Transcript Слайд 1 - Eventry

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
Substances under study
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.
21
11
17
C
3
A
D
17
11
B
progesterone
17a-hydroxyprogesterone
cortisone
The structure analysis
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.
Cortisone (*)
b
c
a
α = β = γ = 90°
Progesterone
17a-hydroxyprogesterone
Cortisone
a
12.559 A
9.831 A
10.040 A
b
13.798 A
23.468 А
23.649 A
c
10.340 A
7.839 А
7.784 A
1791.8
1808.5
1848.1
Cell volume
(A3)
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)
(**)
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
Unit cell of cortisone
Hydrogen bond between the O3 atom
and O17H-group from two neighboring
molecules (“head to tail”).
Cortisone has two hydrogen bonds
between the O3 and O21 and O17 and O21
atoms from two neighboring molecules
The aims of this work:
- to study THz absorption and Raman spectra of progesterone, 17αhydroxyprogesterone 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 DMol3 simulations
THz time-domain spectroscopy
Laser pulse
Delay line
10 nJ, 100 fs, 80 MHz, 790 nm
THz pulse
Emitter
Cryostat
Detector
ZnTe
THz field, a.u.
Sample
0.7
Fourier
transform
0.0
-0.7
-2
0
Time, ps
2
THz amplitude, a.u.
GaAs
1.0
0.5
0.0
0
1
2
Frequency, THz
6
M.M. Nazarov, A.P. Shkurinov, E.A. Kuleshov, V.V. Tuchin, Quantum. Electron.2008. V. 38 (7). P. 647-655.
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
libration
Internal mode
twisting
bending
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
Progesterone spectra
wavenumber, cm
10
20
30
40
50
Intensity, a.u.
Raman: 300 K
Raman: 83K
v2
v
1,0
60
-1
70
80
90
100
a
v3
v4
1
0,5
Intensity, a.u.
0,0
1,2
10
20
30
40
50
60
70
80
90
theory
1,0
100
b
Theoretical absorption spectrum (b).
0,8
0,6
0,4
0,2
Absorption coefficient, a.u.
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 and ν2) and internal modes (ν3,
bending and ν4, twisting).
0,0
1,2
THz-TDS 294 K
THz-TDS 17.8K
1,0
c
0,8
0,6
0,4
0,2
0,0
10
20
30
40
50
60
70
wavenumber, cm
80
90
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).
100
-1
*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. 176180
Such temperature behavior is typical for
the hydrogen bond free molecular
arrangements of the ultimate density.
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, and ν2, 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.
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 bdirection of unit cell
Head to head (O17-O21) bonding
occurs in coil 2 generated by the
screw axis in the c direction.
Cortisone spectra
Raman shift, cm
Intensity, a.u.
20
40
50
60
70
300 K
v
83 K v1 2
1,0
80
v4
a
v3
0,5
0,0
20
1,2
Absorption coefficient, a.u.
30
-1
30
40
50
THz-TDS: 300K
THz-TDS: 18.1 K
calculations
60
70
80
b
1,0
0,8
0,6
0,4
0,2
0,0
20
30
40
50
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.
60
wavenumber, cm
-1
70
80
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).
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-hydroxyprogesterone (1 H-bond)
The frequency ranges of different types of vibrations in molecular
crystals of 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 17αHP–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.
CONCLUSIONS
1. 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.
2. 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.
3. 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.
4. 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.
Thank you for attention