Synthesis and phytotoxicity of new ionic liquids incorporating chiral cations and/or chiral anions

Article abstract of DOI:10.1021/jf062849q

The aim of this work was to synthesize chiral ionic liquids as chiral solvents for organic synthesis and to evaluate the phyto(eco)toxicity of the new products and starting N-alkylimidazoles and their potential environmental influence on soil and plants.

Full text of DOI:10.1021/jf062849q

J. Agric. Food Chem. 2007, 55, 1881−1892 1881
Synthesis and Phytotoxicity of New Ionic Liquids Incorporating
Chiral Cations and/or Chiral Anions
PIOTR BAŁCZEWSKI,*,†,§ BARBARA BACHOWSKA,§ TOMASZ BIAŁAS,†
ROBERT BICZAK,§ WANDA M. WIECZOREK,§,# AND AGNIESZKA BALINÄ SKA
§
Department of Heteroorganic Chemistry, Center of Molecular and Macromolecular Studies,
Polish Academy of Sciences, Sienkiewicza 112, 90-363 Ło´dz´, Poland; Institute of Chemistry and
Environmental Protection, Jan Długosz University, Armii Krajowej 13/15, 42-200 Cze¸stochowa,
Poland; and Institute of General and Ecological Chemistry, Technical University of Ło´dz´,
Z˙ eromskiego 116, 90-924 Ło´dz´, Poland
The aim of this work was to synthesize chiral ionic liquids as chiral solvents for organic synthesis
and to evaluate the phyto(eco)toxicity of the new products and starting N-alkylimidazoles and their
potential environmental influence on soil and plants. Chiral ionic liquids containing anions such as
Cl-, Br-, TsO-, PF6-, NO3-, CF3SO3-, and (+)- and (-)-C6H5CH(OH)C(O)O- were synthesized using
(-)-(1R)-6,6-dimethylbicyclo[3.1.1]hept-2-ene-2-ethyl [(-)-(1R)-nopyl] halides (X ) Cl, Br) and tosylate
in 62-100% yields. The chloride 7 and the nitrate 13 ionic liquids possessed a toxicity dependent on
the applied concentration. The lowest concentration causing a distinct reduction in plant germination/
growth was 100 mg/kg. Spring barley better tolerated the ionic liquids (200 mg/kg) than common
radish (100 mg/kg). The nitrate liquid did not exhibit an inhibiting effect on the germination ability of
seeds. The starting N-methylimidazole used in lower concentrations (1 and 10 mg/kg of soil dry weight)
was not phytotoxic, in contrast to higher doses (>1000 mg/kg).
KEYWORDS: Chiral ionic liquids; (-)-nopyl derivatives; phytotoxicity test; soil; environmental protection
INTRODUCTION
preliminary stage. In this context, a recent application of chiral
alkoxyimidazolinium salts, as precursors of the corresponding
carbenes in highly enantioselective copper-catalyzed conjugate
addition to cyclic enones, is worthy of note (13). The aim of
this work was to synthesize new chiral ionic liquids as new
chiral solvents for organic asymmetric synthesis, structure
elucidation, investigations of physicochemical properties, and
application and finally phyto(eco)toxicity tests of the new
products and starting N-methylimidazole for evaluation of the
potential environmental impact on soil and plants.
Ionic liquids are cheap and versatile alternatives to volatile
organic solvents, and their green character has usually been
justified with their negligible vapor pressure (1-3). Being
interesting targets in academic laboratories, ionic liquids have
until recent years struggled to enter the industrial mainstream,
when two leading chemical companies developed processes that
used these new solvents. On the other hand, there is a little
knowledge of environmental cumulative effects of ionic liquid
use if they were to enter ecosystems via industrial effluents (4,
5). As a solution of this problem, very recently biodegradable
ionic liquids have been engineered (6); however, also in this
case investigations of phyto(eco)toxicity of biodegradation
products should be carried out. Although there are a great
number of publications devoted to different aspects of achiral
ionic liquids, the literature of chiral ionic liquids is surprisingly
very limited (7-12). Chiral ionic liquids, possessing combina-
tions of chiral anions and/or cations, are attractive for their
application in chiral discrimination including asymmetric syn-
thesis and catalysis as well as optical resolution of racemates;
however, the results obtained in this field are still at a
MATERIALS AND METHODS
The 1H NMR (200 and 500 MHz) and 13C NMR (50 and 125 MHz)
spectra were recorded using Bruker AC-200 and Bruker DRX-500
spectrometers. The IR spectra were recorded using an ATI Mattson
Infinity FTIR 60 spectrometer. The mass spectra of pure compounds
were obtained using a Finnigan Mat 95 spectrometer. Column chro-
matography was done using Merck silica gel (F254 60, 70-230 and
270-400 mesh). Organic solvents were distilled before use. All
chemicals were purchased from Sigma-Aldrich and used directly.
Numbering of atoms applied in the experimental part is presented
in the structure below:
* Author to whom correspondence should be addressed (e-mail
pbalczew@bilbo.cbmm.lodz.pl; telephone +48 42 6803202; fax +48 42
6847126).
(-)-(1R)-Nopyl Chloride (2). To a stirred solution of triphenylphos-
phine (25.3 g, 0.09 mol) dissolved in carbon tetrachloride (52 mL)
was added (-)-(1R)-nopol (1) (14.6 g, 15 mL, 0.09 mol), and the
reaction mixture was refluxed for 1 h. After the flask had cooled to
ambient temperature, a white precipitate was removed by filtration.
† Polish Academy of Sciences.
§ Jan Długosz University.
# Technical University of Ło´dz´.
10.1021/jf062849q CCC: $37.00
© 2007 American Chemical Society
Published on Web 02/02/2007

1882 J. Agric. Food Chem., Vol. 55, No. 5, 2007
Bałczewski et al.
be unambiguously attributed); 13C NMR (126 MHz, CDCl3), δ 21.01
(s, CH3-C(6)), 21.59 (s, Ar-CH3), 26.12 (s, CH3-C(6)), 31.22 (s, C(4)),
31.46 (s, C(7)), 36.03 (s, CH2CH2O), 37.95 (s, C(6)), 40.49 (s, C(5)),
45.45 (s, C(1)), 68.55 (s, CH2O), 119.63 (s, C(3)), 127.81 (s, CArH),
129.75 (s, CArH), 133.17 (s, CAr-CH3), 142.55 (s, C(2)), 144.62 (s, CAr-
SO2O). m/e (CI, NH3) calcd for C18H28NSO3 (M + NH4+): 338.1790.
Found: 338.1779.
(-)-1-[(1R)-Nopyl]-3-methylimidazolium Chloride (7). (-)-(1R)-
Nopyl chloride (2) (1.85 g, 0.01mol) was dissolved in 1-methylimi-
dazole (0.83 g, 0.01 mol), and the resulting mixture was heated (NOT
refluxed) to 80-90 °C through 72 h. After cooling to ambient
temperature, a viscous brownish substance was washed with ethyl
acetate (3 × 10 mL). After evaporation of the last portion of the solvent,
the crude ionic liquid was kept under vacuum at 70 °C for 30 min to
The filtrate was evaporated to give a yellowish oil. This oil was
subsequently washed with n-hexane and further purified by filtration
through a silica gel layer using n-hexane as an eluent to afford pure 2
25
25
(13.8 g, 85%): [R]D -47 (c 0.6 in CHCl3); nD 1.4987; IR (film)
cm-1 2986 (m), 2917 (s), 2833 (m), 1468 (m), 1449 (m), 1432(m),
1382 (w), 1365 (m), 1330 (w), 1293 (w), 1265 (w), 1241 (w), 1219
(w), 1118 (w), 1099 (w), 1082 (w), 960 (w), 886 (w), 790 (w), 742
(m); 1H NMR (200 MHz; CDCl3), δ 0.84 (s, 3, CH3-C(6)), 1.16 (d, 1,
J ) 8.5 Hz, C(7)Hendo), 1.28 (s, 3, CH3-C(6)), 1.98-2.13 (m, 2, C(1)H,
C(5)H), 2.21-2.25 (m, 2, C(4)H2), 2.32-2.46 (m, 2+1, CH2CH2Cl,
C(7)Hexo), 3.49 (t, 2, J ) 7.2 Hz, CH2Cl), 5.32 (br s, 1, C(3)H); 13C
NMR (50 MHz, CDCl3), δ 21.15 (s, CH3-C(6)), 26.21 (s, CH3-C(6)),
31.26 (s, C(4)), 31.58 (s, C(7)), 37.99 (s, C(6)), 40.11 (s, CH2CH2Cl),
40.63 (s, C(5)), 42.52 (s, CH2Cl), 45.48 (s, C(1)), 119.19 (s, C(3)),
144.35 (s, C(2)); m/e (CI, DB-1, 30 m, 50-250 °C, 10 °C/min) 93
(61), 105 (75), 149 (M+ + 1 - Cl, 100), 185 (M+(35Cl) + 1, 51), 186
(21), 187 (M+(37Cl) + 1, 17). Calcd for C11H1735Cl (M+): 184.1018.
Found: 184.1021.
25
afford a pure light brown product, 7 (2.53 g, 85% yield): [R]D -18
(c 1.23 in CHCl3); IR (film) cm-1 3377 (bm), 3145 (m), 3073 (m),
3034 (m), 2983 (m), 2935 (s), 2916 (s), 2832 (s), 1712 (m), 1672 (m),
1572 (m), 1466 (m), 1432 (m), 1382 (m), 1365 (m), 1169 (m), 1036
1
(m), 624 (m); H NMR (200 MHz; CDCl3), δ 0.68 (s, 3, CH3-C(6)),
0.94 (d, 1, J ) 8.6 Hz, C(7)Hendo), 1.19 (s, 3, CH3-C(6)), 1.99 (m, 2,
C(1)H, C(5)H), 2.10 (br s, 2, C(4)H2), 2.26-2.36 (m, 1, C(7)Hexo),
2.51 (m, 2, CH2CH2N(A)), 4.05 (s, 3, N(C)-CH3), 4.25 (2 × t, 2, J )
7.4 Hz, J ) 8.6 Hz, CH2CH2N(A)), 5.28 (m, 1, C(3)H), 7.33, 7.57 (2
× br t, 2 × 1, J ) 1.7 Hz, J ) 1.5 Hz, C(D)H, C(E)H), 10.37 (br s,
1, C(B)H); 13C NMR (126 MHz, CDCl3), δ 20.76 (s, CH3-C(6)), 25.85
(s, CH3-C(6)), 31.02 (s, C(4)), 31.41 (s, C(7)), 36.27 (s, N(C)-CH3),
36.88 (s, CH2CH2-N(A)), 37.79 (s, C(6)), 40.22 (s, C(5)), 44.88 (s,
C(1)), 47.67 (s, CH2CH2N(A)), 120.5 (s, C(3)), 121.8, 123.6 (2 × s,
C(D)H, C(E)H), 137.3 (s, C(B)H), 142.2 (s, C(2)). m/e (FAB(+), LSI,
Cs+, 13 keV) calcd for C15H23N2 (M+): 231.1861. Found 231.1867
m/e (FAB(-), LSI, Cs+, 13 keV) 301, 303, 305 (M+ + 2 × Cl-, 90,
60, 9); 35, 37 (100, 31, Cl-).
(-)-(1R)-Nopyl Bromide (3). To a stirred mixture of NaBr (12 g,
116.6 mmol) in dry DMSO (50 mL) was added a solution of (-)-
(1R)-nopyl tosylate (4) (12.5 g, 38.9 mmol) in dry DMSO (30 mL).
After 5 h of stirring at 70 °C, the resulting emulsion was diluted with
water and extracted with n-hexane (3 × 50 mL). The combined organic
fractions were washed once again with water and brine and next dried
over MgSO4. After filtration of the drying agent and evaporation of
hexane, the crude 3 was obtained (5.47 g, 60% yield). Then it was
purified by filtration through the thin silica gel layer using n-hexane
as an eluent to afford pure 3 (2.48 g, 30% yield) as a light-yellow
(-)-1-[(1R)-Nopyl]-3-n-butylimidazolium Chloride (8). (-)- (1R)-
Nopyl chloride 2 (1.69 g, 9.15mmol) was dissolved with 1-butylimi-
dazole (1.15 g, 9.3 mmol), and the resulting mixture was heated (NOT
refluxed) to 70-80 °C through 72 h. After cooling to ambient
temperature, a yellowish precipitate of 8 was washed with ethyl acetate
(3 × 10 mL). After evaporation of the last portion of the solvent, the
crude ionic liquid was kept under vacuum at 70 °C for 30 min to afford
25
25..5
liquid: [R]D -30 (c 0.83 in CHCl3); nD
1.5133; IR (film) cm-1
3420 (bw), 2983 (s), 2917 (m), 2882 (m), 2833 (m), 1462 (w), 1433
(m), 1381 (w), 1366 (w), 1266 (m), 1209 (w), 1047 (m), 887 (w), 790
(m); 1H NMR (200 MHz; CDCl3), δ 0.84 (s, 3, CH3-C(6)), 1.17 (d, 1,
J ) 8.6 Hz, C(7)Hendo), 1.27 (s, 3, CH3-C(6)), 1.90-2.20 (m, 1+1,
C(1)H, C(5)H), 2.20-2.30 (m, 2, C(4)H2), 2.37 (dt, 1, J ) 8.6 Hz, J
) 5.6 Hz, C(7)Hexo), 2.51 (t, 2, J ) 7.6 Hz, CH2CH2Br), 3.35 (t, 2, J
) 7.6 Hz, CH2Br), 5.20-5.40 (m, 1, C(3)H); 13C NMR (50 MHz,
CDCl3), δ 21.21 (s, CH3-C(6)), 26.21 (s, CH3-C(6)), 30.73 (s, CH2-
Br), 31.24 (s, C(4)), 31.61 (s, C(7)), 38.90 (s, C(6)), 40.38 (s, CH2-
CH2Br), 40.62 (s, C(5)), 45.41 (s, C(1)), 119.10 (s, C(3)), 145.10 (s,
C(2)); m/e (CI, isobutane) 149 (M+ + 1 - Br, 41), 229 (M+(79Br) +
1, 100), 231 (M+(81Br) + 1, 96). Calcd for C11H1879Br (M+(79Br) +
1): 229.0592. Found: 229.0590.
(-)-(1R)-Nopyl Tosylate (4). (-)-(1R)-Nopol (1) (4.49 g, 27mmol)
was dissolved in dry pyridine (7 mL), and to this solution was added
p-toluenesulfonyl chloride (5.91 g, 31mmol). The resulting mixture was
placed in a refrigerator for 20 h. Then, the reaction mixture containing
a white precipitate was treated with aqueous solution of HCl (prepared
from 7.5 mL of 36% aqueous solution of HCl and 15 mL of water)
and extracted with diethyl ether (3 × 50 mL). Combined ethereal layers
were dried for 24 h over K2CO3, filtered, and evaporated to afford 4 as
a yellow oil (7.77 g, 88% yield) from which white crystals were
obtained after a few minutes: [R]D25 -26 (c 1.03 in CHCl3); mp 46-
48 °C; IR (film) cm-1 2999 (m), 2971 (m), 2915 (s), 2892 (m), 2864
(m), 2832 (m), 1598 (m), 1460 (m), 1357 (s), 1203 (m), 1189 (s), 1174
(s), 1096 (m), 981 (s), 962 (m), 935 (m), 911 (s), 814 (s), 804 (m),
795 (m), 773 (s), 665 (s), 571 (m), 555 (s); 1H NMR (500 MHz; CDCl3),
δ 0.75 (s, 3, CH3-C(6)), 1.06 (d, 1, J ) 8.7 Hz, C(7)Hendo), 1.22 (s, 3,
CH3-C(6)), 1.92 (dd, 1, JH(1)-H(7) ) 5.3 Hz, JH(1)-H ) 5.3* Hz, C(1)H),
2.04 (br s, 1, C(5)H), 2.17 (AB system, δH1 2.11, δH2 2.23, J ) 17.7
Hz, C(4)H2), 2.25-2.38 (m, 2+1, CH2CH2O, C(7)Hexo), 2.44 (s, 3, Ar-
CH3), 4.01 (t, 2, J ) 7.0 Hz, CH2O), 5.23 (br s 1, C(3)H), 7.33 (d, 2,
J ) 8.1 Hz, CArH), 7.77 (d, 2, J ) 8.1 Hz, CArH) (*, JH(1)-H could not
25
a pure beige product 8 (1.98 g, 63% yield): [R]D -14 (c 1.16 in
CHCl3); mp 64-67 °C (hygroscopic); IR (film) cm-1 3406 (bs), 3265
(s), 3134 (s), 3077 (s), 2959(bs), 2832 (s), 1714 (m), 1677 (m), 1635
(m), 1568 (s), 1466 (s), 1365 (m), 1167 (s), 947 (m), 891 (m), 625
(m); 1H NMR (200 MHz; CDCl3), δ 0.63 (s, 3, CH3-C(6)), 0.82 (t, 3,
J ) 7.3 Hz, N(C)-(CH2)3CH3), 0.87 (1 H, d, JH-H ) 8.1 Hz, C(7)-
Hendo), 1.14 (s, 3 CH3-C(6)), 1.22 (m, 2, N(C)-(CH2)2CH2CH3), 1.77
(m, 2, N(C)-CH2CH2CH2CH3), 1.96 (m, 2, C(1)H, C(5)H), 2.05 (br s,
2, C(4)H2), 2.25 (m, 1, C(7)Hexo), 2.50 (m, 2, CH2CH2N(A)), 4.26 (m,
4, CH2CH2-N(A), N(C)-CH2(CH2)2CH3), 5.24 (m, 1, C(3)H), 7.38,
7.48 (2 × br s, 2 × 1, C(D)H, C(E)H), 10.32 (br s, 1, C(B)H); 13C
NMR (50 MHz, CDCl3,), δ 13.18 (s, N(C)-(CH2)3CH3), 19.10 (s,
N(C)-(CH2)2CH2CH3), 20.72 (s, CH3-C(6)), 25.82 (s, CH3-C(6)),
31.00, 31.42, 31.92 (3 × s, C(4), C(7), N(C)-CH2CH2CH2CH3), 36.79
(s, CH2CH2-N(A)), 37.76 (s, C(6)), 40.19, 44.80 (2 × s, C(1), C(5)),
47.62, 49.41 (2 × s, CH2CH2-N(A), N(C)-CH2(CH2)2CH3), 120.47
(s, C(3)), 121.85 (s, C(D)H, C(E)H), 137.01 (s, C(B)H), 142.23 (s,
C(2)). m/e (FAB(+), LSI, Cs+, 13 keV) calcd for C18H29N2 (M+):
273.2331. Found: 273.2336. m/e (FAB(-), LSI, Cs+, 13 keV) 343,
345, 347 (M+ + 2 × Cl-, 90, 60, 9), 35, 37 (100, 31, Cl-).
(-)-1-[(1R)-Nopyl]-3-methylimidazolium Bromide (9). (-)-(1R)-
Nopyl bromide (3) (1.15 g, 5 mmol) was dissolved in 1-methylimidazole
(0.41 g, 5 mmol). After 10 days of stirring at ambient temperature, the
mixture was heated to 50 °C for 66 h. Three-fold extraction of the
crude reaction mixture with AcOEt followed by drying over MgSO4,
filtration of the drying agent, and evaporation of the solvent gave the
pure product 9 (1.06 g, 74% yield): [R]D25 -15 (c 2.60 in CHCl3); IR
(film) cm-1 3435(bs), 3140 (s), 3063 (s), 2983 (s), 2915 (s), 2832 (s),
1732 (m), 1571 (m), 1466 (s), 1431 (s), 1379 (m), 1365 (m), 1244
(m), 1169 (s), 753 (m), 622 (m); 1H NMR (200 MHz; CDCl3), δ 0.65
(s, 3, CH3-C(6)), 0.91 (d, 1, J ) 8.6 Hz, C(7)Hendo), 1.16 (s, 3, CH3-
C(6)), 1.95-2.00 (m, 1, C(5)H), 2.07 (2 × br s, 2 C(4)H2), 2.20-2.40

Ionic Liquids
J. Agric. Food Chem., Vol. 55, No. 5, 2007 1883
(m, 1, C(7)Hegzo), 2.50 (t, 2, J ) 7.4 Hz, CH2CH2N(A)), 4.02 (s, 3,
N(C)-CH3), 4.23 (t, 2, J ) 7.4 Hz, CH2CH2N(A)), 5.27 (s, 1, C(3)H),
7.37, 7.61 (2 × s, 2 C(D)H, C(E)H), 10.10 (s, 1, C(B)H); 13C NMR
(50 MHz, CDCl3), δ 20.79 (s, CH3-C(6)), 25.88 (s, CH3-C(6)), 31.06
(s, C(4)), 31.47 (s, C(7)), 36.50, 36.90, 37.83 (3 × s, C(6), N(C)-
CH3, CH2CH2-N(A)), 40.31 (s, C(5)), 45.00 (s, C(1)), 47.82 (s,
CH2CH2N(A)), 120.63 (s, C(3)), 121.88, 123.50 (2 × s, C(D)H, C(E)H),
137.03 (s, C(B)H), 142.13 (s, C(2)). m/e (FAB(+), LSI, Cs+, 13 keV)
calcd for C15H23N2 (M+): 231.1861. Found: 231.1855. m/e (FAB(-),
LSI, Cs+, 13 keV) 79 (M-(79Br), 95), 81 (M-(81Br), 93).
CH3), 5.24 (br s, 1, C(3)H), 7.29 (s, 1, C(D)H, C(E)H), 8.47 (br s, 1,
C(B)H); 13C NMR (50 MHz, CDCl3), δ 14.11 (s, N(C)-(CH2)3CH3),
20.08 (s, N(C)-(CH2)2CH2CH3), 21.87 (s, CH3-C(6)), 26.85 (s, CH3-
C(6)), 32.15, 32.52, 32.72 (3 × s, C(4), C(7), N(C)-CH2CH2CH2CH3),
37.67 (s, CH2CH2-N(A)), 38.86 (s, C(6)), 41.33 (s, C(5)), 45.72 (s,
C(1)), 48.80, 50.62 (2 × s, CH2CH2-N(A), N(C)-CH2(CH2)2CH3),
121.76 (s, C(3)), 123.23, 123.31 (2 × s, C(D)H, C(E)H), 135.89 (s,
C(B)H), 143.32 (s, C(2)). m/e (FAB(+), LSI, Cs+, 13 keV) calcd for
C18H29N2 (M+): 273.2331. Found: 273.2333. m/e (FAB(-), LSI, Cs+,
13 keV) 145 (PF6-, 100).
(-)-1-[(1R)-Nopyl]-3-methylimidazolium Tosylate (10). (-)-(1R)-
Nopyl tosylate (4) (1.6 g, 6.9mmol) was dissolved in 1-methylimidazole
(0.41 g, 5 mmol), and the resulting mixture was heated under argon
atmosphere (NOT refluxed) to 70-80 °C through 72 h. Then the crude
product was kept under vacuum at 70 °C for 30 min to afford a
brownish product 10 (1.9 g, 95% yield): [R]D25 -9 (c 2.38 in MeOH);
IR (film) cm-1 3455 (bm), 3148 (m), 3104 (m), 2983 (m), 2916 (m),
2832 (m), 1720 (w), 1574 (w), 1468 (w), 1427 (w), 1382 (w), 1365
(w), 1218 (s), 1194 (s), 1123 (s), 1034 (s), 1012 (s), 816 (m), 683 (s),
(-)-1-[(1R)-Nopyl]-3-methylimidazolium Nitrate (13). To the ionic
liquid 7 (3.87 g, 14.5 mmol) dissolved in acetone (30 mL) was added
an aqueous solution of AgNO3 (2.47 g, 14.5 mmol), and the mixture
was stirred for 24 h at ambient temperature. A white precipitate of
AgCl was filtered off, and acetone was evaporated. The resulting crude
ionic liquid was washed with hexane to give 13 (4.42 g , 99% yield):
[R]D -16 (c 2.13 in CHCl3); IR (film) cm-1 3478 (bm), 3147 (m),
25
3101 (m), 2984 (m), 2916 (m), 2833 (w), 1573 (m), 1465 (m), 1352
(s), 1168 (m), 830 (w), 624 (w); 1H NMR (200 MHz; CDCl3), δ 0.73
(s, 3, CH3-C(6)), 0.99 (d, 2, J ) 8.6 Hz, C(7)Hendo), 1.24 (s, 3, CH3-
C(6)), 1.95-2.10 (m, 1, C(5)H), 2.16 (br s, 2, C(4)H2), 2.25-2.45 (m,
1, C(7)Hegzo), 2.54 (t, 2, J ) 7.2 Hz, CH2CH2N(A)), 3.98 (s, 3, N(C)-
CH3), 4.24 (t, 2, J ) 7.2 Hz, CH2CH2N(A)), 5.31 (s, 1, C(3)H), 7.38,
7.49 (2 × s, 2, C(D)H, C(E)H), 9.67 (s, 1, C(B)H); 13C NMR (50 MHz,
CDCl3), δ 20.87 (s, CH3-C(6)), 25.99 (s, CH3-C(6)), 31.19 (s, C(4)),
31.57 (s, C(7)), 36.13, 36.99, 37.94 (3 × s, C(6), N(C)-CH3, CH2-
CH2-N(A)), 40.38 (s, C(5)), 44.98 (s, C(1)), 47.87 (s, CH2CH2N(A)),
120.64 (s, C(3)), 122.03, 123.46 (2 × s, C(D)H, C(E)H), 137.56 (s,
C(B)H), 142.34 (s, C(2)). m/e (FAB(+), LSI, Cs+, 13 keV) calcd for
C15H23N2 (M+): 231.1861. Found: 231.1861. m/e (FAB(-), LSI, Cs+,
13 keV) 355 (M+ + 2 × NO3-, 44), 62 (NO3-, 100).
1
625 (w), 569 (m); H NMR (500 MHz; CDCl3), δ 0.66 (s, 3, CH3-
C(6)), 0.90 (d, 1, J ) 8.7 Hz, C(7)Hendo), 1.17 (s, 3, CH3-C(6)), 1.90-
1.96 (m, 1, C(1)H), 1.96-2.02 (m, 1, C(5)H,), 2.08 (AB system, δH1
) 2.11, δH2 ) 2.06, J ) 17.7 Hz, C(4)H2), 2.23-2.30 (m, 1, C(7)-
Hexo), 2.27 (s, 3, CH3-CAr), 2.32-2.45 (m, 2, CH2CH2-N(A)), 3.84
(s, 3, N(C)-CH3), 4.05-4.20 (m, 2, CH2CH2-N(A)), 5.17 (s, 1,
C(3)H), 7.08 (d, 2, J ) 7.9 Hz, CArH), 7.24, 7.41 (2 × s, 2, C(D)H,
C(E)H), 7.69 (d, 2, J ) 7.9 Hz, CArH), 9.46 (s, 1, C(B)H); 13C NMR
(50 MHz, CDCl3), δ 20.79 (s, CH3-C(6)), 21.12 (s, CH3-Ar), 25.90
(s, CH3-C(6)), 31.08 (s, C(4)), 31.46 (s, C(7)), 35.35, 36.07, 36.82 (3
× s, C(6), N(C)-CH3, CH2CH2-N(A)), 40.31 (s, C(5)), 44.87 (s, C(1)),
47.57 (s, CH2CH2-N(A)), 120.30 (s, C(3)), 125.63 (s, CArH), 128.54
(s, CArH), 122.21 (2 × s, C(D)H, C(E)H), 137.30 (s, C(B)H), 139.35,
142.33, 143.33 (3 × s, CAr-CH3, CAr-O, C(2)). m/e (FAB(+), LSI,
Cs+, 13 keV) calcd for C15H23N2 (M+): 231.1861. Found: 231.1871.
m/e (FAB(-), LSI, Cs+, 13 keV) 171 (M-, 100).
(-)-1-[(1R)-Nopyl]-3-n-Butylimidazolium Nitrate (14). To a stirred
solution of the ionic liquid 8 (0.31 g, 1 mmol) in acetone (10 mL) was
added an aqueous solution of AgNO3 (0.2 g, 1.2 mmol), and the mixture
was stirred through 24 h at ambient temperature. A white AgCl
precipitate was filtered under reduced pressure. The filtrate was
concentrated, affording oil, which was heated to 70 °C through 30 min
on a vacuum pump to give the brownish yellow viscous liquid 14 (0.33
g, 100% yield); [R]D25 -16 (c 0.81 in CHCl3); nD30 ) 1.4903; IR (film)
cm-1 3450 (bw), 3138 (m), 3098 (m), 3044 (m), 2959 (m), 2934 (m),
2876 (m), 2833 (w), 1565 (m), 1468 (m), 1365 (s), 1345 (s), 1220 (w),
1165 (m), 1034 (w), 753 (m); 1H NMR (200 MHz; CDCl3), δ 0.73 (s,
3, CH3-C(6)), 0.80-1.00 (m, 3+1 N(C)-(CH2)3CH3, C(7)Hendo), 1.24
(s, 3, CH3-C(6)), 1.31 (septet, 2, J ) 7.5 Hz, N(C)-(CH2)2CH2CH3),
1.83 (quint, 2, J ) 7.5 Hz, N(C)-CH2CH2CH2CH3), 1.90-2.10 (m, 2,
C(1)H, C(5)H), 2.10-2.20 (br s, 2, C(4)H2), 2.25-2.50 (m, 1, C(7)-
(-)-1-[(1R)-Nopyl]-3-methylimidazolium Hexafluorophosphate
(11). To a stirred solution of the ionic liquid 7 (0.53 g, 2 mmol) in
water (3 mL) was added an aqueous solution of HPF6 (0.63 g, 2.6 mmol,
c ) 60%), and the mixture was stirred for 12 h at ambient temperature.
The resulting viscous mixture was washed with water (10 × 5 mL) to
gain the neutral pH and afforded a brownish yellow product 11 (0.49
g, 63% yield): [R]D -10 (c 1.94 in MeOH); IR (film) cm-1 3340
25
(bm), 3158 (m), 3118 (m), 2962 (m), 1703 (w), 1575 (w), 1169 (s),
1
1109 (m), 1042 (s), 1007 (s), 884 (m), 754 (m), 580 (m); H NMR
(200 MHz; CDCl3), δ 0.71 (s, 3, CH3-C(6)), 0.97 (d, 1, J ) 8.4 Hz,
C(7)Hendo), 1.22 (s, 3, CH3-C(6)), 2.00-2.06 (m, 2, C(1)H, C(5)H),
2.13 (br s, 2, C(4)H2), 2.28-2.38 (m, 1, C(7)Hexo), 2.48 (t, 2, J ) 7.0
Hz, CH2CH2-N(A)), 3.83 (s, 3, N(C)-CH3), 4.12 (t, 2, J ) 7.1 Hz,
CH2CH2-N(A)), 5.28 (br s, 1, C(3)H), 7.26 (br s, 2, C(D)H, C(E)H),
8.40 (br s, 1, C(B)H); 13C NMR (50 MHz, CDCl3), δ 20.91 (s, CH3-
C(6)), 25.90 (s, CH3-C(6)), 31.16 (s, C(4)), 31.51 (s, C(7)), 35.96 (s,
N(C)-CH3), 36.71 (s, CH2CH2-N(A)), 37.90 (s, C(6)), 40.37 (s, C(5)),
44.85 (s, C(1)), 47.86 (s, CH2CH2N(A)), 120.69 (s, C(3)), 122.15,
123.43 (2 × s, C(D)H, C(E)H), 135.62 (s, C(B)H), 142.25 (s, C(2)).
m/e (FAB(+), LSI, Cs+, 13 keV) calcd for C15H23N2 (M+): 231.1861.
Found: 231.1868. m/e (FAB(-), LSI, Cs+, 13 keV): 145 (PF6-, 100).
(-)-1-[(1R)-Nopyl]-3-n-butylimidazolium Hexafluorophosphate
(12). To a stirred solution of the ionic liquid 8 (0.86 g, 2.8 mmol) in
water (3 mL) was added an aqueous solution of HPF6 (0.88 g, 3.6 mmol,
c ) 60%), and the mixture was stirred through 12 h at ambient
temperature. The resulting viscous mixture was washed with water (10
× 5 mL) to neutral pH to afford a viscous brownish yellow liquid of
the product 12 (1.01 g, 87% yield): [R]D25 -9 (c 2.35 in MeOH); mp
64-67 °C (hygroscopic); IR (film) cm-1 3161 (w), 2962 (w), 2936
(w), 2877 (w), 1566 (w), 1463 (w), 1163 (w), 840 (s), 750 (w), 557
Hexo), 2.55 (m, 2, CH2CH2-N(A)), 4.15-4.35 (m, 4, CH2CH2-N(A),
N(C)-CH2(CH2)2CH3), 5.28 (s, 1, C(3)H), 7.25-7.45 (m, 2, C(D)H,
C(E)H), 9.74 (s, 1, C(B)H); 13C NMR (50 MHz, CDCl3), δ 13.30 (s,
N(C)-(CH2)3CH3), 19.30 (s, N(C)-(CH2)2CH2CH3), 20.91 (s, CH3-
C(6)), 26.03 (s, CH3-C(6)), 31.26, 31.67, 32.04 (3 × s, C(4), C(7),
N(C)-CH2CH2CH2CH3), 36.99 (s, CH2CH2-N(A)), 37.99 (s, C(6)),
40.43, 45.00 (2 × s, C(1), C(5)), 47.91, 49.74 (2 × s, CH2CH2-N(A),
N(C)-CH2(CH2)2CH3), 120.71 (s, C(3)), 121.89, 122.05 (2 × s, C(D)H,
C(E)H), 137.28 (s, C(B)H), 142.50 (s, C(2)). m/e (FAB(+), LSI, Cs+,
13 keV) 171 (54), 187 (37). Calcd for C18H29N2 (M+): 273.2331.
Found: 273.2323. m/e (FAB(-), LSI, Cs+, 13 keV) 397 (M+ + 2 ×
NO3-, 100).
(-)-1-[(1R)-Nopyl]-3-n-butylimidazolium Trifluoromethylosul-
fonate (15). To a stirred solution of the ionic liquid 8 (0.31 g, 1 mmol)
in acetone (10 mL) was added a solid AgCF3SO3 salt (0.31 g, 1.2
mmol), and the mixture was stirred through 24 h at ambient temperature.
A white precipitate of AgCl was filtered off under reduced pressure.
The filtrate was concentrated, affording oil, which was heated to 70
°C through 30 min on a vacuum pump to give the brownish yellow
1
25
(m); H NMR (200 MHz; CDCl3), δ 0.68 (s, 3, CH3-C(6)), 0.82-
viscous liquid 15 (0.26 g, 62% yield): [R]D -8 (c 0.83 in MeOH);
0.94 (m, 4, N(C)-(CH2)3CH3, C(7)Hendo), 1.19 (s, 3, CH3-C(6)), 1.15-
1.31 (m, 2, N(C)-(CH2)2CH2CH3), 1.54-1.84 (m, 2, N(C)-CH2CH2-
CH2CH3), 1.97-2.03 (m, 2, C(1)H, C(5)H), 2.09 (br s, 2, C(4)H2),
2.27-2.37 (m, 1, C(7)Hexo), 2.48 (m, 2, CH2CH2N(A)), 4.10 and 4.14
(2 × t, 4, J ) 6.9 Hz, J ) 7.2 Hz, CH2CH2-N(A), N(C)-CH2(CH2)2-
IR (film) cm-1 3492 (bw), 3145 (w), 3110 (w), 2963 (m), 2937 (m),
2878 (w), 1566 (w), 1462 (w), 1274 (s), 1258 (s), 1225 (s), 1163 (s),
1
1030 (s), 757 (w), 638 (s), 518 (w); H NMR (200 MHz; CDCl3), δ
0.74 (s, 3, CH3-C(6)), 0.80-1.15 (m, 3+1, N(C)-(CH2)3CH3, C(7)-
Hendo), 1.26 (s, 3, CH3-C(6)), 1.15-1.50 (m, 2, N(C)-(CH2)2CH2-

1884 J. Agric. Food Chem., Vol. 55, No. 5, 2007
Bałczewski et al.
CH3), 1.65-2.00 (m, 2, N(C)-CH2CH2CH2CH3), 2.00-2.10 (m, 2,
C(1)H, C(5)H), 2.10-2.25 (m, 2, C(4)H2), 2.25-2.50 (m, 1, C(7)-
exo), 2.50-2.65 (m, 2, CH2CH2-N(A)), 4.05-4.35 (m, 4, CH2CH2-
Mo KR radiation. Measured reflections were 33818 (θmax 38.0°) and
8931 independent (Rint 0.062).
H
Structure solution was determined via a direct method with aniso-
tropic refinement on F2 for all non H atoms; hydrogen atoms attached
to C atoms were included by using a riding model. The structure was
refined over 5900 reflections with I > 2σ (I) (202 refined parameters
with 29.2 reflections on parameter). The correct absolute structure was
proved by Flack parameter (22) x ) 0.02(6). For all data the final wR2
N(A), N(C)-CH2(CH2)2CH3), 5.33 (br s, 1, C(3)H), 7.30-7.35 (m, 2,
C(D)H, C(E)H), 9.07 (s, 1, C(B)H); 13C NMR (50 MHz, CDCl3), δ
13.25 (s, N(C)-(CH2)3CH3), 19.27 (s, N(C)-(CH2)2CH2CH3), 20.90
(s, CH3-C(6)), 25.98 (s, CH3-C(6)), 31.32, 31.87, 31.93 (3 × s, C(4),
C(7), N(C)-CH2CH2CH2CH3), 36.99 (s, CH2CH2-N(A)), 38.04 (s,
C(6)), 40.45, 45.02 (2 × s, C(1), C(5)), 47.96, 49.80 (2 × s, CH2CH2-
N(A), N(C)-CH2(CH2)2CH3), 120.18 (s, C(3)), 120.81 (q, J ) 318
Hz, CF3), 122.03, 122.21 (2 × s, C(D)H, C(E)H), 136.18 (s, C(B)H),
was 0.118, R1 ) 0.061, S ) 0.996, max ∆F ) 0.82 eÅ-3
.
Data processing was carried out with the Oxford Diffraction (23,
24), structure solution with SHELXS (25), and structure refinement
with SHELXL (26).
143.07 (s, C(2)); m/e (FAB(+), LSI, Cs+, 13 keV) 125 (26, M+
-
Nop + H). Calcd for C18H29N2 (M+): 273.2331. Found: 273.2324.
Full details (excluding the structure factors) for the structure have
been deposited at the Cambridge Crystallographic Data Center, as
supplementary publication CCDC-602211, and can be obtained free
of charge on application to CCDC, 12 Union Road, Cambridge
CB2 1EZ, United Kingdom (e-mail deposit@ccdc.cam.ac.uk).
Materials and Methods Used in Phytotoxicity Tests (21). The
phytotoxicity tests for ionic liquids 7 and 13 were carried out in a plant
house using spring barley (Hordeum Vulgare)sa monocotyledonous
plantsand common radish (Raphanus satiVus L. subvar. radicula
Pers.)sa dicotyledonous plant. In four repetitions, pots made of
nonporous plastic of a 90 mm diameter were filled, respectively, with
the control soil and with the soil containing tested ionic liquids in
relevant concentrations. The grain size analysis of the soil used in the
experiment showed that this was a light argillaceous sand containing
10% of flotable particles and 0.9% of organic carbon and having pH
(KCl) ) 5.8. The salinity of the soil was about 70 mg of KCl/1 dm3 of
the soil. Twenty identical seeds of the selected plant species, originating
from the same source, were planted to the prepared pots (Figures 4i
and 5i). Constant parameters such as humidity, light intensity, and
temperature (20 ( 2 °C) were maintained throughout the whole period
of the 14 day test.
The phytotoxicity test comprised two testing cycles: a preliminary
test and a final test. The preliminary test was carried out to determine
the range of concentrations of compounds affecting the soil quality;
therefore, in accordance with the standard, the tested ionic liquids 7
and 13 were introduced to the soil in the following concentrations: 0
mg (control) and 1, 10, 100, and 1000 mg/kg of the soil dry weight. In
the final test, concentrations were arranged in a geometric progression
with a factor of 2, starting from the lowest concentration that reduced
germination and growth of plants. This concentration was found to be
100 mg of the tested compounds per kilogram of the soil; therefore,
concentrations equal to 200, 400, and 800 mg/kg of the soil dry weight
were used in final tests. The ionic liquids were introduced to the soil
in the form of water solutions.
To evaluate the phytotoxicity of ionic liquids 7 and 13 in the applied
concentrations, the germination and (dry and fresh) weights of control
plant sprouts were determined and compared with germination and (dry
and fresh) weight of the sprouts of plants grown in the soil containing
the relevant amounts of the tested chemicals. Visual assessment of any
types of damages of the tested species, such as growth inhibition,
chlorosis, and necrosis, was also carried out and was depicted by digital
photographs of the tested plants. On the basis of the obtained results,
the magnitudes of the the lowest observed effect concentration
(LOEC)sthe lowest concentration causing observable effects in the
form of a reduction in growth and germination compared with the
controlsand the no observed effect concentration (NOEC)sthe highest
concentration not causing any observable toxic effectsswere also
determined.
m/e (FAB(-), LSI, Cs+, 13 keV) 149 (M-, 100).
(-)-1-[(1R)-Nopyl]-3-methylimidazolium (R)-Mandelate (16). To
a stirred solution of sodium salt of (-)-(R)-mandelic acid [obtained
from Na (0.034 g, 1.48 mmol) dissolved in methanol (10 mL) and (-)-
(R)-mandelic acid (0.225 g, 1.48 mmol)] was added the ionic liquid 7
(0.40 g, 1.48 mmol). The mixture was stirred for 24 h at ambient
temperature. Next, methanol was evaporated, acetone was added, and
a precipitate of NaCl was filtered off. The filtrate was evaporated to
25
afford the ionic liquid 16 (0.39 g, 70% yield): [R]D -39 (c 1.06 in
MeOH); IR (film) cm-1 3381 (bm), 3148 (m), 3086 (m), 3063 (m),
3030 (m), 2984 (m), 2914 (m), 2832 (m), 1614 (s), 1574 (m), 1451
(m), 1431 (m), 1364 (s), 1169 (m), 1086 (m), 1057 (m), 737 (m), 700
1
(m), 622 (w); H NMR (200 MHz; CDCl3), δ 0.70 (s, 3, CH3-C(6)),
0.94 (d, 2, J ) 8.6 Hz, C(7)Hendo), 1.21 (s, 3, CH3-C(6)), 1.80-2.10
(m, 2, C(1)H, C(5)H), 2.11 (br s, 2, C(4)H2), 2.15-2.50 (m, 3, C(7)-
Hegzo, CH2CH2N(A)), 3.74 (s, 3, N(C)-CH3), 3.95-4.25 (m, 2,
CH2CH2N(A)), 4.48 (br s, 1, OH), 4.79 (s, 1, CH-COO-), 5.26 (s, 1,
C(3)H), 6.80-7.30 (m, 5, C6H5), 7.41, 7.45 (2 × s, 2, C(D)H, C(E)H),
10.01 (s, 1,C(B)H); 13C NMR (50 MHz, CDCl3), δ 20.86 (s, CH3-
C(6)), 25.99 (s, CH3-C(6)), 31.16 (s, C(4)), 31.52 (s, C(7)), 35.97 (s,
C(6)), 36.90 (s, N(C)-CH3), 37.91 (s, CH2CH2N(A)), 40.43 (s, C(5)),
45.09 (s, C(1)), 47.61 (s, CH2CH2N(A)), 74.50 (s, CH-OH), 120.45,
121.39, 122.83 (3 × s, C(3), C(D), C(E)), 126.30 (s, Arpara), 126.48,
127.58 (2 × s, Arortho, Armeta), 138.45 (s, C(B)), 142.36, 143.58 (2 ×
s, C(2), Ar-C), 176.82 (s, COO-). m/e (FAB(+), LSI, Cs+, 13 keV)
calcd for C15H23N2 (M+): 231.1861. Found: 231.1868. m/e (FAB(-),
LSI, Cs+, 13 keV) calcd for C8H7O3 (Migd-): 151.0395. Found
151.0397.
(+)-1-[(1R)-Nopyl]-3-methylimidazolium (S)-Mandelate (17). The
procedure used was analogous to that decribed for 16 except that (+)-
S-mandelic acid was used: yield (0.33 g, 86%); [R]D25 +14 (c 0.86 in
MeOH); IR (film) cm-1 3347 (bm), 3146 (m), 3084 (m), 3062 (m),
3029 (m), 2983 (m), 2915 (s), 2832 (m), 1618 (s), 1573 (m), 1451
(m), 1431 (m), 1358 (s), 1170 (m), 1085 (m), 1055 (m), 737 (m), 701
(m); 1H NMR (200 MHz; CDCl3), δ 0.74 (s, 3, CH3-C(6)), 0.98 (d, 1,
J ) 8.6 Hz, C(7)Hendo), 1.25 (s, 3, CH3-C(6)), 1.95-2.10 (m, 2, C(1)H,
C(5)H), 2.15 (br s, 2, C(4)H2), 2.25-2. (m, 3,C(7)Hegzo, CH2CH2N-
(A)), 3.80 (s, 3, N(C)-CH3), 4.11 (m, 2, CH2CH2N(A)), 4.64 (br s, 1,
OH), 4.85 (s, 1, CH-COO-), 5.26 (s, 1, C(3)H), 7.00-7.30 (m, 5,
C6H5), 7.47, 7.50 (2 × s, 2, C(D)H, C(E)H), 10.17 (s, 1, C(B)H); 13C
NMR (50 MHz, CDCl3), δ 20.87 (s, CH3-C(6)), 26.00 (s, CH3-C(6)),
31.18 (s, C(4)), 31.53 (s, C(7)), 35.98 (s, C(6)), 36.90 (s, N(C)-CH3),
37.93 (s, CH2CH2N(A)), 40.44 (s, C(5)), 45.11 (s, C(1)), 47.64 (s,
CH2CH2N(A)), 74.47 (s, CH-OH), 120.47, 121.41, 122.82 (3 × s,
C(3), C(D), C(E)), 126.38 (s, Arpara), 126.50, 127.62 (2 × s, Arortho
,
Armeta), 138.35 (s, C(B)), 142.37, 143.44 (2 × s, C(2), Ar-C), 176.88
(s, COO-). m/e (FAB(+), LSI, Cs+, 13 keV) calcd for C15H23N2 (M+):
231.1861. Found: 231.1861. m/e (FAB(-), LSI, Cs+, 13 keV) calcd
for C8H7O3 (Migd-): 151.0395. Found 151.0400.
Evaluation of the significance of the obtained results was performed
using the analysis of variance (Fisher-Snedecor’s F test), whereas the
values of LSD0.95 were calculated using Tukey’s test.
Crystallographic Data for (1R)-(-)-6,6-Dimethylbicyclo[3.1.1]-
hept-2-ene-2-ethyl-N-methyl-3-H-imidazol-1-ium Toluene-4-sul-
fonate (4): C18H24O3S, colorless, needle 0.56 × 0.11 × 0.05 mm from
chloroform, orthorhombic, space group P212121, a ) 6.062(2)Å, b )
14.896(4)Å, c ) 18.347(5)Å, V ) 1656.7(8)Å3, Mr ) 320.44, Z ) 4,
dcalcd ) 1.285 g/cm3, µ ) 0.206 mm-1, T ) 90(2) K, F(000) ) 688.
RESULTS AND DISCUSSION
Synthesis and Properties of New Chiral Ionic Liquids. In
the course of our studies on the synthesis, properties, and
application of chiral ionic liquids, we synthesized a new series
of these compounds based on imidazolium cation containing
Data collection was performed with an Xcalibur PX CCD κ-geom-
etry (Oxford Diffraction) diffractometer with graphite monochromatized

Ionic Liquids
J. Agric. Food Chem., Vol. 55, No. 5, 2007 1885
−)-(1R)-Nopyl Chloride 2, Bromide 3, and Tosylate 4; Quaternization of 1-Alkylimidazoles 5 and 6
Scheme 1. Synthesis of (
Scheme 2. Synthesis of Ionic Liquids from Chlorides 7 and 8 via the Anion Exchange Reaction
the (-)-(1R)-6,6-dimethylbicyclo[3.1.1]hept-2-ene-2-ethyl [(-)-
(1R)-nopyl] moiety.
Further ionic liquids 13-17 were obtained from 7 or 8 via
the anion exchange reactions with silver (NO3-, CF3SO3-) and
sodium salts [(+)-(S)- and (-)-(R)-mandelates] as well as with
60% solution of HPF6 (PF6-) in overall 62-100% yields
(Scheme 2).
The starting materials were 1-alkylimidazoles 5 (R ) Me),
6 (R ) Bun), and (-)-(1R)-nopol (1), which was converted to
the corresponding chloride 2 and tosylate 4 in 85 and 88%
yields, respectively. The bromide 3 was synthesized from the
tosylate 4 in 30% yield (Scheme 1).
All new compounds 7-17, with the exception of 8, were
yellow or yellow-brownish viscous liquids. The compound 8
was a hygroscopic beige solid with mp 64-67 °C. The
remaining ionic liquids contained some small amount of water,
which could be removed at elevated temperatures under vacuum
or atmospheric pressure. For instance, 7 lost water within 30
min at 100 °C (atmospheric pressure) as determined by 1H NMR
monitoring.
In particular, (-)-(1R)-nopyl chloride 2 was obtained as a
very pure product according to the modified literature workup
without requiring distillation (14). Both the chloride 2 and the
bromide 3 turned out to be stable liquids for at least half a year
at 5 °C. Only the tosylate 4 was a solid, which enabled the
X-ray analysis. All starting materials 2-4 were quaternized with
1-alkylimidazoles 5 and 6, leading to the formation of the
corresponding ionic liquids 7-10 in 63-94% yields. The
bromide 3 was more reactive than the chloride 2. Thus, at room
temperature the ratio of 9 to 5 continuously increased from 1:3
and 1:5 to 9:10 after 24 h, 48 h, and 10 days, respectively, but
only at 50 °C/66 h was the imidazole 5 totally consumed. In
contrast, no traces of the product 7 were obtained at 25 °C/8
days, 60 °C/54 h, and 70 °C/31 h; only at 90 °C/29 h was the
majority of the chloride 2 consumed.
The latter was thermally stable up to 150 °C (first 100 °C/30
min and then 150 °C/30 min). Decomposition of 7 began at
1
200 °C after 30 min as deteremined by H NMR spectra (15).
Other properties of the obtained ionic liquid are reported in
Tables 1 and 2. Table 1 shows viscosities of selected ionic
liquids as a function of temperature. In comparison to polyeth-
ylene glycol (PEG 400), the values of viscosities were rather
high, but they decreased rapidly upon warming by 15-20 °C,

1886 J. Agric. Food Chem., Vol. 55, No. 5, 2007
Bałczewski et al.
Scheme 3. 1H 13C NMR (HMQC) Correlation for 10
−
Table 1. Viscositiesa of the Selected Ionic Liquids Measured with a
Brookfield DV-II+ Viscometer
η
(mPa
‚
s) at
45
675
510
349
compd
30
°
C
35
°
C
40
°
C
°
C
50
°
C
55 °C
7
9
10
12
16
2700
1600
1160
5441
8600
74
1570
1100
755
3510
4700
60
1037
770
500
470
353
250
1108
1020
34
333
255
186
800
654
29
2345
2650
49
1588
1600
40.5
PEG 400
a η was measured after storage of samples under vacuum.
Table 2. Miscibilitya with Water and Organic Solvents
ionic liquid
H2O
AcOEt
CHCl3
acetone
7
9
8
10
11
12
14
15
16
17
+
+
+
−
−
−
+
−
+
±
−
−
−
+
+
+
-
±
±
±
+
+
+
+
±
±
+
+
+
+
+
+
+
+
+
+
+
+
+
+
literature (14), we decided to carry out a full spectroscopic
analysis of this rigid structure. This analysis was done on the
basis of correlation spectra and similarity of the signal pattern
in the range of 0.5-2.5 ppm of the 2 and 4 spectra as well as
the X-ray analysis of the latter. In the COSY (1H-1H) spectrum
of 4, the 4.01 ppm triplet corresponding to the CH2CH2O group
was coupled with the 2.25-2.38 ppm multiplet, of which
integration indicated one additional proton (vide infra). A very
clear HMQC (1H-13C) spectrum of 3 showed that this 1H NMR
multiplet was coupled with two peaks in the 13C NMR spectrum
at δ ) 31.5 and 40.0. The latter peak could be assigned to the
CH2CH2O carbon.
a
+, miscible;
−, immiscible;
±
, partially miscible.
enabling stirring. Application at low temperatures required
dilution with classical solvents or with ionic liquids of lower
viscosity.
Analysis of Table 1 shows that all ionic liquids are miscible
with acetone and chloroform with the exception of two
hydrophobic ionic liquids 11 and 12 containing the PF6- anion,
which are partly miscible with chloroform. Three ionic liquids,
7, 8, and 14, containing Cl- and NO3 anions were simulta-
A DEPT spectrum of 4 showed that the 31.5 ppm peak
corresponded to a secondary carbon, which meant that there
should be another group of signals belonging to the second
proton bound to this carbon. It was well illustrated with the
HMQC (1H-13C) spectrum of 2. In this spectrum, the corre-
sponding signal at δ ) 31.6 was coupled with two groups of
1H NMR signals: the 2.25-2.40 multiplet mentioned earlier
for 4 and a one-proton doublet at δ ) 1.16. A very large
difference of these chemical shifts might indicate two geminal
protons of the 7CH2 group of a sterically restrained cyclobutane
ring in the nopyl moiety. A lack of visible couplings of the
latter with 1CH and 5CH methine protons meant that a dihedral
angle between a 7C-H proton and 1C-H or 5C-H bonds was
close to 90° (proton endo). Due to the rigidity of the bicyclo
nopyl moiety, preserved both in liquid and in solid, this finding
might be compared with the dihedral angles calculated from
the X-ray analysis of 4 (vide infra). The corresponding torsion
angles θ ) 99° for H-5C-7C-Hendo and θ ) -99° for H-1C-
7C-Hendo were in good agreement with those obtained from
-
neously miscible with water and chloroform and immiscible with
ethyl acetate, which was utilized in purification and product
separation techniques. Unreacted reagents and nonionic byprod-
ucts were, for instance, removed with ethyl acetate during the
purification of 7 and 8 (Materials and Methods). Simultaneous
miscibility with water and chloroform may be also utilized in
the application of these ionic liquids in enantioselective phase
transfer catalysis reactions.
Spectroscopic Analysis. In-depth NMR studies of the starting
2-4 and the obtained ionic liquids were carried out for a detailed
analysis of the (-)-(1R)-nopyl framework, which was not solved
unambigously in the literature, at least for (-)-(1R)-nopyl
chloride (2) (14). At the outset 1H NMR (200 MHz) spectra of
the obtained ionic liquids showed that H-1 and H-5 methine
protons of the (-)-(1R)-nopyl moiety in 7 were shielded almost
identically and resonated at δH ) 1.96-2.01. Locations of H-7
axial and H-7 equatorial methylene protons were much more
differentiated (δH ) 1.36). On the other hand, the H-4
pseudoaxial and H-4 pseudoequatorial protons of the second
methylene group in the nopyl ring did not show such a great
differentiation and resonated at δH ) 2.10, appearing in the
spectrum as a broad singlet. It was also noteworthy that signals
of N+dCH protons were shifted downfield (δH ) 10.32, 10.37)
in a series of the chloride ion containing ionic liquids (7 and 8)
and upfield (δH ) 8.40, 8.47) in the PF6 series (11 and 12).
Moreover, in the latter, signals of N+sCHdCHsN protons
were indistinguishable singlets at δH ) 7.26 and 7.29, respec-
tively.
1
NMR. Two multiplets in the H NMR spectrum of 4 at δ )
1
5
1.92 and 2.04 corresponded to CH and CH methine protons,
respectively, on the basis of the finding that the first multiplet
did not correlate (1H-13C/COSY) with the 2.17 ppm AB system
of the 4CH2 methylene group, whereas the second one correlated
very strongly.
Similar relationships were found for the (-)-(1R)-nopyl
moiety in ionic liquids on the basis of the similarity of the
1
corresponding signal patterns. The example of H-13C NMR
correlation for the ionic liquid 10 is shown in Scheme 3. None
of the obtained ionic liquids could be X-ray analyzed due to
the reasons below.
Because unambiguous assignment of some 13C NMR reso-
nances in the (-)-(1R)-nopyl moiety in 2 was not done in the

Ionic Liquids
J. Agric. Food Chem., Vol. 55, No. 5, 2007 1887
Figure 1. Molecular structure of 4, showing 50% probability ellipsoids.
Table 3. Selected Geometric Parameters (Ångstroms, Degrees) in 4
S1
−
O1
O2
1.5728 (11)
1.4253 (12)
S1
−
C12
O3
1.4282 (12)
1.7572 (16)
S1
−
S1−
O2
O2
O3
O1
−
S1
S1
S1
S1
−
−
−
−
O1
O3
O1
C12
109.64 (7)
119.49 (7)
104.00 (7)
104.43 (7)
O2
−
S1-C12
108.87 (7)
109.33 (7)
118.63 (9)
−
−
−
O3−S1−C12
C11
−
O1−
S1
S1
C11
−
O1-S1
−
O2
44.12 (12)
C11
−
O1−
−C12
−72.39 (12)
C11
−
O1 S1
−
−O3
173.00 (10)
Figure 3. Packing of molecules of 4 in the unit cell.
Scheme 4. Model Diels−Alder Reaction of Cyclopentadiene with Ethyl
Acrylate
X-ray Analysis of (-)-(1R)-Nopyl Tosylate (4). The tosylate
4, as the only solid among the starting materials, was synthesized
for full NMR resolution of the rigid nopyl moiety based on
comparison of dihedral angles obtained from NMR and X-ray
analyses. It is worth noting that the ionic liquid 8 was the only
solid among the obtained ionic liquids; however, it was too
hygroscopic to give suitable crystals for X-ray analysis.
Table 4. Diels
in the Molar Ratio 2:1
−Alder Reaction of Cyclopentadiene with Ethyl Acrylate
The molecular structure of 4 is shown in Figure 1, and
selected geometric parameters are given in Table 3.
The SsC, SsO, and SdO bond lengths were close to
standard values. The configuration at the C1 atom was R. The
six-membered rings C1, C2, C3, C4, C5, and C6 and C1, C2,
C3, C4, C5, and C7 had envelope conformations. Atoms C6
and C7 deviated from the plane of C1, C2, C3, C4, and C5 by
-1.067(2) and 1.088(2), respectively. The puckering angle for
the four-membered ring was 139.7(1)° and was already observed
in ref 16.
Figure 2 shows a Newman projection along the S-O1 bond,
taking C11 as reference. The C12-S1-O1-C11 torsion angle
was -72.39(12)°, which corresponded to a synclinal conforma-
tion. Such a situation was also observed for aromatic sulfonates
(17). Packing in the unit cell is shown in Figure 3.
ionic liquid/
solvent system, ratio
time
(h)
temperature
C)
entry
(°
endo/exoa
1
2
3
7/CH2Cl2, 1.1:1
7/CH2Cl2, 1.1:1
MIMBF4 only
2.5
24
24
24
1.5
26
24
24
2.5
24
25
25
23
23
25
25
0
0
45
0
25
0
35
0
0
0
3.7
3.7
4.1
5.1
3.9
4.2
3.8
4.1
3.5
4.0
3.6
3.4
2.9
2.7
4
7/MIMBF4,b 1:4.1
7/CH2Cl2, 1.8:1
7/CH2Cl2, 1.8:1
CH2Cl2 only
5c
6
7
8
9
10
11
12
13
14
CH2Cl2 only
CH2Cl2 only
16/CH2Cl2, 1:1.3
16/THF, 1.2:1
16/C6H6, 1.2:1
17/CH2Cl2, 1:1.3
17/C6H6, 1.1:1
0
0
Application of New Chiral Ionic Liquids. The synthesized
ionic liquids 7, 16, and 17 were employed in the model Diels-
Alder reaction of ethyl acrylate and cyclopentadiene (18) used
in a ratio of 1:2, respectively (Scheme 4). The electron-rich
double bond in the (-)-(1R)-nopyl moiety is unreactive in this
reaction, and we expected a good endo/exo selectivity at low
temperature, assuming the donor (dien)-acceptor (dienophile)-
donor (ionic liquid) model involving electron-rich and electron-
deficient double bonds of cyclopentadiene, acrylate, and chiral
ionic liquid in a highly ordered self-organized transition state.
a Ratios obtained after deconvolution of signals due to endo/exo isomers at
3.20/3.0318 b N-Methylimidazolium tetrafluoroborate (MIMBF4). c Experiment
carried out with evaporation of CH2Cl2 during the reaction.
δ
)
.
This model might be supported by a Lewis acid type complex-
ation and hydrogen bonding involving the OH group of the
mandelates.
Depending on temperature (0-45 °C) and the solvent system
used, the endo/exo ratios oscillated around 3.6/1 and were
similar to those obtained in classical organic solvents or water
(18-20) (Table 4). The best ratio of 5.1/1 was obtained in a
mixture of the chiral 7 and achiral MIMBF4 ionic liquids at 0
°C (entry 4, Table 4). The interesting result was an observation
of a measurable difference in endo/exo ratios for reactions
carried out in the (R)-mandelate 16 versus the (S)-mandelate
17 at 0 °C (1.4-fold increase), showing a certain modest
contribution of complexation, hydrogen bonding, and the chiral
environment of ionic liquid in the transient electron donor-
Figure 2. Newman projection along the S−O1 bond in 4.

1888 J. Agric. Food Chem., Vol. 55, No. 5, 2007
Bałczewski et al.
Table 5. Changes in Basic Parameters of the Phytotoxicity Test for Spring Barley Following the Introduction of 7 (in Milligrams per Kilogram of Soil
Dry Weight) to the Soil
no. of
seeds
planted
% germination
relative to
control
crop
fresh wt
(g/pot)
% crop
relative
to control
mean wt of
single plant
(g)
% of single
plant wt relative
to control
dry wt
(mg/g of
fresh wt)
% dry wt
relative to
control
no. of
plants
sample
Preliminary Test
0, control
1
10
100
20
20
20
20
20
18
18
19
18
16
100
100
106
100
89
2.017
100
100
113
80
0.114
0.112
0.120
0.090
0.020
100
98
105
79
0.0819
0.0806
0.0819
0.0934
0.1519
100
98
100
114
185
2.014
2.270
1.606
0.324
1000
16
18
Final Test
200
400
800
20
20
20
18
18
16
100
100
89
1.485
0.926
0.461
74
46
23
0.084
0.053
0.028
74
46
25
0.1003
0.1161
0.1403
122
142
171
LSD0.95
)
1
LSD0.95
)
0.285
LSD0.95
)
0.009
LSD0.95
)
0.0022
Table 6. Changes in Basic Parameters of the Phytotoxicity Test for Common Radish Following the Introduction of 7 (in Milligrams per Kilogram of
Soil Dry Weight) to the Soil
no. of
seeds
planted
% germination
relative to
control
crop
fresh wt
(g/pot)
% crop
relative
to control
mean wt of
single plant
(g)
% of single
plant wt relative
to control
dry wt
(mg/g of
fresh wt)
% dry wt
relative to
control
no. of
plants
sample
Preliminary Test
0, control
1
10
100
20
20
20
20
20
18
18
18
17
5
100
100
100
94
2.571
100
105
96
0.146
0.148
0.140
0.133
100
102
96
0.0617
0.0600
0.0619
0.0698
100
97
100
113
2.721
2.464
2.036
79
91
1000
28
Final Test
200
400
800
20
20
20
15
12
10
83
67
56
1.066
0.487
41
19
0.070
0.039
48
27
0.1005
0.1555
163
252
LSD0.95
)
2
LSD0.95
)
0.261
LSD0.95
)
0.013
LSD0.95
)
0.0067
Table 7. Changes in Basic Parameters of the Phytotoxicity Test for Spring Barley Following the Introduction of 13 (in Milligrams per Kilogram of Soil
Dry Weight) to the Soil
no. of
seeds
planted
% germination
relative to
control
crop
fresh wt
(g/pot)
% crop
relative
to control
mean wt of
single plant
(g)
% of single
plant wt relative
to control
dry wt
(mg/g of
fresh wt)
% dry wt
relative to
control
no. of
plants
sample
Preliminary Test
0, control
1
10
100
20
20
20
20
20
18
19
18
18
19
100
106
100
100
106
1.793
100
113
104
87
0.102
0.106
0.104
0.085
0.029
100
105
103
84
0.0805
0.0805
0.0806
0.0950
0.1234
100
100
100
118
185
2.023
1.870
1.566
0.556
1000
31
28
Final Test
200
400
800
20
20
20
20
19
19
111
106
106
1.361
0.980
0.638
76
55
36
0.069
0.052
0.033
68
52
33
0.1019
0.1102
0.1214
127
137
151
LSD0.95
)
1
LSD0.95
)
0.115
LSD0.95
)
0.006
LSD0.95
)
0.0013
acceptor-donor model. The Diels-Alder reaction performed
in the system of 7/CH2Cl2 (1.8/1) did not occur at -28 °C within
2.5 days.
with control soil. Optimum conditions for growth and develop-
ment of the selected plant species were maintained for the
duration of the experiment.
Effect of Selected Ionic Liquids 7 (Chloride) and 13
(Nitrate) on Germination and Growth of Superior Plants.
Phytotoxicity Test. The influence of selected ionic liquids 7
(chloride) and 13 (nitrate) introduced to the soil on germination
and early stages of growth and development of superior plants
was investigated using the phytotoxicity test based on the ISO-
11269-2:1995 International Standard (21). In this test, the seeds
of selected species of land superior plants [spring barley
(Hordeum Vulgare) and common radish (Raphanus satiVus L.
subvar. radicula Pers.] were planted in pots containing soil to
which a test chemical compound had been added and in pots
The ionic liquids were introduced to the soil in the form of
water solution in the following concentrations: 0, 1, 10, 100,
and 1000 mg/kg of the soil dry weight in a preliminary test
and also in concentrations of 200, 400, and 800 mg/kg of the
soil dry weight in the final test.
The obtained results concerning the effect of ionic liquids 7
and 13 on the germination and growth of spring barley and
common radish at early stages are shown in Tables 5-8 and
in Figures 4 and 5 (see also the Supporting Information).
Preliminary tests showed that ionic liquids used in concentra-
tions of 1 and 10 mg/kg of the soil dry weight did not have any

Ionic Liquids
J. Agric. Food Chem., Vol. 55, No. 5, 2007 1889
Table 8. Changes in Basic Parameters of the Phytotoxicity Test for Common Radish Following the Introduction of 13 (in Milligrams per Kilogram of
Soil Dry Weight) to the Soil
no. of
seeds
planted
% germination
relative to
control
crop
fresh wt
(g/pot)
% crop
relative
to control
mean wt of
single plant
(g)
% of single
plant wt relative
to control
dry wt
(mg/g of
fresh wt)
% dry wt
relative to
control
no. of
plants
sample
Preliminary Test
0, control
1
10
100
20
20
20
20
20
18
18
18
19
15
100
100
100
106
83
3.091
100
108
91
0.170
0.182
0.155
0.101
100
107
91
0.0698
0.0651
0.0686
0.0930
100
93
98
3.346
2.825
1.877
61
59
133
1000
Final Test
200
400
800
20
20
20
19
17
15
106
94
83
1.340
1.098
43
19
0.072
0.066
42
37
0.1044
0.1498
150
215
LSD0.95
)
2
LSD0.95
)
0.469
LSD0.95
)
0.016
LSD0.95
)
0.0055
significant effect on the germination and growth of either plant
tested, which was indicated by the percentage of germination,
the magnitude of fresh and dry weight of sprouts, and the crop
fresh weight calculated per plant (Tables 5-8). This observation
was in accordance with the standard for tested substances that
were considered to be nontoxic, if the rate of germinated seeds
and the overall fresh weight of the plants differed by not more
than (10% compared to the control sample. Also, in the case
of the visual assessment, no visible differences in the appearance
of the plants were observed for the above concentrations
compared to the control objects; that is, no growth inhibition
or chlorotic and necrotic changes were found (Figures 4 and
5). The early signs of a potential toxicity of the ionic liquid 7
(chloride) could be observed after application of 100 mg of the
tested substance per kilogram of soil, which was reflected chiefly
by a drop in the fresh weight of sprouts of approximately 20%
for spring barley and 22% for common radish. The ionic liquid
13 (nitrate), applied in the identical concentration, also brought
about reductions in the crop of the experimental plants by
approximately 13 and 39% for barley and radish, respectively,
compared with the control. Similar correlations could be found
when the effect of the tested substances, applied in a concentra-
tion of 100 mg/kg of soil, on the crop fresh weight per plant
was analyzed. At the same time, neither changes in the
appearance of the plants nor differences in their germinations
were found at this concentration of the ionic liquids. The highest
of the applied concentrationss1000 mg/kg of the soil dry
weightsturned out to be highly toxic for both experimental
plants, which was evidenced by substantial changes in all
phytotoxicity test parameters discussed and by the presented
digital photos of barley and radish plants (Tables 5-8; Figures
4 and 5; Supporting Information).
Figure 4. Digital photographs of common radish on the 14th day (a−h) after introducing to the soil specific amounts of 7 (in mg/kg of soil dry weight);
(i) planted radish seeds, the 1st day.

1890 J. Agric. Food Chem., Vol. 55, No. 5, 2007
Bałczewski et al.
Figure 5. Digital photographs of spring barley on the 14th day (a−h) after introducing to the soil specific amounts of 13 (in mg/kg of soil dry weight);
(i) planted barley seeds, the 1st day.
The results obtained from the preliminary tests were con-
firmed by independently performed final tests. Increasing the
concentration of ionic liquids 7 and 13 to 200, 400, and 800
mg per kilogram of the soil dry weight resulted in a systematic
decrease in the crop fresh weight of total sprouts and the crop
fresh weight per plant as well as a large increase in dry weight,
both for spring barley and for common radish. The observed
changes were greater when a higher concentration of the
chemical compounds was applied (Tables 5-8). Moreover, in
the case of the dicotyledonous plant, a constant drop in plant
germinations was also found, which was much greater upon
application of 7 (chloride). The ionic liquid 13 (nitrate) gave a
slight decrease in germination of radish, whereas no differences
in plant germination between the control and tested objects were
observed for spring barley. Starting from the concentration equal
to 200 mg of tested substance per kilogram of soil, a progressive
inhibition of growth and permanent damage to the plants could
be seen, which was particularly noticeable on radish plants
(Figures 4 and 5).
barley is a more resistant plant which fairly well tolerates test
ionic liquid concentrations of up to 200 mg/kg of soil, whereas,
for radish, the growth and development inhibiting concentration
is 100 mg/kg of the soil dry weight. The ionic liquid, applied
in the form of nitrate salt, did not exhibit an inhibiting effect
on the germination ability of seeds.
Phytotoxicity Test for N-Methylimidazole 5. It was inter-
esting to compare the phytotoxicity of N-methylimidazole 5 used
as a common substrate in syntheses of ionic liquids with the
phytotoxicity of ionic liquids 7 and 13 as well as to evaluate
the phytotoxicities of this compound itself and ionic liquids
contaminated by the unreacted substrate.
In pot experiments carried out according to the phytotoxicity
test based on the ISO-11269-2:1995 International Standard (21),
it was found that N-methylimidazole 5 applied in high concen-
tration (1000 mg/kg of soil dry weight) considerably inhibited
the growth and germination of higher plants. Lower concentra-
tions (1 and 10 mg/kg of soil dry weight) did not cause any
changes in basic phytotoxicity test parameters and did not
influence the appearance of tested plants (Figures 6 and 7;
Tables 9 and 10).
On the basis of the obtained results one can state that both
ionic liquids 7 and 13 are chemical compounds showing
potential toxicity, with the toxic effect being dependent chiefly
on the applied concentration. The highest concentration of the
compounds tested, which did not cause a distinct reduction in
the plant germination and growth (NOEC), was estimated at a
level of 10 mg/kg of the soil dry weight, whereas the lowest
concentration causing a reduction in plant growth/germination
(LOEC) was 100 mg of the respective substance per kilogram
of the soil dry weight. From an analysis of the variation in all
phytotoxicity parameters, it can also be noted that common
In conclusion, the phytotoxicity of N-methylimidazole 5 is
comparable with the phytotoxicity of tested ionic liquids 7 and
13.
In the context of a limited literature concerning the synthesis
and application of chiral ionic liquids, we synthesized new ionic
liquids with chiral anion and/or chiral cation incorporating the
(-)-(1R)-nopyl moiety from the chiral pool. A combination of
the solution NMR studies with X-ray analysis allowed a full
NMR resolution of this rigid bicyclic structure. A nonreacting

Ionic Liquids
J. Agric. Food Chem., Vol. 55, No. 5, 2007 1891
Figure 6. Digital photographs of common radish seedlings on the 14th day (a−e) after introducing to the soil specific amounts of N-methylimidazole (in
mg/kg of soil dry weight).
Figure 7. Digital photographs of spring barley seedlings on the 14th day (a−e) after introducing to the soil specific amounts of N-methylimidazole (in
mg/kg of soil dry weight).
Table 9. Changes in Basic Parameters of the Phytotoxicity Preliminary Test for Spring Barley Following the Introduction of N-Methylimidazole (in
Milligrams per Kilogram of Soil Dry Weight) to the Soil
no. of
seeds
planted
% germination
relative to
control
crop
fresh wt
(g/pot)
% crop
relative
to control
mean wt of
single plant
(g)
% of single
plant wt relative
to control
dry wt
(mg/g of
fresh wt)
% dry wt
relative to
control
no. of
plants
sample
0, control
1
10
100
1000
20
20
20
20
20
19
18
20
19
18
100
95
105
100
95
1.956
1.789
1.993
1.886
0.160
100
91
102
96
0.103
0.099
0.100
0.102
0.009
100
97
97
99
9
0.0804
0.0763
0.0791
0.0803
0.1287
100
94
98
100
160
8
LSD0.95
)
1
LSD0.95
)
0.078
LSD0.95
)
0.004
LSD0.95
)
0.0073
Table 10. Changes in Basic Parameters of the Phytotoxicity Preliminary Test for Common Radish Following the Introduction of N-Methylimidazole (in
Milligrams per Kilogram of Soil Dry Weight) to the Soil
no. of
seeds
planted
% germination
relative to
control
crop
fresh wt
(g/pot)
% crop
relative
to control
mean wt of
single plant
(g)
% of single
plant wt relative
to control
dry wt
(mg/g of
fresh wt)
% dry wt
relative to
control
no. of
plants
sample
0, control
1
10
100
1000
20
20
20
20
20
18
18
19
18
11
100
100
105
100
61
2.369
2.584
2.260
1.996
0.537
100
109
95
84
23
0.136
0.140
0.119
0.111
0.049
100
103
87
82
35
0.0816
0.0818
0.0825
0.0862
0.2286
100
100
101
106
280
LSD0.95
)
2
LSD0.95
)
0.171
LSD0.95
)
0.007
LSD0.95
)
0.0046
double bond of the nopyl moiety in a sense of the Diels-Alder
reaction was introduced to structures of ionic liquids in order
to check the sandwich electron acceptor-donor model of this
reaction including electron-rich and electron-deficient double
bonds and chiral environment of the ionic liquid. To our
knowledge, this is the first such reaction performed in both
diastereomeric ionic liquids including R- and S-mandelate
anions.

1892 J. Agric. Food Chem., Vol. 55, No. 5, 2007
Bałczewski et al.
(11) Baudequin, C.; Baudoux, J.; Levillain, J.; Cahard, D.; Gaumont,
A.-C.; Plaquevent, J.-C. Ionic liquids and chirality: opportunities
and challenges. Tetrahedron: Asymmetry 2003, 14, 3081-3093
and refs cited therein.
(12) Ge´nisson, Y.; Lauth-de, V. N.; Andre, C.; Baltas, M.; Gorrichon,
L. New chiral imidazolinic derivatives. Tetrahedron: Asymmetry
2005, 16, 1017-1023.
(13) Clavier, H.; Coutable, L.; Guillemin, J.-C.; Mauduit, M. New
bidentate alkoxy-NHC ligands for enantioselective copper-
catalysed conjugate addition. Tetrahedron: Asymmetry 2005, 16,
921-924.
(14) Abraham, R. J.; Jones-Parry, R.; Giddings, R. M.; Guy, J.;
Whittaker, D. 3-Acetoxy-6,6-dimethylbicyclo[3.1.1]heptane-2-
spiro-1-cyclopropane from nopylamine deamination. J. Chem.
Soc., Perkin Trans. 1 1998, 643-646.
In light of the introduction for the first time to industrial
processes of bulky amounts of ionic liquids, we noted a necessity
to check the phyto(eco)toxicity of not only the obtained chiral
ionic liquids but also N-methylimidazole, which was a common
starting material in the syntheses of all imidazole-based ionic
liquids. We revealed their substantial toxicity to plants and soil
depending on the applied concentrations and type of plant
(monocotyledonous, >200 mg; and dicotyledonous, >100 mg/
kg of the soil dry weight), which should be seriously taken into
account by industry and environmenta; protection agencies in
case of possible environment pollution. Our results call attention
to the necessity for further investigations on the influence of
the ionic liquids, the starting materials used in their syntheses,
and the biodegradation products on various elements of eco-
systems.
(15) Baranyai, K. J.; Deacon, G. B.; MacFarlane, D. R.; Pringle, J.
M.; Scott, J. L. Thermal degradation of ionic liquids at elevated
temperatures. Aust. J. Chem. 2004, 57, 145-147.
(16) Begley, M. J.; Gill, G. B.; Wallace, B. X-Ray structure analysis
of the tosylate ester of (1S,5S)-6,6-dimethyl-2-[(2S)-3,3,3-
trichloro-2-hydroxypropyl]bicyclo[3.1.1]hept-2-ene, the major
product of the iron(III) chloride-catalysed ene addition of chloral
to (-)-(1S,5S)-pin-2(10)-ene. J. Chem. Soc., Perkin Trans. 1
1978, 93-97.
(17) Manivannan, V.; Vembu, N.; Nallu, M.; Sivakumar, K.; Linden,
A. Phenyl 4-toluenesulfonate: supramolecular aggregation through
weak C-H...O and C-H..π interactions Acta Crystallogr. 2005,
E61, o690-o692.
(18) Clapham, G.; Shipman, M. Selective Lewis acid complexation
of 2-hydroxyethyl esters using competitive Diels-Alder reactions
as a mechanistic probe. Tetrahedron 2000, 56, 1127-1134.
(19) Diego-Castro, M. J.; Hailes, H. C. Studies on the use of
surfactants in aqueous Diels-Alder reactions. Tetrahedron Lett.
1998, 39, 2211-2214.
(20) Kumar, A.; Pawar, S. S. Rate acceleration and subsequent
retardation of Diels-Alder reactions in LiClO4-diethyl ether:
an experimental investigation. J. Org. Chem. 2001, 66, 7646-
7652.
(21) ISO 11269-2: Soil qualitysdetermination of the effect of
pollutants on soil florasPart 2: effect of chemicals on the
emergence and growth of higher plants; International Organi-
sation for Standarization: Geneva, Switzerland, 1995.
(22) Flack, H. D. On enantiomorph-polarity estimation. Acta Crys-
tallogr. A 1983, 39, 876-881.
(23) Oxford Diffraction. Data Collection Program, CrysAlisCCD,
version 1.171; Oxford Diffraction Poland: Wrocław, Poland,
2003.
(24) Oxford Diffraction. Data Reduction Program, CrysAlisRED,
version 1.171; Oxford Diffraction Poland: Wrocław, Poland,
2003.
(25) Sheldrick, G. M. SHELXS97; University of Go¨ttingen, Germany,
1997.
ACKNOWLEDGMENT
We thank Prof. P. Kubisa (CM&MS PAS) for enabling
measurements of viscosities and T. Biedron´ (MSc) (CM&MS
PAS) for technical assistance.
Supporting Information Available: Digital photographs
showing results of the phytotoxicity tests involving spring barley
and ionic liquid 7 as well as common radish and ionic liquid
13. This material is available free of charge via the Internet at
http://pubs.acs.org.
LITERATURE CITED
(1) Welton, T. Room-temperature ionic liquids. Solvents for syn-
thesis and catalysis. Chem. ReV. 1999, 99, 2071-2083.
(2) Dupont, J.; de Souza, R. F.; Suarez, P. A. Z. Ionic liquid (molten
salt) phase organometallic catalysis. Chem. ReV. 2002, 102,
3667-3692.
(3) Wasserscheid, P.; Keim, W. Ionic liquidssnew solutions for
transition metal catalysis. Angew. Chem., Int. Ed. 2000, 39,
3772-3789.
(4) Jastorff, B.; Mo¨lter, K.; Behrend, P.; Bottin-Weber, V.; Filser,
J.; Heimers, A.; Ondruschka, B.; Ranke, J.; Schaefer, M.;
Schro¨der, H.; Stark, A.; Stepnowski, P.; Stock, F.; Sto¨rmann,
R.; Stolte, S.; Welz-Biermann, V.; Ziegert, S.; Tho¨ming, J.
Progress in evaluation of risk potential of ionic liquids-basis for
an eco-design of sustainable products. Green Chem. 2005, 7,
362-372.
(5) Sheldon, R. A. Green solvents for sustainable organic synthe-
sis: state of the art. Green Chem. 2005, 7, 267-278.
(6) Gathergood, N.; Scammells, P.; Garcia, T. Biodegradable ionic
liquids. Part III. The first readily biodegradable ionic liquids.
Green Chem. 2006, 8, 156-160.
(7) Jain, N.; Kumar, N. A.; Chauhan, S.; Chauhan, S. M. S. Chemical
and biochemical transformations in ionic liquids. Tetrahedron
2005, 61, 1015-1060.
(8) Ding, J.; Armstrong, D. W. Chiral ionic liquids: synthesis and
applications. Chirality 2005, 17, 281-292.
(26) Sheldrick, G. M. SHELXL97; University of Go¨ttingen, Germany,
1997.
(9) Wasserscheid, P.; Bo¨smann, A.; Bolm, C. Synthesis and proper-
ties of ionic liquids derived from the chiral pool. Chem. Commun.
2002, 200-201.
(10) Baudequin, C.; Bre´geon, D.; Levillain, J.; Guillen, F.; Plaquevent,
J.-C.; Gaumont, A.-C. Chiral ionic liquids, a renewal for the
chemistry of chiral solvents? Design, synthesis and applications
for chiral recognition and asymmetric synthesis. Tetrahedron:
Asymmetry 2005, 16, 3921-3945.
Received for review October 4, 2006. Revised manuscript received
December 12, 2006. Accepted December 12, 2006.
JF062849Q