Carbonyl Diisocyanate CO(NCO)2: Synthesis and Structures in Solid State and Gas Phase.

A modified synthesis for carbonyl diisocyanate, CO(NCO)2, starting from trichloroisocyanuric acid and diphosgene is described. In addition to the previously reported (13)C NMR resonances, the (15)N NMR shift is determined for the first time. The structure in the solid state was determined by X-ray diffraction (XRD) on in situ grown crystals, that in the gas phase was experimentally determined by electron diffraction (GED) and for single molecules theoretically by quantum-chemical calculations. The structures are compared and discussed with related systems. Quantum-chemical calculations as well as GED and XRD prove syn-syn to be the conformation of lowest energy. In quantum-chemical calculations and GED the presence of a syn-anti conformer was confirmed and the structure of this conformer was determined.

Halogenotrinitromethanes: a combined study in the crystalline and gaseous phase and using quantum chemical methods.

The halogenotrinitromethanes FC(NO2 )3 (1), BrC(NO2 )3 (2), and IC(NO2)3 (3) were synthesized and fully characterized. The molecular structures of 1-3 were determined in the crystalline state by X-ray diffraction, and gas-phase structures of 1 and 2 were determined by electron diffraction. The Hal-C bond lengths in F-, Cl-, and Br-C(NO2 )3 in the crystalline state are similar to those in the gas phase. The obtained experimental data are interpreted in terms of Natural Bond Orbitals (NBO), Atoms in Molecules (AIM), and Interacting Quantum Atoms (IQA) theories. All halogenotrinitromethanes show various intra- and intermolecular non-bonded interactions. Intramolecular N⋅⋅⋅O and Hal⋅⋅⋅O (Hal=F (1), Br (2), I (3)) interactions, both competitors in terms of the orientation of the nitro groups by rotation about the C-N bonds, lead to a propeller-type twisting of these groups favoring the mentioned interactions. The origin of the unusually short Hal-C bonds is discussed in detail. The results of this study are compared to the molecular structure of ClC(NO2 )3 and the respective interactions therein.

Multiply nitrated high-energy dense oxidizers derived from the simple amino acid glycine.

Various energetic polynitro esters, carbamates, and nitrocarbamates that were derived from the amino acid glycine were fully characterized by single-crystal X-ray diffraction, vibrational spectroscopy (IR and Raman), multinuclear NMR spectroscopy, elemental analysis, and differential scanning calorimetry (DSC). Owing to their positive oxygen balance, the suitability of these compounds as potential oxidizers in energetic formulations was investigated and discussed. In addition, the heats of formation of the products were calculated by using the Gaussian 09 program package at the CBS-4M level of theory. From these values and the calculated densities (from the X-ray data), several detonation parameters, such as detonation pressure, velocity, energy, and temperature, were computed by using the EXPLO5 code. Furthermore, their sensitivities towards impact, friction, and electrostatic discharge were tested by using a drop hammer, a friction tester (both BAM certified), and a small-scale electrical-discharge device, respectively.

Chemistry and structures of hexakis(halogenomethyl)-, hexakis(azidomethyl)-, and hexakis(nitratomethyl)disiloxanes.

An investigation of the structures and chemistry of substituted hexamethyl disiloxanes ((XCH2)3Si)2O; X=F, Cl, Br, I, N3 , and ONO2) is reported. New synthetic routes to the precursor hexakis(chloromethyl)disiloxane are presented. The products with X=Cl, Br, I, and N3 were characterized by NMR, IR, and Raman spectroscopy. In addition, the single-crystal structures of the products with X=Cl, Br, and I are discussed in detail. The compounds with X=F and ONO2 were not obtained in their pure form; instead investigations of the decomposition products revealed their conversion into intermediates. Theoretical calculations of the gas-phase structures at the B3LYP/cc-pVDZ, B3LYP/3-21G, MP2/6-31G*, and MP2/3-21G levels of theory are used to explain the chemical and physical behavior of the compounds with X=Cl, Br, I, N3, and ONO2. A new decomposition pathway of hexakis(nitratomethyl)disiloxane is presented and is used to explain their remarkable instability. The energetic properties and values of the nitrate and azide derivatives were calculated at the CBS-4M level of theory by using the improved EXPLO5 computer code version 6.01.