Nitromethane molecules

Refractive indexes of these systems are given in Fig. 3 and in Tables 10-13, They all show positive deviations from additivity in volume fractions of the components, which increase in the order nitrobenzene < m-nitroi oluene < o-nitrotoluene. This confirms that the addition compounds formed by these aromatic nitrocompounds with sulphuric acid are more and more stable in this order, which is the order of increasing basicities. Rathex unexpectedly, however, the system with nitromethane shows high positive deviations from additivity, which equal those in the system with. o-nitrotoluene, This fact might be due to the small dimensions of the nitromethane molecules, which are therefore Jess likely to cause the disruption of the structure of sulphuric acid and thus U lower the Tefractive indexes of the mixtures, than the larger molecules of the aromatic nitrocompounds. 

The electrochemical oxidation of 2,3,4,5-tetraanisylpyrrole (121) in nitromethane at the second wave resulted in the formation of a cation, the reaction of which depended on the reaction temperature [Eq. (88)]. At 15°C a 90% yield of 2-hydroxy-2,3,4,5-tetraanisylpyrrole (122) was formed, whereas at 90°C the major product resulted from incorporation of a nitromethane molecule into the ring, giving a tetraanisylpyridine (123a or 123b)177 [Eq. (88)]. 

Figure 7-11. A cartoon representation of the multi-component assembly of an encapsulating ligand. The white disc represents a pre-formed cap within the starting ligand and the shaded disc the new cap that has been built from a number of components. For example, in the ligand 7.9, the shaded cap is built from three formaldehyde molecules and a nitromethane molecule.

The most explicit and definitive study of the decomposition of isolated nitromethane molecules is that by Wodtke, Hintsa, and Lee [87, 88]. They used infrared multiphoton excitation to dissociate nitromethane in a... 

Other flexible molecular models of nitromethane were developed by Politzer et al. [131,132]. In these, parameters for classical force fields that describe intramolecular and intermolecular motion are adjusted at intervals during a condensed phase molecular dynamics simulation until experimental properties are reproduced. In their first study, these authors used quantum-mechanically calculated force constants for an isolated nitromethane molecule for the intramolecular interaction terms. Coulombic interactions were treated using partial charges centered on the nuclei of the atoms, and determined from fitting to the quantum mechanical electrostatic potential surrounding the molecule. After an equilibration trajectory in which the final temperature had been scaled to the desired value (300 K), a cluster of nine molecules was selected for a density function calculation from which... 

Figure 15 The relationship between the packings in [(i 6-C6H6)2Ru][BF4]2 MeN02 and [(r 6-C6H6)2Ru][BF4]2. Upon removal of the nitromethane molecule, the solvated form converts into the unsolvated form.

Nitromethane condenses with suitable dialdehydes in an alkaline medium to give cyclic products in which the methyl groups of two nitromethane molecules are incorporated into a ring. Thus the reagent reacts with glyoxal to give a mixture of isomeric inositol derivatives, one of which (1) can be obtained in pure form due to... 

Figure 4. Time variation of intramolecular C-H andN-O, and the intermolecular O H bonds fora single nitromethane molecule.

The proton transfer process described above is uniquely associated with the condensed fluid phase of nitromethane. This bond specificity is remarkable, since in the gas phase the C-N bond is the weakest in the molecule (Do = 60.1 kcal/mol) [46], and is therefore expected to be the dominant dissociation channel and the initial step in the decomposition of nitromethane, even at high temperature. In contrast, the C-H bond is the strongest in the nitromethane molecule. 

Notably, the dramatic stretching of four C-H bonds, one in each nitromethane molecule of the unit cell, occurs under stress in y when V/Vo is between 59% and 62%, with an estimated pressure of 25-40 GPa more precisely, these bond lengths are stretched by more than 10-12% of their original values in this case. The increase of strain in y above 50% causes these bonds to be stretched further and leads to the abstraction of their protons. This indication of proton dissociation corresponds to the steep part of the curve in Fig. 2, and renders the y and x compressions qualitatively different. 

Mulliken charges changes of carbon and hydrogen of the nitromethane molecules 1 and 2 in the unit cell under uniaxial compression along b. 

Figure 18. Relative rate constants for the production of (CH3N02) anions in electron transfer reactions between laser excited Cs(ns), Cs nd, Xe nf), Rb(nc(), and Rb(ns) Rydberg atoms and nitromethane molecules.

For the accurate calculation of it is necessary to know the values of the rotation barrier The latter were calculated by us using MOPAC 6 and for the rotation around x and y axes they are 1.8 and 7.5 kcal, respectively. These values correlate well with the energy of NO rotation in the nitromethane molecule [91]. The correction coefficient cp was also determined using the Pitzer tables [92]. Although the latter are designed for symmetric rotators as Pitzer has shown, they can be successfully applied for the approximate estimation of the thermodynamical functions of asymmetric rotators. 

Finally it invites us to take care of dissipation and its origin. A quantum mechanical study of the dissodation of nitromethane molecule in the "active" exdted electronic state 1A2 indicated that 96% of the dissociation energy is transferred as kinetic energy in the dissodation fragments, Mriiile only 6% is taken away by vibrations and rotations. Consequently, no dissipation energy due to internal molecular motions will be considered in detonation models here. 

Figure IX-H-18. Comparison of the absorption cross sections for a series of halogen-atom-substituted nitromethane molecules. Data for CH3NO2 from Calvert and Pitts (1966) CCI3NO2 fromAllston et al. (1978) CCI2FNO2, CCIF2NO2, and CF3NO2 from Fazekas andTakacs (1983).

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