Synthesis, Crystal Structure, and Magnetic Property of four Manganese(II) Complexes with Bulky Schiff bases Derived from Amantadine and Rimantadine

Article abstract of DOI:10.1134/S1070328419030047

Abstract: The reactions of manganese(II) chloride tetrahydrate and four bulky Schiff base ligands derived from amantadine (or rimantadine) and salicylaldehyde (or 4-methoxysalicylaldehyde) generated four?novel?complexes, C₃₄H₄₂Cl

Full text of DOI:10.1134/S1070328419030047

ISSN 1070-3284, Russian Journal of Coordination Chemistry, 2019, Vol. 45, No. 3, pp. 230–237. © Pleiades Publishing, Ltd., 2019.
Synthesis, Crystal Structure, and Magnetic Property
of Four Manganese(II) Complexes with Bulky Schiff Bases Derived
from Amantadine and Rimantadine1
X. D. Jina, *, X. X. Fenga, L. C. Bua, W. C. Wanga, J. Tonga, P. Zhanga, Y. D. Qia, and C. Yanga
aCollege of Chemistry, Liaoning University, Shenyang, 110036 P.R. China
*e-mail: jinxudong@lnu.edu.cn
Received March 3, 2018; revised October 4, 2018; accepted October 20, 2018
Abstract—The reactions of manganese(II) chloride tetrahydrate and four bulky Schiff base ligands derived
from amantadine (or rimantadine) and salicylaldehyde (or 4-methoxysalicylaldehyde) generated
four novel complexes, C34H42Cl2MnN2O2 (I), C36H46Cl2MnN2O4 (II), C38H50Cl2MnN2O2 (III), and
C40H54Cl2MnN2O4 (IV), respectively. These complexes were characterized by melting point, infrared spec-
tra, elemental analysis, magnetic susceptibility, molar conductance and single-crystal X-ray diffraction (CIF
files CCDC nos. 1540253 (I), 1540254 (II), 1540255 (III), 1540256 (IV)). Single-crystal X-ray diffraction
analysis reveals that I, III and IV crystallize in the orthorhombic system with space groups P212121, Pbcn and
Pcan, respectively, whereas II crystallizes in the monoclinic system with space group P21/n. Each asymmetric
unit for I–IV consists of one manganese(II) atom, two Schiff base ligands and two chlorine atoms. The cen-
tral manganese(II) atoms lie on a twofold rotation axis in III and IV, whereas manganese(II) atoms lie on gen-
eral positions in I and II. In these complexes molecules, manganese(II) atoms is four-coordinated via two
chlorine atoms and two oxygen atoms from the corresponding Schiff base ligands, forming a distorted tetra-
hedral geometry.
Keywords: manganese(II) complexes, bulky Schiff base, synthesis, crystal structure, magnetic property
DOI: 10.1134/S1070328419030047
INTRODUCTION
icance, it has been reported that the overexposure causes
neurotoxicity manifested as extrapyramidal symptoms
similar to those observed in Parkinson disease [18–20].
In addition, manganese(II) Schiff base complexes dis-
played significant magnetic properties in the field of
magneto-chemistry [21]. Based on the reasons above, we
designed and managed to synthesize a series of manga-
nese(II) complexes for attempting to evaluate their bio-
logical and medical activates as well as magnetic
physics. As an extension of our previous work on metal
complexes with bulky Schiff bases derived from amanta-
dine or rimantadine [22–28], in this paper, four four-
coordinated manganese(II) complexes bis(2-((E)-ada-
mantan-1-yliminomethyl)phenolato-kO)dichloroman-
ganese(II) (I), bis(2-((E)-adamantan-1-yliminome-
thyl)-5-methoxyphenolato-kO)dichloromanganese(II)
In many countries, amantadine (SymmetrelTM) and
rimantadine (FlumadineTM) have been used as effica-
cious remedies to prevent or treat seasonal influenza [1–
5]. In addition, they can alleviate the Parkinson syn-
drome [6, 7]. Salicylaldehyde and its derivatives were
used to produce efficient herbicides, insecticides and
fungicides [8]. The Schiff bases derived from a reaction of
aromatic aldehydes and aliphatic amines represent an
important series of widely studied organic ligands owing
to their biological and anti-cancer activity [9–12], they
also brought about many metal-based pharmaceuticals
[13–15]. For instance, transition metal complexes with
Schiff bases were found exhibiting biological activity as
antibiotics, antiviral and antitumour agents because of
their specific structures [16, 17]. Manganese (Mn) is an
essential trace element and necessary for physiological
processes that support development, growth and neuro-
nal function for human health. Manganese can also
function as a cofactor for enzymes, regardless of its signif-
(II),
bis(2-((E)-1-(adamantan-1-yl)ethyliminome-
thyl)phenolato-kO)dichloromanganese(II) (III), and
bis(2-((E)-1-(adamantan-1-yl)ethyliminomethyl)-5-me-
thoxyphenolato-kO)dichloromanganese(II) (IV), res-
pectively, were synthesized.
1
The article is published in the original.
230

SYNTHESIS, CRYSTAL STRUCTURE, AND MAGNETIC PROPERTY
231
salicylaldehyde (304 mg, 2.0 mmol) in 20 mL anhy-
drous ethanol for 1 h and then cooled to room tem-
perature, respectively. the colored Schiff base precipi-
tates were obtained after one week under slow solvent
evaporation.
L1: 439 mg, yield 86%, yellowish powder, m.p. 92.0~
92.7°C [30].
R1
R2
N
H
O
Mn
Cl
Cl
O
H
N
R2
L2: 371 mg, yield 65%, yellow powder, m.p. 106.3~
106.7°C [27].
R1
L3: 419 mg, yield 74%, yellowish powder, m.p. 88.3~
88.6°C [28].
I: R1 = H, R2 = adamantan-1-yl;
L4: 470 mg, yield 75%, yellowish powder, m.p.
102.8~103.3°C [28].
II: R1 = OCH3, R2 = adamantan-1-yl;
III: R1 = H, R2 = 1-(adamantan-1-yl)ethyl;
IV: R1 = OCH3, R2 = 1-(adamantan-1-yl)ethyl.
Synthesis of the complexes. Four novel complexes
were prepared in a similar procedure starting from
their corresponding freshly synthetic Schiff base
ligands and manganese(II) chloride tetrahydrate in
anhydrous ethanol, respectively.
Manganese(II) chloride tetrahydrate (198 mg,
1.0 mmol) in 10 mL anhydrous ethanol was added to a
solution of a Schiff base ligand (2.0 mmol) in 10 mL
anhydrous ethanol. The mixture was stirred at 30°C
for 2 h, concentrated until a large amount of precipi-
tate was observed, and then cooled to room tempera-
ture. The pearlescent solids were suction filtered,
washed with anhydrous ethanol, and dried under vac-
uum to afford each complex.
Their structures were characterized by the means of
IR, elemental analysis, molar conductance and sin-
gle-crystal X-ray diffraction. Their magnetic behavior
was investigated.
EXPERIMENTAL
Materials and methods. All chemicals and solvents
were purchased from Sinopharm Chemical Reagent
Co., Ltd., and were of analytical grade and used as
received. Elemental analysis was carried out on Perkin
Elmer Flash EA 1112. Infrared spectrum (IR) was
scanned in the range 4000 to 400 cm–1 with KBr pel-
lets on a Nicolet NEXUS FT-IR 5700 spectropho-
tometer. Melting points were measured on a WRS-1B
micro melting point apparatus, which was not cor-
rected. The molar conductance of the complexes in
DMF (1.0 × 10–3 mo1 L–1) was measured on a DDS-
11A conductometer. Temperature-dependent mag-
netic measurements were carried out on a Quantum
Design SQUID MPMS-XL-7 magnetometer under
an applied field of 1 K Oe in the temperature range of
2–300 K. The experimental data were corrected for
the diamagnetism of the sample holder, measured in
the same range of field and temperature, and for the
intrinsic diamagnetic contribution for the sample esti-
mated through Pascal’s constants for all constituent
atoms [29].
I: 461 mg, yield 72%, yellow powder, m.p. 298.2°C.
IR (KBr; ν, cm–1): 3421 w, 2919 m, 2853 m, 1638 s,
1609 s, 1541 s, 1489 s, 1311 m, 1240 m, 1203 m, 1153 m,
1081 w, 901 w, 767 w, 582 w.
For C34H42N2O2Cl2Mn (M = 636.54)
Anal. calcd., % C, 64.16
Found, % C, 64.15
H, 6.65
H, 6.67
N, 4.40
N, 4.43
II: 326 mg, yield 47%, yellowish powder, m.p.
267.2°C. IR (KBr; ν, cm–1): 3433 w, 2914 m, 2853 m,
1638 s, 1611 s, 1534 s, 1489 m, 1358 m, 1302 m, 1228 s,
1118 m, 1084 m, 1025 m, 848 w, 605 w, 535 w.
For C36H46N2O4Cl2Mn (M = 696.59)
Synthesis of the ligands. Schiff base ligands, 2-((E)-
Anal. calcd., % C, 62.07
Found, % C, 62.05
H, 6.66
H, 6.69
N, 4.02
N, 4.04
adamantan-1-yliminomethyl)phenol (L1), 2-((E)-ada-
mantan-1-yliminomethyl)-5-methoxyphenol
(L2),
2-((E)-1-(adamantan-1-yl)-ethyliminomethyl)phenol
(L3) and 2-((E)-1-(adamantan-1-yl)ethyliminomethyl)-
5-methoxyphenol (L4) were prepared analogously to the
literatures [27, 28, 30].
The Schiff base ligands were prepared by refluxing
a mixture of amantadine hydrochloride (375 mg,
2.0 mmol) or rimantadine hydrochloride (432 mg,
2.0 mmol), KOH (112 mg, 2.0 mmol) and salicylalde-
hyde (244 mg, 2.0 mmol) or 4-methoxy substituted
III: 428 mg, yield 62%, yellow powder, m.p.
252.4°C. IR (KBr; ν, cm–1): 3409 w, 2904 s, 2848 m,
1644 s, 1606 s, 1541 s, 1487 s, 1323 w, 1281 w, 1238 m,
1147 m, 1028 w, 902 w, 767 m, 578 w, 527 w.
For C38H50N2O2Cl2Mn (M = 692.64)
Anal. calcd., % C, 65.90
Found, % C, 65.87
H, 7.28
H, 7.31
N, 4.04
N, 4.05
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 45 No. 3 2019

232
JIN et al.
(a)
(b)
C(16)
C(9)
C(17)
C(23)
C(24)
C(26)
N(2)
C(22)
C(21)
C(5)
C(6)
C(32)
C(30)
C(28)
C(4)
C(3)
C(7)
O(4)
C(31)
C(15)
C(8)
C(25)
C(33)
C(34)
C(12)
C(20)
C(27)
C(19)
C(1)
O(1)
N(1)
O(3)
C(36)
C(14)
C(13)
C(29)
C(11)
C(2)
Mn(1)
C(10)
C(35) C(29)
Cl(2)
Cl(1)
Mn(1)
C(14)
C(15)
C(13)
Cl(2)
C(11)
C(10)
O(1)
C(26)
N(2)
N(1)
C(1)
Cl(1)
C(19)
C(20)
O(2)
C(23)
C(24)
C(28)
C(30)
C(2)
C(8)
O(2)
C(18)
C(25)
C(9) C(18)
C(12)
C(34)
C(3)
C(6)
C(16)
C(31)
C(32)
C(27)
C(33)
C(7)
C(17)
C(4)
C(5)
C(22)
C(21)
(c)
(d)
C(5)
C(4)
O(3)
C(19)
C(5)
C(7)
C(6)
N(1)
C(9)
C(4)
C(7)
C(3)
C(3)
C(6)
N(1)
C(17A)
C(18A)
C(16A)
C(2)
C(1)
O(1)
Mn(1)
C(8)
C(2)
C(11)
C(8)
C(1)
O(1)
C(12A)
C(11A)
C(15)
C(16A)
C(17A)
C(12A)
C(17)
C(20)
C(16)
C(15)
C(14)
C(13A)
C(9)
O(3)
C(19)
C(18A)
C(10A)
C(10)
Cl(1A)
C(10A)
C(10)
C(18)
C(15A)
Cl(2)
C(12)
C(13)
Cl(2A)
Cl(1)
C(16)
C(13)
C(19A)
C(14A)
Mn(1)
C(9A)
C(8A)
C(9A)
C(20A)
N(1A)
C(11)
C(14A)
C(13A)
O(1A)
O(1A)
C(2A)
C(18)
C(15A)
C(12)
C(8A)
N(1A)
C(1A)
C(6A)
C(14)
C(11A)
C(1A)
C(2A)
C(3A)
C(4A)
C(17)
C(19A)
C(7A)
C(6A)
C(7A)
C(5A)
O(3A)
C(3A)
C(4A)
C(5A)
Fig. 1. Molecular structures of I (a), II (b), III (c), and IV (d). Hydrogens are omitted for clarity.
IV: 419 mg, yield 56%, yellowish powder, m.p. age [35]. The hydrogen atoms were generated geomet-
271.8°C. IR (KBr; ν, cm–1): 3423 w, 2905 m, 2849 m,
1643 s, 1611 s, 1524 s, 1490 m, 1371 m, 1318 m, 1232 s,
1221 m, 1025 w, 975 w, 848 w, 801 w, 529 w.
rically. All calculations were performed on a personal
computer with the SHELXL-2014 crystallographic
software package. The details of the crystal parame-
ters, data collection and refinement are summarized
in Table 1. Selected bond lengths and angles with their
estimated standard deviations are given in Table 2. The
molecular structures of four complexes are shown in
Fig. 1, they were visualized by Diamond [36].
For C40H54N2O4Cl2Mn (M = 752.69)
Anal. calcd., % C, 63.83
Found, % C, 63.79
H, 7.23
H, 7.26
N, 3.72
N, 3.71
Supplementary material for structures has been
deposited with the Cambridge Crystallographic Data
Centre (CCDC nos. 1540253 (I), 1540254 (II),
1540255 (III), 1540256 (IV); deposit@ccdc.cam.ac.uk
or http://www.ccdc.cam.ac.uk).
X-ray crystallography. Single crystals of four com-
plexes suitable for X-ray analysis were grown from a
solution of CH3OH/CH2Cl2 (1 : 1, v/v) using solvent
evaporation. The crystallographic data collections
were conducted on a Bruker Smart Apex II CCD with
graphite monochromated MoKα radiation (λ =
0.71073 Å) at 293(2) or 298(2) K using the ω-scan
technique [31]. The data were integrated by using the
SAINT program, which also corrected the intensities
for Lorentz and polarization effect [32]. An empirical
absorption correction was applied using the SADABS
program [33]. The structures were solved by direct
methods using the program SHELXS-2014 [34]. All
non-hydrogen atoms were refined anisotropically on
F 2 by the full-matrix least-squares technique using the
RESULTS AND DISCUSSION
The C, H, N contents both theoretically calculated
values and found values for all complexes are in agree-
n
ment with the formula of MnCl
(n = 1, 2, 3, 4), it
2L
suggests that complexes I–IV con2sist of one manga-
nese(II), two chloride atoms and two ligands. All the
complexes are soluble in methanol, dichloromethane
and chloroform, the complexes are less soluble than
their corresponding ligands in other solvents, such as
SHELXL and OLEX2 crystallographic software pack- ethanol, tetrahydrofuran, benzene and ethyl acetate.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY
Vol. 45
No. 3
2019

SYNTHESIS, CRYSTAL STRUCTURE, AND MAGNETIC PROPERTY
Table 1. Crystallographic data and structure refinement for complexes I–IV
Value
233
Parameter
I
II
III
IV
Fw
636.54
0.21 × 0.19 × 0.18
Orthorhombic
Yellow
696.59
0.20 × 0.18 × 0.17
Monoclinic
Yellowish
692.64
0.20 × 0.18 × 0.16
Orthorhombic
Yellow
752.69
Crystal size, mm
Crystal system
Color
Space group
a, Å
b, Å
c, Å
β, deg
V, Å3
0.20 × 0.16 × 0.10
Orthorhombic
Yellowish
Pcan
P212121
P21/n
Pbcn
10.2574(7)
16.5613(10)
18.2282(14)
90.00
12.3933(6)
17.4322(7)
16.7841(10)
102.948(5)
3533.9(3)
14.4168(11)
10.7556(7)
23.1167(17)
90.00
12.2858(6)
13.4127(7)
24.7093(12)
90.00
3096.5(4)
3584.5(4)
4071.7(4)
Z
4
4
4
4
θ Range, deg
Index ranges
2.72–25.32
2.60–25.10
2.83–23.86
0.91–0.95
–12 ≤ h ≤ 7,
–12 ≤ k ≤ 19,
–21≤ l ≤ 19
–7 ≤ h ≤ 14,
–20 ≤ k ≤ 19,
–19 ≤ l ≤ 17
–12 ≤ h ≤ 18,
–13 ≤ k ≤ 12,
–28 ≤ l ≤ 28
–14 ≤ h ≤ 14,
–15 ≤ k ≤ 12,
–29≤ l ≤ 29
ρ, g cm–3
µ, mm–1
1.365
1.309
1.283
1.228
0.633
0.565
0.552
0.495
Reflections collected/
8128/4856 (0.0313)
13418/6211 (0.0243)
9372/3676 (0.041)
24031/3589 (0.032)
unique (Rint)
Refinement parameters
GOOF
370
1.005
406
1.024
205
1.007
224
1.077
F(000)
1340
1468
1468
1596
T, K
293(2)
293(2)
293(2)
298(2)
R1/wR2 (I > 2σ(I))*
R1/wR2 (all data)
0.0454/0.0896
0.0659/0.1011
0.39/–0.26
0.0603/0.1593
0.0939/0.1848
0.80/–0.42
0.0547/0.1307
0.1096/0.1633
0.36/–0.22
0.0545/0.1483
0.0641/0.1573
0.30/–0.21
Largest difference peak
and hole, e Å–3
2
2
2
2 1/2
2
* R = Σ||F | – |F ||/|F |, wR = [Σw(
–
) /Σw( ) ]
Fo
.
Fo Fc
1
o
c
o
2
at near frequency 1228–1240 cm–1. In addition, in low
frequency regions, the presence of absorptions at 486–
535 cm–1 for complexes reveals Mn–O vibrations,
indicating that oxygen of the Schiff base ligands is
coordinated to manganese(II).
The molar conductance values (ΛM) in DMF for I–IV
are 33.3, 35.3, 32.9 and 30.1 S cm2 mol–1, indicating a
non-electrolyte behavior [37].
The broad and intensity absorptions at 3409–
3443 cm−1 for ligands and complexes can be attributed
to O–H stretching vibration, illustrating that phenolic
hydroxyls of ligands are not deprotonated as the com-
plexes are formed. The strongest absorptions at 1630,
1625, 1630, and 1623 cm–1 for ligands as well as 1638,
1638, 1644, and 1643 cm–1 for complexes are identi-
fied as C=N stretching vibration. In metal complexes
these bands undergo upward shift by 8, 13, 14, and
20 cm–1 are due to the effect of intramolecular hydro-
gen. The spectra of ligands show strong bands at
1221–1281 cm–1, which are assigned to C–O stretch-
ing vibration, these bands were observed in complexes
In each asymmetric unit of I–IV, there is only one
independent complex molecule. The central manga-
nese(II) atom is four-coordinated via two chlorine
atoms and two oxygen of phenolic hydroxyls of two
monodentate ligands. The coordination geometry
about the manganese atom in all complexes were dis-
torted tetrahedral as indicated by an index τ4, value of
τ4 = 0.85, 0.88, 0.93 and 0.94 for I, II, III, and IV,
respectively (the structure index is defined as τ4 =
[360 – (α + β)]/141° [38], where α and β are the larg-
est coordination angles), τ4 = 0.00 for an ideal square
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 45 No. 3 2019

234
JIN et al.
Table 2. Selected bond length (Å) and angles (deg) in complexes I–IV*
Bond
Mn(1)–Cl(1)
Mn(1)–Cl(2)
Mn(1)–O(1)
d, Å
Bond
Mn(1)–O(2)
N(1)–C(7)
N(2)–C(24)
d, Å
I
2.3124(12)
2.3346(13)
2.028(3)
2.050(3)
1.289(5)
1.291(5)
II
Mn(1)–Cl(1)
Mn(1)–Cl(2)
Mn(1)–O(1)
2.3528(13)
2.3217ω(13)
2.040(3)
Mn(1)–O(3)
N(1)–C(7)
N(2)–C(26)
2.033(3)
1.298(5)
1.290(5)
III
N(1)–C(7)
Mn(1)–Cl(1)
Mn(1)–O(1)
2.3278(10)
2.028(2)
1.284(4)
1.462(4)
N(1)–C(8)
IV
Mn(1)–Cl(2)
Mn(1)–O(1)
2.3332(8)
2.0213(19)
N(1)–C(7)
N(1)–C(8)
1.282(4)
1.459(4)
Angle
ω, deg
Angle
ω, deg
I
Cl(1)Mn(1)Cl(2)
O(1)Mn(1)O(2)
Cl(1)Mn(1)O(1)
Cl(1)Mn(1)O(2)
116.32(6)
96.70(12)
110.89(10)
124.20(9)
Cl(2)Mn(1)O(1)
Cl(2)Mn(1)O(2)
C(7)N(1)C(8)
110.40(11)
96.03(8)
126.7(4)
126.2(3)
C(24)N(2)C(25)
II
Cl(1)Mn(1)Cl(2)
O(1)Mn(1)O(3)
Cl(1)Mn(1)O(1)
Cl(1)Mn(1)O(3)
122.50(6)
103.62(11)
112.85(8)
100.60(8)
Cl(2)Mn(1)O(1)
Cl(2)Mn(1)O(3)
C(7)N(1)C(9)
103.84(9)
112.14(9)
127.6(3)
127.3(3)
C(26)N(2)C(27)
III
Cl(1)Mn(1)O(1A)
Cl(1)Mn(1)Cl(1A)
O(1)Mn(1)O(1A)
Cl(1)Mn(1)O(1)
115.51(6)
93.71(13)
113.03(7)
109.79(8)
126.1(3)
117.0
C(7)N(1)C(8)
C(7)N(1)H(1)
IV
Cl(2)Mn(1)Cl(2A)
O(1)Mn(1)O(1A)
Cl(2)Mn(1)O(1)
115.26(5)
95.12(13)
112.62(6)
Cl(2)Mn(1)O(1A)
C(7)N(1)C(8)
C(7)N(1)H(1)
109.76(7)
126.1(3)
117.0
i
ii
* Symmetry codes: –x + 1, y, –z + 3/2; x, –y + 1, –z + 1/2.
planar and τ4 = 1.00 for an ideal tetrahedral. The dis- planes
defined
by
O(1)Mn(1)O(2)
and
Cl(1)Mn(1)Cl(2) is 79.75° for I, by O(3)Mn(1)O(1)
and Cl(2)Mn(1)Cl(1) is 82.83° for II, by
torted tetrahedral geometry with the smallest angle of
O(2)Mn(1)Cl(2) 96.03(8)° for I, O(3)Mn(1)Cl(1)
100.60(8)° for II, O(1A)Mn(1)O(1) 93.71(13)° for III Cl(1A)Mn(1)Cl(1) and O(1A)Mn(1)O(1) is 87.56° for
i
III, and by Cl(2)Mn(1)Cl(2A) and O(1A)Mn(1)O(1)
is 87.86° for IV. The two phenyl rings are in the inter-
secting planes with a dihedral angle of 76.28°, 83.67°,
80.95°, and 76.93° for I, II, III, and IV, respectively.
And I–IV are expected for a typical Schiff base ligand
(symmetry code: –x + 1, y, –z + 3/2), and
O(1A)Mn(1)O(1) 95.12(13)° for IV (symmetry code:
ii x, –y + 1, –z + 1/2); the biggest angle of
O(2)Mn(1)Cl(1) 124.20(9)° for I, Cl(2)Mn(1)Cl(1)
122.50(6)° for II, Cl(1A)Mn(1)Cl(1) 115.51(6)° for
III, and Cl(2)Mn(1)Cl(2A) 115.26(5)° for IV, where
(containing
a
short C=N bond distance of
the dihedral angle between the two coordination 1.289(5)/1.291(5) Å for I, 1.298(5)/1.290(5) Å for II,
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SYNTHESIS, CRYSTAL STRUCTURE, AND MAGNETIC PROPERTY
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(a)
(b)
H(12A)
C(12A)
H(15A)
C(15)
Cl(2)
C(9)
H(9A)
C(15)
H(15A)
(c)
(d)
Cl(1)
Cl(1A)
Cl(2) Cl(2A)
H(7)
C(7)
H(7)
C(7)
C(7)
H(7)
H(7)
C(7)
Fig. 2. The short contacts (C–H···Cl and/or C–H···π) in I (a), II (b), III (c), and IV (d) packing.
1.284(4) Å for III, and 1.282(4) Å for IV) coordinated
to a metal centre. this coordination pattern of the
manganese(II) complexes is similar to that of zinc(II)
complexes we previously reported [22, 27]. Crystal
structures of I–IV also involve significant intramolec-
ular hydrogen bonds between the imino N and phenol
O atoms forming an additional six-membered ring
because of no deprotonated ligands. The distances of
O–H, H···N and O···N are 0.85/0.85, 1.79/2.02 and
2.580(6)/2.628(5) Å for I, 0.90/0.90, 1.91/1.95 and
2.602(4)/2.588(4) Å for II, N–H, H···O and N···O are
0.86, 1.91 and 2.593(3) Å for III, 0.86, 1.92 and
2.597(3) Å for IV. The hydrogen bond angles O–H···N
are 153°/128° for I and 132°/126° for II, N–H···O are
135° for III and 134° for IV.
In both III and IV, C(8) and C(8A) positions are
chiral centers (RR), other stereoisomers (SS) can be
identified easily in the lattice. In general, they show
the diastereoisomer (RR/SS) (Figs. 1c and 1d).
Although these complexes molecules possess no π–π
stacking interactions, weak C–H···π in I and II or C–
H···Cl interactions in III and IV certainly are respon-
sible for the packing (Fig. 2, Table 3).
The variable-temperature magnetic susceptibilities
of I–IV were measured in an applied magnetic field of
1000 Oe in the temperature range of 2–300 K. The
χ T and −1 versus T plots are shown in Fig. 3, respec-
χM
tiMvely, in which the χM is the molar magnetic suscepti-
bility. It can be observed that the magnetism behavior
of four complexes is quite identical. At room tempera-
Table 3. Weak C–H···Cl and/or C–H···π interactions in the complexes packing
Distance, Å
H···A
Angle
D–H···A, deg
Compound
D–H···A
Symmetry code
D–H
D···A
I
C(9)–H(9A)···Cl(2) –1/2 + x, 3/2 – y, –z
C(12)–H(12A) → Cg –1/2 + x, 3/2 –y, –z
C(15)–H(15A) → Cg –x, –y, 1 – z
0.97
0.98
0.98
0.93
0.93
2.80
2.85
2.82
2.73
2.68
3.770(8)
3.697(4)
3.844(8)
3.549(5)
3.569(3)
178
145
146
148
159
II
III
IV
C(7)–H(7)···Cl(1)
–1/2 + x, –1/2 + y, 3/2 – z
C(7)–H(7)···Cl(2A) 1/2 + x, 1/2 + y, 1/2 – z
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 45 No. 3 2019

236
JIN et al.
(a)
(b)
80
60
40
20
0
80
60
40
20
0
4.2
4.1
4.0
4.3
4.2
4.1
0
100
200
300
0
100
200
300
T, K
T, K
(c)
(d)
80
60
40
20
0
80
60
40
20
0
4.3
4.2
4.1
4.2
4.1
4.0
0
100
200
300
0
100
200
300
T, K
T, K
Fig. 3. Thermal variation of magnetic susceptibility, χ T versus T (square) and −1 versus T (filled circle) of I (a), II (b), III (c),
χM
M
and IV (d) under an applied field of 1000 Oe in the temperature range of 2–300 K.
ture, the values of the χMT product are 3.98, 4.07, tice, presence of the zero-field splitting (ZFS) of the
Mn2+ ions, and the presence of a paramagnetic impu-
rity is indicated by the increase of the magnetic sus-
ceptibility at low temperatures [39–41].
4.04, and 4.07 cm3 K mol–1 for I, II, III, and IV,
respectively, which is near the calculated spin-only
value of 4.375 cm3 K mol–1 for high-spin Mn2+ ions
(g = 2 and S = 5/2). On decreasing the temperature,
the χMT value increases gradually and reach to the
Thus, four manganese(II) complexes have been
prepared and their structures were characterized by
the means of melting point, elemental analysis, IR and
molar conductance. Single-crystal X-ray diffraction
analysis reveals that each Schiff base serves as
monodentate ligand coordinating through an oxygen
atom in I–IV, or to be more exact, the central manga-
nese(II) atom is four-coordinated via two chlorine
atoms and two oxygen atoms from the corresponding
Schiff base ligands. The geometry around the metal
atom in I–IV is distorted tetrahedral structure. Mag-
netic studies reveal that I–IV exhibit ferromagnetic
properties, respectively.
maximum 4.20, 4.26, 4.22, and 4.27 cm3 K mol–1 at
17.93, 21.95, 24.91, and 18.95 K, respectively, then
decrease rapidly, down to 4.09, 4.19, 4.08, and
4.18 cm3 K mol–1 around 5 K. Between 5 and 300 K,
the −1 versus T curves of I–IV were fitted, and fitting
χM
results were all linear, so the behavior of the magnetic
susceptibility obeys the Curie–Weiss rule ( −1 = (T –
χM
θ)/C), with C = 3.98 cm3 K mol–1, θ = 2.80 K for I,
C = 4.07 cm3 K mol–1, θ = 2.65 K for II, C = 4.04 cm3
K mol–1, θ = 2.35 K for III, and C = 4.07 cm3 K mol–1,
θ = 2.50 K for IV. The nature of the χMT versus T plot
(300–20 K) and the positive θ value clearly indicates
that the dominant ferromagnetic interaction in I–IV.
Thus, the decrease sharply in χMT upon cooling in the
low temperature range of 20–5 K might be ascribed to
the effect of several factors: weak antiferromagnetic
ACKNOWLEDGMENTS
This work was financially supported by Foundation
of Liaoning Provincial Department of Education
Innovation Team Projects (grant no. LT2017010); the
Cause of Public Welfare Scientific Research Fund
interactions between the Mn2+ ions in the crystal lat- (grant no. 2015005008); Shenyang Science and Tech-
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SYNTHESIS, CRYSTAL STRUCTURE, AND MAGNETIC PROPERTY
237
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