metal-organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
and the substituents on the aryl rings. To test this idea, we
prepared a series of complexes by systematically varying the
substituents on the aryl rings and found that it was possible to
obtain completely separated anions and cations in columnar
stacking structures. We report herein the crystal structure of
the title compound, (I), which has columnar packing.
ISSN 0108-2701
2-Methyl-1-(4-nitrobenzyl)pyri-
dinium bis(maleonitriledithiolato)-
nickelate(III)
Xiao-Ming Ren,a Hai-Fang Li,b Pei-Heng Wua* and
Qing-Jin Mengb
aDepartment of Electronic Science and Engineering, Nanjing University, Nanjing
210093, People's Republic of China, and bCoordination Chemistry Institute and State
Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093,
People's Republic of China
In the anion of (I), the Ni atom exhibits square-planar
coordination geometry involving four S atoms, and the ®ve-
membered nickel-containing rings are slightly puckered
(Fig. 1), as has been found in other [M(mnt)2]n structures
(Plumlee et al., 1975). The average SÐNiÐS bond angle
within the ®ve-membered ring is 92.50 (5)ꢁ and the average
Correspondence e-mail: yjfeng@nju.edu.cn
Received 2 January 2001
Accepted 1 June 2001
Ê
NiÐS bond distance is 2.1477 (13) A. Other chemically
In the title complex, 2-methyl-1-(4-nitrobenzyl)pyridinium
bis(1,2-dicyanoethene-1,2-dithiolato)nickelate(III), (C13H13-
N2O2)[Ni(C4N2S2)2], the most prominent general structural
feature of the complex is the completely segregated columnar
stacks of anions and cations. Within the cation column, there
may be stacking interactions between adjacent nitro groups
and benzene rings.
equivalent but crystallographically non-equivalent bond
distances within the anion differ by less than three s.u.'s and
compare well with those found in [Ni(mnt)2] complexes
(Brunn et al., 1987). The anion is non-planar and the CN
groups bend away from the plane of the four S atoms. The CN
group with the largest deviation is C1 N1 and the deviations
from the plane de®ned by the four S atoms are 0.294 (6) and
Ê
0.167 (6) A for N1 and C1, respectively. The cation adopts a
conformation where the dihedral angle between the benzene
ring and the C14/C15/N6 reference plane is 44.5 (4)ꢁ, and the
Comment
Recently, considerable interest has been focused on low-
dimensional molecular solids with novel magnetic properties,
such as spin-Peierls transitions (Brown et al., 1998) and room-
temperature spin bistability (Fujita & Awaga, 1999). Our aim
is to construct quasi-one-dimensional molecule-based
magnetic materials formed by plate-like maleonitriledithiol-
ene (mnt) anionic metal complexes [M(mnt)2] (M is NiIII,
PdIII or PtIII). These types of low-dimensional materials are
associated with columnar crystallographic packing. Previous
work has shown that the geometry of the counter-cations
strongly in¯uences the stacking structure of this type of
material. Therefore, it is important to select particular
counter-cations in order to obtain columnar crystallographic
packing. The ground-state conformations of benzylpyridinium
derivatives have been extensively investigated by many tech-
niques, and results to date have indicated that the spatial
orientation of the benzene and pyridine rings depends on both
the electronic and steric properties of the substituents on the
aryl rings (Bulgarevich et al., 1994). The different conforma-
tions available to benzylpyridinium derivatives may lead to
differences in the geometry of the cations suf®cient to in¯u-
ence the stacking structures of the complexes in the solid state.
As a result, the ion-pair complexes consisting of [M(mnt)2]
anions and benzylpyridinium-derived cations present a unique
opportunity for the systematic investigation of the funda-
mental relationship between the stacking structure in the solid
Figure 1
The molecular structure of complex (I) with the atom-numbering scheme
and 50% probability displacement ellipsoids. H atoms have been omitted
for clarity.
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1022 # 2001 International Union of Crystallography
Printed in Great Britain ± all rights reserved
Acta Cryst. (2001). C57, 1022±1024
Ren
