Correlation Between Molecular Charge Properties and Impact Sensitivity of Explosives: Nitrobenzene Derivatives

Abstract

Nitrobenzenic explosives can have high energy density and low impact sensitivity. In this work, the density functional theory (DFT) charge density of 50 nitrobenzenic molecules was analyzed using the Distributed Multipole Analysis (DMA) method to investigate the impact sensitivity of their explosives. The DMA monopole, dipole and quadrupole electric multipoles localized on the atoms of a molecule provide a very detailed picture of the molecular charge density and have a clear chemical interpretation. The DMA multipoles of each molecule were used to develop models correlating molecular charge properties and impact sensitivity of nitrobenzenic explosives, which is quantified by the quantity h50. Three models previously applied to 17 nitroaromatic molecules (J. Phys. Chem. A 115, 9055, 2011) are now examined for a larger dataset of 50 molecules. Model 1 used the nitro group charge as a single parameter for h50 prediction, Model 2 additionally included the quadrupole values of the benzene ring atoms (a measure of charge delocalization) and Model 3 included the dipole moment (indicator of site polarization) of the nitro groups of each molecule, as well as the average C−NO2 bond distance, which quantifies bond strength. Two additional new models that include the quadrupole values of the nitro group were also proposed. The original three models (Models 1–3), as well as the new models (4‐5), applied to the set of 50 nitrobenzenic molecules, displayed good results even when compared with the previous work. Among the computed DMA electrical multipole values, two proved to be essential for developing a good model, as found before for the smaller set: the DMA quadrupole values of the ring atoms that quantify the degree of electronic delocalization in the ring and the total DMA charge (monopole) values of the explosophore nitro group.

Unimolecular Decomposition Reactions of Picric Acid and Its Methylated Derivatives─A DFT Study

“… 85 − 88 For geometry optimizations, M06-2X seems to yield results of similar accuracy to those obtained using B3LYP. 57 , 89 , 90 With the additional knowledge that M06-2X is commonly employed in studies on energetic materials, 10 , 28 , 40 , 52 , 91 applying it for the current work seems appropriate. To produce reliable vibrational frequencies, it proved necessary to employ a larger integration grid than the standard choice in NWChem.…”

Expanding the Knowledge of the Selective-Sensing Mechanism of Nitro Compounds by Luminescent Terbium Metal–Organic Frameworks through Multiconfigurational ab Initio Calculations

“…Currently, luminescent chemical sensors are an alternative of interest to use for detecting explosives or some principal compounds used in their manufacture such as nitrobenzene (NB), nitromethane (NM), and 2,4,6-trinitrotoluene (TNT), among others . In this sense, the in situ rapid detection of nitro compounds has become one of the main targets for chemical sensor design. , The high interest in such compounds is mainly from a security standpoint, because these compounds or their mixtures have high explosive power. , Nitro compounds are also employed in a variety of industrial operations, including agrochemicals and industrial explosives. , Some of these compounds, such as nitromethane (NM) and nitrobenzene (NB), have a wide range of applications as fuel additives in motorsport vehicles or chemical synthesis, among others. , Thus, the easy access to these compounds is pointed out as the reason for their use as a precursor for improvised explosive devices (IEDs). , Metal–organic frameworks (MOFs) are promising candidates for detecting nitro compound explosives in situ . These systems have extended network structures with a hybrid nature that are formed by nodes (metal ions or metal clusters) connected to each other by organic ligands (named linkers). , Among diverse luminescent MOFs, lanthanides-based MOFs (Ln-MOFs) are very attractive for the development of luminescent chemical sensors.…”

QSAR Studies on Nitrobenzene Derivatives using Hyperpolarizability and Conductor like Screening model as Molecular Descriptors

“…Modern pesticides typically contain a nitrobenzene derivative as their active ingredient, which protects plants and crops (4). Nitrobenzene-based explosives, which are often low in sensitivity and great in performance, have been utilized in warlike weapons as one sort of explosive (5).…”

“…Figure5 The value of (a) α, (b) β, (c) γ and (d) COs area of ortho, meta and para-substituted nitrobenzenes calculated using PM6 .…”