Synthesis, single-crystal X-ray diffraction, NLO and DFT studies of centrosymmetric 4-amino-3,5-dimethyl-1H-pyrazolium citrate monohydrate salt

Abstract

An organic salt compound 4-amino-3,5-dimethyl-1H-pyrazole (ADMP) has been combined with citric acid and crystallised at room temperature, forming a new molecular salt 4-amino-3,5-dimethyl-1H-pyrazolium citrate (ADMPCA) as a monohydrate. The compound was then structurally characterised by single-crystal X-ray diffraction (XRD), spectral analysis of FTIR, NMR and UV, and thermal studies. The structural analysis has shown that the ADMP molecules participate in the dominant hydrogen-bonding patterns forming a ladder-like structure via charge-assisted N⁺–H···O, O–H···O and N–H···O hydrogen bonds. The Hirshfeld surface analysis has been performed to understand the importance of intermolecular interactions in the stability of the salt structure. Theoretical studies were performed employing the DFT/B3LYP/6-311++G(d,p) level of theory to investigate Non-linear optical (NLO) behaviour, first-order hyperpolarisability, dipole moment and polarisability. The molecular properties, such as natural charge analysis and MESP analysis, were also explored in the present study.

GRAPHICAL ABSTRACT

KEYWORDS:

• 4-amino-3,5-dimethyl-1H-pyrazolium citrate monohydrate salt
• XRD
• DFT
• Hirshfeld surface analysis
• NLO

Acknowledgements

The author B. Radhika acknowledges the University Grants Commission (UGC), Government of India, for assisting through Junior Research Fellowship.

Authors contribution

B. Radhika contributed to investigation; J. Prashanth contributed to Methodology, Software and Data curation; B. Srinivas contributed to conceptualisation and resources; S. Jyothi contributed to Formal analysis, Writing – Original Draft; B. Venkatram Reddy Wrote – Reviewed and Edited.

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No potential conflict of interest was reported by the authors.

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