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3290.3 and 3365.7 cmꢂ1 for crystalline HIF-4 (Fig. 10C). The Biotechnology (BT/PR6413/MED/14/802/2005) and the Depart-
results obtained by FTIR study on HIF-4 suggest that, both inter ment of Science and Technology's FIST program (SR/FST/PSI-
and intra molecular hydrogen bonding exist in amorphous or 174/2012).
semi crystalline powder sample of HIF-4. Thus, there is band
spread at the higher frequency edge and is contributed by the
effect of intra-molecular hydrogen bonding on O–H stretching.
It is assumed that the intermolecular hydrogen bonds are
References
´
´
shorter and therefore have lower O–H stretching frequencies
than intramolecular hydrogen bonds.31 The intramolecular
hydrogen bonding contribution to O–H stretching has vanished
when crystal is formed (Fig. 10C).
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4. Conclusions
Efforts to obtain the crystals of HIF-4 using conventional crys-
tallization techniques are not successful. Thus, we have used
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logical molecules.13 Single crystal X-ray crystallographic studies
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Conflicts of interest
Authors declare no conict of interest.
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Acknowledgements
Abdul Ajees Abdul Salam acknowledges the MAHE intramural 21 D. Cremer and J. A. Pople, J. Am. Chem. Soc., 1975, 97, 1354–
research grant (MAHE/DREG/PhD/IMF/2019). We gratefully 1358.
acknowledge support for this work from the Department of 22 M. Nardelli, J. Appl. Crystallogr., 1995, 28, 659.
© 2021 The Author(s). Published by the Royal Society of Chemistry
RSC Adv., 2021, 11, 20123–20136 | 20135