scispace - formally typeset
Search or ask a question
Journal ArticleDOI

4,6‐Di­chloro‐2‐methyl­thio‐5‐phenyl­pyrimidine

01 Mar 2001-Acta Crystallographica Section E-structure Reports Online (International Union of Crystallography)-Vol. 57, Iss: 3
TL;DR: The structure of the title compound, C11H8Cl2N2S, comprises two unique molcules with the dihedral angles between the two linked rings for each molcule being 77.1
Abstract: The structure of the title compound, C11H8Cl2N2S, comprises two unique mol­ecules with the dihedral angles between the two linked rings for each mol­ecule being 77.1 (1) and 78.4 (1)°. Only one C—H⋯X short contact exists from an aromatic C—H group to a Cl atom.
Citations
More filters
Journal ArticleDOI
TL;DR: In this paper, the molecular structure, vibrational spectra and photochemistry of 5-methoxy-1-phenyl-1H-tetrazole (5MPT) were studied by matrix isolation infrared spectroscopy and DFT(B3LYP)/6-311++G(d,p) calculations.
Abstract: The molecular structure, vibrational spectra and photochemistry of 5-methoxy-1-phenyl-1H-tetrazole (5MPT) were studied by matrix isolation infrared spectroscopy and DFT(B3LYP)/6-311++G(d,p) calculations. According to the calculations, only one double degenerated-by-symmetry minimum exists in the ground state PES of the compound. In this structure, the dihedral angle between the two rings (phenyl and tetrazole) is ca. 30 ◦ , whereas the methoxyl group stays nearly in the plane of the tetrazole ring. In consonance with the theoretical predictions, only one molecular species was experimentally observed in the as-deposited argon matrices. Theoretical calculations were also used to help in assignment of the experimental spectrum of the compound, the calculated spectrum showing a very good agreement with the experimental data. In situ UVirradiation (λ > 235 nm) of the matrix-isolated 5MPT induced unimolecular decomposition of the compound, which led mainly to production of methylcyanate and phenylazide, this latter further reacting to yield, as final product, 1-aza-1,2,4,6-cycloheptatetraene. 3-Methoxy-1-phenyl-1Hdiazirene was also observed experimentally as minor product, resulting from direct elimination of molecular nitrogen from 5MPT. © 2005 Elsevier B.V. All rights reserved.

26 citations

Journal ArticleDOI
TL;DR: The spectrum of the as-deposited matrix of 5EPT closely matches that of the most stable conformer predicted theoretically, pointing to the existence of only this conformer in the low-temperature matrixes.
Abstract: A combined matrix isolation FT-IR and theoretical DFT(B3LYP)/6-311++G(d,p) study of the molecular structure and photochemistry of 5-ethoxy-1-phenyl-1H-tetrazole (5EPT) was performed. A new method of synthesis of the compound is described. Calculations show three minima, very close in energy and separated by low-energy barriers (less than 4 kJ mol-1), in the ground-state potential energy profile of the molecule. The method of matrix isolation enabled the reduction of the number of populated conformational states in the experiment at low temperature due to the effect known as conformational cooling. As a result, the spectrum of the as-deposited matrix of 5EPT closely matches that of the most stable conformer predicted theoretically, pointing to the existence of only this conformer in the low-temperature matrixes. In this structure, the dihedral angle between the two rings, phenyl and tetrazole, is ca. 30°, whereas the ethyl group stays nearly in the plane of the tetrazole ring and is as far as possible from...

25 citations

Journal ArticleDOI
TL;DR: In this article, the minimum energy conformation of 1-phenyltetrazole (C7N4H6) and 5-chloro-1-phenyl and tetrazole was investigated in the presence of argon matrixes and at room temperature.

22 citations

References
More filters
Book ChapterDOI
TL;DR: The methods presented in the chapter have been applied to solve a large variety of problems, from inorganic molecules with 5 A unit cell to rotavirus of 700 A diameters crystallized in 700 × 1000 × 1400 A cell.
Abstract: Publisher Summary X-ray data can be collected with zero-, one-, and two-dimensional detectors, zero-dimensional (single counter) being the simplest and two-dimensional the most efficient in terms of measuring diffracted X-rays in all directions. To analyze the single-crystal diffraction data collected with these detectors, several computer programs have been developed. Two-dimensional detectors and related software are now predominantly used to measure and integrate diffraction from single crystals of biological macromolecules. Macromolecular crystallography is an iterative process. To monitor the progress, the HKL package provides two tools: (1) statistics, both weighted (χ2) and unweighted (R-merge), where the Bayesian reasoning and multicomponent error model helps obtain proper error estimates and (2) visualization of the process, which helps an operator to confirm that the process of data reduction, including the resulting statistics, is correct and allows the evaluation of the problems for which there are no good statistical criteria. Visualization also provides confidence that the point of diminishing returns in data collection and reduction has been reached. At that point, the effort should be directed to solving the structure. The methods presented in the chapter have been applied to solve a large variety of problems, from inorganic molecules with 5 A unit cell to rotavirus of 700 A diameters crystallized in 700 × 1000 × 1400 A cell.

31,667 citations

Journal ArticleDOI
TL;DR: In this article, the behaviour of the Rogers's η parameter for enantiomorph-polarity estimation is examined theoretically and experimentally on simulated intensity data for seven well-assorted compounds.
Abstract: The behaviour of Rogers's η parameter for enantiomorph-polarity estimation is examined theoretically and experimentally on simulated intensity data for seven well-assorted compounds. An alternative parameter x, based on incoherent scattering from twin components related by a centre of symmetry, is also considered. It is found that both parameters are very well adapted to implementation in a least-squares program and converge well. The η parameter can give false and over-precise indications of chirality-polarity for structures which are nearly centrosymmetric, whereas the x parameter does not have this fault and converges more rapidly than η.

9,932 citations

Journal ArticleDOI
TL;DR: A least-squares procedure is described for modeling an empirical transmission surface as sampled by multiple symmetry-equivalent and/or azimuth rotation-equ equivalent intensity measurements.
Abstract: A least-squares procedure is described for modeling an empirical transmission surface as sampled by multiple symmetry-equivalent and/or azimuth rotation-equivalent intensity measurements. The fitting functions are sums of real spherical harmonic functions of even order, ylm(− u0) + ylm(u1), 2 ≤ l = 2n ≤ 8. The arguments of the functions are the components of unit direction vectors, −u0 for the reverse incident beam and u1 for the scattered beam, referred to crystal-fixed Cartesian axes. The procedure has been checked by calculations against standard absorption test data.

7,395 citations