Cu...Xbridged contacts (X = N or O) between adjacent molecules in the crystal structures of (I) and three analogous previously reported compounds, and the corresponding uncertainty about the effective coordination number of the CuII centre, density functional theory (DFT) calculations were used to elucidate the degree of covalency in these contacts. The calculated Wiberg and Mayer bond‐order indices reveal that the Cu...O contact can be considered as a coordination bond, whereas the amine group forming a Cu...N contact is not an effective participant in the coordination environment. 相似文献
88.
Lei Wang Man Zhang Ying‐Ying Jin Qing Lu Qi Fang 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(1):69-74
Three 1‐phenylindolin‐2‐one derivatives, namely 1‐phenylindolin‐2‐one, C14H11NO, (I), 5‐bromo‐1‐phenylindolin‐2‐one, C14H10BrNO, (II), and 5‐iodo‐1‐phenylindolin‐2‐one, C14H10INO, (III), have been synthesized and their structures determined. Compounds (I) and (II) crystallized in the centrosymmetric space groups Pbca and P21/c, respectively, while compound (III) crystallized in the polar space group Aea2. Density functional theory (DFT) calculations show that the molecular dipole moment gradually decreases in the order (I) > (II) > (III). The relatively smaller dipole moment of (III) and the larger non‐electrostatic intermolecular interactions may be the main reasons for the noncentrosymmetric and polar structure of (III). 相似文献
89.
《Acta Crystallographica. Section C, Structural Chemistry》2017,73(7):508-516
In the structure of 2‐(4‐chloroanilino)‐1,3,2λ4‐diazaphosphol‐2‐one, C12H11ClN3OP, each molecule is connected with four neighbouring molecules through (N—H)2…O hydrogen bonds. These hydrogen bonds form a tubular arrangement along the [001] direction built from R 33(12) and R 43(14) hydrogen‐bond ring motifs, combined with a C (4) chain motif. The hole constructed in the tubular architecture includes a 12‐atom arrangement (three P, three N, three O and three H atoms) belonging to three adjacent molecules hydrogen bonded to each other. One of the N—H groups of the diazaphosphole ring, not co‐operating in classical hydrogen bonding, takes part in an N—H…π interaction. This interaction occurs within the tubular array and does not change the dimension of the hydrogen‐bond pattern. The energies of the N—H…O and N—H…π hydrogen bonds were studied by NBO (natural bond orbital) analysis, using the experimental hydrogen‐bonded cluster of molecules as the input file for the chemical calculations. In the 1H NMR experiment, the nitrogen‐bound proton of the diazaphosphole ring has a high value of 17.2 Hz for the 2J H–P coupling constant. 相似文献
90.