The comparision of NQR-NMR tensors and chemical reactivity of Mirtazapine and Normirtazapine analogues using quantum mechanics methods
Subject Areas :
Arezoo Tahan
1
(Semnan Branch, Islamic Azad University, Semnan, Iran.)
Mahya Khojandi
2
(2Department of chemistry, Central Tehran Branch, Islamic Azad University, ,Tehran ,Iran)
Keywords: Normirtazapine, NMR chemical shielding, Mirtazapine, NQR tensors,
Abstract :
The density functional theory (DFT) methods were used to investigate and compare NMR-NQR tensors and chemical reactivity of mirtazapine and normirtazapine compounds. The obtained results in B3LYP/6-311++G** level of theory showed that the values of NMR chemical shielding and NQR tensors of nitrogen nuclei in the considered analogues are dependent on chemical media, molecular structure and resonance interactions. So that, nitrogen atoms with identical positions in two analogues revealed the almost same NQR tensors, and chemical shielding values around themselves. NBO analysis also represented that resonance energy value related to LP(1) N10→ 𝛔* or π* interactions is the most value among all resonance interactions in both considered structures. Based on NBO analysis and NMR-NQR results, it can be deduced that by increasing participation of lone pairs of nitrogen atoms in the ring resonance interactions and aromaticity development in normirtazapine structure, the values of NQR tensors were increased; while in mirtazapine structure, by increasing negative charge on nitrogen atoms, the values of NQR and NMR tensors around them were increased.The comparision of reactivity criteria of two investigated analogues using NBO analysis represented that the structural differences of two analogues didn’t have remarkable effects on their chemical reactivity.
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