Syntheses, crystal structures, and magnetic properties of two molecular materials by self-assembly of bis(maleonitriledithiolato)nickelate monoanion and substituted benzyltriphenylphosphinium

Article abstract of DOI:10.1016/j.molstruc.2010.07.042

Two molecular materials, [3RBzTPP][Ni(mnt)₂] (mnt^2- = maleonitriledithiolate, [3RBzTPP]⁺ = 3-R-benzyltriphenylphosphinium, R = CN(1), F(2)), have been investigated and characterized by elemental analyses, IR, UV spectroscopy, X-ray diffraction and magnetic susceptibility measurements. The [Ni(mnt)₂]^- anions of 1 and 2 stack into a column through the Ni?S or/and S?S interactions with a Ni?S distance of 3.765 for 1 and with the Ni?S and S?S distances of 3.654 and 3.681 for 2. The weak CH?N, CH?F hydrogen bonds and π?π stacking interactions result in the forming of a 3D network structure. Magnetic susceptibility measurements in the temperature range 2-300 K show that 1 shows an antiferromagnetic coupling behavior with θ = -9.3 K, and 2 exhibits a spin-gap transition with Δ/k_b = 945.0 K around 217 K.

Full text of DOI:10.1016/j.molstruc.2010.07.042

Journal of Molecular Structure 981 (2010) 139–145
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Syntheses, crystal structures, and magnetic properties of two molecular materials
by self-assembly of bis(maleonitriledithiolato)nickelate monoanion and substituted
benzyltriphenylphosphinium
Xing Chen a, Hai-Lian Zhou a, Jing-Hua Lin a, Qian Huang a, Hong-Rong Zuo a, Jia-Rong Zhou a, Chun-Lin Ni a,
,
*
Xue-Lei Hu b
a Department of Applied Chemistry, Institute of Biomaterial, College of Science, South China Agricultural University, 510642 Guangzhou, PR China
b School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, 430073 Wuhan, PR China
a r t i c l e i n f o
a b s t r a c t
Two molecular materials, [3RBzTPP][Ni(mnt)2] (mnt2ꢀ = maleonitriledithiolate, [3RBzTPP]+ = 3-R-benzyl-
triphenylphosphinium, R = CN(1), F(2)), have been investigated and characterized by elemental analyses,
IR, UV spectroscopy, X-ray diffraction and magnetic susceptibility measurements. The [Ni(mnt)2]ꢀ anions
of 1 and 2 stack into a column through the Niꢁ ꢁ ꢁS or/and Sꢁ ꢁ ꢁS interactions with a Niꢁ ꢁ ꢁS distance of
3.765 Å for 1 and with the Niꢁ ꢁ ꢁS and Sꢁ ꢁ ꢁS distances of 3.654 Å and 3.681 Å for 2. The weak CAHꢁ ꢁ ꢁN,
Article history:
Received 9 April 2010
Received in revised form 26 July 2010
Accepted 27 July 2010
Available online 3 August 2010
CAHꢁ ꢁ ꢁF hydrogen bonds and
p p stacking interactions result in the forming of a 3D network structure.
ꢁ ꢁ ꢁ
Keywords:
Magnetic susceptibility measurements in the temperature range 2–300 K show that 1 shows an antifer-
3-Substituted benzyltriphenylphosphinium
Bis(maleonitriledithiolato)nicklelate
monoanion
romagnetic coupling behavior with h = ꢀ9.3 K, and 2 exhibits a spin-gap transition with
D/kb = 945.0 K
around 217 K.
Ó 2010 Elsevier B.V. All rights reserved.
Crystal structures
Magnetic properties
Spin-gap transition
1. Introduction
materials. Recently, we have been investigating the syntheses,
crystal structures, weak interactions and magnetic properties of
the ion-pair complexes by self-assembly of the [Ni(mnt)2]ꢀ anion
and substituted benzyltriphenylphosphinium cations such as
[BzTPP]+ [22], [oClBzTPP]+ [23], [4CNBzTPP]+ and [4ClBzTPP]+
[24]. In order to extend our studies, here we have used [3RBzTPP]+
(R = CN, F) as counter-cations to obtain two new ion-pair com-
plexes [3CNBzTPP][Ni(mnt)2] (1) and [3FBzTPP][Ni(mnt)2] (2). As
a result, when we changed the R group of 3-position on the phenyl
ring of the benzyl group from CN to F, the crystal system, the stack-
ing pattern of the anions and cations, the overlapping mode of the
anions, and the magnetic properties of the molecular materials
have significantly been changed.
Duo to their ability to assemble in the solid state with the non-
covalent bond such as short Sꢁ ꢁ ꢁS, Mꢁ ꢁ ꢁS (M = Ni, Cu or Pd),
CAHꢁ ꢁ ꢁX (X = N, S, F, Cl, Br, O, etc.) or
pꢁ ꢁ ꢁp stacking interactions
[1–5], transition metal complexes of the dithiolenes have been
widely used as functional materials for a number of applications,
including conducting and magnetic materials dyes [6], non-linear
optical materials [7–9], and electro-active substrates in olefin sep-
aration methods [10]. The stacking mode of the molecular of these
materials can be tuned through changing the metal [11] ions or
modification of the organic dithiolene ligands [12–15], and the
counter-cations [16,17]. In this regard, the spin molecular system
based on [M(mnt)2]ꢀ (M = Ni, Pd or Pt) had been synthesised and
proved to be good building block to construct molecular materials
which exhibit an attractive planar configuration and the highly
sensitive magnetic coupling [18–21]. The work in our laboratory
is to find more suitable multifunctional organic cations to tune
the crystal stacking structure of the molecular solids containing
the [M(mnt)2]ꢀ anion, and obtain some new molecular magnetic
2. Experimental
All reagents and chemicals were purchased from commercial
sources and were used as received. Disodium maleonitriledithiol-
ate (Na2mnt) was synthesized follow the published procedure
[25]. 3-cyanobenzyltriphenylphosphinium bromide ([3CNBzTPP]
Br) and 3-fluorobenzyltriphenylphosphinium bromide ([3FBzTPP]
Br) were prepared by literature methods [26]. A similar method
for preparing [4CNBzTPP][Ni(mnt)2] was used to prepare [3CNBz
TPP][Ni(mnt)2] and [3FBzTPP][Ni(mnt)2] [24].
* Corresponding author. Tel.: +86 20 85282568; fax: +86 20 85282366.
E-mail address: niclchem@scau.edu.cn (C.-L. Ni).
0022-2860/$ - see front matter Ó 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.molstruc.2010.07.042

140
X. Chen et al. / Journal of Molecular Structure 981 (2010) 139–145
2.1. Synthesis of [3CNBzTPP][Ni(mnt)2](1)
2.4. Crystal structure determination
A methanol solution (10 mL) of Na2mnt (370 mg, 1 mmol) was
added to a methanol solution (10 mL) of NiCl2ꢁ6H2O (240 mg,
1 mmol) while stirring, and the mixture was continuously stirred
for 45 min at room temperature. The equal amount of I2 was dis-
solved in 30 mL methanol, and added to the above solution at
one portion, the mixture was warmed at 45 centigrade for
15 min, then 30 mL methanol solution of [3CNBzTPP]Br (505 mg,
1.1 mmol) was dropped to the mixture slowly, cooled down after
another 1.5 h when all the [3CNBzTPP]Br was added. The product
was collected via filtration, wasted with cool methanol and diethyl
ether, and air-dried. Yield: 490 mg, 68%. Anal. Calc. for
The X-ray single-crystal data for 1 and 2 were measured on a Bru-
ker Smart APEX CCD area detector. Graphite-monochromated Mo
Ka radiation (k = 0.71073 Å) and the x-scan technique were used
to collect the data sets. The crystallographic data, the conditions
for the intensity data collection, and some features of the structure
refinements are listed in Table 1. The structures were solved by di-
rect methods and refined by full-matrix least-squares methods on
F2 employing the Bruker’s SHELXTL [27]. All non-hydrogen atoms
were refined with anisotropically. The hydrogen atoms were located
on calculated positions, and their isotropic displacement factors
were set to 1.2 times the value of the equivalent isotropic displace-
ment parameters of the corresponding parent atoms. Significant
bond parameters for 1 and 2 are given in Tables 2 and 3.
C
34H21N5NiPS4: C, 56.92; H, 2.95; N, 9.76%; Found: C, 56.97; H,
3.08; N, 9.65%. IR spectrum (cmꢀ1):
(CN), 2235 w, 2208 s;
(C@C) of mnt2ꢀ, 1439 s. UV spectrum (nm): 288, 269, 311.
m
m
2.2. Synthesis of [FBzTPP][Ni(mnt)2](2)
3. Results and discussion
Compound 2 was prepared by the same processing as that of 1.
Yield: 482 mg, 67%. Anal. Calc. for C33H21N4NiFPS4 (2): C, 55.79; H,
2.98; N, 7.89%. Found: C, 55.85; H, 3.10; N, 7.83%. IR (KBr, cmꢀ1): IR
3.1. Description of crystal structures
The X-ray study of [3CNBzTPP][Ni(mnt)2](1) reveals that it crys-
tallizes in monoclinic lattice with P21/n group, and a labeled ORTEP
plot of the asymmetric unit of 1 is shown in Fig. 1. The structure
spectrum (cmꢀ1):
m
(CN), 2207 s;
m m(CAF),
(C@C) of mnt2ꢀ, 1438 s.
1111 s. UV spectrum (nm): 249, 287, 269, 312.
The black single-crystals suitable for the X-ray structure analy-
ses were obtained by slowly cooling the solution of 1 and 2 in
MeCN about 2 days at 5° below 0 °C.
Table 2
Selected bond lengths and bond angles for 1.
2.3. Instrumental procedures
Bond length (Å)
Ni(1)AS(1)
Ni(1)AS(2)
Ni(2)AS(3)
Ni(2)AS(4)
S(1)AC(2)
S(2)AC(4)
S(3)AC(6)
S(4)AC(8)
N(5)AC(34)
2.148(1)
2.148(1)
2.135(1)
2.142(1)
1.722(3)
1.727(3)
1.722(4)
1.720(4)
1.142(6)
P(1)AC(15)
P(1)AC(21)
P(1)AC(27)
P(1)AC(33)
N(1)AC(1)
N(2)AC(3)
N(3)AC(5)
N(4)AC(7)
1.817(3)
1.799(3)
1.800(3)
1.786(3)
1.137(5)
1.139(5)
1.133(5)
1.135(7)
Elemental analyses of C, H, and N were run on a Model 240
Perkin Elmer CHN instrument. UV–Vis absorption spectrum in
MeCN (1.0 ꢂ 10ꢀ6 mol Lꢀ1) in the region of 230–700 nm was ob-
tained by Shimadzu UV-2500 spectrophotometer. IR spectra were
recorded from KBr pellets on a Nicolet FT-IR spectrophotometer
in 4000–400 cmꢀ1 regions. Magnetic susceptibility measurements
were performed with a Quantum Design instrument with a
super-conducting quantum interference device (SQUID) magne-
tometer working in the temperature range of 2–300 K under an
external magnetic filed of 2000 Oe. Diamagnetic corrections were
estimated from Pascal’s tables.
Bond angles (°)
S(1)ANi(1)AS(2)
S(1)ANi(1)AS(2)#1
S(3)ANi(2)AS(4)
S(3)ANi(2)AS(4)#2
Ni(1)AS(1)AC(2)
Ni(1)AS(2)AC(4)
Ni(2)AS(3)AC(6)
87.16(3)
92.84(3)
87.99(4)
92.01(4)
102.81(11)
102.96(11)
103.95(12)
Ni(2)AS(4)AC(8)
C(15)AP(1)AC(21)
C(15)AP(1)AC(27)
C(15)AP(1)AC(33)
C(21)AP(1)AC(27)
C(21)AP(1)AC(33)
C(27)AP(1)AC(33)
103.77(12)
108.58(14)
111.65(14)
106.83(13)
109.24(13)
110.23(14)
110.28(14)
Table 1
Crystal data and structure refinement for 1 and 2.
Compounds
1
2
Symmetry transformations used to generate equivalent atoms: #1 = ꢀx, ꢀy + 2, ꢀz;
#2 = ꢀx + 1, ꢀy, ꢀz.
Empirical formula
Formula weight
T (K)
C
34H21N5NiPS4
C33H21N4NiFPS4
710.46
291(2)
717.48
291(2)
Wavelength
Crystal system
Space group
a (Å)
b (Å)
c (Å)
0.71073 Å
Monoclinic
P21/n
8.8772(13)
17.460(3)
21.894(3)
90
93.737(2)
90
3386.3(9)
4
0.71073 Å
Triclinic
P-1
Table 3
Selected bond lengths and bond angles for 2.
8.5367(11)
13.6664(18)
14.9912(19)
99.786(2)
103.369(2)
100.488(2)
1631.5(4)
2
Bond length (Å)
Ni(1)AS(1)
Ni(1)AS(2)
Ni(1)AS(3)
Ni(1)AS(4)
S(1)AC(2)
S(2)AC(3)
S(3)AC(6)
S(4)AC(7)
2.150(1)
2.146(1)
2.152(1)
2.144(1)
1.723(5)
1.723(5)
1.716(5)
1.720(4)
P(1)AC(15)
P(1)AC(21)
P(1)AC(27)
P(1)AC(33)
N(1)AC(1)
N(2)AC(4)
N(3)AC(5)
N(4)AC(8)
1.823(5)
1.793(4)
1.796(4)
1.795(4)
1.138(7)
1.139(8)
1.129(8)
1.133(7)
a
(°)
b (°)
c
(°)
Volume (Å3)
Z
Density (calculated) (mg/m3)
Absorption coefficient (mmꢀ1
F(0 0 0)
1.407
0.899
1468
1.446
0.935
726
)
Bond angles (°)
Crystal size (mm3)
Reflections collected
Independent reflections
Data/restraints/parameters
Goodness of fit on F2
0.11 ꢂ 0.15 ꢂ 0.21
0.07 ꢂ 0.12 ꢂ 0.19
S(1)ANi(1)AS(2)
S(1)ANi(1)AS(3)
S(1)ANi(1)AS(4)
S(2)ANi(1)AS(3)
S(2)ANi(1)AS(4)
S(3)ANi(1)AS(4)
Ni(1)AS(1)AC(2)
Ni(1)AS(3)AC(6)
92.72(5)
178.15(6)
87.61(5)
87.35(5)
179.67(5)
92.32(5)
Ni(1)AS(4)AC(7)
C(15)AP(1)AC(21)
C(15)AP(1)AC(27)
C(15)AP(1)AC(33)
C(21)AP(1)AC(27)
C(21)AP(1)AC(33)
C(27)AP(1)AC(33)
F(1)AC(10)AC(11)
103.35(16)
108.3(2)
109.1(2)
110.1(2)
109.5(2)
110.8(2)
109.2(2)
116.3(6)
23,789
11,767
5968(Rint = 0.051)
5968/0/409
1.013
R1 = 0.0388
wR2 = 0.0910
R1 = 0.0661
wR2 = 0.1114
5689 (Rint = 0.028)
5689/0/397
1.014
R1 = 0.0494
wR2 = 0.1448
R1 = 0.0680
wR2 = 0.1697
Final R indices [I > 2
r(I)]
103.16(16)
103.43(16)
Final R indices (all data)
Symmetry transformations used to generate equivalent atoms: #1: ꢀx, ꢀy, ꢀz + 1.

X. Chen et al. / Journal of Molecular Structure 981 (2010) 139–145
141
Fig. 1. ORTEP plot (30% probability ellipsoids) showing the molecule structure of 1.
consists of two halves of the [Ni(mnt)2]ꢀ anion and one
[3CNBzTPP]+ cation. The Ni(III) ion of the [Ni(mnt)2]ꢀ anion shows
a square-planar coordination geometry. The NiAS bond distances
and the SANiAS bond angles (Table 2) within the five-membered
rings agree well with those of [4CNBzTPP][Ni(mnt)2] [24]. By com-
paring [3CNBzTPP][Ni(mnt)2](1) with [4CNBzTPP][Ni(mnt)2][24],
some significant differences are found: (a) for the cation, the dihe-
dral angles h1, h2, h3, and h4 between the C(14)AC(15)AP(1) refer-
ence plane and four phenyl rings are different, these angles for 1
are 97.5(h1)°, 156.4(h2)°, 88.5(h3)°, and 94.0(h4)° for the
C(9)AC(14), C(16)AC(21), C(22)AC(27) and C(28)AC(33) rings
respectively, while 86.3°, 89.8°, 43.9° and 124.8° for the latter;
(2) the crystal system and space group are different, the former
crystallizes in monoclinic lattice with P21/n group, while the latter
does in triclinic with P-1 group; (3) the stacking mode of the anions
is different, the anions of [3CNBzTPP][Ni(mnt)2](1) stack a column
through Niꢁ ꢁ ꢁS weak interactions with a Niꢁ ꢁ ꢁS distance of 3.765 Å
and the Ni(III) ions form a magnetic chain (Fig. 2a), while the an-
ions of the latter form a dimer; (4) the overlapping mode of the an-
ions in a column is different, the former is the Niꢁ ꢁ ꢁS mode (Fig. 2b),
while the latter is Sꢁ ꢁ ꢁRing mode [24]; (5) the weak interactions be-
tween the cations are different, there are two interactions in the
[3CNBzTPP]+ cations such as CAHꢁ ꢁ ꢁN hydrogen bond with a
dihedral angles h1, h2, h3, and h4 change from 97.5°, 156.4°, 88.5°
and 94.0° to 79.9°, 87.6°, 53.7° and 63.7°; (3) in a column of the an-
ions (Fig. 4b), the overlapping mode of anions change from the
Niꢁ ꢁ ꢁS mode to the Sꢁ ꢁ ꢁS and Niꢁ ꢁ ꢁS modes [Figs. 5a and 5b], with
the Sꢁ ꢁ ꢁS and Niꢁ ꢁ ꢁS distances of 3.681 Å and 3.654 Å; and the an-
ions stack into a column through Sꢁ ꢁ ꢁS and Niꢁ ꢁ ꢁS interactions
and the Ni(III) ions form a magnetic chain. In addition, the
[3CNBzTPP]+ cations form a dimer by CAHꢁ ꢁ ꢁF weak interaction
with C(19)ꢁ ꢁ ꢁF(1) distance of 3.371 Å (Fig. 5c). The packing diagram
of 2 as viewed along a axis is shown in Fig. 5d, no obvious interac-
tions were found between the anions and cations.
By comparing the structures of 1,
2 and [4CNBzTPP]
[Ni(mnt)2][24], when the position of substituted group on the phe-
nyl ring of benzyl group from 4 to 3 or the 3-substituted group
from CN to F, the dihedral angles h1, h2, h3 and h4 between the
CACAP reference plane and the phenyl rings, weak interactions,
the stacking pattern of the cations and anions, and the overlapping
mode of the anions are significantly changed. These evident
changes in the crystal structure may further influence on the mag-
netic properties of these molecular solids.
3.2. Magnetic properties of 1 and 2
C(15)ꢁ ꢁ ꢁN(5i) (i = x + 1, y, z) distance of 3.384 Å and
pꢁ ꢁ ꢁp stacking
The variable-temperature (2–300 K) magnetic data for 1 under
an applied field of 2000 Oe, expressed as vm (emu molꢀ1), are
interaction with a distance of 3.551 Å between the phenyl rings
(Fig. 2c). The [3CNBzTPP]+ cation associate with the [Ni(mnt)2]ꢀ
anion via CAHꢁ ꢁ ꢁN weak interaction with the C(15)ꢁ ꢁ ꢁN
(1ii)(ii = ꢀx + 1/2, y ꢀ1/2, ꢀz + 1/2) distance of 3.369 Å. These weak
interactions may play an important role in the stacking and stabi-
lizing of the structure and result in the forming of a 3D network
structure for 1 [Fig. 3].
shown in Fig. 6a. As the temperature is lowered, the vmT value de-
creased from 0.305 emu K molꢀ1 at 300 K to 0.0256 emu K molꢀ1 at
2.0 K, indicative of an antiferromagnetic exchange. The magnetic
susceptibility data in the temperature phase (50–300 K) of 1 can
be finely fitted to the Curie–Weiss law with C = 0.352 emu K molꢀ1
and h = ꢀ9.3 K (the red1 solid line in inset of Fig. 6a).
As shown in Fig. 4a, the unit cell of 2 comprises a [Ni(mnt)2]ꢀ
anion and a [3FBzTPPl]+ cation. The X-ray study reveals that when
the 3-substituted group on the phenyl ring of benzyl group is chan-
ged from CN to F, some evident changes in crystal structure are
found: (1) the crystal system changes from monoclinic for 1 to tri-
clinic for 2, and the space group changes from P21/n to P-1; (2) the
As for 2, when the temperature decreases, the value of
vmT
slightly decreases from 0.370 emu K molꢀ1 at 300 K to
0.0954 emu K molꢀ1 at 217 K, and as the sample is continuously
1
For interpretation of color in Fig. 6, the reader is referred to the web version of
this article.

142
X. Chen et al. / Journal of Molecular Structure 981 (2010) 139–145
(a)
(b)
(c)
Fig. 2. (a) The column and 1D chain of the anions through weak NiꢁꢁꢁS interactions between the anions for 1. (b) The Nꢁ ꢁ ꢁS overlapping mode of the anions for 1. (c) The
CAHꢁ ꢁ ꢁN hydrogen bonds and ꢁ ꢁ ꢁ stacking interactions between the cations for 1.
p
p
constant, C is a constant corresponding to the contribution of the
magnetic impurity, v0 contributes from the core diamagnetism
and the possible Van Vleck paramagnetism. A reasonable fit to the
data within the range of 2–225 K for 2 is shown in Fig. 6b (the
red solid line), and the corresponding parameters are given as
cooled, the magnetic susceptibilities decrease exponentially
(Fig. 6b), indicating that 2 shows the characteristics of a spin gap
system [28–30]. The transition temperature is evaluated as the
temperature at the maximum of the d(vmT)/dT derivative, that is,
ꢃ217 K for 2 (inset of Fig. 6b). The magnetic susceptibility from 2
follows:
a
= 3.96,
D
/kb = 945.04 K,
v
0 = 3.0 ꢂ 10ꢀ5 emu molꢀ1, C =
to 225 K may be simulated by the formula [31]:
6.6 ꢂ 10ꢀ4 emu K molꢀ1
,
and R = 5.0 ꢂ 10ꢀ5 (R is defined as
vm
¼
a
expðꢀ
D
=kbTÞ=T þ C=T þ v0
2
2
Rð
vcmalcd
ꢀ
vmobsdÞ /ðvmobsdÞ )). The magnetic coupling between
[Ni(mnt)2]ꢀ anions is very sensitive to the overlap fashion of neigh-
boring [Ni(mnt)2]ꢀ anions and intermolecular contacts [32], and the
where
energy,
a is a constant corresponding to the dispersion of excitation
D
is the magnitude of the spin gap, kb is the Boltzmann

X. Chen et al. / Journal of Molecular Structure 981 (2010) 139–145
143
Fig. 3. Packing diagram of a unit cell for 1 as viewed along a axis.
(a)
(b)
Fig. 4. (a) ORTEP plot (30% probability ellipsoids) showing the molecule structure for 2. (b) The column and 1D chain of the anions through weak Niꢁ ꢁ ꢁS and Sꢁ ꢁ ꢁS interactions
between the anions for 2.

144
X. Chen et al. / Journal of Molecular Structure 981 (2010) 139–145
(a)
(b)
(c)
(d)
Fig. 5. (a) The Niꢁ ꢁ ꢁS overlapping mode of the anions for 2. (b) The Sꢁ ꢁ ꢁS overlapping mode of the anions for 2. (c) The CAHꢁ ꢁ ꢁF weak interactions between the cations for 2. (d)
Packing diagram of 2 as viewed along a axis.

X. Chen et al. / Journal of Molecular Structure 981 (2010) 139–145
145
nylphosphinium, R = CN(1), F(2)). The [Ni(mnt)2]ꢀ anions of 1
and 2 stack into a column through the Niꢁ ꢁ ꢁS or/and Sꢁ ꢁ ꢁS interac-
tions. The changes of the position or atom of the substituted group
result in the changes of the weak interactions, the stacking pattern
of the cations and anions, and the overlapping mode of the anions.
These evident changes in the crystal structure may further result in
the difference in magnetic properties, that is, 1 shows an antiferro-
magnetic coupling behavior, while 2 exhibits a spin-gap transition
around 217 K.
0.36
0.30
0.24
0.18
0.12
0.06
0.00
(a)
1000
800
600
400
200
0
Acknowledgements
0
50 100 150 200 250 300
T (K)
This work has been partially supported by the key Academic
Program of the 3rd phase ‘‘211 Project” of South China Agricultural
University (No. 2009B010100001) and the Science and Technology
Project (Nos. 2008B080701011, 2007B011000008) from Guang-
dong Science and Technology Department.
0
50
100
150
200
250
300
T (K)
(b)
12
0.40
0.32
0.24
0.16
0.08
0.00
T = 217 K
10
8
References
6
[1] T. Akutagawa, T. Motokizawa, K. Matsuura, S. Nishihara, S.I. Noro, T. Nakamura,
J. Phys. Chem. 12 (2006) 5897.
4
[2] M.L. Mercuri, S. Curreli, P. Deplano, L. Pilia, A. Serpe, E.F. Trogu, J.A. Schlueter, E.
Coronado, C.J. Gómez-García, J. Phys. IV, France 114 (2003) 425.
[3] N. Robertson, L. Cronin, Coord. Chem. Rev. 227 (2002) 93.
[4] L. Ouahab, Coord. Chem. Rev. 178–180 (1998) 1501.
[5] H. Nakajima, M. Katsuhara, M. Ashizawa, T. Kawamoto, T. Mori, Inorg. Chem.
43 (2004) 6075.
[6] K.L. Marshall, G. Painter, K.A. Lotito, A.G. Noto, P. Chang, Mol. Cryst. Liq. Cryst.
47 (2006) 449.
[7] P. Romaniello, F. Lelj, M. Arca, F.A. Devillanova, Theor. Chem. Acc. 117 (2007)
621.
[8] C.A.S. Hill, A. Charlton, A.E. Underhill, K.M.A. Malik, M.B. Hursthouse, A.I.
Karaulov, S.N. Oliver, S.V. Kershaw, J. Chem. Soc. Dalton Trans. (1995) 587.
[9] P. Romaniello, F. Lelj, J. Mol. Struct.: Theochem. 636 (2003) 23.
[10] K. Wang, E.I. Stiefel, Science 291 (2001) 106.
[11] C.L. Ni, Q. Huang, H.R. Zuo, Y. Hou, Q.J. Meng, J. Coord. Chem. 62 (2009) 1502.
[12] C.H. Lin, C.G. Chen, M.L. Tsai, G.H. Lee, W.F. Liaw, Inorg. Chem. 47 (2008)
11435.
[13] K.M. Sung, R.H. Holm, J. Am. Chem. Soc. 124 (2002) 4312.
[14] A. Davison, N. Edelstein, R.H. Holm, A.H. Maki, Inorg. Chem. 3 (1964) 814.
[15] W.B. Pei, J.L. Liu, J.S. Wu, X.M. Ren, D.W. Gu, L.J. Shen, Q.J. Meng, J. Mol. Struct.
918 (2009) 160.
2
0
0
50 100 150 200 250 300
T (K)
0
50
100
150
200
250
300
T (K)
Fig. 6. (a) Plot of
T for 2 (inset: plot of d(
theoretic calculations and detailed fitting procedure described in the text).
v
mT versus T for 1 (inset: plot of vꢀm1 versus T)). (b) Plot of
mT)/dT versus T). The solid line is reproduced from the
vm versus
v
[16] M.G. Liu, C.L. Ni, C.J. Mao, J. Coord. Chem. 59 (2006) 1775.
[17] C.L. Ni, L.L. Yu, L.M. Yang, Inorg. Chim. Acta 359 (2006) 1383.
[18] J. Nishijo, E. Ogura, J. Yamaura, A. Miyazaki, T. Enoki, T. Takano, Y. Kuwatani, M.
Iyoda, Solid State Commun. 116 (2000) 661.
[19] J.L. Xie, X.M. Ren, Y. Song, W.W. Zhang, W.L. Liu, C. He, Q.J. Meng, Chem.
Commun. (2002) 2346.
[20] X.M. Ren, Q.J. Meng, Y. Song, C.S. Lu, C.J. Hu, Inorg. Chem. 41 (2002) 5686.
[21] Z.P. Ni, X.M. Ren, J. Ma, J.L. Xie, C.L. Ni, Z.D. Chen, Q.J. Meng, J. Am. Chem. Soc.
127 (2005) 14330.
[22] C.L. Ni, Y.Z. Li, Q.J. Meng, Coord. Chem. 9 (2005) 759.
[23] Y. Hou, J.R. Zhou, X.P. Liu, L.L. Yu, C.L. Ni, Trans. Met. Chem. 33 (2008) 411.
[24] J.R. Zhou, C.L. Ni, L.L. Yu, L.M. Yang, Inorg. Chim. Acta 361 (2008) 400.
[25] A. Davison, R.H. Holm, Inorg. Synth. 10 (1967) 8.
magnetic exchange nature depends highly on the interplane dis-
tance (d) and the rotation angle (h) [21]. Therefore, the difference
between the magnetic behavior of 1, 2 and [4CNBzTPP][Ni(mnt)2]
[24] may be understood. Compound 1 has a uniform column; the
molecules are located on inversion centers, so the successive
p p interactions are equivalent. As a result, this compound 1 is
ꢁ ꢁ ꢁ
paramagnetic. On the contrary, the molecules in compound 2 are
located on general positions, so that the column is dimerized. The
spin gap is the direct consequence for 2. The spin-gap transition
results from the magnetic exchange constant changing due to the
non-uniform compression of the magnetic chain, the slippage of
the [Ni(mnt)2]ꢀ stack and the anisotropic contraction of the crystal
on the temperature is lowered [33].
[26] S.B. Bulgarevich, D.V. Bren, D.Y. Movshovic, P. Finocchiaro, S. Failla, J. Mol.
Struct. 317 (1994) 147.
[27] SHELXTL, Version 5.10. Structure Determination Software Programs, Bruker
Analytical X-ray Systems, Inc., Madison, Wisconsin, USA, 2000.
[28] Y. Fujii, T. Goto, W. Fujita, K. Awaga, Physica B 329–333 (2003) 973.
[29] S. Nishihara, T. Akutagawa, T. Hasegawa, T. Nakamura, Chem. Commun. (2002)
408.
4. Conclusions
[30] C. Rovira, Chem. Eur. J. 6 (2000) 1723.
[31] L.C. Isett, D.M. Rosso, G.L. Bottger, Phys. Rev. B 22 (1980) 4739.
[32] A.T. Coomber, D. Beljonne, R.H. Friend, J.L. Brédas, A. Charlton, N. Robertson,
A.E. Underhill, M. Kurmoo, P. Day, Nature 380 (1996) 144.
[33] X.M. Ren, S. Nishihara, T. Akutagawa, S. Noro, T. Nakamura, W. Fujita, K.
Awaga, Chem. Phys. Lett. 418 (2006) 423.
In conclusion, the crystal structures and magnetic properties
were presented for two molecular materials, [3RBzTPP][Ni(mnt)2]
(mnt2ꢀ = maleonitriledithiolate,
[3RBzTPP]+ = 3-R-benzyltriphe-