1111-89-3Relevant articles and documents
Electron distribution in a stable carbene
Arduengo III, Anthony J.,Dias, H. V. Rasika,Dixon, David A.,Harlow, Richard L.,Klooster,Koetzle
, p. 6812 - 6822 (2007/10/02)
The synthesis and characterization of the stable carbene perdeuterio-1,3,4,5-tetramethylimidazol-2-ylidene (2) are reported. The neutron and X-ray diffraction data from single crystals of this perdeuterocarbene are used to determine the electron distribution in the molecule. Neutron diffraction data were collected at 80 and 173K on 2. The experimentally determined electron density is very closely matched by density functional calculations which show that 2 is a true carbene with negligible ylidic character.
Pressure Dependence of the Rate Constants for the Reactions CH3 + O2 and CH3 + NO from 3 to 10E4 Torr
Kaiser, E. W.
, p. 11681 - 11688 (2007/10/02)
A relative rate technique is used to measure the pressure dependence of the rate constants for reaction 1 (CH3 + O2 + M -> CH3O2 + M) and reaction 3 (CH3 + NO + M -> CH3NO + M) relative to reaction 2 (CH3 + Cl2 -> CH3Cl + Cl).The pressure dependence of the rate constant of reaction 3 at 297 K can be represented in the Troe equation by the parameters (k3)0 = (3.5 +/- 0.4)E-30 cm6 molecule-2 s-1, (k3)infinite = (1.68 +/- 0.1)E-11 cm3 molecule-1 s-1, and Fcent = 0.46.The values of k3 are identical to those observed in recent absolute rate measurements at 296 K and 27-600 Torr, verifying that the rate constant chosen for reaction 2, k2 = 3.95E-12 exp(-530/RT), is both pressure independent and correct at 296 K.This value of k2 was used to determine absolute values of k1 from the k1/k2 in N2 diluent for pressures between 3 and 11000 Torr at 297 K, between 20 and 1500 Torr at 370 K, and between 40 and 1500 Torr at 264 K.All data in N2 can be fitted using the following parameters in the Troe equation: (k1)0 = (7.56 +/- 1.1)E-31 (T/300)-3.64+/-1.0 cm6 molecule-2 s-1; (k1)infinite = (1.31 +/- 0.1)E-12 (T/300)1.2+/-0.8 cm3 molecule-1 s-1; Fcent = 0.48 (264 K), 0.46 (297 K), 0.42 (370 K).Error limits include statistical error and the uncertainty in k2.In He, N2, and SF6 diluents the relative third-body efficiencies are 0.56 : 1.0 : 1.52, respectively, assuming that Fcent is independent of diluent.The high-pressure limit in SF6 is identical to that in N2.Rate constant ratios were also measured at 297 K for CD3 + O2 + M -> CD3O2 + M (1D) between 5 and 6000 Torr.Assuming that k2D = k2, the limiting rate constants using Fcent = 0.46 are (k1D)0 = (11.8 +/- 1.6)E-31 cm6 molecule-2 s-1 and (k1D)infinite = (1.38 +/- 0.08)E-12 cm3 molecule-1 s-1.
Darstellung und Struktur von Methylnatrium. Strukturbestimmung an NaCD3-Pulvern bei 1.5 und 300 K durch Neutronen- und Synchrotonstrahlenbeugung
Weiss, Erwin,Corbelin, Siegfried,Cockcroft, Jeremy Karl,Fitch, Andrew Nicholas
, p. 1629 - 1634 (2007/10/02)
Methylsodium (NaCD3) has been obtained by the reaction of methyllithium with sodium tert-butoxide.Its crystal structure has been determined from NaCD3 powder samples using the combination of neutron and synchroton radiation diffraction techniques.Studies at 1.5 and 300 K show a new structure type (orthorhombic, space group I222, Z = 16).Na and C atomic positions have been obtained from synchroton radiation data and subsequently D positions by neutron diffraction.The complete structure has been refined using Rietveld methods. - Half of the ions are arranged in tetramers, (NaCD3)4, similar to those in methyllithium.The orientation of the methanide ions with respect to the three next Na ions is staggered.The remaining 8 Na and 8 methanide ions interconnect the tetramers by Na - C contacts; their Na ions are arranged in zigzag chains.Thus, the structure of methylsodium shows elements of the methyllithium and methylpotassium structure.All methanide ions are trigonal-pyramidal with C -D 109 pm and D - C - D angles of 106 deg (1.5 K).Na - C distances vary from 253 to 291 pm, depending upon the methylNa orientation.IR data of NaCD3 are given.
