O . P . Cherkasova , I.N. Smirnova, M . M . Nazarov ,

1. Saratov Fall Meeting 2011, XV International School for Junior Scientists and Students on Optics, Laser Physics & Biophotonics September 27 - 30, 2011 Saratov, Russia Investigation of the effect of hydrogen bonding in molecular crystals on absorption and Raman spectra O.P. Cherkasova,I.N. Smirnova, M.M. Nazarov, E.V. Fedulova, A.V. Kargovsky, A.P. Shkurinov Institute of Laser Physics SB RAS, Novosibirsk, Russia Departament of Physics and International Laser Center, M.V.Lomonosov Moscow State University , Moscow, Russia

2. 21 Substances under study 11 17 17 C D A B Progesterone, 17a-hydroxyprogesterone and cortisone are cyclopentaphenanthrene derivatives and belong to corticosteroid hormones. These hormones carry out the most important regulatory functions and influence on many physiological processes. They have the same base structure and differ only by the position of OH-group in steroid basis, which result in essential changes of hormone-receptor recognition and DNA interaction. 11 3 progesterone 17a-hydroxyprogesterone cortisone

3. The structure analysis b Cortisone (*) All the molecules under study are aggregated into the molecular crystals with the same orthorhombic space group (P212121) with four molecules in a cell of a similar volume. c a α = β = γ = 90° (**) Thus, it may be supposed that the influence of a crystal lattice motions on the THz spectra can also be analyzed and the spectral features associated molecular motions can be highlighted. * http://www.ccdc.cam.ac.uk ** W.L. Duax, D.A. Norton, Atlas of steroid structure. N.Y: Plenum press (1975)

4. Hydrogen bonding in molecular crystals of corticosteroid hormones Unit cell of progesterone The molecules in the crystal are linked by Van Der Waals forces Unit cell of 17a-hydroxyprogesterone No hydrogen bond Hydrogen bond between the O3 atomand O17H-group from two neighboring molecules (“head to tail”). Unit cell of cortisone Cortisone has two hydrogen bonds between the O3 and O21and O17and O21 atoms from two neighboring molecules

5. The aims of this work: • to study THz absorption and Raman spectra of progesterone, 17α-hydroxyprogesterone and cortisone in the frequency range 3-110 cm-1 • in the temperature range from 18 K to 300 K • - to estimate the role of hydrogen bonding in molecular crystals on spectra • - to use the density functional theory (DFT) calculations for the qualitative interpretation of the experimental data. • - to assign all observed bands using DMol3simulations

6. THz time-domain spectroscopy Laser pulse Delay line 10 nJ, 100 fs, 80 MHz, 790 nm THz pulse Cryostat Detector Emitter GaAs ZnTe Sample Fourier transform 6 M.M. Nazarov, A.P. Shkurinov, E.A. Kuleshov, V.V. Tuchin, Quantum. Electron.2008. V. 38 (7). P. 647-655.

7. Solid-state DFT calculations were performed using the DMol3 software package.Molecules were optimized within the unit cell parameters specified by the X-ray diffraction study as reported in the Cambridge Structural Database (http://www.ccdc.cam.ac.uk). All calculated modes were divided into external (E) and internal (I). External mode Internal mode twisting bending libration translation I.N. Smirnova, D. A. Sapozhnikov, A.V. Kargovsky at al., Assignment of the lowest-lying terahertz and Raman signatures in corticosteroids by solid-state density function theory, in print

8. Progesterone spectra The progesterone room temperature Raman* spectrum (a) has several basic bands at 30 (ν1), 37 (ν2), 53 (ν3) and 99 cm-1 (ν4), which are assigned to external modes (sliding, ν1 andν2) and internal modes (ν3, bending and ν4, twisting). Theoretical absorption spectrum (b). The THz absorption spectra (c) have several narrow absorption bands at 41 (ν1), 55 (ν2), 70 (ν3) and 98 cm-1 (ν4), which correspond to internal modes (ν1- ν3, bending, and ν4, twisting). The decrease of the temperature only makes the Raman and THz lines sharper and their shift to the higher wavenumbers takes place. The temperature shift is the maximum for internal modes, namely twisting (ν4). Such temperature behavior is typical for the hydrogen bond free molecular arrangements of the ultimate density. *O. P. Cherkasova, V.A. Volodin, V.A. Minaeva, B.F. Minaev, G.V. Baryshnikov. Vestnik Novosibirsk State University. Series: Physics. 2010. V. 5, issue 4. P. 176- 180

9. 17α-hydroxyprogesterone is differ from progesterone by only a presence of the OH-group in the C17 position of the steroid nucleus that is resulted in the formation of a hydrogen bond between the O3 and O17 atoms, which stabilizes the molecules within the layer and does not allow itself to deform the molecule at lower temperatures. Raman spectrum has several basic bands at 25 (ν1), 36 (ν2), 51 (ν3) and 66 cm-1 (ν4), which is assigned to external modes (ν1,sliding, andν2, libration) and internal modes (bending, ν3 and ν4). THz absorption spectrum has only two well defined absorption maxima at 53 (ν2) and 66 cm-1 (ν3). These bands correspond to the bending of molecules. Upon cooling the changes of relative intensities of the bands and their sharpening up are observed, thus some broad at room temperature bands split into several narrower bands, but the positions of bands is almost not shifted.

10. Cortisone In the crystal packing of cortisone two types of helical coils are formed by hydrogen bonding. Head to tail (O21- O3) bonding occurs in coil 1 generated by the screw axis in the b-direction of unit cell Head to head (O17-O21) bonding occurs in coil 2 generated by the screw axis in the c direction.

11. Cortisone spectra Raman spectrum has four broad bands, at 35 (ν1, bending), 40 (ν2, bending of end group), 62 (ν3,twisting) and 75 cm-1 (ν4,twisting), which at 83 K shift to the higher frequencies and their bandwidths reduce. The temperature shift is the maximum for ν4, twisting. THz absorption spectrum of cortisone has two intensive absorption maxima at 64.5 (ν4, twisting) and 78.5 cm-1. The bands get narrow upon cooling that allows resolving more peaks. We analyzed the temperature dynamics of the bands at 44.6 (ν1, twisting), 52 (ν2, bending), 57.5 (ν3, bending) and at 64.5 cm-1. As there is in Raman spectra, the maximal temperature shift is observed for twisting motions (ν1 and ν4).

12. The temperature shifts (Δν, cm-1) for basic bands in THz and Raman spectra depends on hydrogen bonds in molecules. . 1 – progesterone 2 – cortisone (2 H-bond) 3 - 17a-hydroxy-progesterone (1 H-bond)

13. The frequency ranges of different types of vibrations in molecular crystalsof steroids The translations in progesterone are observed in the range up to 44 cm-1, in 17α-HP – up to 30 cm-1 (with separate vibrations 55.7 and 65.2 cm-1) and in the cortisone there is only two translation modes on 27.5 cm-1 and 35.3 cm-1. These changes are explained by the appearance of hydrogen bond, that tight the neighbor molecules. The librations are presented in the spectra of progesterone in the range up to 60 cm-1, for 17α-HP–up to 49 cm-1, for cortisone – up to 35 cm-1 (with an additional mode 46.9 cm-1). Similarly, the lower edges of ranges of bending and twisting vibrations are shifted to lower frequencies, correspondingly, 51.6 cm-1 and 75 cm-1 for progesterone, 45 and 69 cm-1 for 17α-HP and 30 and 55 cm-1 for cortisone. The absence of hydrogen bonds can explain high mobility of the molecules in the crystal of progesterone and a large number of possible vibrations. In the crystal 17α-HP there is one hydrogen bond, so the range of translations gets narrow and the range of librations shifts to the lower frequencies. In the crystal of cortisone there are two hydrogen bonds, so the molecules move one against another in the plane hardly and there is only two possible mode, and even in the low frequency region all molecules are bound together so hard, that any libration movement leads to twisting.

14. CONCLUSIONS • Substances under study have several intense features, which were assigned using DMol3 simulations and the estimation of external and internal impacts in observed vibrational bands was made. • It was obtained, that external modes in progesterone are observed in the range up to 45 cm-1, in 17α-hydroxyprogesterone – up to 30 cm-1 and in the cortisone there is no sliding. • We observe the different temperature dynamics of the THz and Raman band positions if the temperature goes down. The maximal temperature shift is observed for twisting motions. • Such temperature behavior depends on ability of a molecule to form hydrogen bonds. So, the absence of hydrogen bonds can explain high mobility of the molecules in the crystal of progesterone and maximum band shifts. In the crystal 17α-hydroxyprogesterone there is one hydrogen bond that is resulted to rigid position of molecules within the layer and the absence of band shifts. Cortisone has two different types of hydrogen bonds which lead to a weakening of tight coupling in the layer and the appearance of coupling between the layers.

15. Thank you for attention