Four new copper(II) complexes with di-substituted s-triazine-based ligands

Article abstract of DOI:10.1016/j.ica.2011.06.041

In this paper, two di-substituted triazine-based ligands, 6-chloro-N,N,N′N′-tetrakis-pyridin-2-ylmethyl-[1,3,5]triazine-2, 4-diamine (L1), and 6-chloro-N,N′-bis-pyridin-2-ylmethyl-N,N′-bis- thiophen-2-ylmethyl-[1,3,5]triazine-2,4-diamine (L2), have been prepared. Reaction of CuCl₂·2H₂O and Cu(NO₃) ₂·3H₂O with L1 and L2 results in the formation of [Cu₂Cl₄(L1)]·3MeOH (compound 1), [Cu ₄(NO₃)₈(L1)₂]·2.07CH ₂Cl₂·0.93MeOH (compound 2), [Cu₂Cl ₄(L2)₂] (compound 3) and [Cu(NO₃) ₂(L2)]·CH₂Cl₂ (compound 4), respectively, which have been fully characterized and determined by single-crystal X-ray crystallography, FT-IR, elemental analysis, thermogravimetric measurement and magnetic susceptibility. The dinuclear compound 1 shows strong π-π interactions between the neighboring pyridine rings. The nitrate-π (1,3,5-triazine ring) interaction with the distance of 2.755 in compound 2, is the closest contact reported so far. Compounds 3 and 4 are mononuclear copper(II) compounds, in which none of thiophene rings coordinates with copper(II) ion. In addition, the different orientations of two thiophene rings in compounds 3 and 4 lead to the π-π and CH ₂Cl₂-π (thiophene ring) interactions in compound 4, but not in compound 3.

Full text of DOI:10.1016/j.ica.2011.06.041

Inorganica Chimica Acta 376 (2011) 350–357
Contents lists available at ScienceDirect
Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
Four new copper(II) complexes with di-substituted s-triazine-based ligands
⇑
Jinfeng Chu, Wei Chen, Guangxun Su, Yu-Fei Song
State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 100029 Beijing, PR China
a r t i c l e i n f o
a b s t r a c t
0
0
Article history:
In this paper, two di-substituted triazine-based ligands, 6-chloro-N,N,N N -tetrakis-pyridin-2-ylmethyl-
[
Received 31 March 2011
Received in revised form 22 June 2011
Accepted 29 June 2011
0
0
1,3,5]triazine-2,4-diamine (L1), and 6-chloro-N,N -bis-pyridin-2-ylmethyl-N,N -bis-thiophen-2-ylmethyl
[1,3,5]triazine-2,4-diamine (L2), have been prepared. Reaction of CuCl O and Cu(NO ꢀ3H O with
ꢀ2H
L1 and L2 results in the formation of [Cu Cl (NO (L1) ]ꢀ2.07CH Cl
(L1)]ꢀ3MeOH (compound 1), [Cu
0.93MeOH (compound 2), [Cu Cl (L2) ] (compound 3) and [Cu(NO Cl (compound 4), respec-
(L2)]ꢀCH
-
2
2
3
)
2
2
2
4
4
)
3 8
2
2
2
Available online 7 July 2011
ꢀ
2
4
2
3
)
2
2
2
tively, which have been fully characterized and determined by single-crystal X-ray crystallography, FT-IR,
elemental analysis, thermogravimetric measurement and magnetic susceptibility. The dinuclear com-
Keywords:
Copper
Triazine
Non-covalent interactions
pound 1 shows strong
p–p interactions between the neighboring pyridine rings. The nitrate–p (1,3,5-
triazine ring) interaction with the distance of 2.755 Å in compound 2, is the closest contact reported so
far. Compounds 3 and 4 are mononuclear copper(II) compounds, in which none of thiophene rings coor-
dinates with copper(II) ion. In addition, the different orientations of two thiophene rings in compounds 3
and 4 lead to the
p
–
p
and CH
2
Cl
2
–
p
(thiophene ring) interactions in compound 4, but not in compound 3.
Ó 2011 Elsevier B.V. All rights reserved.
1
. Introduction
Supramolecular chemistry involves the intelligent utilization of
lone pairs, which offer great opportunities for the formation of
non-covalent interactions. The crystal structures of the resulting
compounds 1–4 feature the anticipated non-covalent interactions,
leading to the formation of novel 1D and 2D supramolecular
arrays.
non-covalent interactions and all biological systems are based on
these efficient interactions [1–4]. Non-covalent interactions such
as hydrogen bonding and p–p interactions, play vital roles in defin-
ing supramolecular assemblies both in solution and the solid state,
and they have recently been extended to those interactions be-
2
. Experimental
tween electron-rich molecule and an electron-deficient
5–7].
The s-triazine ring is a remarkable building block to generate
p ring
2
.1. Materials and general methods
[
The solvents used in the reactions were dried according to stan-
supramolecular interactions [8]. This is closely related to its struc-
tural characteristics, which include (1) three nitrogen atoms can
give rise to coordination or hydrogen bonds; (2) the electron defi-
cient character of triazine ring allows the formation of a variety of
supramolecular interactions that appear to be of great significance
for the stabilization of some biological macromolecules [9]. A thor-
ough examination of the literature on the triazine-based supramo-
lecular assemblies indicates that despite the fact that there are a
large number of tri-substituted compounds have been reported
so far [8,10], little attention has been paid to the di-substituted
dard procedures. All reactions were performed under an inert
atmosphere, under strictly anhydrous conditions. All reagents
was purchased from commercial sources and used without further
purification. The compound of di-(2-picolyl)amine was obtained by
reaction of one equivalent of pyridin-2-yl-methylamine and one
equivalent of pyridine-2-carbaldehyde in MeOH and further
4
reduced by adding excess amount of NaBH . The compound pyri-
din-2-ylmethyl-thiophen-2-ylmethyl-amine was obtained by reac-
tion of one equivalent of pyridin-2-yl-methylamine and one
equivalent of thiophene-2-carbaldehyde in MeOH and further
0
0
triazine derivatives. In this study, 6-chloro-N,N,N N -tetrakis-
pyridin-2-ylmethyl-[1,3,5]triazine-2,4-diamine (L1), and 6-chloro-
4
reduced by adding excess amount of NaBH . C, H and N analyses
were carried out in Peking University using Vario elemental
analysis III instrument. Fourier transform infrared (FT-IR) spectra
were recorded on a Bruker Vector 22 infrared spectrometer, using
0
0
N,N -bis-pyridin-2-ylmethyl-N,N -bis-thiophen-2-ylmethyl-[1,3,
]-triazine-2,4-diamine (L2) (see Scheme 1) have been designed
with N- and S-coordinating groups and non-coordinating Cl with
5
1
the KBr pellet method. H NMR spectra were recorded on Bruker
4
00 MHz spectrometers at room temperature. Magnetic suscepti-
⇑
Corresponding author. Tel./fax: +86 10 64431832.
E-mail addresses: songyf@mail.buct.edu.cn, songyufei@hotmail.com (Y.-F. Song).
bility measurements were performed in the temperature range
2–300 K using a Quantum Design MPMS XL-7 SQUID magnetome
0
020-1693/$ - see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2011.06.041

J. Chu et al. / Inorganica Chimica Acta 376 (2011) 350–357
351
2.3. Synthesis of compounds 1–4
S
N
N
N
N
N
N
2.3.1. Synthesis of compound 1
A solution of L1 (70 mg, 0.14 mmol) in MeOH (5 ml) was added
dropwise to a solution of CuCl O (46 mg, 0.28 mmol) in MeOH
(5 ml) and the resulting green solution was left undisturbed at room
temperature. Blue crystals suitable for X-ray crystallography were
obtained after slow evaporation of the above solution for one week.
N
N
N
N
N
N
2
ꢀ2H
2
N
N
N
N
S
Cl
Cl
ꢁ
1
Yield: 36.0 mg, (30%); IR (KBr, cm ): 3463(m), 1608(m), 1562(s),
518(s), 1472(m), 1435(m), 1407(m), 1351(s), 1307(m), 1217(m),
1145(m), 1031(m), 839(w), 807(w), 761(w), 733(m). Anal. Calc. for
L1
L2
1
0
0
Scheme 1. The molecular structures of 6-chloro-N,N,N N -tetrakis-pyridin-2-
ylmethyl-[1,3,5]triazine-2-4-diamine (L1), 6-chloro-N,N -bis-pyridin-2-ylmethyl-
0
30
C H36Cl
5 2 9 3
Cu N O : C, 41.18; H, 4.15; N, 14.41. Found: C, 41.33; H,
0
N,N -bis-thiophen-2-ylmethyl-[1,3,5]triazine-2,4-diamine (L2).
4
.26; N, 14.17%.
ter equipped with a 7 T magnet. Thermogravimetric (TG) analysis
was carried out on a locally produced HCT-2 thermal analysis sys-
2.3.2. Synthesis of compound 2
A solution of L1 (50.0 mg, 0.09 mmol) in CH Cl2 (5 ml) was
2
ꢁ1
tem in flowing N
2
with a heating rate of 10 °C min
.
added dropwise to
a
solution of Cu(NO3)2€ꢀ3H O (46.5 mg,
2
Suitable single-crystals of complexes 1–4 were mounted onto
the end of a thin glass fiber using Fomblin oil. X-ray diffraction
intensity data were measured at 93 K on a Rigaku diffractometer
0.19 mmol) in MeOH (5 ml) and the resulting green solution was
left undisturbed at room temperature. Blue-green crystals suitable
for X-ray crystallography were obtained after slow evaporation
of the above solution for 1 week. Yield: 29.3 mg, (32%); IR (KBr,
[
k(Mo Ka) = 0.7107 Å]. Structure solution and refinement were
ꢁ1
carried out with SHELXS-97 [11] and SHELXL-97 [12] via WINGX [13].
Corrections for incident and diffracted beam absorption effects
were applied using empirical numerical methods [14]. The
cm ): 3445(m), 3069(w), 2962(w), 1611(s), 1569(s), 1517(s),
1487(s), 1386(s), 1282(s), 1223(s), 1155(s), 1106(m), 1018(w),
976(w), 867(w), 809(w), 766(m), 649(w). Anal. Calc. for C57H54.86
2
weighted R-factor wR and goodness of fit S are based on F , conven-
Cl7.14Cu N26O24.42: C, 34.19; H, 2.76; N, 18.19. Found: C, 34.28; H,
4
2
tional R-factors R are based on F, with F set to zero for negative F .
2.99; N, 17.92%.
2
The threshold expression of F > 2
r is used only for calculating
2
R-factors(gt) etc. R-factors based on F are statistically about twice
as large as those based on F, and R-factors based on all data will be
even larger.
2.3.3. Synthesis of compound 3
2 2
A solution of L2 (50 mg, 0.09 mmol) in CH Cl (5 ml) was added
to a solution of CuCl
and the resulting solution was filtered and left undisturbed at
room temperature. Deep blue crystals suitable for X-ray crystallo-
2
ꢀ2H
2
O (28 mg, 0.19 mmol) in MeOH (5 ml)
2
2
.2. Ligand synthesis
graphic measurement were obtained after five days. Yield:
.2.1. Synthesis of L1
ꢁ1
2
1
1
8
C
3
9.1 mg, (46%); IR (KBr, cm ): 3451(m), 2924(w), 1659(w),
609(m), 1562(s), 1522(s), 1473(m), 1442(m), 1406(m), 1350(s),
289(m), 1253(w), 1218(m), 1152(m), 1108(w), 1057(w), 980(w),
69(w), 840(w), 809(w), 768(m), 729(w), 655(w). Anal. Calc. for
The ligand L1 was prepared in a similar way to the reported
1
procedure [15]. Yield: 2.88 g (56%). H NMR (400 MHz, d-CDCl
3
,
ppm) d = 4.84 (s, 4H, CH
2
), 5.05 (s, 4H, CH
2
), 8.54 (d, 2H), 6.92 (d,
2
2
1
8
6
H) 8.43 (d, 2H), 7.66 (t, 2H), 7.20 (s, 4H), 7.18 (t, 2H), 7.05 (t,
H). IR (KBr, cm ): 3448(w), 1572(s), 1491(s), 1436(m), 1412(s),
356(m), 1320(m), 1237(m), 1171(m), 1083(w), 974(w), 947(w),
25
H22Cl
3 7 2
CuN S : C, 45.88; H, 3.39; N, 14.98. Found: C, 45.52; H,
ꢁ1
.47; N, 14.72%.
62(w), 804(w), 761(m), 619(w). Anal. Calc. for C27
9
H24ClN : C,
2.3.4. Synthesis of compound 4
3.59; H, 4.74; N, 24.72. Found: C, 63.71; H, 4.53; N, 24.47%.
+
A solution of L2 (50 mg, 0.09 mmol) in CH Cl (5 ml) was added
dropwise to a solution of Cu(NO
MeOH (5 ml) and the resulting green solution was left undisturbed
at room temperature. Blue-green crystals suitable for X-ray crys-
tallography were obtained after slow evaporation of the above
2
2
2 2
EI-MS (positive mode, CH Cl ): m/z = 510 [MH] .
3
2
) ꢀ3H
2
O (46 mg, 0.19 mmol) in
2
.2.2. Synthesis of L2
,4,6-Trichloro-[1,3,5]triazine (1.07 g, 5.8 mmol) was dissolved
in tetrahydrofurane (50 ml). N-Ethyldiisopropylamine (DIPEA)
1.50 g, 11.6 mmol) was added and the mixture was cooled to
°C. Then, pyridin-2-ylmethyl-thiophen-2-ylmethyl-amine (2.37
2
ꢁ1
solution for 2 weeks. Yield: 30.5 mg, (40%); IR (KBr, cm ):
(
0
3
1
1
7
444(w), 3073(w), 2943(w), 1609(s), 1556(s), 1500(s), 1383(s),
322(s), 1286(s), 1223(s), 1177(m), 1131(m), 1104(m), 1060(w),
035(m), 1005(s), 966(m), 933(w), 861(m), 833(m), 801(m),
g, 11.6 mmol) was added dropwise in 30 min. After the completion
of the addition, the clear reaction mixture was warmed to room
temperature and kept at 40 °C for 48 h. Thereafter, the reaction
mixture was cooled to 0 °C. N-Ethyldiisopropylamine hydrochlo-
ride was removed by filtration and the filtrate was concentrated
under reduced pressure. The slightly yellow precipitate was iso-
9 3 6 2
65(m), 709(s), 654(w), 626(w). Anal. Calc. for C26H24CuN Cl O S :
C, 39.40; H, 3.05; N, 15.91. Found: C, 39.71; H, 3.43; N 15.42%.
3. Results and discussion
lated on a glass filter and washed with cold ethanol to remove
1
N-ethyldiisopropylamine hydrochloride. Yield: 1.84 g (61%).
NMR (400 MHz, d-CDCl , ppm) d = 4.74 (s, 1H, CH
CH ), 4.93 (s, 1H, CH ), 4.99 (t, 3H, CH ), 5.06 (d, 2H, CH
t, 1H), 6.86 (t, 1H), 6.93 (t, 1H), 7.02 (t, 1H), 7.22 (t, 1H), 7.64 (t,
1
1
H
Both ligands L1 and L2 were prepared in relatively good yields
by reaction of one equivalent of cyanuric chloride and two equiv-
alents of di-(2-picolyl)amine or pyridin-2-ylmethyl-thiophen-
2-ylmethylamine at 40 °C for 48 h, which resulted in the formation
of L1 in 56% and L2 in 61% yield, respectively [15].
Compounds 1–4 were prepared by the treatment of the corre-
sponding metal salts with L1 or L2 at room temperature. The
molecular structures and unusual supramolecular characteristics
of 1–4 are shown in Figs. 1–5. The crystallographic data of 1–4
3
2
), 4.82 (s, 1H,
), 6.79
2
2
2
2
(
ꢁ
1
H), 8.55 (t, 1H). IR (KBr, cm ): 3445(w), 1573(s), 1494(s),
420(m), 1312(m), 1222(m), 940 (m), 852(w), 798(w), 702(m).
Anal. Calc. for C25
H22ClN S
7 2
: C, 57.74; H, 4.26; N, 18.85. Found: C,
Cl ):
5
7.66; H, 4.13; N, 18.57%. EI-MS (positive mode, CH
2
2
+
m/z = 519.3 [MH] .

3
52
J. Chu et al. / Inorganica Chimica Acta 376 (2011) 350–357
Fig. 1. (a) The crystal structure of 1 with the atoms labeling; hydrogen atoms and solvent molecules have been omitted for clarity. (b)
neighboring pyridine rings. (c) The hydrogen bonds between methanol oxygens and the coordinated chlorides, and between two neighboring methanol molecules; CH
interaction between the methanol molecule and the neighboring pyridine ring in 1. (d) The crystal packing shows the pyridyl-Hꢀ ꢀ ꢀCl weak hydrogen bonds (dashed lines) of 1.
p
–p
interactions between the
3
OH–
p

J. Chu et al. / Inorganica Chimica Acta 376 (2011) 350–357
353
Fig. 2. (a) The crystal structure of 2 with atom labeling; hydrogen atoms and solvent molecules have been omitted for clarity. (b) The crystal packing shows the
p
-stacking of
the pyridyl moieties through the structure viewed along the crystallographic a axis with 2-D nature. (c) The crystal packing shows the pyridyl-Hꢀ ꢀ ꢀO–nitrate weak hydrogen
bonds (dashed lines) of 2.
have been summarized in Table 1 and the selected bond lengths
are listed in Table 2.
dipicolylamine unit of the L1 (s = 0.08, where s is 0 and 1 for the
perfect square pyramidal and trigonal pyramidal geometries,
respectively) [16]. The bond angles in the basal plane range from
87.38(11)° to 177.28(12)°, indicating the distortion generated by
the semicoordination of the N(2) atom with the Cu(1)–N(2) bond
length of 2.6422(37) Å. The coordination of Cu(2) can be described
3.1. Compound 1
The crystal structure of 1 with the molecular formula of
[
Cu
4
Cl
8
(L1)
2
]ꢀ6MeOH is illustrated in Fig. 1a. The asymmetric unit
as a distorted trigonal bipyramid geometry (s = 0.33) with two pyr-
contains two dinuclear copper(II) compounds. Each copper(II) ion
is coordinated by three nitrogens from dipicolylamine unit of L1
and two chloride anions with a CuN
dination of Cu(1) can be best described as distorted square pyrami-
dal with the axial position occupied by the N(2) from
idine nitrogens occupying the axial positions at normal distances
and the bond angle of N(7)–Cu(2)–N(9) 158.98(15)°. The Cu–N
and Cu–Cl distances are in the range of 1.965(4)–2.409(4) Å, and
2.2741(12)–2.2972(12) Å, respectively. The in-plane angles vary
from 98.23(9)° to 139.36(5)°, away from the ideal angle of 120°
3 2
Cl donor set. The pentacoor-
a

3
54
J. Chu et al. / Inorganica Chimica Acta 376 (2011) 350–357
complexes in the asymmetric unit of compound 2 show slight dif-
ferent bond lengths and bond angles. The copper(II) ions are che-
lated by three nitrogens from dipicolylamine moiety of L1 and
2 3
two nitrate ions, which results in a CuO N coordination environ-
ment. The pentacoordination of Cu(1) can be best described as dis-
torted square pyramidal with the axial position occupied by the
N(2) from a dipicolylamine unit (s = 0.01) [16]. The bond angles
in the basal plane range from 84.80(13)° to 171.51(13)°, reflecting
the distortion generated by the semicoordination of the N(2) atom
(
Cu(1)–N(2) distance of 2.4766(3) Å). The coordination of Cu(2) can
be described as a distorted trigonal bipyramid geometry ( = 0.36)
with two pyridine nitrogen atoms occupying the axial positions
N(7)–Cu(2)–N(9) = 163.10(15)°). The Cu–N and Cu–O bond
lengths are in the range of 1.947(4)–2.153(3) Å, and 2.078(3)–
.132(3) Å, respectively. The in-plane angles vary from 80.72(11)°
s
(
2
to 141.74(12)°, away from the ideal angle of 120° for a perfect tri-
gonal bipyramid geometry. The coordination environments of
Cu(3) and Cu(4) are similar to those of Cu(1)and Cu(2), respec-
tively. Two copper(II) ions are in the distance of 6.5997(7) or
Fig. 3. The oxygen–
triazine rings in 2.
p
interaction between the coordinated nitrate anions and the s-
6.6900(7) Å. As shown in Fig. 2b, p–p interactions between two
adjacent pyridine rings could be observed with the C–C distances
of 3.702 or 3.758 Å, and the dihedral angles of 17.303° or
for a perfect trigonal bipyramid geometry of a copper(II) ion. Two
copper(II) ions in the dinuclear complex are in the distance of
1
8.882°, respectively. Moreover, the crystal packing shows the pyr-
idyl-Hꢀ ꢀ ꢀO-nitrate weak hydrogen bonds of 2 with the C–Hꢀ ꢀ ꢀO
7
.2324(1) or 7.2212(1) Å in the asymmetric unit.
It is noted that strong interactions could be observed
bond lengths in the range of 3.072–3.372 Å, and bond angles
p–p
1
11.24–159.88° (Fig. 2c), respectively.
between the neighboring pyridine rings with the C–C distances
of 3.329, 3.271, 3.397 and 3.337 Å, and the dihedral angles of
Interestingly, the oxygen atom in one of the coordinated nitrate
anions resides just above the triazine ring (Fig. 3) with the distance
of 2.755 Å between the nitrate oxygen and the centroid of triazine
ring. The angle of the nitrate oxygenꢀ ꢀ ꢀcentroid axis to the plane of
the triazine ring is 83.82°, providing proof that the oxygen atom is
located perfectly on the triazine moiety. A comprehensive exami-
nation of all crystal structures deposited in the Cambridge Struc-
1
6.40°, 12.08°, 22.23° and 20.24°, respectively (Fig. 1b). As shown
in Fig. 1c, hydrogen bonds exist between two neighboring metha-
nol molecules with the bond lengths of O–Hꢀ ꢀ ꢀO of 2.771 and
2
.803 Å, and between methanol oxygens and the coordinated Cl
with the bond distance of O–Hꢀ ꢀ ꢀCl in the range of 3.162–
3
.300 Å. Furthermore, CH OH– interactions could be observed
3
p
tural Database reveals that 21 chloride–
nitrate– close contacts could be found in the pyridine rings in
the solid-state structures, and only 3 chloride– close contacts
and 10 nitrate– close contacts have been found in terms of
,3,5-triazine ring (Table 3). To the best of our knowledge the ni-
p close contacts and 359
with the distance of 3.344 Å between the methanol oxygens and
the centroid of the pyridine rings in 1, which might be a conse-
quence of the attractive interaction. The crystal packing of 1 shows
weak hydrogen bonds of pyridyl-Hꢀ ꢀ ꢀCl between two adjacent
interlayers with C–Hꢀ ꢀ ꢀCl bond distances ranging from 3.431 to
p
p
p
1
trate–p interaction with the distance of 2.755 Å in compound 2
3
.698 Å, and bond angles of 132.86–162.02° (Fig. 1d), respectively.
represents the closest contact reported so far.
3.2. Compound 2
3.3. Compounds 3 and 4
The reaction of one equivalent of L1 with two equivalents of
Cu(NO
3
)
2
ꢀ3H
2
O yields a dinuclear copper complex of 2. A molecular
The reaction of one equivalent of L2 and two equivalents of
plot of the crystal structure of 2 without including the lattice
2 3 2
CuCl and Cu(NO ) results in the formation of compound 3 and
solvent molecules is shown in Fig. 2a. Two dinuclear copper(II)
4, respectively. The molecular structure of the asymmetric unit of
Fig. 4. The crystal structure of 3 shows the mononuclear copper complex in the asymmetric unit; hydrogen atoms have been omitted for clarity.

J. Chu et al. / Inorganica Chimica Acta 376 (2011) 350–357
355
Fig. 5. (a) The crystal structure of 4 shows the mononuclear Cu(II) compound with the atom labeling; hydrogen atoms and dichloromethane solvent molecules have been
omitted for clarity. (b) and (c) are the crystal packing of 4, showing the interactions between the pyridine rings and thiophene rings.
p–p
compound 3 contains two mononuclear copper compound, in
which the copper(II) ion is coordinated by two pyridine nitrogens,
one nitrogen from the triazine unit and two chloride anions (Fig. 4).
rings are far more less investigated compared with those of six-
membered rings. It should be pointed out that (1) none of the thi-
ophene rings coordinates with copper ions in both compounds 3
and 4; (2) two thiophene rings in compound 3 appear in clockwise
orientation, whereas those in compound 4 in counterclockwise ori-
3 2
As such, the copper ion shows a N Cl square pyramidal coordina-
tion environment with = 0.10. A molecular plot of mononuclear
s
compound 4 without lattice solvent molecules is shown in
Fig. 5a, in which Cu(1) is coordinated by two nitrate oxygens,
two pyridine nitrogens and one nitrogen from the triazine ring
entation. As a result, the
pyridine rings and thiophene rings (Fig. 5b and c) and the CH
(thiophene ring) interactions are only observed in 4, but not in 3.
p
–
p
interactions between the neighboring
Cl
2
2
–p
3 2
with a CuN O donor set. Additionally, we have observed the sol-
vent– interactions between CH
deficient thiophene rings with the Cl –
p
2
Cl
2
molecules and the electron-
3.4. FT-IR spectroscopy
ꢁ
p distance of 3.449 Å
(
Fig. S1). To the best of our knowledge, the interactions between
FT-IR spectroscopy results (Fig. S2) indicate that the C@N
neutral molecules and five-membered rings such as thiophene
stretching vibrations of pyridine rings appear at 1571 and

3
56
J. Chu et al. / Inorganica Chimica Acta 376 (2011) 350–357
Table 1
Crystallographic data and refinement details for 1–4.
Compounds
1
2
3
4
Empirical formula
Formula weight
Crystal system
Space group
a (Å)
C
30
H
36Cl15Cu
2
N
9
O
3
C
57
H
54.86Cl7.14Cu
4
N
26
O
24.42
C
50
H
44Cl
6
Cu
N
2 14
S
4
C
26 3 9 6 2
H24Cl CuN O S
875.01
monoclinic
P2(1)
10.8152(14)
13.8418(18)
24.269(3)
90
93.495(2)
90
3626.3(8)
4
2002.34
monoclinic
P2(1)
10.6939(14)
29.458(4)
13.5972(18)
90
111.917(2)
90
3973.9(9)
4
1309.02
triclinic
P-1
792.55
triclinic
P-1
10.3896(11)
15.9031(15)
18.583(2)
113.575(3)
93.461(6)
97.040(5)
2772.6(5)
4
11.255(2)
b (Å)
c (Å)
11.3310(19)
13.383(3)
98.630(2)
109.170(2)
92.626(2)
1585.6(5)
2
a
(°)
b (°)
(°)
c
3
V (Å )
Z
Temperature (K)
93(2)
1.603
1.587
93(2)
1.673
1.387
93(2)
1.568
1.257
93(2)
1.660
1.131
ꢁ
3
D
calc (g cm
)
ꢁ
1
l
(cm
)
Total reflections
Independent reflections
GOF
29 503
15 774
0.998
32 273
16 615
1
16 622
10 253
0.999
11 948
6351
1
R
1
(I > 2
wR (I > 2
(all data)
wR (all data)
r
(I))
0.0463
0.1024
0.0511
0.106
0.0426
0.1044
0.0456
0.1077
0.0435
0.0988
0.0546
0.1069
0.0346
0.0737
0.0394
0.0764
2
r(I)
R
1
2
Table 2
Selective bond lengths (Å) of Compounds 1–4.
Compound 1
Cu(1)–N(1)
Cu(1)–Cl(3)
Cu(2)–Cl(5)
2.021(4)
2.2666(12)
2.2741(12)
Cu(1)–N(3)
Cu(2)–N(7)
Cu(2)–N(8)
2.059(4)
1.965(4)
2.409(4)
Cu(1)–Cl(2)
Cu(2)–N(9)
Cu(2)–Cl(4)
2.2623(12)
1.976(4)
2.2972(12)
Compound 2
Cu(1)–O(4)
Cu(1)–N(1)
Cu(2)–N(7)
Cu(2)–N(8)
1.976(3)
2.008(3)
1.956(3)
2.153(3)
Cu(1)–O(1)
Cu(1)–N(2)
Cu(2)–O(7)
1.980(3)
2.477(3)
2.078(3)
Cu(1)–N(3)
Cu(2)–N(9)
Cu(2)–O(10)
1.991(3)
1.947(4)
2.132(3)
Compound 3
Compound 4
Cu(1)–N(6)
Cu(1)–Cl(3)
Cu(2)–N(13)
Cu(2)–N(12)
2.016(3)
2.2753(8)
2.023(3)
2.593(2)
Cu(1)–N(1)
Cu(1)–N(5)
Cu(2)–Cl(6)
2.022(2)
2.579(2)
2.2503(8)
Cu(1)–Cl(2)
Cu(2)–N(8)
Cu(2)–Cl(5)
2.2581(8)
2.004(3)
2.3057(8)
Cu(1)–O(1)
Cu(1)–O(4)
1.9792(15)
2.0151(14)
Cu(1)–N(7)
Cu(1)–N(5)
1.9935(18)
2.3895(18)
Cu(1)–N(2)
2.0033(17)
3.5. Magnetic susceptibility measurements
Table 3
ꢁ
3ꢁ
–p
Cl –
p
and NO
close contact in CSD.
Magnetic susceptibility measurements have been performed on
the crystalline powders of 1 and 2 at 0.1 Tesla in the range of 6
–300 K. The plot of T versus the T [with being the magnetiza-
tion per copper(II) ion] is illustrated in Fig. S3. At 300 K, T = 0.83
Close
contacts
Ring
Number of
anion–
contacts
observed
Mean anion
centroid
distance (D,
Å)
Relative standard
deviation of the
data set (RSD,%)
p
2
v
v
(
six-
member
ring)
v
3
ꢁ1
for 1 and 0.88 cm K mol for 2, respectively, which are very close
to the expected values for two uncoupled copper(II) ions
(T = 0.84 cm K mol for paramagnetic systems). The value of vT
does not change upon cooling to 9 K, suggesting there are no inter-
Cl–
p
1,3,5-
3
3.332
n.a.
3
ꢁ1
triazine
pyridine
1,3,5-
triazine
pyridine 359
21
10
3.427
3.160
3
6.5
3ꢁ
NO
–p
actions between copper(II) ions. After that, it starts to decrease and
3
ꢁ1
3
ꢁ1
reaches to 0.53 cm K mol for 1 and 0.79 cm K mol for 2 at
K, respectively.
3.302
4
2
n.a. stands for ‘‘not available’’.
3.6. TG studies
ꢁ
1
ꢁ1
1
1
491 cm in L1, which shift to 1563 and 1523 cm in 1, 1566 and
As shown in Fig. S4, the TG results of 1 confirm the initial
ꢁ1
517 cm in 2, respectively. The above results reveal the coordi-
weight loss of about 10%, corresponding to the loss of MeOH before
200 °C. With the increase of temperature, 1 starts to decompose
from 250 °C. Compound 2 shows the first well defined event asso-
ciated with CH Cl and MeOH loss of ca. 10% before 190°, and then
2 2
2 starts to decompose. Compound 3 starts to decompose at ca.
nation of L1 with copper(II) ions. In terms of L2, the C@N stretching
vibrations of pyridine rings could be observed at 1571 and
ꢁ1
ꢁ1
1
1
493 cm , which shift to 1563 and 1523 cm in 3, 1558 and
ꢁ1
506 cm in 4 after coordination with copper(II) ions. Further-
more, the bending vibrations of pyridine rings of L1 and L2 appear
300 °C. Compound 4 shows a series of events with the initial
ꢁ1
at 971 and 972 cm , while the corresponding vibrations shift to
2 2
weight loss of CH Cl ca.10% before 200 °C, which is followed by
ꢁ1
9
79, 977, 980, 960 cm in 1–4, respectively.
the decomposition of compound 4 directly.

J. Chu et al. / Inorganica Chimica Acta 376 (2011) 350–357
357
4
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