Mesomorphic and crystal–crystal phase transitions are chain
min.−1 between 323–523 K. Measurements were performed in
length depend and irreversible.
triplicate.
Polarising light microscopy
Experimental
Phase textures were examined under polarized light, on samples
sandwiched between glass slides and coverslips, using a James
Swift polarizing light microscope. The slides and coverslips
were first immersed in an aqueous solution of 0.2% PVA. It was
then heated to ca. 373 K, for a few minutes and cooled to
ambient temperature, in order to produce good textures for
examination.
The white microcrystalline solids were prepared by metathesis
between sodium salt of n-alkanoic acids (Aldrich, 95+%), in
ethanol, and an excess of aqueous silver nitrate (Aldrich, 99.9%)
at ca. 343 K. The sodium salts were prepared by dissolving n-
alkanoic acid in ca. 50 cm3 of ethanol and combining this sol-
ution with ca.50 cm3 of ethanol containing a stochiometric
amount of sodium hydroxide (Aldrich, 99.9%). Subsequently, an
aqueous solution of silver nitrate was added, drop-wise with stir-
ring, to sodium alkanoate solution. This resulted in immediate
precipitation of a white solid. After stirring for a further 30 min.,
at ambient temperature, the precipitate was collected by filtration,
washed thrice with a solution of 1 : 1 acetone–methylene chlor-
ide mixture and vacuum dried for 24 h. The compounds were
then stored in the dark (because of their sensitivity to light), in a
desiccator over silica gel. (yield: ca. 90%).
Density measurements
Densities were determined at ambient temperature, in triplicate,
by the mass–volume ratio method,11 in n-hexane. The method
gave excellent results, when used to determine known values for
solid lead and lithium n-alkanoates.12,13
References
FTIR-spectroscopy
1 F. J. Buono and M. L. Feldman, Kirk-Othmer Encyclopedia of Chemical
Technology, ed. H. F. Mark, D. F. Othmer, C. G. Overberger and
G. T. Seaborg, Wiley, New York, 3rd edn, 1979, vol. 8, p. 34.
2 R. G. Bossert, J. Chem. Educ., 1950, 27, 10.
3 T. C. Huang, H. Toraya, T. N. Blanton and Y. Wu, J. Appl. Crystallogr.,
1993, 26, 180.
4 V. Vand, A. Aitken and R. K. Campbell, Acta Crystallogr., 1949, 2 (6), 398.
5 K. Binnemans, R. Van Deun, B. Thijs, I. Vanwelkenhuysen and
I. Geuens, Chem. Mater., 2004, 16, 2021.
6 L. P. Olson, D. R. Whitcomb, M. Rajeswaran, T. N. Blanton and
B. J. Stwertka, Chem. Mater., 2006, 18, 1667.
Infrared spectra were recorded from ground samples, that were
deposited on a quartz window, on a Bruker Tensor 37 FT-IR
spectrometer in the range of 4000–400 cm−1 at a resolution of
1 cm−1. Variable temperature measurements were made using a
specially constructed devise which was calibrated for tempera-
ture control prior to each measurement.
Solid-state 13C NMR spectroscopy
7 I. Weissbuch, J. Maewski, K. Kjaer, J. Als-Nielsen, M. Lahav and
L. Leiserowitz, J. Phys. Chem., 1993, 97, 12848.
8 P. Pyyko, Chem. Rev., 1997, 97, 597.
9 F. A. Cotton, X. Feng, M. Matusg and R. Poli, J. Am. Chem. Soc., 1988,
110, 7077.
10 P. Pyykko and F. Mendizabal, Chem.–Eur. J., 1997, 3, 1458.
11 Hand Book of Chemistry and Physics, ed. R. C. Weast and D. E. Lide,
CRC press, Florida, 49th edn, 1968–9, pp. F-73.
12 H. A. Ellis, N. A. S. White, I. Hassan and R. Ahamad, J. Mol. Struct.,
2002, 642, 71.
13 H. A. Ellis, N. A. S. White, R. A. Taylor and P. T. Maragh, J. Mol.
Struct., 2005, 738, 205.
14 R. A. Taylor, H. A. Ellis, P. T. Maragh and N. A. S. White, J. Mol.
Struct., 2006, 787, 113.
High resolution solid state spectra were collected, at room temp-
erature, using a Bruker Avance 200 MHz spectrometer. Measure-
ments were carried out at 50.32 MHz using CP and MAS with
1
high-power H decoupling for 3.6 μs pulse intervals and a 5.0 s
recycle time using a 7 mm probe. Typically, 1024 scans were
collected with a sweep width of 21.93 k Hz in 0.05 s. For acqui-
sition, processing and plotting of the spectra, XWin NMR 3.5
computer software was used. TMS was used as reference at
0 ppm.
15 H. Li, W. Bu, W. Qi and L. Wu, J. Phys. Chem. B, 2005, 109, 21669.
16 N. A. S. White and H. A. Ellis, J. Mol. Struct., 2008, 888, 386.
17 S. J. Lee, S. W. Hon, H. J. Choi and K. Kim, J. Phys. Chem. B, 2002,
106, 2892.
18 P. N. Nelson, H. A. Ellis and R. A. Taylor, J. Mol. Struct., 2011, 986, 10.
19 R. A. Taylor, H. A. Ellis and P. T. Maragh, J. Mol. Struct., 2009, 921, 118.
20 G. F. Marques, H. D. Burrows and M. G. Miguel, J. Chem. Soc., Faraday
Trans., 1998, 94 (12), 1729.
X-ray diffraction
Powder date were collected on a Bruker D5005 Diffractometer
with nickel filtered Cu-Kα, radiation (λ = 1.54056 Å) from
unground samples, finely deposited on standard plastic holders,
specially designed to minimize preferred orientation. The X-ray
tube was operated at 45 kV and 35 mA at a time per step of 2 s
for 2 h between 2θ of 2–60°.
21 E. L Smith and M. D. Porter, J. Phys. Chem., 1993, 97, 8032.
22 T. Ishioka, Y. Shibata, M. Takahashi and I. Kanesaka, Spectrochim. Acta,
Part A, 1998, 54, 1811.
23 H. A. Ellis, Mol. Cryst. Liq. Cryst., 1986, 139, 281.
24 R. G. Snyder, J. Mol. Spectrosc., 1961, 7, 116.
Differential scanning calorimetry (D.S.C.)
25 H. A. Ellis and A. de Vries, Mol. Cryst. Liq. Cryst., 1988, 163, 133.
26 R. W. Corkery, Phys. Chem. Chem. Phys., 2004, 6, 1534.
27 B. P. Tolochko, S. V. Chernov, S. G. Nikitenko and D. R. Whitcomb,
Nucl. Instrum. Methods Phys. Res., Sect. A, 1998, 405, 428.
28 Revised Nuffield Book of Data, ed. H. Ellis, H. D. Harrison and H. D
B. Jenkins, Longman, Aylesbury, 4th edn, 1984, ch. 4.7, pp. 52.
29 M. R. Barr, B. A. Dunnel and R. F. Grant, Can. J. Chem., 1963, 41, 1188.
30 G. Berchiesi, M. A. Berchiesi, G. G. Lobbia and D. Leonesi, Gazz.
Chim. Ital., 1976, 106, 549.
D.S.C. measurements were performed, in triplicate, on unground
samples encased in standard alumina crucibles (100 μL), using a
Setaram 560 system flushed with argon. The instrument was cali-
brated for temperature using pure indium, zinc and lead samples.
Thermograms were collected from freshly prepared samples,
each weighing between 2–4 0.02 mg at a heating rate of 2.0 K
2638 | Dalton Trans., 2012, 41, 2632–2638
This journal is © The Royal Society of Chemistry 2012