2D crystal structure, magnetic behavior and theoretic analysis of two new molecular solids based on Ni(maleonitriledithiolate)2 monoanion with substituted 2-aminopyridinium

Article abstract of DOI:10.1016/j.ica.2009.11.013

Two new molecular solids, [BzPyNH₂][Ni(mnt)₂](1) and [2-NpCH₂PyNH₂][Ni(mnt)₂](2) (mnt^2- = maleonitriledithiolate, [BzPyNH₂]⁺ = 1-benzyl-2-aminopyridinium and [2-NpCH₂PyNH₂]⁺ = 1-(2′-naphthylmethylene)-2-aminopyridinium) have been characterized structurally and magnetically. The Ni(Sh{cyrillic}) ions of 1 and 2 form a 1D magnetic chain within a [Ni(mnt)₂]^- column through Ni?N or π?π interactions. Some weak interactions observed in 1 and 2 give further rise to a 2D structure. The overlapping fashions of the [Ni(mnt)₂]^- anions are different when the 2-aminopyridine ring was fixed and the phenyl ring changed into the naphthyl ring of the cation. Magnetic susceptibility measurements in the temperature range 2-300 K show that 1 is weak antiferromagnetic coupling, while 2 exhibits a novel and interesting spin-gap transition around 140 K with Δ/k_b = 381.4 K.

Full text of DOI:10.1016/j.ica.2009.11.013

Inorganica Chimica Acta 363 (2010) 424–429
Contents lists available at ScienceDirect
Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
2D crystal structure, magnetic behavior and theoretic analysis
of two new molecular solids based on Ni(maleonitriledithiolate)2
monoanion with substituted 2-aminopyridinium
Yong Hou a, Wen-Tao Yin a, Xiao-Dan Xie a, Xing Chen a, Jia-Rong Zhou a, Hong-Rong Zuo a, Qian Huang a,
b
Le-Min Yang a, Chun-Lin Ni a, , Xue-Lei Hu
*
a Department of Applied Chemistry, Centre of Inorganic Functional Materials, 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 new molecular solids, [BzPyNH2][Ni(mnt)2](1) and [2-NpCH2PyNH2][Ni(mnt)2](2) (mnt2ꢀ = maleo-
nitriledithiolate, [BzPyNH2]+ = 1-benzyl-2-aminopyridinium and [2-NpCH2PyNH2]+ = 1-(20-naphthylm-
ethylene)-2-aminopyridinium) have been characterized structurally and magnetically. The Ni(I) ions
Article history:
Received 25 August 2009
Received in revised form 5 November 2009
Accepted 9 November 2009
Available online 14 November 2009
of 1 and 2 form a 1D magnetic chain within a [Ni(mnt)2]ꢀ column through Niꢁ ꢁ ꢁN or
p p interactions.
ꢁ ꢁ ꢁ
Some weak interactions observed in 1 and 2 give further rise to a 2D structure. The overlapping fashions
of the [Ni(mnt)2]ꢀ anions are different when the 2-aminopyridine ring was fixed and the phenyl ring
changed into the naphthyl ring of the cation. Magnetic susceptibility measurements in the temperature
range 2–300 K show that 1 is weak antiferromagnetic coupling, while 2 exhibits a novel and interesting
Keywords:
Bis(maleonitriledithiolate)nickelate(III)
anion
Substituted 2-aminopyridinium
Crystal structure
spin-gap transition around 140 K with
D/kb = 381.4 K.
Ó 2009 Elsevier B.V. All rights reserved.
Magnetic properties
Spin-gap transition
1. Introduction
molecular solids based on [Ni(mnt)2]ꢀ anion. The present work
reports crystal structures and magnetic behaviors of two newly
The magnetic, super-conducting and optical properties of
molecular solids based on [M(dithiolate)2] (M = Ni, Pd, or Pt ions)
have been the focus of considerable current attention [1–5]. Coom-
ber and co-workers in 1996 discovered that NH4ꢁNi(mnt)2ꢁH2O
shows a ferromagnetic behavior below 4.5 K, suggesting that
magnetic exchange between [Ni(mnt)2]ꢀ anions is very sensitive
to not only the overlap fashion of neighboring [Ni(mnt)2]ꢀ anions
but also intermolecular contacts, and small structural change can
result in large changes in the materials properties of molecular sol-
ids based on the [Ni(mnt)2]ꢀ monoanion [6]. Substituted benzylpy-
ridinium derivatives have been proved to be multifunctional
counter-cation of [M(mnt)2]ꢀ anion, which may make the anions
a diverse number of stacking and overlapping modes and results
in versatile magnetic properties such as ferromagnetic ordering
at low-temperature, magnetic transition, meta-magnetism, spin-
Peierls-like transitions and spin-gap transition [7–12]. These find-
ings have prompted us to further investigate the influence of the
substituent groups in the pyridine and benzene rings of the coun-
ter-cation on the stacking pattern and magnetic properties of
prepared
molecular
solids,
[BzPyNH2][Ni(mnt)2](1)
and
[2-NpCH2PyNH2][Ni(mnt)2](2) ([BzPyNH2]+ = 1-benzyl-2-amino-
pyridinium and [2-NpCH2PyNH2]+ = 1-(20-naphthylmethylene)-2-
aminopyridinium). The Ni(I) ions of both 1 and 2 form a 1D zigzig
magnetic chain through Niꢁ ꢁ ꢁN or
pꢁ ꢁ ꢁp interactions, while the sig-
nificantly different overlapping modes of the neighboring
[Ni(mnt)2]ꢀ anions resulted in the different magnetic properties
that 1 shows antiferromagnetic behavior and 2 exhibits an inter-
esting spin-gap transition around 140 K.
2. Experimental
2.1. General materials and techniques
Disodium maleonitriledithiolate (Na2mnt), 1-benzyl-2-amino-
pyridinium bromide ([BzPyNH2]Br), and 1-(20-naphthylmethyl-
ene)-2-aminopyridinium bromide ([2-NpCH2PyNH2]Br) were
synthesized following the literature procedures [13,14]. A similar
method for preparing [IBzNH2Py]2[Ni(mnt)2] was utilized to pre-
pare [BzPyNH2]2[Ni(mnt)2] and [2-NpCH2PyNH2]2[Ni(mnt)2] [15].
C, H and N analyses were performed by a Model 240 Perkin–Elmer
instrument. IR spectra were recorded on a Nicolet Avatar 360 FT-IR
* Corresponding author. Tel.: +86 20 85282568; fax: +86 20 85282366.
E-mail address: niclchem@scau.edu.cn (C.-L. Ni).
0020-1693/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2009.11.013

Y. Hou et al. / Inorganica Chimica Acta 363 (2010) 424–429
425
(400–4000 cmꢀ1 region) spectrophotometer in KBr pellets. Vari-
able-temperature magnetic data for 1 and 2 were obtained over
the temperature range of 2–300 K using a Quantum Design
MPMS-XL super-conducting quantum interference device (SQUID)
magnetometer, and the experimental data were corrected for dia-
magnetism of the constituent atoms estimated from Pascal’s
constants.
MeCN/i-PrOH (v/v = 2:1) mixture. Table 1 provides a summary of
the crystallographic data for 1 and 2. Data were collected on a
Smart APEX CCD area detector using graphite monochromated
Table 2
Selected bond parameters for 1 and 2.
Complex
1
2
2.2. Synthesis of [BzPyNH2][Ni(mnt)2](1)
Bond distances (Å)
Ni(1)–S(1)
Ni(1)–S(2)
Ni(1)–S(3)
Ni(1)–S(4)
S(1)–C(2)
S(2)–C(3)
S(3)–C(6)
S(4)–C(7)
2.1432(10)
2.1533(10)
2.1455(10)
2.1647(10)
1.720(4)
1.719(4)
1.727(4)
1.714(3)
2.1464(7)
2.1402(7)
2.1504(7)
2.1501(8)
1.717(2)
1.719(2)
1.720(2)
1.721(2)
A CH3COCH3 solution (10 mL) of I2 (140 mg, 0.55 mmol) was
slowly added to a CH3COCH3 solution (50 mL) of [BzPyNH2]2[-
Ni(mnt)2] (709 mg, 1.0 mmol) and the mixture was stirred for
24 h. The mixture was concentrated under reduced pressure until
the volume was reduced to about 20 mL. After initial filtration, to
the dark filtration was added 30 mL i-PrOH and stored in a refrig-
erator overnight. About 425 mg of black micro-crystals formed
were filtered off, washed with MeOH and dried in vacuum. Yield:
81%. Anal. Calc. for C20H13NiN6S4: C, 45.81; H, 2.50; N, 16.03.
Bond angles(°)
S(1)–Ni(1)–S(2)
S(1)–Ni(1)–S(4)
S(2)–Ni(1)–S(3)
S(3)–Ni(1)–S(4)
92.51(4)
87.33(3)
87.42(3)
92.75(3)
92.22(3)
88.04(3)
86.92(3)
92.74(3)
Found: C, 45.77; H, 2.53; N, 15.98%. IR (KBr, cmꢀ1):
3430s; (CH2), 2924m and 2852m; (CN), 2207s;
(C@C) of mnt2ꢀ
1458m.
v(NH2),
v
v
v
,
Dihedral angles (°)
CAr–CH2–NPy and UAr (h1)
CAr–CH2–NPy and UPy (h2)
UAr and UPy (h3)
90.0
0
90.0
118.0
82.1
66.3
2.3. Synthesis of [2-NpCH2PyNH2][Ni(mnt)2](2)
The procedure for preparing 2 was analogous to that for 1.
Yield: 74%. Anal. Calc. for C24H15NiN6S4: C, 50.19; H, 2.63; N,
14.63. Found: C, 50.23; H, 2.68; N, 14.59%. IR (KBr, cmꢀ1):
v
(NH2), 3438s;
v(CH2), 2919m and 2853m; v(CN), 2207s; v(C@C)
of mnt2ꢀ, 1461m.
2.4. Crystal structure determination
The single crystals suitable for the X-ray structure analysis of 1
and 2 were obtained by evaporating the solution prepared in
Table 1
Crystallographic Data for 1 and 2.
Complex
1
2
Empirical formula
Formula weight
Wavelength (Å)
Space group
C20H13NiN6S4
524.33
0.71073
C24H15NiN6S4
574.37
0.71073
P21/m
P21/n
Crystal system
monoclinic
monoclinic
Unit cell dimensions
a (Å)
b (Å)
c (Å)
8.704(1)
7.026(1)
18.466(3)
90
8.101(1)
23.786(2)
13.488(1)
90
a
(°)
b (°)
98.67(1)
90
1116.4(3), 2
1.560
106.46(1)
90
2492.5(4), 4
1.531
c
(°)
V (Å3), Z
Dcalc (g/cm3)
Absorption coefficient
F (0 0 0)
1.264
534
1.140
1172
Crystal size (mm3)
Maximum and minimum
transmission
0.23 ꢂ 0.18 ꢂ 0.11 0.23 ꢂ 0.18 ꢂ 0.12
0.873 and 0.760
0.875 and 0.780
h range for date collection (°)
Limiting indices
2.2–25.0
1.7–25.0
ꢀ10 6 h 6 9
ꢀ8 6 k 6 8
ꢀ21 6 l 6 21
8059
ꢀ9 6 h 6 9
ꢀ28 6 k 6 27
ꢀ16 6 l 6 16
17 982
Reflections collected
Independent reflections
2143
4394
(Rint
)
0.040
1.015
0.060
1.000
Goodness-of-fit (GOF) on F2
R1
wR2
0.0343, 0.0399
0.1233, 0.1312
0.0372, 0.0471
0.1012, 0.1061
0.40 and ꢀ0.42
Largest difference in peak and hole 0.34 and ꢀ0.30
Fig. 1. (a) ORTEP plot showing the structure of 1. (b) Side view of the anions stack of
1 showing the uniform space linear-chain of [Ni(mnt)2]ꢀ anions.
(e Å–3
)

426
Y. Hou et al. / Inorganica Chimica Acta 363 (2010) 424–429
Table 3
Mo Ka radiation (k = 0.71073 Å). The structures were solved by di-
Intermolecular hydrogen bonds for 1 and 2.
rect methods, and non-hydrogen atoms were refined anisotropi-
cally using full matrix least-squares based on F2. In two
structures, the C–H hydrogen atoms were placed in calculated
positions, assigned isotropic thermal parameters, U(H) = 1.2Ueq(C),
and allowed to ride on their parent atoms. The N–H hydrogen
D–Hꢁ ꢁ ꢁA
Compound 1
d(Dꢁ ꢁ ꢁH)
d(Hꢁ ꢁ ꢁA)
d(Dꢁ ꢁ ꢁA)
\(DHA)
N(6)–H(6B)ꢁ ꢁ ꢁN(4)#1
0.860
0.930
2.200
2.620
3.054(5)
3.332(5)
170.0
134.0
N(15)–H(15)ꢁ ꢁ ꢁN(3)#1
atoms were located from
DF maps and refined isotropically. All
Compound 2
N(6)–H(6A)ꢁ ꢁ ꢁN(2)#2
0.860
2.500
2.968(3)
115.0
computations were carried out using Bruker’s SHELXTL program sys-
tem [16]. Selected bond lengths and bond angles for 1 and 2 are
listed in Table 2.
Symmetry code: #1 = x + 1, y, z + 1; #2 = ꢀx + 1, ꢀy, ꢀz.
[Ni(mnt)2]ꢀ anion and [BzPyNH2]+ cation (Table 3): (1) N(6)–
H(6B)ꢁ ꢁ ꢁN(4i) (symmetry code: i = x + 1, y, z + 1) hydrogen bond
with a N(6)ꢁ ꢁ ꢁN(4i) distance of 3.054 Å; (2) C(15)–H(15)ꢁ ꢁ ꢁN(3ii)
3. Results and discussion
3.1. Crystal structures
(symmetry code: ii = x + 1, y, z + 1) hydrogen bond with
a
C(15)ꢁ ꢁ ꢁN(3ii) distance of 3.332 Å; (3)
p p interactions between
CN group and pyridine ring with a distance of 3.513 Å. These weak
ꢁ ꢁ ꢁ
An ORTEP drawing of 1 in an asymmetric unit is shown in
Fig. 1a with one [Ni(mnt)2]ꢀ anion and a [BzPyNH2]+ cation. The
Ni(III) ion in the [Ni(mnt)2]ꢀ anion is coordinated by four sulfur
atoms of two mnt2ꢀ ligands, and exhibits square-planar coordina-
tion geometry. The Ni–S bond distance and S–Ni–S bond angles are
in agreement with those of the previously reported molecular sol-
ids based on [Ni(mnt)2]ꢀ anion [7–12]. In the [BzPyNH2]+ moiety,
the dihedral angle of the C(12)–C(13)–N(5) reference plane are
90.0°(h1) for benzene ring and 0.0°(h2) for pyridine ring, respec-
tively. The phenyl ring and the pyridine ring make a dihedral angle
of 90.0°(h3). Within a [Ni(mnt)2]ꢀ anions stacking column, the
Ni(III) ions of [Ni(mnt)2]ꢀ anions form a 1D uniform chain with
the Niꢁ ꢁ ꢁNi distance of 6.370 Å through intermolecular Niꢁ ꢁ ꢁN,
interactions give further rise to a 2D structure (Fig. 2b).
In order to investigate effect of the substituted group in the
counter-cation on the overlapping fashion of the [Ni(mnt)2]ꢀ an-
ions and the packing pattern of the molecular solids based on
[Ni(mnt)2]ꢀ anion, [2-NpCH2PyNH2][Ni(mnt)2](2) is prepared by
utilizing the starting material [2-NpCH2PyNH2]Br instead of
[BzPyNH2]Br. The crystal structural analysis has revealed that the
coordination geometries of the anion and cation of 2 are essentially
identical to those described above for 1, while the dihedral angles
h1, h2, and h3 are 118.0°, 82.1° and 66.3° for [2-NpCH2PyNH2]+ cat-
ion, respectively, which are markedly different from those of 1. The
stacking columns of the anions and the cations for 2 along the
direction of a-axis are shown in Fig. 3a. In a cationic column, the
adjacent cations stacked in chair-type conformation (Fig. 3b) and
Sꢁ ꢁ ꢁC or
p
ꢁ ꢁ ꢁ
p
interactions (Fig. 1b). The nearest Niꢁ ꢁ ꢁN and Sꢁ ꢁ ꢁC
distances are 3.604 and 3.723 Å. The overlapping fashion between
neighboring anions along the stacking direction is Ni–N mode
(Fig. 2a). Three weak interactions are observed between
form a 1D column by the
pꢁ ꢁ ꢁp stacking interactions between the
Fig. 2. (a) The ring–ring overlapping fashion of [Ni(mnt)2]ꢀ anions of 1. (b) The packing diagram for 1 as viewed along the b-axis.

Y. Hou et al. / Inorganica Chimica Acta 363 (2010) 424–429
427
Fig. 3. (a) The packing diagram for 2 as viewed along the a-axis. (b) Chair-type conformation of the cations in 2. (c) Side view of the anions stack of 2 showing the alternating
space linear-chain of [Ni(mnt)2]ꢀ anions.
naphthyl rings with a vertical distance of 3.626 Å. Within the anion
column, the Ni(III) ions form a 1D alternating chain with Niꢁ ꢁ ꢁNi
distances being 4.201 and 6.617 Å through intermolecular Niꢁ ꢁ ꢁS,
3.2. Magnetic properties
The variable-temperature (2–300 K) magnetic data for 1 under
an applied field of 2000 Oe, expressed as vm (emu molꢀ1), are
Sꢁ ꢁ ꢁS,
p p interactions (Fig. 3c). Two overlapping fashions of the
ꢁꢁ
neighboring [Ni(mnt)2]ꢀ anions are depicted in Fig. 4a and b. The
weak N–Hꢁ ꢁ ꢁN hydrogen bond between the anion and the cation
observed in the 2 (Table 3) results in the formation of 2D structure
(Fig. 3a).
From the point of view of structure analysis for 1 and 2, when we
have fixed the 2-aminopyridine ring and changed the phenyl ring
into the naphthyl ring, the dihedral angles h1, h2, and h3, as well
as the overlapping modes of the anions in the crystal are markedly
different. In addition, some weak interactions in 1 and 2 play
important roles in the molecular stacking and magnetic coupling.
shown in Fig. 5a. As the temperature is lowered, the vmT value de-
creased from 0.379 at 300 K to 0.142 emu K molꢀ1, indicative of
very weak antiferromagnetic exchange. The magnetic susceptibil-
ity data in the temperature phase (2–300 K) of 1 can be finely fitted
to the Curie-Weiss law with C = 0.376 emu K molꢀ1 and h = ꢀ4.2 K
(the red solid line in Fig. 5a). The very weak antiferromagnetic cou-
pling situation is consistent with the structure of 1.
For 2, it is very interesting that the
as the temperature is lowered (Fig. 5b): at first it gradually increase
to a maximum at 210 K, and below the temperature the vm value
vm varies in a complex way

428
Y. Hou et al. / Inorganica Chimica Acta 363 (2010) 424–429
Fig. 4. (a) The Ni-ring overlapping fashion of [Ni(mnt)2]ꢀ anions of 2. (b) The ring–ring overlapping fashion of [Ni(mnt)2]ꢀ anions of 2.
of structure analysis for 2, the magnetic interaction between the
0.06
0.05
0.04
0.03
0.02
0.01
0.00
Ni(1) and Ni(1A) ions (Fig. 4a) is larger that that between the
Ni(1) and Ni(1B) ions (Fig. 4b). Therefore, the magnetic susceptibil-
ity data in the high-temperature phase (120–300 K) of 2 can be fit-
ted using simple dinuclear model approximation (the Hamiltonian
being H = ꢀ2JSASB) (Eq. (1) [23]:
vm ¼ ð2Nb2g2=kTÞð1 ꢀ
Þ=ð3 þ expðꢀ2J=kTÞÞ
q
þ ðNb2g2=2kTÞ
q
ð1Þ
where N, g, k, b and
q have their usual meanings, and J is the ex-
0
50 100 150 200 250 300
T (K)
change coupling parameter describing the magnetic interaction be-
tween any two neighbouring s = 1/2 spins. The best-fit parameters
obtained by least-squares fit are: g = 1.99, J = ꢀ251.7 cmꢀ1
,
3.0
2.4
1.8
1.2
0.6
0.0
= 4.8 ꢂ 10ꢀ2
and
R = 8.6 ꢂ 10ꢀ6
(R
is
defined
as
2.5
q
T = 140.4 K
P
P
2
2
2.0
ð
vcmalcd
ꢀ
vombsdÞ =
ð
vombsdÞ Þ. The magnetic susceptibilities in the
1.5
1.0
0.5
0.0
low-temperature phase (2–120K) may be estimated by the formula
(Eq. (2) [24]:
0
50 100 150 200 250 300
T (K)
vm
¼
a
expðꢀ
D
=kbTÞ=T þ C=T þ v0
ð2Þ
where
a is a constant value corresponding to the dispersion of exci-
tation energy, is the magnitude of the spin-gap, v0 contributes
D
from the core diamagnetism and the possible Van Vleck paramag-
netism, and the other symbols have their usual meanings. The
best-fitting curve is shown in Fig. 5b, and the corresponding param-
0
50 100 150 200 250 300
T (K)
eters are given as follows:
a
= 1.90,
D
/kb = 381.4 K, C = 5.4 ꢂ
10ꢀ3 emu K molꢀ1
,
v
0 = 5.0 ꢂ 10ꢀ5 emu molꢀ1, and R = 2.9 ꢂ 10ꢀ6
.
Fig. 5. Plots of vm vs. T for 1(a) and 2(b) (inset: plot of d(vmT)/dT vs. T). The solid
lines are reproduced from the theoretic calculations and detailed fitting procedure
described in the text.
According to the results, the value of the parameter 2D/kbTc (Tc is
the transition temperature) are estimated to be 5.43 for 2, which
is higher than the ideal value of 3.53 derived from the BCS formula
in a weak coupling regime. This result thus means that the spin-gap
transition is not a pure spin-Peierls transition [25,26].
decreases abruptly to a minimum around 60 K, and finally in-
creases again upon further cooling to 2 K. The room temperature
Derivatives of benzylpyridinium (abbreviated as [RBzPy]+) have
been proved to serve as flexible cations which can be adjusted via
modifying the nature of the groups on the aromatic rings, and the
molecular configuration may be determined by three dihedral an-
gles (h1, h2, and h3) [27]. When we have fixed the 2-aminopyridine
ring and changed the phenyl ring into the naphthyl ring, these
dihedral angles were changed from 90.0°, 0° and 90.0° for 1 to
118.0°, 82.1° and 66.3° for 2. The overlapping fashions of the
[Ni(mnt)2]ꢀ anions are markedly different for 1 and 2 (Figs. 2a,
v
mT, value of 0.286 emu K molꢀ1 is significantly lower that the ex-
pected value (0.375 emu K molꢀ1) or NiIII (s = 1/2) that is magneti-
cally isolated, and the value of
mT decreases to 0.226 emu K molꢀ1
around 210 K when the temperature decreases. Below this temper-
ature, the m decreases exponentially and exhibits the characteris-
tics of a spin-gap system [17–22]. The transition temperature is
evaluated as the temperature at the maximum of the d( mT)/dT
derivative, that is, ꢃ140 K (inset of Fig. 5b). From the point of view
v
v
v

Y. Hou et al. / Inorganica Chimica Acta 363 (2010) 424–429
429
4a and b). For 2, On the temperature is lowered, the non-uniform
References
compression of the magnetic chain and slippage of the [Ni(mnt)2]ꢀ
stack due to the anisotropic contraction of the crystal result in the
magnetic exchange constant changing and trigger a spin-gap
transition.
[1] N. Robertson, L. Cronin, Coord. Chem. Rev. 227 (2002) 93.
[2] E. Canadell, Coord. Chem. Rev. 185–186 (1999) 629.
[3] C. Rovira, Chem. Eur. J. 6 (2000) 1723.
[4] T. Akutagawa, T. Nakamura, Coord. Chem. Rev. 226 (2002) 3.
[5] M.M. Torrent, H. Alves, E.B. Lopes, M. Almeida, K. Wurst, J.V. Gancedo, J.
Veciana, C. Rovira, J. Solid State Chem. 168 (2002) 563.
[6] 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.
[7] 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.
[8] J.L. Xie, X.M. Ren, Y. Song, Y. Zou, Q.J. Meng, J. Chem. Soc., Dalton Trans. (2002)
2868.
[9] X.M. Ren, Q.J. Meng, Y. Song, C.L. Lu, C.J. Hu, X.Y. Chen, Z.L. Xue, Inorg. Chem. 41
(2002) 5931.
[10] C.L. Ni, Z.P. Ni, Z.F. Tian, Q.J. Meng, Synth. Met. 158 (2008) 1015.
[11] C.L. Ni, D.B. Dang, Y.Z. Li, S. Gao, Z.P. Ni, Z.F. Tian, Q.J. Meng, J. Solid State Chem.
178 (2005) 100.
[12] J.L. Xie, X.M. Ren, Y. Song, W.W. Zhang, W.L. Liu, C. He, Q.J. Meng, Chem.
Commun. (2002) 2346.
[13] A. Davison, R.H. Holm, Inorg. Synth. 10 (1967) 8.
[14] S.B. Bulgarevich, D.V. Bren, D.Y. Movshovic, P. Finocchiaro, S. Failla, J. Mol.
Struct. 317 (1994) 147.
4. Conclusion
Two new molecular solids, [BzPyNH2][Ni(mnt)2](1) and
[2-NpCH2PyNH2][Ni(mnt)2](2)
(mnt2ꢀ = maleonitriledithiolate,
[BzPyNH2]+ = 1-benzyl-2-aminopyridinium
and
[2-NpCH2Py
NH2]+ = 1-(20-naphthylmethylene)-2-aminopyridinium) have been
characterized structurally and magnetically. The Ni(I) ions of 1
and 2 form a 1D magnetic chain within a [Ni(mnt)2]ꢀ anions col-
umn through Niꢁ ꢁ ꢁN or
p p interactions. The overlapping fash-
ꢁ ꢁ ꢁ
ions of the [Ni(mnt)2]ꢀ anions are different when we have fixed the
2-aminopyridine ring and changed the phenyl ring into the
naphthyl ring. Magnetic susceptibility measurements in the tem-
perature range 2–300 K show that 1 displays weak antiferromag-
[15] C.L. Ni, Y. Song, Q.J. Meng, Chem. Phys. Lett. 419 (2006) 351.
[16] SHELXTL
, Version 5.10. Structure Determination Software Programs, Bruker
netic coupling (h = ꢀ4.2 K, while
2
exhibits
a
novel and
Analytical X-ray Systems, Inc., Madison, Wisconsin, USA, 2000.
[17] Y. Fujii, T. Goto, W. fujita, K. Awaga, Physica B 329–333 (2003) 973.
[18] S. Nishihara, T. Akutagawa, T. Hasegawa, T. Nakamura, Chem. Commun. (2002)
408.
[19] C. Yasuda, S. Todo, M. Matsumoto, H. Takayama, J. Phys. Chem. Solids 63
(2002) 1607.
[20] S. Nishihara, T. Akutagawa, T. Hasegawa, S. Fujiyama, T. Nakamura, J. Solid
State Chem. 168 (2002) 661.
[21] C.L. Ni, Y.Z. Li, D.B. Dang, Z.P. Ni, Z.F. Tian, Z.R. Yuan, Q.J. Meng, Inorg. Chem.
Commun. 8 (2005) 105.
interesting spin-gap transition around 140 K with
D/kb = 384.1 K.
Supplementary material
CCDC 711739 and 711740 contain the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
[22] D.B. Dang, C.L. Ni, Y. Bai, Z.F. Tian, Z.P. Ni, L.L. Wen, Q.J. Meng, S. Gao, Chem.
Lett. 5 (2005) 680.
[23] X.M. Ren, T. Akutagawa, S. Nishihara, T. Nakamura, Synth. Met. 150 (2005) 57.
[24] L.C. Isett, D.M. Rosso, G.L. Bottger, Phys. Rev. B 22 (1980) 4739.
[25] C.L. Ni, D.B. Dang, Y. Song, S. Gao, Y.Z. Li, Z.P. Ni, Z.F. Tian, L.L. Wen, Q.J. Meng,
Chem. Phys. Lett. 396 (2004) 353.
[26] X.M. Ren, Q.J. Meng, Y. Song, C.S. Lu, C.J. Hu, Inorg. Chem. 41 (2002) 5686.
[27] X.M. Ren, S. Nishihara, T. Akutagawa, S. Noro, T. Nakamura, W. Fujita, K.
Awaga, Z.P. Ni, J.L. Xie, Q.J. Meng, R.K. Kremer, J. Chem. Soc., Dalton Trans.
(2006) 1988.
Acknowledgements
The authors thank the Science and Technology Project (No.
2007B011000008, No. 2008B080703005) from Guangdong Science
and Technology Department and the President’s Science Founda-
tion of South China Agricultural University (No. 2008X015) for
financial support of this work.