Colchiceine complexes with lithium, sodium and potassium salts-spectroscopic studies

Article abstract of DOI:10.5562/cca2871

Colchiceine complexes with Li⁺, Na⁺ and K⁺ cations have been synthesized and studied by ¹H and ¹³C NMR, FT-IR, FAB MS and UV-Vis. It has been shown that colchiceine forms stable complexes especially with lithium cation and the most stable structures of the complexes are those in which the acetamide groups are involved in the coordination process. The structures of the colchiceine complexes with Li⁺, Na⁺ and K⁺ cations are discussed in details.

Full text of DOI:10.5562/cca2871

O R I G I N A L S C I E N T I F I C P A P E R
Croat. Chem. Acta 2016, 89(3), 297–308
Published online: November 2, 2016
DOI: 10.5562/cca2871
Colchiceine Complexes with Lithium, Sodium and
Potassium Salts − Spectroscopic Studies
Joanna Kurek,* Piotr Barczyński
Faculty of Chemistry, Laboratory of Chemistry for Heterocyclic Compounds, A. Mickiewicz University, Umultowska 89b, 61-614 Poznań, Poland
Corresponding author’s e-mail address: joankur@amu.edu.pl
*
RECEIVED: March 20, 2016  REVISED: August 19, 2016  ACCEPTED: August 31, 2016
Abstract: Colchiceine complexes with Li , Na and K cations have been synthesized and studied by H and 13C NMR, FT-IR, FAB MS and UV-Vis.
+
+
+
1
It has been shown that colchiceine forms stable complexes especially with lithium cation and the most stable structures of the complexes are
+
+
+
those in which the acetamide groups are involved in the coordination process. The structures of the colchiceine complexes with Li , Na and K
cations are discussed in details.
Keywords: colchiceine, complexes of colchiceine, NMR spectra, FT-IR, FAB MS spectra, UV-Vis spectra.
treatment of Mediterranean fever.[2] Compound 1 is known
INTRODUCTION
[
3]
to be sensitive to light and hydrolysis. Colchiceine 2 (10-
demetoxy-10-hydroxy-colchicine) in Figure 1 and β- and γ-
lumicolchicine are the main degradation products of
colchicine.
OLCHICINE 1, in Figure 1, is a tropolone alkaloid of
Colchicum autumnale. It shows antimitotic, anti-
C
[
1]
fibrotic and anti-inflammatory activity and can efficiently
alleviate the symptoms of gout attack when applied in the
early phase. More recently, it has been introduced in the
Compound 2, an important intermediate in the
synthesis of colchicine C-10 derivatives, can be obtained
from colchicine 1 by a gentle hydrolysis with hydrochloric
[
4]
acid. Colchiceine 2 is also a useful reagent for many
chemical reactions on ring C, for example tosylation or
mesylation to obtain known derivatives or to produce new
compounds. Upon tosylation or mesylation, 2 is a mixture
of two products with substituent at C-9 (biologically-
inactive isocolchicinoids) and C-10 (biologically-active
colchicinoids) carbon atom, is caused by tosyl group
[
5–7]
migration.
It is necessary for biologically active compounds to
be easily analysed and detected by analytical methods, for
example TLC and HPLC. HPLC analyses of 2 turned out to be
more difficult than of 1 and Colchicum plant extracts.
Colchiceine can be present in plant extracts besides
colchicine, or can appear as a degradation product on
[
8–11]
storage of 1.
Colchiceine can easily form complexes
Figure 1. Structure and carbon atom numbering of
Colchicine 1 and Colchiceine 2.
with most of silica based phases, which can be explained by
the properties of its ring system especially ring C with a
This work is licensed under a Creative Commons Attribution 4.0 International License.

298
J. KUREK and P. BARCZYŃSKI: Colchiceine Complexes with Salts …
hydroxyl group at C-10 position and neighbouring carbonyl
group at carbon atom C-9. It is difficult to detect and
separate colchiceine from plant extracts because of its
chelating properties. To extensively recovery of colchiceine
from silica column matrixes in a HPLC analysis a suitable
metal cation in salt form, which can form complexes with 2
was added. For better separation of 2 from a mixture of
alkaloids in plant extracts, usually inorganic salts are added.
For instance to aqueous solution of 2, ferric chloride is
added to get a coloured complex, then the solution is
extracted with chloroform. In the HPLC analysis copper
sulphate usually was added to the mobile phase to form
Mackay et al. in 1998 obtained hydrated crystals of
copper(II) colchiceine, belonging to the tetragonal space
[
16]
group. In this structure the tropolonic oxygens, from two
colchiceine molecules, are coordinated to the copper atom
in this bis-chelated complex to form a square planar
arrangement. The positions of three water molecules are
clearly defined. An intricate hydrogen-bonding system links
the complex and water molecules into a three-dimensional
[
16]
network in the crystal.
In the previous work we have reported the
coordination process of colchicine with iodides and
perchlorates monovalent metal ions (lithium, sodium and
[3,12,13]
[25]
coloured complexes of metal-colchiceine.
After administration of colchicine, colchiceine has
potassium salts). Although colchicine is a very important
commercially available alkaloid, its complexes (except in
Ref. 25) and complexes of colchicine derivatives like
colchiceine have not been thoroughly characterized yet.
The complexation process of colchiceine with
monovalent metal ions has not been studied yet. This fact
has prompted us to obtain and examine colchiceine
[
14]
been reported as a metabolite in rats, but it has not been
[
15]
demonstrated to occur in humans. Mourelle et al. have
proposed that colchiceine acts as an antioxidant and
protective agent against lipid peroxidation in a rat model of
[
16]
liver injury. 10-Demetoxy-10-hydroxy-colchicine (colchi-
ceine) has not been confirmed to occur in humans, but is
+
+
+
complexes 3–8 with monovalent cations: Li , Na and K .
Molecular structures for all obtained colchiceine complexes
were established by of 1D and 2D NMR, IR, UV and mass
spectral analysis. From the practical point of view this
process of complexation can be useful for isolation
colchicines from plant extracts.
[
17,18]
produced in rodents by the same CYP homolog.
In a
biochemical model of liver injury, 2 is the metabolite,
[
19]
suggested to have beneficial effects. It has been shown
[
15,20]
that 2 prevents acute and chronic CCl
Furthermore in an earlier study, 2 has been shown to
prevent lipid peroxidation the centerpiece of CCl -induced
4
injury in rats.
4
injury. Protection against lipid peroxidation has also been
EXPERIMENTAL
observed in a rat model of biliary obstruction in which 2 was
[
21]
Material
compared with vitamin E.
High concentrations of
colchiceine has also been shown to protect reduced
glutathione (GSH) against oxidation by atmospheric oxygen
and to prevent oxygen-induced inactivation of enzymes
Colchiceine was synthesized from colchicine (Aldrich) by
[
26]
acidic hydrolysis in the mild conditions.
colchiceine is a monohydrate compound. The colchiceine
complexes 3-8 with salts (LiClO , LiI, NaClO , NaI, KI, KSCN
Obtained
[
22]
with catalytically essential sulfhydryl groups.
In vivo
4
4
experiments have suggested that 2 acts as an effective
from Aldrich) were obtained by dissolving of the respective
salts and colchiceine in the 1:1 ratio in methanol.
Complexes were prepared from colchiceine (96 mg, 0,25
mmol) and lithium iodide (33 mg, 0,25 mmol), lithium
perchlorate (27 mg, 0.25 mmol), sodium iodide (38 mg,
0.25 mmol), sodium perchlorate (31 mg, 0.25 mmol),
potassium iodide (42 mg, 0.25 mmol), potassium
thiocyanate 24 mg, 0.25 mmol), respectively. Each mixture
was stirred for 24h in room temperature. The crystalline
products were obtained by slow evaporation of the solvent.
Carbon atom numbering of colchicine 1 and
colchiceine 2 is shown in Figure 1.
antioxidant at pharmacologically relevant concentra-
[
21]
tions, although direct evidence for 2 radical scavenging
activity and protection against lipid peroxidation is
[15]
lacking.
Moreover, colchiceine has been demonstrated to be
less toxic than colchicine in the evaluation of the effect on
cytochrome P450 (CYP) expression. It has been concluded
that colchiceine is not cytotoxic in primary human
[
23]
hepatocytes.
Interestingly, colchiceine has better
antifibrotic properties than colchicine, it can be used as a 1
[20]
substitute with anticipated fewer side-effects.
Colchiceine, a closely related structural analogue of
colchicine with a C-ring tropolone, has been shown to be a
potent inhibitor of microtubule assembly in vitro. The
mechanism of inhibition is mediated through binding to
tubulin although potentially not through the colchicine
(3) Complex Colchiceine - Lithium Iodide
103 mg; yield 84 %; m.p. 110–112 °C, Anal. Calcd. for
21 6 2
C H23NO ·LiI·3.5H O: C, 43.22; H, 5.11; N, 2.41. Found: C,
−1
43.49; H, 5.31; N, 2.55. IR(KBr) ṽ/cm : 3411 m, 3246 m,
2998 w, 2937 w, 2856 w, 1656 s, 1602 s, 1540 m, 1489 m,
1454 m, 1276 m, 1195 s, 1139 m, 483 w. IR (nujol/fluorolub)
[
24]
receptor site.
−1
The formation of complexes between colchicines
ṽ/cm : 3397 m, 3243 m, 3045 w, 2952 w, 2922 w, 2853 w,
and cations has not been the subject of great interest. Only
2727 w, 1655 s, 1602 s, 1537 m, 1488 m, 1452 m, 1404 w,
Croat. Chem. Acta 2016, 89(3), 297–308
DOI: 10.5562/cca2871

J. KUREK and P. BARCZYŃSKI: Colchiceine Complexes with Salts …
299
1
349 w, 1274 w, 484 w (vs, very strong; s, strong; m,
53.37 (C-7), 151.30 (C-7a), 124.81 (C-8), 173.06 (C-9),
168.41 (C-10), 117.88 (C-11), 142.13 (C-12), 135.95 (C-12a),
medium; w, weak; and also in further text regarding IR
−1
1
spectra (ṽ/cm )). H NMR (300 MHz, DMSO-d
.79 (s, HC-4), 2.15 (m, H C-5), 2.55 (m, H C-5), 1.94 (m,
C-6), 2.13 (m, H C-6), 4.35 (m, HC-7), 7.30 (s, HC-8), 7.31
d, J = 11.81 Hz, HC-11), 7.13 (d, J = 11.81 Hz, H C-12), 3.77
s, CH O-1), 3.51 (s, CH O-2), 3.83 (s, CH O-3), 1.88 (s, H C-
4), 8.63 (d, J = 7.14 Hz, NH). 13C NMR (75 MHz, DMSO-d
6
) δ/ppm:
61.53 (CH
3
O-1), 61.30 (CH
3
O-2), 56.50 (CH
OH max/nm (/ mol−1
dm cm ): 350 (16762), 223 (36109).
3
O-3), 170.42 (C-
6
H
(
(
1
2
2
13), 22.77 (C-14). UV-visible in CH
3
3
−1
2
2
(5) Complex Colchiceine - Potassium Iodide
135 mg; yield 98 %; m.p. 94–96 °C, Anal. Calcd. for
3
3
3
3
6
)
21 6 2
C H23NO ·KI·2H O: C, 42.82; H, 4.56; N, 2.38. Found: C,
−1
δ/ppm: 149.68 (C-1), 125.60 (C-1a), 140.48 (C-2), 152.82 (C-
42.72; H, 4.42; N, 2.31. IR (KBr) ṽ/cm : 3438 m, 3359 m,
3128 m, 2997 w, 2938 w, 2859 w, 2833 w, 1653 s, 1611 s,
1553 m, 1490 m, 1454 m, 1276 m, 1195 m, 1136 m, 482 w.
3
5
1
6
1
), 107.70 (C-4), 133.69 (C-4a), 29.24 (C-5), 36.50 (C-6),
1.61 (C-7), 149.94 (C-7a), 123.91 (C-8), 172.00 (C-9),
68.54 (C-10), 118.07 (C-11), 139.91 (C-12), 134.54 (C-12a),
−1
IR (nujol/fluorolub) ṽ/cm : 3418 m, 3244 m, 3051 w, 2953
0.71 (CH
3), 22.50 (C-14). H NMR (300 MHz, CD
C-5), 2.55 (m, H C-5), 2.09 (m, H
C-6), 4.41 (m, HC-7), 7.51 (s, HC-8), 7.25 (d, J =
.48 Hz, HC-11), 7.48 (d, J = 7.25 Hz, HC-12), 3.59 (s, CH O-
), 3.82 (s, CH O-2), 3.87 (s, CH O-3), 1.94 (s, H C-14), 7.65
CN) δ/ppm:
51.04 (C-1), 126.37 (C-1a), 141.74 (C-2), 154.39 (C-3),
08.44 (C-4), 135.75 (C-4a), 30.03 (C-5), 37.87 (C-6), 53.53
3
O-1), 60.69 (CH
3
O-2), 55.87 (CH
CN) δ/ppm: 6.74
C-6),
3
O-3), 168.90 (C-
w, 2926 w, 2855 w, 2725 w, 1657 s, 1609 s, 1543 m, 1489
1
1
3
m, 1453 m, 1403 m, 1349 m, 1275 m, 484 w. H NMR (300
(
s, HC-4), 2.15 (m, H
2
2
2
MHz, DMSO-d
(m, H C-5), 1.98 (m, H
7), 7.34 (s, HC-8), 7.36 (d, J = 11.81 Hz, HC-11), 7.18 (d, J =
6
) δ/ppm: 6.81 (s, HC-4), 2.13 (m, H
2
C-5), 2.54
2
7
1
.25 (m, H
2
2
2
C-6), 2.12 (m, H2C-6), 4.37 (m, HC-
3
3
3
3
11.81 Hz, HC-12), 3.80 (s, CH
CH O-3), 1.89 (s, H
NMR (75 MHz, DMSO-d
3
O-1), 3.54 (s, CH
C-14), 8.65 (d, J = 7.31Hz, 1H – NH).
3
O-2), 3.85 (s,
d, J = 4.41 Hz, NH). 13C NMR (75 MHz, CD
13
C
(
3
3
3
1
1
6
) δ/ppm: 149.75 (C-1), 125.49 (C-
1a), 140.46 (C-2), 152.85 (C-3), 107.71 (C-4), 134.07 (C-4a),
29.19 (C-5), 36.88 (C-6), 51.62 (C-7), 149.91 (C-7a), 124.07
(C-8), 171.57 (C-9), 168.32 (C-10), 118.08 (C-11), 139.99 (C-
(
1
(
2
C-7), 151.31 (C-7a), 124.85 (C-8), 172.94 (C-9), 168.43 (C-
0), 118.20 (C-11), 142.30 (C-12), 136.24 (C-12a), 61.62
CH O-1), 61.30 (CH O-2), 56.53 (CH O-3), 171.23 (C-13),
2.77 (C-14). UV-visible in CH
OH max/nm ( / mol−1 dm3
3
3
3
12), 134.52 (C-12a), 60.70 (CH
(CH O-3), 168.53 (C-13), 22.48 (C-14). H NMR (300 MHz,
CD CN) δ/ppm: 6.74 (s, HC-4), 2.21 (m, H C-5), 2.55 (m, H C-
5), 2.03 (m, H C-6), 2.19 (m, H C-6), 4.42 (m, HC-7), 7.52 (s,
HC-8), 7.25 (d, J = 7.48 Hz, HC-11), 7.48 (d, J = 7.25 Hz, HC-
12), 3.61 (s, CH O-1), 3.84 (s, CH O-2), 3.87 (s, CH O-3), 1.94
(s, H
C-14), 7.44 (d, J = 4.42 Hz, NH). 13C NMR (75 MHz,
CD CN) δ/ppm: 151.00 (C-1), 126.48 (C-1a), 141.70 (C-2),
3 3
O-1), 60.67 (CH O-2), 55.88
1
3
3
−1
cm ): 349.5 (17444), 224 (35853).
3
2
2
(
4) Complex Colchiceine - Sodium Iodide
2
2
131 mg; yield 93 %; m.p. 98–100 °C, Anal. Calcd. for
C
21
H23NO
6
·NaI·3H
2
O: C, 41.38; H, 4.76; N, 2.29. Found: C,
3
3
3
−1
41.70; H, 4.71; N, 2.27. IR (KBr) ṽ/cm : 3436 m, 3252 m,
2998 w, 2937 w, 2856 w, 2836 w, 1659 s, 1608 s, 1541 m,
1489 m, 1453 m, 1275 m, 1196 m, 1137 m, 483 w. IR
3
3
154.30 (C-3), 108.41 (C-4), 135.78 (C-4a), 30.06 (C-5), 37.86
(C-6), 53.35 (C-7), 151.29 (C-7a), 124.75 (C-8), 173.09 (C-9),
168.24 (C-10), 117.66 (C-11), 142.12 (C-12), 135.94 (C-12a),
−1
(
nujol/fluorolub) ṽ/cm : 3407 m, 3245 m, 3046 m, 2953 m,
2937 w, 2855 w, 2728 w, 1659 s, 1606 s, 1534 m, 1489 m,
1
1455 m, 1404 m, 1349 m, 1276 m, 484 w. H NMR (300
61.49 (CH
3
O-1), 61.28 (CH
3
O-2), 56.49 (CH
3
O-3), 170.17 (C-
MHz, DMSO-d
m, H C-5), 1.97 (m, H
.32 (s, HC-8), 7.34 (d, J = 11.81Hz, HC-11), 7.16 (d, J = 11.81
Hz, HC-12), 3.79 (s, CH O-1), 3.53 (s, CH O-2), 3.85 (s, CH O-
), 1.88 (s, H
C-14), 8.65 (d, J = 7.32 Hz, NH). 13C NMR (75
MHz, DMSO-d ) δ/ppm: 49.75 (C-1), 125.56 (C-1a), 140.50
C-2), 152.88 (C-3), 107.74 (C-4), 133.98 (C-4a), 29.24 (C-5),
6
) δ/ppm: 6.81 (s, HC-4), 2.13 (m, H
2
C-5), 2.53
13), 22.74 (C-14). UV-visible in CH
3
OH max/nm (/ mol−1
3
−1
(
7
2
2
C-6), 2.11 (m, H C-6), 4.34 (m, HC-7),
2
dm cm ): 350.5 (17292), 222.5 (39813).
(6) Complex Colchiceine - Lithium Perchlorate
114 mg; yield 94 %; m.p. 100–102 °C, Anal. Calcd. for
3
3
3
3
3
21 6 4 2
C H23NO ·LiClO ·2.5H O: C, 46.93; H, 5.21; N, 2.61. Found:
−1
6
C, 46.54; H, 5.11; N, 2.55. IR (KBr) ṽ/cm : 3394 m, 3245 m,
3059 w, 3000 w, 2939 w, 2859 w, 2838 w, 1654 s, 1606 s,
1543 m, 1489 m, 1456 m, 1277 m, 1196 m, 1143 m, 1087
vs, 1044 m, 918 w, 625 w, 484 w. IR (nujol/fluorolub)
(
36.91 (C-6), 51.65 (C-7), 149.95 (C-7a), 124.07 (C-8), 171.74
(
(
1
C-9), 168.53 (C-10), 118.12 (C-11), 140.00 (C-12), 134.56
C-12a), 60.74 (CH O-1), 60.72 (CH O-2), 55.91 (CH O-3),
68.61 (C-13), 22.51 (C-14). 1H NMR (300 MHz, CD
CN)
C-5), 2.54 (m, H C-5), 2.08
C-6), 4.42 (m, HC-7), 7.53 (s, HC-8),
.24 (d, J = 7.48 Hz, HC-11), 7.48 (d, J = 7.24 Hz, HC-12), 3.60
s, CH O-1), 3.84 (s, CH O-2), 3.87 (s, CH O-3), 1.95 (s, H C-
4), 7.54 (d, J = 4.42 Hz, NH). 13C NMR (75 MHz, CD
CN)
−1
3
3
3
ṽ/cm : 3573 m, 3526 m, 3366 m, 2951 w, 2925 w, 2855 w,
3
2726 w, 1629 s, 1611 s, 1552 m, 1491 m, 1456 m, 1404 m,
1
δ/ppm: 6.74 (s, HC-4), 2.21 (m, H
m, H C-6), 2.25 (m, H
2
2
1349 m, 1278 m, 1094 vs, 1011 m, 920 w, 625 w, 483 w. H
(
7
(
1
2
2
NMR (300 MHz, DMSO-d
C-5), 2.55 (m, H C-5), 1.94 (m, H
4.34 (m, HC-7), 7.31 (s, HC-8), 7.33 (d, J = 11.81 Hz, HC-11),
7.15 (d, J = 11.81 Hz, HC-12), 3.77 (s, CH O-1), 3.51 (s, CH O-
2), 3.83 (s, CH O-3), 1.88 (s, H C-14), 8.64 (d, J = 7.42 Hz,
NH). 13C NMR (75 MHz, DMSO-d
) δ/ppm: 149.82 (C-1),
6
) δ/ppm: 6.79 (s, HC-4), 2.13 (m,
H
2
2
2
C-6), 2.11 (m, H C-6),
2
3
3
3
3
3
3
3
δ/ppm: 150.99 (C-1), 126.46 (C-1a), 141.67 (C-2), 154.26 (C-
), 108.40 (C-4), 135.78 (C-4a), 30.05 (C-5), 37.86 (C-6),
3
3
3
6
DOI: 10.5562/cca2871
Croat. Chem. Acta 2016, 89(3), 297–308

300
J. KUREK and P. BARCZYŃSKI: Colchiceine Complexes with Salts …
1
1
25.59 (C-1a), 140.55 (C-2), 152.95 (C-3), 107.76 (C-4),
34.14 (C-4a), 29.29 (C-5), 36.97 (C-6), 51.69 (C-7), 150.02
(8) Complex Colchiceine - Potassium Thiocyanate
109 mg; yield 91 %; m.p. = 98–100 °C, Anal. Calcd. for
(
C-7a), 124.18 (C-8), 171.71 (C-9), 168.47 (C-10), 118.16 (C-
21 6 2
C H23NO ·KSCN·2.5H O: C, 50.09; H, 5.31; N, 5.31. Found:
−1
1
(
1), 140.09 (C-12), 134.63 (C-12a), 60.80 (CH
CH O-2), 55.91 (CH
NMR (300 MHz, CD CN) δ/ppm: 6.74 (s, HC-4), 2.22 (m, H
), 2.56 (m, H C-5), 1.96 (m, H C-6), 2.26 (m, H C-6), 4.37
m, HC-7), 7.46 (s, HC-8), 7.26 (d, J = 7.48 Hz, HC-11), 7.48
d, J = 7.25 Hz, HC-12), 3.60 (s, CH O-1), 3.83 (s, CH O-2),
.87 (s, CH O-3), 1.92 (s, H C-14), 7.48 (d, J = 4.37 Hz, NH).
C NMR (75 MHz, CD CN) δ/ppm: 151.08 (C-1), 126.41 (C-
3
O-1), 60.77
O-3), 168.69 (C-13), 22.55 (C-14). H
C, 49.98; H, 5.36; N, 5.29. IR (KBr) ṽ/cm : 3360 m, 3256 m,
3052 w, 2999 w, 2938 w, 2856 w, 2837 w, 1661 s, 1609 s,
1544 m, 1489 m, 1453 m, 1274 m, 1196 m, 1136 m, 2051
1
3
3
3
2
C-
−1
5
(
(
3
1
2
2
2
m. IR (nujol/fluorolub) ṽ/cm : 3370 m, 3249 m, 3052 w,
2952 w, 2936 w, 2856 w, 2727 w, 1658 s, 1608 s, 1539 m,
1
3
3
1488 m, 1456 m, 1404 m, 1348 m, 1274 m, 2054 s. H NMR
3
3
(300 MHz, DMSO-d
5), 2.53 (m, H C-5), 1.96 (m, H
(m, HC-7), 7.33 (s, HC-8), 7.36 (d, J = 11.81 Hz, HC-11), 7.18
(d, J = 11.81 Hz, HC-12), 3.79 (s, CH O-1), 3.53 (s, CH O-2),
O-3), 1.88 (s, H3C-14), 8.67 (d, J = 7.42 Hz, NH).
) δ/ppm: 150.04 (C-1), 125.73
6
) δ/ppm: 6.82 (s, HC-4), 2.14 (m, H
2
C-
3
3
2
2
C-6), 2.11 (m, H C-6), 4.36
2
1
3
a), 141.78 (C-2), 154.45 (C-3), 108.48 (C-4), 135.81 (C-4a),
0.06 (C-5), 37.91 (C-6), 53.49 (C-7), 151.19 (C-7a), 125.07
3
3
(
(
5
C-8), 172.98 (C-9), 168.48 (C-10), 117.95 (C-11), 142.36
C-12), 136.29 (C-12a), 61.65 (CH O-1), 61.35 (CH O-2),
6.54 (CH O-3), 170.08 (C-13), 22.69 (C-14). UV-visible in
CH OH max/nm (/ mol dm cm ): 348.5 (16192), 231
27017).
3.85 (s, CH
3
1
3C NMR (75 MHz, DMSO-d
3
3
6
3
(C-1a), 140.72 (C-2), 153.16 (C-3), 107.89 (C-4), 134.36 (C-
4a), 29.26 (C-5), 36.95 (C-6), 51.73 (C-7), 150.24 (C-7a),
124.38 (C-8), 171.92 (C-9), 168.63 (C-10), 118.32 (C-11),
−1
3
−1
3
(
(
7) Complex Colchiceine - Sodium Perchlorate
140.29 (C-12), 134.80 (C-12a), 60.84 (CH
3
O-1), 60.81 (CH
O-3), 168.93 (C-13), 22.51 (C-14), 129.78
CN) δ/ppm: 6.73 (s, HC-4),
C-5), 1.99 (m, H C-6), 2.24 (m,
C-6), 4.39 (m, HC-7), 7.48 (s, HC-8), 7.23 (d, J = 7.48 Hz,
HC-11), 7.48 (d, J =7.23 Hz, HC-12), 3.61 (s, CH O-1), 3.82 (s,
CH O-2), 3.88 (s, CH O-3), 1.92 (s, H C-14), 7.44 (d, J = 4.39
Hz, NH). 13C NMR (75 MHz, CD
CN) δ/ppm: 151.15 (C-1),
3
O-
1
C
25 mg; yield 93 %; m.p. 102−104 °C, Anal. Calcd. for
2), 55.95 (CH
(SCN). H NMR (300 MHz, CD
3
1
21
H
23NO
6
·NaClO
4
·2H
2
O: C, 47.27; H, 4.95; N, 2.57. Found:
3
−1
C, 47.24; H, 4.87; N, 2.52. IR (KBr) ṽ/cm : 3364 m, 3261
m, 3063 m, 2998 w, 2940 w, 2858 w, 2839 w, 1662 s, 1611
s, 1544 m, 1490 m, 1455 m, 1276 m, 1196 m, 1140 m,
108 m, 1090 vs, 1043 m, 918 w, 626 w, 484 w. IR
nujol/fluorolub) ṽ/cm : 3538 m, 3363 m, 3260 m, 2996
2.22 (m, H
2
C-5), 2.54 (m, H
2
2
H
2
3
1
(
3
3
3
−1
3
w, 2939 w, 2858 w, 2725 w, 1659 s, 1609 s, 1540 m, 1489
m, 1454 m, 1405 m, 1350 m, 1277 m, 1092 vs, 1044 m,
126.59 (C-1a), 141.81 (C-2), 154.37 (C-3), 108.48 (C-4),
135.85 (C-4a), 30.14 (C-5), 37.92 (C-6), 53.36 (C-7), 151.36
(C-7a), 124.83 (C-8), 173.03 (C-9), 168.49 (C-10), 117.71 (C-
9
19 w, 624 w, 484 w. 1H NMR (300 MHz, DMSO-d
6
)
δ/ppm: 6.80 (s, HC-4), 2.13 (m, H
.96 (m, H C-6), 2.11 (m, H C-5), 4.35 (m, HC-7), 7.33 (s,
HC-8), 7.35 (d, J = 11.81 Hz, HC-11), 7.17 (d, J = 11.81 Hz,
HC-12), 3.79 (s, CH O-1), 3.53 (s, CH O-2), 3.85 (s, CH O-
), 1.88 (s, H
C-14), 8.65 (d, J =7.36 Hz, NH). 13C NMR (75
MHz, DMSO-d ) δ/ppm: 150.03 (C-1), 125.74 (C-1a),
40.74 (C-2), 153.16 (C-3), 107.89 (C-4), 134.33 (C-4a),
9.27 (C-5), 36.96 (C-6), 51.73 (C-7), 150.21 (C-7a), 124.36
2
C-5), 2.53 (m, H
2
C-5),
11), 142.16 (C-12), 136.10 (C-12a), 61.55 (CH
(CH O-2), 56.54 (CH O-3), 170.69 (C-13), 22.70 (C-14),
131.49 (SCN). UV-visible in CH
OH max/nm (/ mol−1 dm3
cm ): 350 (16200), 230 (28341).
(2) Colchiceine C21 ·H O, m.p. 148–150 °C.
3
O-1), 61.34
1
2
2
3
3
3
−1
3
3
3
3
3
H
23NO
6
2
6
Physical Measurements
1
2
−1
The NMR spectra of 2 and its 1:1 complexes 3–8 (0.07 mol L )
with monovalent metal cations salts were recorded in CD CN
solutions using a Varian Gemini 300 MHz spectrometer. All
spectra were locked to deuterium resonance of CD CN. The
CN were carried out at the
(
(
C-8), 171.95 (C-9), 168.67 (C-10), 118.32 (C-11), 140.28
3
C-12), 134.81 (C-12a), 60.84 (CH
5.73 (CH
MHz, CD
m, H C-5), 1.97 (m, H
), 7.47 (s, HC-8), 7.25 (d, J = 7.49 Hz, HC-11), 7.49 (d, J
7.24 Hz, HC-12), 3.61 (s, CH O-1), 3.84 (s, CH O-2), 3.87
O-3), 1.90 (s, H
C-14), 7.54 (d, J =4.39 Hz, NH). 13
NMR (75 MHz, CD CN) δ/ppm: 151.09 (C-1), 126.50 (C-1a),
41.78 (C-2), 154.39 (C-3), 108.49 (C-4), 135.86 (C-4a),
0.11 (C-5), 37.93 (C-6), 53.41 (C-7), 150.32 (C-7a), 124.91
3
O-1), 60.81 (CH
3
O-2),
1
5
3
O-3), 168.94 (C-13), 22.52 (C-14). H NMR (300
3
1
3
CN) δ/ppm: 6.73 (s, HC-4). 2.21 (m, H
2
C-5), 2.56
H NMR measurements in CD
3
(
2
2
C-6), 2.25 (m, H C-6), 4.40 (m, HC-
2
operating frequency 300.075 MHz; flip angle 45°; spectral
width 4500 Hz; acquisition time 2.0 s; relaxation delay 1.0 s
and T = 293.0 K, using TMS as the internal standard. No
window function or zero filling was used. Digital resolution
was 0.2 Hz per point. The error of chemical shift value was
0.01 ppm. 13C NMR spectra were recorded at the operating
7
=
3
3
(
s, CH
3
3
C
3
1
3
frequency 75.454 MHz; pw = 60°; sw = 19000 Hz; at = 1.8 s; d
1
(
(
5
C-8), 173.02 (C-9), 168.38 (C-10), 117.82 (C-11), 142.28
C-12), 136.18 (C-12a), 61.59 (CH O-1), 61.38 (CH O-2),
6.56 (CH O-3), 170.46 (C-13), 22.71 (C-14). UV-visible in
CH OH max/nm (/ mol dm cm ): 349 (16917), 231
28146).
= 1.0 s; T = 293.0 K and TMS as the internal standard. Line
3
3
broadening parameters were 0.5 or 1 Hz. The error of
1
13
3
chemical shift value was 0.01 ppm. The H and C NMR
signals were assigned for each species using one or two-
dimensional (COSY, HETCOR, HMBC in inverse mode) spectra.
−1
3
−1
3
(
Croat. Chem. Acta 2016, 89(3), 297–308
DOI: 10.5562/cca2871

J. KUREK and P. BARCZYŃSKI: Colchiceine Complexes with Salts …
301
3
Table 1. Value of λmax and  in UV-Vis spectra of 2 and its complexes 3–8 in (CH OH)
3
/ (mol−1 dm cm−1)
3
Compound
λ
max1 / nm
350.5
349.5
350
350.5
348.5
349

1
/ (mol-1 dm cm−1)
λ
max2 / nm
243.5
224
223
222.5
231
231
230

2
2
3
4
5
6
7
8
34887
17444
16762
17292
16192
16917
16200
62699
35853
36109
39813
27017
28146
28341
350
The FT-IR spectra of 2 and its 1:1 complex 3–8 (0.07
mol dm ) were recorded in the mid infrared region in KBr
pellets, fluorolub/ nujol mixture for obtained complexes 3–
the complexes with perchlorate salts 6–7 and thiocyanate
8. The UV-Vis data for the 1:1 complexes of colchicine with
monovalent cations 3–8 in methanol show the influence of
−3
8
and in CD
LiClO . The spectra were taken with an IFS 113v FT-IR
spectrophotometer (Bruker, Karlsruhe) equipped with a
3
CN for colchiceine and its complex 6 with
2
salts only on the λmax2 and ε values, which means that the
4
effect of coordination process is stronger on benzenoic
moiety than on tropolonic moiety. In the UV-Vis spectra of
the benzenoic moiety, hypsochromic shifts were observed
for all obtained colchiceine complexes 3–8 of bothλmax1 and
−1
DTGS detector; resolution 2 cm , NSS=125. A cell with Si
windows and wedge-shaped layers was used to avoid
interferences (mean layer thickness 170 μm). Each FT-IR
spectrum was measured by acquisition of 64 scans. All
manipulations with the substances were performed in a
λ
max2 for iodide and perchlorate salts. The hypsochromic
shifts of λmax1 for tropolonic moiety is very weak. The
hypsochromic shift of λmax2 observed for colchiceine
complexes with iodide salts 3–5 was stronger than that for
perchlorates 6–7 and thiocyanate 8, and it was the
strongest for the complex of colchiceine with potassium
iodide 5, which means that the type of anion also influences
the coordination process.
2
carefully dried and CO -free glove box.
The UV-Vis spectra were recorded in methanol by
JASCO V-550 spectrophotometer at 200–600 nm range.
Liquid secondary ion mass spectra (FAB MS) were
obtained with AMD 604 two sector mass spectrometer of
reverse B/E geometry, made by AMD Intectra (Germany). A
+
NMR Measurements
CsI gun supplied the primary ion beam (12 keV, Cs ). The
secondary ion beam was accelerated to 8 kV. Samples of
the complexes studied were dissolved in 3-nitrobenzyl
alcohol (Aldrich).
Elemental analysis of colchiceine complexes was
carried out by means of a Elementarz Analyser Vario EL III.
Melting point was determined on BUCHI SMP-20. Melt-
Temp II apparatus (Laboratory Devices Inc.)
The NMR spectra of colchiceine complexes 3–8 were
recordered in two different solvents to compare a possible
interaction between the ligand (colchiceine) and the
solvent as well as to establish the effect of the nature of
1
13
solvents on the values of chemical shifts. The H and
NMR data of 2 and its complexes with iodides 3–5,
perchlorates 6–7 and thiocyanate 8 in DMSO-d and in
C
6
CD
3
CN solution are given in Experimental Section.
RESULTS AND DISCUSSION
1H NMR Spectra
Colchiceine and respective inorganic salts (LiClO
4
, LiI,
The chemical shift of proton at OH (hydroxyl group at C-10)
in 2 cannot be obtained experimentally on account of the
very low activation energy. Colchiceine exists in the form of
two tautomers, which follows from intramolecular proton
transfer on the tropolone moiety (between two oxygens at
NaClO , NaI, KSCN, KI) at the ratio 1:1 M were dissolved in
4
methanol and were stirred for 24h at room temperature.
Compounds 3–8 were obtained as pale to dark yellow
solids with very good yields. The complexes were studi-
1
13
[27]
ed by spectral analysis: UV-Vis, H and C NMR, FT-IR
and MS FAB.
C-9 and C-10).
1
The H NMR spectra of colchiceine complexes 3–8 do
not show significant changes in the values of chemical shifts
of respective hydrogen atoms, as has been also observed
earlier for other biologically active compounds like
UV-Vis Measurements
The UV-Vis spectrum of colchiceine 2 in methanol (Table 1.)
shows two bands at λmax1 350 and λmax2 243.5 nm assigned
to the tropolonic and benzenoic moieties in the colchiceine
[
25,28–32]
monensin, oligomycin and complexes of colchicine.
The slightest changes of proton chemical shifts have
molecule, respectively. The values of ε
in comparison to colchiceine but those of ε
1
and ε
2
change much
are higher for
been observed for the amide group. Apart from these
values, H NMR spectra give no additional information on
1
2
the colchiceine complexes with iodides 3–5 and lower for
the structure of the complexes studied.
DOI: 10.5562/cca2871
Croat. Chem. Acta 2016, 89(3), 297–308

302
J. KUREK and P. BARCZYŃSKI: Colchiceine Complexes with Salts …
1
Table 2. Selected chemical shifts of protons in the H NMR in CD
3
CN
Hydrogen
atom
Chemical shifts (ppm), δ
H
multiplicity, J / Hz
6
2
3
4
5
7
8
H
H
2
2
C-5
2.18 m
2.15 m
2.55 m
2.09 m
2.25 m
2.21 m
2.54 m
2.08 m
2.25 m
2.21 m
2.55 m
2.03 m
2.19 m
2.22 m
2.56 m
1.96 m
2.26 m
2.21 m
2.56 m
1.97 m
2.25 m
2.22 m
2.54 m
1.99 m
2.24 m
2
.54 m
2.09 m
.23 m
C-6
2
HC-8
HC-11
HN
7.48 s
7.24 d 7.48
7.16 d 6.32
7.51 s
7.25 d 7.48
7.65d 4.41
7.53 s
7.24 d 7.48
7.54 d 4.42
7.52 s
7.25 d 7.48
7.44 d 4.42
7.46 s
7.26 d 7.48
7.48 d 4.37
7.47 s
7.25 d 7.49
7.54 d 4.39
7.48 s
7.23 d 7.48
7.44 d 4.39
1
The H NMR spectra of colchiceine complexes 3–8 in
the cation, the weaker the complex interaction with the
acetamide group. Figure 2. shows the changes in the
position of the chemical shift of proton at NH group of
acetamide substituent in colchiceine and its complexes
with lithium iodide 3 and perchlorate 6.
If only lithium cation had impact on the
complexation process in both complexes 3 and 6, the
position of the chemical shift of proton from the NH group
would be almost the same, Figure 2. It can be easily
observed that the type of anion also influences the position
of proton in the acetamide group.
acetonitrile, similarly as those of colchiceine complexes 3–
in DMSO-d , show the signals of protons assigned to three
6
o-methoxyl groups whose positions do not change much
after the complexation process. Some selected data on
proton chemical shifts in acetonitrile are given in the Table
8
2
. Slight changes in chemical shifts are observed for
methylene protons at carbon atoms C5 and C6 (ring B). The
proton at the carbon atom C-8 observed as a singlet
showed considerable change in chemical shift for
colchiceine complex with sodium perchlorate 4.
The differences in chemical shifts of protons of the
acetamide substituent at C-7 position gave the greatest
changes, as a result of the complexation process, changing
from 7.16 ppm in 2 to 7.44–7.65 ppm in 3–8. The proton
signal whose position was the most changed in this region
of the spectra of complexes 3–8 was observed in
colchiceine complex with lithium perchlorate 6. The
changes in the values of chemical shift decrease in the
1
3
C NMR spectra
Some selected data on chemical shifts in 13C NMR spectra
6
of colchiceine complexes 3–8 in DMSO-d are given in the
Table 3. 13C NMR spectra of these complexes are much
more informative than H NMR spectra. The chemical shifts
of o-methoxy carbons do not change much after the
complexation process and the most shifted ones are those
in complex 7 and 8. The differences in chemical shifts of
1
+
+
+
following order Li > Na > K , which suggests that the larger
6
Table 3. Selected carbon-13 chemical shifts for colchiceine 2 and its complexes 3–8 (in DMSO-d )
Carbon atom
Chemical shifts (δ/ppm)
2
3
4
5
6
7
8
C-1
C-1a
C-2
149.73
125.53
140.49
152.87
134.05
51.58
149.68
125.60
140.48
152.82
133.69
51.61
149.75
125.56
140.50
152.88
133.98
51.65
149.75
125.49
140.46
152.85
134.07
51.62
149.82
125.59
140.55
152.95
134.14
51.69
150.03
125.74
140.74
153.16
134.33
51.73
150.04
125.73
140.72
153.16
134.36
51.73
C-3
C-4a
C-7
C-7a
C-8
149.95
124.06
171.57
168.35
118.07
139.96
134.52
60.70
149.94
123.91
172.00
168.54
118.07
139.91
134.54
60.71
149.95
124.07
171.74
168.53
118.12
140.00
134.56
60.74
149.91
124.07
171.57
168.32
118.08
139.99
134.52
60.70
150.02
124.18
171.71
16.47
150.21
124.36
171.95
168.67
118.32
140.28
134.81
60.84
150.24
124.38
171.92
168.63
118.32
140.29
134.80
60.84
C-9
C-10
C-11
C-12
C-12a
118.16
140.09
134.63
60.80
CH
CH
CH
3
3
3
O-1
O-2
O-3
60.66
60.69
60.72
60.67
60.77
60.81
60.81
55.82
55.87
55.91
55.88
55.91
55.73
55.95
C-13
168.49
168.90
168.61
168.53
168.69
168.94
168.93
Croat. Chem. Acta 2016, 89(3), 297–308
DOI: 10.5562/cca2871

J. KUREK and P. BARCZYŃSKI: Colchiceine Complexes with Salts …
303
carbon atom C-13 of carbonyl group do not depend on the
type of monovalent cation. Signal assigned to carbonyl
carbon atom C-13 is most shifted in 3, 6 and 7 ranging from
a)
b)
c)
168.90 to 168.95 ppm (168.49 ppm in 2). Signal of carbonyl
carbon atom C-9for colchiceine appears at 171.57 ppm, but
for colchiceine complexes with lithium iodide 3 shifts to 172
ppm. The chemical shifts of carbonyl carbon atom C-9
+
+
+
decrease in the following order Li → Na → K for iodides
+
+
+
and Na → K → Li for perchlorates 6 and 7 and thiocyanate
. This observation suggests that in complexation process
8
in colchiceine complex with lithium iodide 3 both carbonyl
groups are involved. Some changes after complexation
process are also visible in chemical shifts for carbon atoms
on ring B. For carbon atoms C-7 and C-7a the greatest
change in chemical shifts are observed in colchiceine
complex 7 and 8. The carbon atoms C-11, C-12 and C-12a
on the C ring shift much in colchiceine complexes 7 and 8.
For carbon atoms on ring A C-1, C-1a, C-2, C-3, C-4a the
greatest change in chemical shifts are observed in
colchiceine complex 7 and 8.
13
Some selected
colchiceine complexes 3–8 are given in the Table 4. The
NMR spectra of colchiceine complexes 3–8 in CD
similarly to those of complexes 3–8 in DMSO-d , show the
C NMR chemical shifts of
1
3
C
3
CN
6
signals of carbons assigned to three o-methoxyl groups do
not change much after the complexation process. The
chemical shifts of carbon atoms from the three o-methoxyl
+
+
+
groups decrease in the following order Li → Na → K , both
for iodides and perchlorates.
The chemical shifts of carbon atoms show that both
carbonyl group at C-7 position (acetamide group) and C-9 in
the tropolone ring C are involved in the coordination. The
+
+
+
complexation process of Li , Na and K cations results in
changes in the chemical shifts of the carbon atoms of the
tropolone ring C of colchiceine and at the acetamide
substituent (carbon from carbonyl group) at C-7 position.
The chemical shifts of carbon atom C-13 of acetamide group
depend on the type of monovalent cation and increase in
+
+
+
+
the following order Li → Na → K for iodides 3–5 and K →
+
+
Li → Na for perchlorates 6–7 and thiocyanate 8. The most
upfield shift of C-13 carbonyl carbon atom was observed in
6
(complex with lithium perchlorate), while the most
downfield shift was found in 8 with respect to 2. On the
other hand signal of carbonyl carbon atom C-9 in colchiceine
appears at 173.30 ppm, but for colchiceine complexes with
lithium iodide 3 shifts slightly downfield to 172.94 ppm. The
chemical shifts of carbonyl carbon atom C-9 decrease in the
following order Li+ → Na+ → K+ for iodides and for
perchlorates 6 and 7 and thiocyanate 8.
FT-IR Measurements
1
3
Figure 2. H NMR spectra (CD CN) in the range of 6.4–8.2
To be able to make comparison to the results of the
ppm of: a) colchiceine 2, b) complex with lithium
perchlorate 6 and c) complex with lithium iodide 3.
[
25]
previous work on colchicine complexes, the IR spectra of
DOI: 10.5562/cca2871
Croat. Chem. Acta 2016, 89(3), 297–308

304
J. KUREK and P. BARCZYŃSKI: Colchiceine Complexes with Salts …
Table 4. Selected chemical shifts of carbon atoms in the 13C NMR in CD
CN
3
Chemical shifts (ppm) CD CN
3
Carbon atom
2
3
4
5
6
7
8
C-1
C-1a
C-2
151.44
151.04
150.99
151.00
151.08
126.41
141.78
154.45
135.81
30.06
151.09
151.15
126.83
142.15
154.71
136.29
30.21
126.37
141.74
154.39
135.75
30.03
126.46
141.67
154.26
135.78
30.05
126.48
141.70
154.30
135.78
30.06
126.50
141.78
154.39
135.86
30.11
126.59
141.81
154.37
135.85
30.14
C-3
C-4a
C-5
C-7
53.47
53.53
53.37
53.35
53.49
53. 41
150.32
173.02
168.38
117.82
142.28
136.18
61.59
53.36
C-7a
C-9
151.56
173.30
168.74
117.81
142.43
136.07
61.64
151.31
172.94
168.43
118.20
142.30
136.24
61.62
151.30
173.06
168.41
117.88
142.13
135.95
61.53
151.29
173.09
168.24
117.66
142.12
135.94
61.49
151.19
172.98
168.48
117.95
142.36
136.29
61.65
151.36
173.03
168.49
117.71
142.16
136.10
61.55
C-10
C-11
C-12
C-12a
CH
CH
CH
3
3
3
O-1
O-2
O-3
61.46
61.30
61.30
61.28
61.35
61.38
61.34
56.66
56.53
56.50
56.49
56.54
56.56
56.54
C-13
170.43
171.23
170.42
170.17
170.08
170.46
170.69
colchiceine and its complexes 3–8 were collected both in
solid state – KBr pellets and in a nujol/fluorolub while those
of two carbonyl groups of tropolone and the acetamide
group, respectively, these two bands are slightly shifted
−1
−1
of 2 and 6 in CD
3
CN solutions. Initial examination of these
from 1611 cm and 1653 cm in 2 to the region of 1602–
1610 cm−1 and 1662–1653 cm in colchiceine complexes 3–
8. The strongest shift of the band assigned to the carbonyl
group of tropolone ring C is observed in colchiceine
complex with lithium iodide 3. The strongest shift of the
band assigned to the acetamide group is observed in
−1
spectra showed that some differences in position, shape
and intensity of respective bands can be observed in
spectra obtained in KBr pellets, nujol/fluorolub and in
CD
3
CN solutions.
The FT-IR spectra of colchiceine complexes 3–5 with
monovalent cations and, for comparison, the spectrum of
colchiceine 2 all in KBr pellets are shown in Figure 3 and
Figure 1S (Supporting Information).
1
00
2
9
0
3
4
5
From crystallographic studies it is well known that
colchiceine in the solid state exist as a monohydrate. In the
FT-IR spectrum, the stretching vibration of amine group
80
70
6
5
4
3
2
1
0
0
0
0
0
0
0
−1
observed as a broad band with a maximum at 3357 cm .
The same band is also observed in the spectra of
colchiceine complexes with monovalent cations 3–8, but
the maximum of the broad band is shifted toward higher
wavenumbers depending on the type of cation in the
following order K→ Na→ Li for iodides 3–5 and K ≈ Na → Li
in perchlorates 6–7 and thiocyanate 8. This observation
indicates that in the solid, not only the cation but also the
type of anion has impact on the complexation process. The
strongest shift of this band is observed in 3. Cation and
anion together with water molecules are involved in the
complexation process. In the region of stretching vibrations
1659
1656
1653
1553
1602
1611
1
608
1541
1540
1
750
1700
1650
1600
1550
1500
-1
Wavenumbers [cm ]
Figure 3. FT-IR spectra (KBr) of colchiceine 2 and its
complexes with lithium iodide 3, sodium iodide 4 and
Croat. Chem. Acta 2016, 89(3), 297–308
DOI: 10.5562/cca2871

J. KUREK and P. BARCZYŃSKI: Colchiceine Complexes with Salts …
305
100
+
+
+
and Li → Na → K in perchlorates. In the FT-IR spectrum,
2
6
the NH stretching vibrations of colchiceine produces the
band with a maximum at 3359 cm . In the FT-IR spectra of
−1
7
5
2
5
0
5
0
colchiceine complexes the same band is observed but
shifted towards lower wavenumbers, to 3245 cm− in
complexes with iodide salts. The bands assigned to NH
stretching vibrations of colchiceine complexes with iodides
are much more shifted than those of the colchiceine
complexes with perchlorates. The absence of any band in
1
1
647
1
629
1
552
1
491
−1
the usual carbonyl range (1720–1670 cm ) can be
1611
explained by the conjunction of carbonyl group with
unsaturated group or aromatic ring that lowers the
carbonyl frequencies. In the region of stretching vibrations
of C=O group two bands are present, one assigned to the
tropolone moiety and the other to acetamide groups. The
shape and intensity of bands differ from those in the
spectrum of colchiceine. The band of carbonyl group of
tropolone moiety does not shifts much in comparison to
the band assigned to the carbonyl group from acetamide,
1
553
1
700
1650
1600
1550
1500
1450
-
1
Wavenumber [cm ]
Figure 4. FT-IR spectra (nujol/fluorolub) of Colchiceine
Complexes with lithium perchlorate 6 in the region of
carbonyl group 1700–1450cm .
−1
−
1
which shifts towards higher wavenumbers from 1647 cm
colchiceine complex with sodium perchlorate 7.
The FT-IR spectra of 1 show very characteristic
absorption bands of tropolone ring in the colchicine
molecule, appearing in the region of 1624–1605 cm ,
570–1538 cm and 1280–1250 cm , the first two are
assigned to the stretching vibrations of ṽ(C=C), but in the IR
spectra of colchiceine these bands appear in the region of
553 cm and 1276 cm . It was supposed that in the
tropolone ring C, the active hydrogen was statically located
between the two oxygen atoms (on hydroxyl and carbonyl
group) in such a way that the resonance was possible
without zwitterion formation by shifts of the double bond
and OH bonds as indicated.
colchiceine complexes 3–8 show the bands assigned to the
in 2 to 1655−1657 cm−1 in complexes 3–8 as a result of
complexation process. Only in complex 6 this carbonyl band
shifts toward lower wavenumbers from 1647 cm to 1629
cm . The strongest shift of the bands assigned to ṽ(CO)
vibrations of acetamide group, from 1647 cm in
colchiceine to 1657 cm , was observed in its complex with
K 5, while for the tropolone carbonyl group the greatest
shift was from 1611 cm in 2 to 1602 cm in complex 3
with lithium iodide.
−1
−1
−1
−
1
−1 [26]
−1
1
−1
+
−1
−1
−1
−1
1
The bands assigned to the tropolone moiety
(unsaturated resonant system of ring C) appear at
−1
−1
−1
−1
1611cm , 1553 cm , 1349 cm and 1278cm in the FT-IR
spectra of colchicine 1 and colchiceine 2. As expected, the
same bands appear in the FT-IR spectra of colchiceine
complexes 3−8 at somewhat different frequencies and with
different relative intensities.
[
33]
The FT-IR spectra of
stretching vibrations of amine group and hydroxyl group in
−
1
the region of 3650–2500 cm . These bands are shifted
towards higher wavenumbers in comparison to their
position in the spectrum of 2, which is a result of the
presence of water molecules in the crystalline structure of
colchiceine complexes 3–8.
The FT-IR spectra in the nujol/fluorolub of respective
complex 6 are shown in Figures 2S–3S (Supporting
Information) and Figure 4, colchiceine is present as a
monohydrate and in its FT-IR spectra the band assigned to
The FT-IR spectra of 2 and its complex with lithium
perchlorate 6 in CD CN solutions were also obtained and
3
the data are given in Table 5 and shown in Figure 5 and
Figure 4S (Supporting Information). For comparison, the
data for colchicine 1 and its complex with lithium
[
25]
perchlorate 1a, are also given. Changes in the shape and
intensity of the bands are easily observed. The bands
assigned to the stretching vibrations of NH group are
[34]
−1
water molecule is present.
shifted to the lower wavenumbers from 3371 cm for 2 to
+
The stretching vibrations of this water molecule is
3358 cm−1 for its complex 6 with Li cation. In the region of
stretching vibrations of C=O bonds of the carbonyl group of
tropolone and acetamide groups, two bands appear and
shift towards lower wavenumbers in comparison to the FT-
IR spectrum of colchiceine. After the complexation process,
the band assigned to the stretching vibrations of carbonyl
observed in the FT-IR spectra as a band with a maximum at
about 3447 cm . The same bands are also observed in the
spectra of the colchiceine complexes with Li , Na and K
cations, but their maximum is slightly shifted towards
lower wavenumbers, in a way dependent on the type of
−
1
+
+
+
+
+
+
−1
cation in the following sequence: K → Na → Li in iodides,
which was also observed for the complexes of colchicine,
group of acetamide group is shifted from 1681 cm for 2 to
[25]
−1
1662 cm for 6, which implies that the carbonyl group of
DOI: 10.5562/cca2871
Croat. Chem. Acta 2016, 89(3), 297–308

306
J. KUREK and P. BARCZYŃSKI: Colchiceine Complexes with Salts …
−
1
100
Table 5. Wavenumbers (cm ) in FT-IR spectra in acetonitrile
for 2 and its complex 6 and colchicine 1 and its complex with
lithium perchlorate 1a.
2
6
[25]
80
60
40
20
Wavenumbers / cm−1
Assignments
2
6
1
1a
vOH
vNH
3538
3536
3544
3539
3371
3358
3369
3367
3
3
2
206
167
998
3229
3160
2998
3095
3090
2943
3163
3002
2944
1596
1596
1617
1556
vCH
1615
1662
1551
1681
vC=O
vC=O
vC=C
vC=C
1681
1617
1596
1556
1660
1615
1596
1551
1680
1618
1591
1575
1664
1614
1592
1573
1
750
1700
1650
1600
1550
1500
-
1
Wavenumber [cm ]
Figure 5. FT-IR spectra of Colchiceine 2 and its Complex with
lithium perchlorate 6 (CD CN): 1700–1575cm .
3
−1
acetamide substituent at C-7 rather is involved in the
complexation process rather than the carbonyl group of
tropolone ring C. As can be concluded the complexation
process involves especially the carbonyl group of
acetamide substituent at C-7 rather than the carbonyl
group of tropolone ring C.
IR spectra were recorded (solid state, suspension or
solution) did not affect behavior of the band assigned to
−
ClO
4
group. The symmetric bending band usually present
at ≈ 460 cm−1 after the complexation process is shifted
−1
towards higher wavenumbers for 6 and 7 to 484 cm , but
these shifts are irrespective of the type of cation and the
medium in which IR spectra were recorded (solid state,
suspension or solution). The symmetric stretching band is
The presence of free perchlorate anions ClO −
manifested by four fundamental vibration bands:
is
4
−1
symmetric stretching band at ≈ 932 cm , symmetric
−1
−1
bending band at ≈ 460 cm , asymmetric stretching band at
shifted towards lower wavenumbers 918−920 cm for the
−
1
≈
1115 cm and asymmetric bending band at ≈ 630
IR spectra in KBr and nujol/fluorolub and this change does
not depend on type of cation, but in CD CN solution for
3
complex 6 only a slight change by 2cm−1 is observed.
−
1 [35,36]
cm .
The IR spectra of colchiceine complexes: with
lithium perchlorate 6 and with sodium perchlorate 7 show
the bands assigned to perchlorate anions and their
wavenumbers are given in the Table 6 and Figure 6. The
FAB MS Measurements
−1
broad band at ≈ 1115 cm assigned to asymmetric
stretching is shifted towards lower wavenumbers as a
result of complexation process and also in case of presence
of water molecules in complexes 6 and 7. These
observations were made for the spectra of the samples in
KBr pellet, nujol/fluorolub suspension andfor complex 6 for
In Fast Atom Bombardment (FAB) MS mass spectra,
molecular ions of colchiceine with respective monovalent
+
+
+
metal ions as Li , Na and K in stoichiometry 1:1 can be
observed, respectively. The relevant data are given in the
Table 7.
For all complexes, except 5, formation of complexes
in stoichiometry in 2:1 is also observed. For complex 6
3
CD CN solution, which means that the medium in which the
Table 6. Wavenumbers of free perchlorate anion and in complexed form of ClO
perchlorate 6 and colchiceine complex with sodium perchlorate 7
−: as colchiceine complex with lithium
4
Wavenumbers / cm−1
Assignment
−
Free ClO
4
6
6
6
7
7
KBr
nujol/fluorolub
CD
3
CN
KBr
nujol/fluorolub
1
104
1108
1090
1043
918
626
484
1
. vas
1087
1094
1011
1092
1044
≈
1115
1100
096
1
044
1
2
3
4
. vsym
. δas
≈ 932
≈ 630
≈ 460
918
625
484
920
625
483
930
625
483
919
624
484
. δsym
Croat. Chem. Acta 2016, 89(3), 297–308
DOI: 10.5562/cca2871

J. KUREK and P. BARCZYŃSKI: Colchiceine Complexes with Salts …
307
100
colchiceine complexes with lithium iodide and lithium
perchlorate.
6
7
In our previous work it has been found that
colchicine forms complexes with lithium, sodium and
potassium iodides, perchlorates and thiocyanate. In
comparison to our previous work of colchicine complexes,
colchiceine forms complexes in which in complexation
process perchlorate anions are also involved, what was
observed especially in colchiceine complex with lithium
perchlorate.
75
50
25
0
9
18
4
84
6
26
1
043
4
84
1044
625
1
087
Supplementary Information. Supporting information to the
paper is enclosed to the electronic version of the article at:
http://dx.doi.org/10.5562/cca2871.
1
090
1100
1000
900
800
700
600
500
400
-1
Wavenumber [cm ]
Figure 6. FT-IR spectra of colchiceine complex with lithium
perchlorate 6 and colchiceine complex with sodium
perchlorate 7 in the range of 1200–400cm ClO anion.
4
REFERENCES
−1
−
[1]
A. Brossi, H. J. Yeh, M. Chrzanowska, J. Wolff, E.
Hamel, C.M. Lin, F .Quin, M. Suffness, J. Silverton,
Med. Res. Rev. 1988, 8, 77.
signals at m/z = 392 and also at m/z = 778 appear, which
indicates not only 1:1 but also 2:1 stoichiometry, of two
colchiceine molecules and one lithium cation. Moreover, in
[2]
[3]
[4]
[5]
M. Klintscher, C. Beham – Schmidt, H. Radner, G.
Henning, P. Roll, Forensic Sci. Int. 1999, 106, 191.
A. Körner, S. Kohn, J. Chromatogr. A. 2005, 1089,
141.
M. Schonharting, G. Mende, G. Siebert, H.-S. Z.
Physiol. Chem. 1974, 355, 1991.
M. Cavazza, F. Pietra, Tetrahedron Lett. 2003, 44,
1895.
M.P. Staretz, S.B. Hastie, J. Org. Chem. 1991, 56, 428.
M. Cavazza, M. Zandomeneghi, F. Pietra, J. Chem.
Soc. Perkin Trans. 1 2002, 560.
6
two other signals with low intensity (%) were observed,
which can be assigned to much more complicated
stoichiometry with perchlorate anion at m/z = 498, which
indicates a connection colchiceine molecule to two lithium
cations and one perchlorate anion and also m/z = 884 two
colchiceine molecules to two lithium cations and one
perchlorate anion. It can be easily observed that formation
of complicated stoichiometry depends on the kind of cation
and decreases in the order lithium, sodium to potassium
cation.
[6]
[7]
[8]
G. Forni, G. Massarani, J. Chromatogr. 1977, 131,
444.
[
[
9]
A. E. Klein, P.J. Davis, Anal. Chem. 1980, 52, 2432.
10] Y. H. Caplan, K. G. Orloff, B. C. Thompson, J. Anal.
Toxicol. 1980, 4, 153.
CONCLUSIONS
Series of new colchiceine complexes were obtained and
described by spectral analysis. In the present work it was
found that exchanging just one substituent in colchicine
molecule at C-10 carbon atom from methoxyl to hydroxyl
group on tropolone ring C causes huge changes in
[11] D. Jarvie, J. Park, M. J. Stewart, Clin. Tox. 1979, 14,
375.
[12] E. Lacey, R. L. Brady, J. Chromatogr. 1984, 315, 233.
[13] A. Maruˇska, O. Kornyˇsova, J. Chromatogr. A 2006,
1112, 319.
1
complexes formation. The strongest changes in the H and
[14] T. Tateischi, P. Soucek, Y. Caraco, F. P. Guengerich,
A. J. J. Wood, Biochem. Pharm. 1997, 5, 111.
1
3
C NMR and in the FT-IR spectra were observed for
Table 7. Main signals in FAB MS mass spectra of colchiceine complexes 3–8
+
Col-2M
+
X
−
(%)
+
2Col-2M
+
X (%)
−
Complex
Col-M (%)
2Col-M (%)
3
4
5
6
7
8
392 (100)
408 (90)
424 (88)
392 (98)
408 (85)
424 (80)
-
-
-
778 (5)
794 (4)
-
778 (5)
794 (3)
810 (2)
-
-
-
498 (10)
884 (5)
-
-
-
-
DOI: 10.5562/cca2871
Croat. Chem. Acta 2016, 89(3), 297–308

308
J. KUREK and P. BARCZYŃSKI: Colchiceine Complexes with Salts …
[
[
[
[
15] M. Mourelle, R. Fraginals, L. Rodrigez, L. Favari, V.
Perez–Alvarez, Life Sci. 1989, 45, 891.
16] M. F. Mackay, R. W. Gable, J. D. Morrison, L. O.
Satzke, Austr. J. Chem. 1999, 52, 333.
17] M. Schonharting, G. Mende, G. Siebert, Z. Hoppe-
Seyler's, Physiol. Chem. 1974, 355, 1391.
18] M. Modriansky, Y. Y. Tyurina, V. A. Tyurin, T.
Matsura, A. A. Shvedova, J. C. Yalowich, Toxicology
[26] J. W. Cook, J. D. Loudon, in: R. H. Manske (Ed.), The
alkaloids,Vol. 2,AcademicPress,NewYork,1952,p. 261.
[27] J. Elguero, R. N. Muller, A. Blade-Font, R. Faure, E. J.
Vincent, Bull. Soc. Chim. Belg. 1980, 89, 193.
[28] B. Gierczyk, G. Schroeder, P. Przybylski, B. Brzeziński,
F. Bartl, G.Zundel, J. Mol. Struct. 2005, 738, 261.
[29] A. Huczyński, P. Przybylski, B. Brzeziński, F. Bartl,
Biopolymers 2006, 81, 282.
2
002, 177, 105.
[30] A. Huczyński, P. Przybylski, B. Brzeziński, F. Bartl,
Biopolymers 2006, 82, 491.
[31] A. Huczyński, P. Przybylski, B. Brzeziński, F. Bartl, J.
Phys. Chem. B 2006, 110, 15615.
[32] A. Huczyński, D. Michalak, P. Przybylski, B.
Brzeziński, F. Bartl, J. Mol. Struct. 2006, 797, 99.
[33] G. P. Scott, D. S Tarbell, J. Amer. Chem. Soc. 1950, 72,
240.
[
[
19] M. Rodriguez, J. Cerbon-Ambriz, M. L. Munoz, Arch.
Med. Res. 1998, 29, 109.
20] A. A. Nava-Ocampo, S. Suster, P. Muriel, Europ. J.
Clin. Invest. 1997, 27, 77.
21] P. Muriel, O. R. Suarez, J. Appl. Toxicol. 1994, 14, 423.
22] R. C. Schnell, G. Vali, J. Atmos. Sci. 1976, 33, 1554.
23] Z. Dvoraka, J. Ulrichovaa, L. Pichard-Garciab, M.
[
[
[
Modrianskya,P. Maurelb,Toxicol. in Vitro 2002, 16, 219.
24] S. B. Hastie, T. L. Macdonald, Biochem. Pharmacol.
[34] D. J. Morrrison, Acta Cryst. 1951, 4, 69.
[35] Y. Chen, Y.-H. Zhang, L.-J. Zhao, Phys. Chem. Chem.
Phys. 2004, 6, 537.
[
[
1990, 39, 1271.
25] J. Kurek, Wł. Boczoń, P. Przybylski, B. Brzeziński, J.
Mol. Struct. 2007, 846, 13.
[36] D. L. Lewis, E. D. Esters, D. J. Hodgson, J. Cryst. Mol.
Struct. 1975, 5, 67.
Croat. Chem. Acta 2016, 89(3), 297–308
DOI: 10.5562/cca2871

Supporting Information
Colchiceine Complexes with Lithium, Sodium and Potassium
Salts - Spectroscopic Studies
Joanna Kurek, Piotr Barczyński
Figures of FT-IR spectra
Figure 1S. FT IR spectra (KBr) of colchiceine 2 and its complexes with lithium iodide 3,
sodium iodide 4 and potassium iodide 5 at the range 3750-2500cm-1
1
00
90
80
70
60
50
40
30
20
10
0
3357
3
124
3252
2998
3
411
3436
3
359
2
3
4
5
3500
3000
Wavenumbers [cm ]
2500
-
1
Figure 2S. FT IR spectra (nujol/fluorolub) of colchiceine complex with lithium perchlorate 6
at the range 4000-400cm-1
100
75
50
25
0
2
6
4000
3500
3000
2500
2000
1500
1000
500
-1
Wavenumber [cm ]

Figure 3S. FT IR spectra (nujol/fluorolub) of Colchiceine Complexes with lithium
perchlorate 6 in the region of 3750-2750cm-
1
100
3447
7
5
2
5
0
5
0
3359
3
366
3129
2
951
3
526
3
573
2
6
3
750
3500
3250
3000
2750
-1
Wavenumber [cm ]

Figure 4S. FT IR spectra of Colchiceine 2 and its Complex with lithium perchlorate 6
-1
-1
(
CD
3
CN): a) 4000-500cm , b) 3750-2750cm
a)
100
8
6
4
2
0
0
0
0
2
6
4000
3500
3000
2500
2000
1500
1000
500
-1
Wavenumber [cm ]
b)
1
00
3
167
160
3538
80
60
40
20
3206
3618
3
3229 3210
3371
3
358
2998
3
536
2
6
3500
3000
-
1
Wavenumber [cm ]