Original Study Abstracts
1. Aim or purpose
BA-M has numerous and important pharmacological applications such as anti-HIV, anti-tumor, anti-cancer , anti-inflammatory, anti-bacterial activities, and so on [1]. The aim of this paper is to present some electron density and optical properties results on our grown betulinic acid methanol monosolvate (BA-M) crystal.
2. Materials and methods
BA (C30H48O3 ) with molar mass 456.71 g/mol and methanol CH3OH having molar mass 32.04 g/mol and boiling point of 65oC were mixed. 13.5 mg BA in 5 ml CH3OH (10×0.5L) were warmed up to 63oC for 15 minutes. The mixture was stirred all the time during experiment till BA was dissolved and was cooled down very slowly to room temperature. BA-M molecules are extracted from BA-M molecular crystal by method described in CRYSTAL 14 manual [2]. The experimental FTIR spectra were recorded and collected in 4000-400 cm-1 spectral range with a resolution of 2 cm-1. For calculations of electron density and FTIR optical absorption spectra the BT-M molecule, was extracted from BA-M monosolvate molecular crystal based on typical fragmentation scheme and chemical connectivity.
Molecular properties such Electron Density, Electrostatic potential, Laplacian of density and Critical points of the BA-M molecules have been simulated for the first time, using the refinement strategy based on multipolar atom model implemented in MoPro suite software [3]. We also calculated FTIR vibrational frequencies of BA-M molecule in harmonic approxmation based on the DFT analytically calculation of the second derivative of the energy with respect to nuclear position.
4. Conclusions
In this paper we have presented the results of our research on the recrystallization grown method and some electron density and optical properties of BA-M crystal. We have extracted the BT-M molecule from BA-M molecular crystal using a fragmentation scheme and chemical connectivity. Both experimental and theoretical results confirm that the methanol solvent form an integral part of the corresponding crystal’s unit cell, with a certain stoichiometric ratio to host molecules, bounded to the crystal lattice by hydrogen bonding, which improve the stability of the corresponding lattice.

References
1. W.Tang, N.H.Chen, G.Q. Li, G.C.Wang and Y.L.Li, 2014, Crystal structure of betulinic acid methanol monosolvate ,Acta Cryst., E70, 01242-01243.
2. R. Dovesi, V. R. Saunders, C. Roetti, R. Orlando, C. M. Zicovich-Wilson, F. Pascale, B. Civalleri, K. Doll, N. M. Harrison, I. J. Bush, P. D’Arco, M. Llunell, M. Causa and Y. Noel CRYSTAL14, (2014) CRYSTAL14 User’s Manual. University of Torino, Torino.
3.C. Jelsch, B. Guillot, A. Lagoutte, C. Lecomte, 2005,Advances in protein and small charge-density refinement methods using MoPro, J. Appl. Crystallogr., 38, 38-54.

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