Synthesis and crystal structure of complexes of manganese(II), cobalt(II), and nickel(II) isothiocyanates with ε-caprolactam

Article abstract of DOI:10.1134/S0036023612080086

The possibility of ε-caprolactam (CPL) to coordinate to manganese(II), cobalt(II), and nickel(II) rhodanides has been investigated. New complexes trans-[M(CPL)₄(NCS)₂], where M = Mn (I), Co (II), and Ni (III), have been synthesized. The complexes have been studied by chemical analysis and IR spectroscopy. According to X-ray diffraction, complexes are isostructural to each other and crystallize in monoclinic space group P2 ₁/c₃ Z = 2. For I: a = 6.9457(2) A?, b = 17.7751(6) A?, c = 12.8999(4) A?, β = 104.2670(10)°, V = 1543.51(8) A?³, Pcalc = 1.342 g/cm³, R₁ = 0.0426. For II: a = 6.8925(2) A?, b = 17.8189(8) A?, c = 12.7278(6) A?, β = 104.421(2)°, V = 1513.93(11) A?³, Pcalc = 1.377 g/cm³, R₁ = 0.0280. For III: a = 6.7804(2), b = 18.4631(4), c = 12.4841(3), β = 105.2950(10)°, V = 1507.49(7) ³, Pcalc = 1.382 g/cm³, R₁ = 0.0273. Structures I-III are molecular; the metal atom in each of them coordinates four CPL molecules and two NCS groups via oxygen and nitrogen atoms, respectively. Pleiades Publishing, Ltd., 2012.

Full text of DOI:10.1134/S0036023612080086

ISSN 0036ꢀ0236, Russian Journal of Inorganic Chemistry, 2012, Vol. 57, No. 8, pp. 1067–1072. © Pleiades Publishing, Ltd., 2012.
Original Russian Text © S.V. Kochnev, E.V. Peresypkina, A.V. Virovets, T.G. Cherkasova, 2012, published in Zhurnal Neorganicheskoi Khimii, 2012, Vol. 57, No. 8, pp. 1143–1148.
COORDINATION COMPOUNDS
Synthesis and Crystal Structure of Complexes of Manganese(II),
Cobalt(II), and Nickel(II) Isothiocyanates with ꢀCaprolactam
ε
S. V. Kochneva, E. V. Peresypkinab, A. V. Virovetsb, and T. G. Cherkasovaa
a Kuzbass State Technical University, Vesennyaya ul. 28, Kemerovo, 650000 Russia
b Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, pr. Akademika Lavrent’eva 3,
Novosibirsk, 630090 Russia
eꢀmail: ctg.htnv@kuzstu.ru
Received April 6, 2011
Abstract—The possibility of
nickel(II) rhodanides has been investigated. New complexes transꢀ[M(CPL)4(NCS)2], where M = Mn (
Co (II), and Ni (III), have been synthesized. The complexes have been studied by chemical analysis and IR
spectroscopy. According to Xꢀray diffraction, complexes are isostructural to each other and crystallize in
monoclinic space group 21/ = 2. For = 6.9457(2) = 17.7751(6) = 12.8999(4)
104.2670(10) R1 = 0.0426. For II = 6.8925(2) = 17.8189(8)
= 1543.51(8) Å3, calc = 1.342 g/cm3
= 12.7278(6) = 104.421(2) R1 = 0.0280. For III
= 1513.93(11) Å3, ρcalc = 1.377 g/cm3
6.7804(2) = 18.4631(4) = 12.4841(3) = 105.2950(10)
= 1507.49(7) Å3, calc = 1.382 g/cm3
R1 = 0.0273. Structures III are molecular; the metal atom in each of them coordinates four CPL molecules
ε
ꢀcaprolactam (CPL) to coordinate to manganese(II), cobalt(II), and
I),
P
c
,
Z
I:
a
Å,
b
Å,
c
Å,
β
=
Å,
°
,
V
Å
ρ
,
:
a
Å
,
b
c
,
β
°
,
V
,
: a =
Å,
b
Å
,
c
Å,
β
°,
V
ρ
,
I–
and two NCS groups via oxygen and nitrogen atoms, respectively.
DOI: 10.1134/S0036023612080086
Among the ambidentate ligands, NCS– thiocyanꢀ responding metal rhodanide and
ꢀcaprolactam (in a
ε
ate groups attract the researchers’ attention due to the 1 : 4 molar ratio) were dissolved in a minimal volume
possibility of being coordinated by both hard and soft of water; the resulting solutions were left for 2–4 days
acids according to the HSAB concept [1]. The interest for further crystallization. The precipitated crystals
towards the complexes based on these ligands is due to were separated from the mother liquor by vacuum filꢀ
a high biological activity of the compounds comprisꢀ tration.
ing these groups [2, 3]. Moreover, these complexes can
Manganese was determined gravimetrically as
presumably be used to synthesize more complex polyꢀ
manganese(II) sulfate according to a conventional
nuclear compounds.
procedure [10]. Nickel was ascertained by precipitaꢀ
tion with dimethylglyoxime, cobalt by titration with
EDTA, and carbon and hydrogen by burning a
weighed sample in an oxygen flow. The analysis results
In of the continuation of our studies of the strucꢀ
tures of complexes with caprolactam [4–9], we have
been synthesized new complexes of composition
transꢀ[M(CPL)4(NCS)2], where M = Mn (I), Co (II),
are listed in Table 1.
and Ni (III), CPL is caprolactam, and studied them
by Xꢀray diffraction.
IR spectra were recorded as KBr tablets on an
InfralumꢀFT 801 spectrophotometer over the 500–
4000 cm–1 range. The major frequencies of the absorpꢀ
EXPERIMENTAL
tion bands are as follows: for
I
(
, cm–1): 3292m,
ν
Synthesis. Metal rhodanides were synthesized via 3217m, 3042m, 2853m, 2070s, 1639s, 1497m, 822w,
exchange reactions between sulfates of these metals 757m; for II
, cm–1): 3287m, 3205m, 3038m,
with barium rhodanide. Weighed portions of the corꢀ 2852m, 2084s, 1636s, 1497m, 823w, 767m; for III ( ,
(
ν
ν
Table 1. Results of chemical analysis for compounds I–III
Compound
Element
I
II
III
Mn
C
H
Co
C
H
Ni
C
H
Found (wt %)
For [M(CPL)4(NCS)2]
anal. calcd. (%)
9.12
8.80
50.10
50.06
7.04
7.05
9.42
9.38
49.21
49.35
6.89
7.01
9.35
9.21
49.25
49.76
6.69
7.00
1067

1068
KOCHNEV et al.
Table 2. Crystallographic characteristics and details of the Xꢀray experiment and refinement of compounds
I–III
I
II
III
CCDC deposition number
CCDC 817420
C26H44MnN6O4S2
623.73
CCDC 817421
C26H44CoN6O4S2
627.72
CCDC 817422
C26H44NiN6O4S2
627.50
Formula
FW
Temperature, K
Crystal system
Space group
Z
150.0(2)
100.0(2)
100.0(2)
Monoclinic
Monoclinic
Monoclinic
P
21/c
P21/
c
P
21/
2
c
2
2
a
, Å
, Å
6.9457(2)
17.7751(6)
12.8999(4)
104.2670(10)
1543.51(8)
1.342
6.8925(2)
17.8189(8)
12.7278(6)
104.421(2)
1513.93(11)
1.377
6.7804(2)
18.4631(4)
12.4841(3)
105.2950(10)
1507.49(7)
1.382
b
c
, Å
β
, deg
, Å3
V
ρcalc, g/cm3
, mm–1
(000)
Crystal dimensions, mm
range, deg
μ
0.604
0.746
0.824
F
662
666
668
0.10
2.29–30.51
9, –23
–18
×
0.09
×
0.09
0.80
2.82–29.67
6, –24
–17
×
0.20
×
0.20
0.60
2.78–29.62
7, –20
–10 l 15
×
0.45 0.35
×
θ
Reflection index range
–9
≤
h
≤
≤
k
≤
22,
–9
≤
h
≤
≤
k
≤
19,
–8
≤
h
≤
≤
k 24,
≤
≤
l
≤
12
≤
l
≤
16
≤
≤
Reflections measured
15083
4330
8644
3370
8291
3398
Independent reflections
Reflections with
Number of refined parameꢀ
ters
R1
I
≥
2
σ
(
I
)
2721 (
R
int = 0.0504)
179
2941 (
R
int = 0.0223)
179
3011 (
R
int = 0.0229)
178
(I
> 2σ(I
))
0.0426
0.0957
1.001
0.0280
0.0691
1.041
0.0273
0.0688
1.044
wR2 (all reflections)
GOOF (all reflections)
Residual electron density
(min/max), e/Å3
–0.509/0.343
–0.278/0.313
–0.353/0.360
cm–1): 3287m, 3194m, 3036m, 2852m, 2095s, 1637s, refined by the fullꢀmatrix leastꢀsquares method in the
1499m, 823w, 768m).
Xꢀray diffraction. The crystallographic characterisꢀ
tics and details of the Xꢀray diffraction experiment for
anisotropic approximation for nonꢀhydrogen atoms
using the SHELXL program package [12]. The hydroꢀ
gen atoms of caprolactam molecules were refined at
geometrically calculated positions. The atomic coorꢀ
dinates and thermal parameter values were deposited
with the Cambridge Crystallographic Data Center
(deposition numbers CCDC 817420–817422).
Selected bond lengths and bond angles for comꢀ
complexes I–III are presented in Table 2. All meaꢀ
surements were carried out according to a standard
procedure on a BrukerꢀNonius X8Apex fourꢀcircle
automated diffractometer equipped with a CCD area
detector (molybdenum anode,
ite monochromator) at low temperature to eliminate
the conformational disorder of the caprolactam moleꢀ
λ
= 0.71073 Å, graphꢀ
pounds I–III are given in Table 3. The geometrical
characteristics of hydrogen bonds are listed in Table 4.
cules. Reflection intensities were measured in the
and scan modes for narrow (0.5 ) frames to
= 50.0 . Absorption correction was applied empiriꢀ
cally using the SADABS program [11]. Structure was
ϕ
ꢀ
θ
ω
°
2
RESULTS AND DISCUSSION
°
I
All complexes are airꢀstable and readily soluble in
solved by direct methods; the resulting model was used water, ethanol, acetone, dimethylformamide, and
to refine structures II and III. The structures were dimethyl sulfoxide.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 57 No. 8 2012

SYNTHESIS AND CRYSTAL STRUCTURE OF COMPLEXES OF MANGANESE(II)
Table 3. Bond lengths and bond angles in structures III
1069
I–
Compound
Bond
I
II
III
d
, Å
d
, Å
d
, Å
M(1)–N(1)
M(1)–N(1)#1
M(1)–O(1)#1
M(1)–O(1)
M(1)–O(2)
M(1)–O(2)#1
N(1)–C(1)
2.1598(17)
2.1598(17)
2.2101(12)
2.2101(12)
2.2367(13)
2.2367(13)
1.158(2)
1.623(2)
1.261(2)
1.321(2)
1.463(3)
1.503(2)
1.538(3)
1.522(3)
1.527(3)
1.522(3)
1.258(2)
1.318(2)
1.466(2)
1.501(3)
1.533(3)
1.520(3)
1.516(3)
1.513(3)
2.0514(15)
2.0514(15)
2.1456(11)
2.1456(11)
2.1652(12)
2.1652(12)
1.160(2)
1.6348(18)
1.261(2)
1.321(2)
1.469(2)
1.505(2)
1.545(2)
1.528(3)
1.521(3)
1.526(3)
1.261(2)
1.317(2)
1.467(2)
1.502(2)
1.538(3)
1.528(3)
1.516(3)
1.518(2)
2.0162(11)
2.0162(11)
2.1071(9)
2.1071(9)
2.1256(9)
2.1256(9)
1.1602(17)
1.6378(14)
1.2643(16)
1.3214(17)
1.4691(18)
1.5027(19)
1.5429(18)
1.526(2)
C(1)–S(1)
O(1)–C(11)
N(11)–C(11)
N(11)–C(16)
C(11)–C(12)
C(12)–C(13)
C(13)–C(14)
C(14)–C(15)
C(15)–C(16)
O(2)–C(21)
N(21)–C(21)
N(21)–C(26)
C(21)–C(22)
C(22)–C(23)
C(23)–C(24)
C(24)–C(25)
C(25)–C(26)
Angle
1.524(2)
1.527(2)
1.2618(16)
1.3138(18)
1.4666(18)
1.5046(19)
1.539(2)
1.526(2)
1.518(2)
1.519(2)
ω
, deg
ω
, deg
ω
, deg
N(1)M(1)O(1)
N(1)M(1)O(2)
92.85(6)
92.76(6)
92.68(5)
92.17(5)
92.66(4)
91.79(4)
C(1)N(1)M(1)
N(1)C(1)S(1)
159.25(16)
179.0(2)
160.83(14)
179.19(17)
128.13(10)
125.02(15)
121.47(15)
119.78(15)
118.72(15)
111.09(14)
113.86(15)
115.06(16)
114.27(15)
112.75(15)
128.33(11)
127.60(15)
120.37(15)
120.10(15)
119.53(15)
115.75(16)
114.64(17)
114.61(15)
113.73(15)
114.94(15)
161.42(11)
178.91(13)
129.09(9)
124.97(12)
121.60(12)
119.39(12)
118.99(12)
111.05(11)
114.01(11)
115.23(12)
114.17(12)
112.68(11)
129.82(9)
127.28(12)
120.74(12)
119.82(12)
119.43(12)
115.18(12)
114.60(13)
114.66(12)
113.70(12)
114.48(12)
C(11)O(1)M(1)
C(11)N(11)C(16)
O(1)C(11)N(11)
O(1)C(11)C(12)
N(11)C(11)C(12)
C(11)C(12)C(13)
C(14)C(13)C(12)
C(15)C(14)C(13)
C(14)C(15)C(16)
N(11)C(16)C(15)
C(21)O(2)M(1)
C(21)N(21)C(26)
O(2)C(21)N(21)
O(2)C(21)C(22)
N(21)C(21)C(22)
C(21)C(22)C(23)
C(24)C(23)C(22)
C(25)C(24)C(23)
C(24)C(25)C(26)
N(21)C(26)C(25)
127.80(12)
125.08(17)
121.35(17)
120.11(16)
118.52(17)
111.53(16)
113.92(17)
115.19(18)
114.30(18)
112.98(17)
127.53(13)
127.56(16)
120.51(17)
120.34(18)
119.16(17)
115.43(19)
115.15(19)
114.26(17)
114.02(17)
114.91(17)
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 57 No. 8 2012

1070
KOCHNEV et al.
Table 4. Geometrical parameters of hydrogen bonds in structures
I–III
Distance, Å
Coordiꢀ
nates
of atom A
DHA angle, deg
D–H···A contact
H···A
II
D···A
II
D–H
I
III
I
III
I
II
III
–
x
+ 1,
+ 1,
z
N(11)–H(11A)···O(2) 0.88 2.08 2.01
N(21)–H(21A)···O(1) 0.88 2.13 2.07
N(21)–H(21A)···O(1) 0.88 2.62 2.66
1.98 2.885(2) 2.8183(19) 2.7826(15) 152 152
2.03 2.9074(19) 2.8484(18) 2.8370(15) 147 147
2.84 3.124(2) 3.1321(18) 3.2260(15) 117 114
151
152
108
–y
–
x
,
y,
z
–
x,
+ 1,
–y
–z
An increased frequency ν(СS) in the IR spectra of metrical characteristics of the ligands remain virtually
unchanged (Table 3).
the complexes indicates that the rhodanide group is
coordinated to the metal via the nitrogen atom [13]. A
The structures of compounds I–III contain four
intramolecular hydrogen bonds (2.78–2.91 Å long)
between the NH groups and oxygen atoms of neighꢀ
decreased frequency (СО) characterizes the formaꢀ
ν
tion of a metal–oxygen coordination bond [14]. Thus,
the IR data are in a close agreement with the XRD
data, according to which a transitionꢀmetal atom is
coordinated to four CPL molecules via oxygen atoms
and to two NCS groups via nitrogen atoms (Fig. 1).
boring CPL molecules (Fig. 1, Table 4), which are
2+
similar to those observed in [Cu(CPL)6
]
[15] and
[Ln(CPL)8
]
3+ cations [5–9]. Furthermore, molecules
within a crystal are bound via weaker intermolecular
hydrogen bonds (3.12–3.22 Å) to form chains stretchꢀ
Compounds I–III have molecular structure and are
ing along the a axis (Fig. 2). Molecular packings in I–
isostructural to each other. The coordination polyheꢀ
dron of the metal atom is a distorted octahedron
(Table 3), where the nitrogen atoms of isothiocyanate
groups are in the transꢀpositions to each other. There
is a systematic increase in M–O and M–N bond
III are distorted due to the formation of intermolecuꢀ
lar bonds in the bcc lattice (Fig. 3).
According to the CCDC data [16], only five CPL
complexes with yttrium(III) and copper(II) have
lengths in the Mn–Co–Ni series; however, the geoꢀ been structurally characterized for
d metals,
C(23)
C(22)
C(24)
C(21)
C(25)
O(2)
O(11)#
Mn(1)
C(26)
N(21)
N(11)#
N(1)
C(1)
S(1)
O(1)
C(11)
C(12)
O(21)#
N(11)
C(16)
C(13)
C(14)
C(15)
Fig. 1. Molecular structure of
I (ellipsoids of atomic displacements at 50% probability level). The enumeration scheme for atoms
in II and III coincides with that for
I. Dashed lines show the intramolecular hydrogen bonds.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 57 No. 8 2012

SYNTHESIS AND CRYSTAL STRUCTURE OF COMPLEXES OF MANGANESE(II)
1071
C
N
H
S
M
Fig. 2. Molecule chain stretching along the
atoms of the CH groups are omitted.
a axis in crystal structures I–III. Dashed lines show hydrogen bonds. The hydrogen
2
H
C
N
O
S
Co
b
c
Fig. 3. BCC distorted molecular packing in structures of
atoms of the CH groups are omitted.
I–
III shown by an example of transꢀ[Co(CPL) (NCS) ]. The hydrogen
4
2
2
of the C=O group. Thus, complexes I–III are the first
example of coordination of manganese, cobalt, and
nickel atoms to εꢀcaprolactam.
*
*
2
namely,
(Cp*
[
=
], [
]
Cp YCl CPL
2
⋅
CPL
pentamethylcyclopentadienyl, [17]),
[15],
Cu2(
C6H12 [19]. In all cases,
Cp YCl CPL
(
)
(
)
2
[Y(CPL)(H2O)4Fe(CN)6
[Cu(CPL)6][Cu(CPL)Cl3 2
CH3COO)4(CPL)2 2CPL
]
]
[18], and
[
μꢀ
According to the HSAB concept [1], Mn(II) ion is
classified as a hard acid, Co(II) ions is classified as a
]
⋅
⋅
CPL molecules are coordinated via the oxygen atom soft acid, whereas Ni(II) is an intermediate acid.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 57 No. 8 2012

1072
KOCHNEV et al.
9. E. V. Cherkasova, E. V. Peresypkina, A. V. Virovets,
However, these differences do not manifest themselves
upon complexation: all rhodanide groups are bound to
the complexing metals via a hard nitrogen atom. Simꢀ
ilar behavior was previously observed in molecular
complexes of rhodanides of these metals and amiꢀ
dopyrine [20] and in the already known [13] octaheꢀ
dral complexes with other neutral organic monoꢀ and
bidentate ligands.
et al., Acta Crystallogr., Sect. C 63, m195 (2007).
10. W. F. Hillebrand, G. E. Lundell, H. A. Bright, and
J. I. Hoffman, Applied Inorganic Analysis with Special
Reference to the Analysis of Metals, Minerals, and Rocks
(Wiley, New York, 1958; Khimiya, Moscow, 1960).
11. G. M. Sheldrick, SADABS. Program for Empirical Xꢀray
Absorption Correction (BrukerꢀNonius, 1990–2004).
12. G. M. Sheldrick, Acta Crystallogr., Sect. A 64, 112
(2008).
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