6,6′-Dimethyl-1,1′,5,5′-tetraaza-6,6′-bi(bicyclo[3.1.0]hexane): synthesis and investigation of molecular structure by quantum-chemical calculations, NMR spectroscopy and X-ray diffraction analysis

Abstract

A new diaziridine derivative with two bicyclic diaziridine-containing moieties in one molecule, 6,6'dimethyl-1,1',5,5'-tetraaza-6,6'-bi(bicyclo[3.1.0]hexane) (BiDiMDAH), has been synthesized for the rst time. Its molecular structure has been investigated in the gas phase by means of quantum-chemical (QC) calculations, in CDCl 3 solution by 1D and 2D NMR spectroscopy and in the solid state by the X-ray diffraction (XRD) technique. It was found by QC calculations that BiDiMDAH molecule in a free state presents a single conformer of C 2 symmetry with trans orientation of the of the methyl groups about two carbons connecting diaziridine cycles. The 5-memebered rings in BiDiMDAH molecule has been found to be essentially planar. In order to explain conformational preferences of BiDiMDAH Natural Bond Orbitals (NBO) and Atoms in Molecules (AIM) analyses have been performed. According to the XRD data BiDiMDAH crystallizes in space group P2 1 /c with molecular structure similar to that obtained by the means of QC calculations. The data of NMR spectroscopy has revealed that only one conformer is present in CDCl 3 solution in agreement with the data of QC and XRD studies. The gaseous standard enthalpy of formation of BiDiMDAH has been estimated to be 443.8 ± 5.0 kJ/mol by means of G4 theory.

Enthalpy of formation of 6-phenyl-1,5-diazabicyclo[3.1.0]hexane by combustion calorimetry and theoretical approach for efficient prediction of thermochemistry of diaziridines

“…4 Recent progress in the synthesis of sweeteners includes the use of diaziridine-based derivatives. 10 The molecular structure of the unsubstituted 1,5-diazabicyclo[3.1.0]hexane (DABH) 11 and some of its derivatives [12][13][14][15][16] was investigated by gas-phase electron diffraction. X-ray diffraction studies were performed on PDABH 17 and other derivatives of DABH.…”

“…X-ray diffraction studies were performed on PDABH 17 and other derivatives of DABH. 15,[17][18][19][20] Available experimental data allowed for a better understanding of the conformational behavior of DABHs in the gaseous and crystalline phases. 20 Due to its high enthalpy of formation and low toxicity, DABH was found to be a promising liquid propellant as an alternative to toxic hydrazine derivatives.…”

“…X-ray diffraction studies were performed on PDABH 17 and other derivatives of DABH. 15,17–20 Available experimental data allowed for a better understanding of the conformational behavior of DABHs in the gaseous and crystalline phases. 20…”

“…The experimental value of the standard molar enthalpy of formation of crystalline diaziridine obtained in this work and the calculated value for the gas phase allow us to estimate the standard molar enthalpy of sublimation of PDABH at 298. 15…”