3D binary copper(I) 3,5-dibutyl-1,2,4-triazolate: Synthesis, structure and topology

Article abstract of DOI:10.1007/s10870-010-9961-x

Binary copper(I) 3,5-dibutyl triazolate has been prepared from 3,5-dibutyl triazole and Cu(NO₃)₂ under hydrothermal condition. This complex crystallizes in tetragonal I4₁/a with a = b = 17.622(3) A, c = 15.842(3) A and exhibits a 3D structure of either four-connected lvt or three-connected lvt-a topology. Binary copper(I) 3,5-dibutyl triazolate exhibits a 3D structure of either four-connected lvt or three-connected lvt-a topology.

Full text of DOI:10.1007/s10870-010-9961-x

J Chem Crystallogr (2011) 41:434–437
DOI 10.1007/s10870-010-9961-x
NOTE
3D Binary copper(I) 3,5-dibutyl-1,2,4-triazolate: Synthesis,
Structure and Topology
•
•
•
Yong-Hui Wang Hong Xu Guang Yang
Hong-Wei Hou
Received: 4 July 2009 / Accepted: 31 December 2010 / Published online: 13 January 2011
Ó Springer Science+Business Media, LLC 2011
Abstract Binary copper(I) 3,5-dibutyl triazolate has been
prepared from 3,5-dibutyl triazole and Cu(NO3)2 under
hydrothermal condition. This complex crystallizes in
˚
tetragonal I41/a with a = b = 17.622(3) A, c = 15.842(3)
˚
A and exhibits a 3D structure of either four-connected lvt
or three-connected lvt-a topology.
elusive to date. In order to obtain this as-yet-missing
compound, we attempted to use 3,5-dibutyl triazole as the
starting material, which avoided the involvement of
organonitrile in the reaction system. In this paper, we report
the synthesis, structure of Cu(3,5-Bu2tz) (Scheme 1). A
topological analysis of the structure is also presented.
Keywords Synthesis Á Crystal structure Á Copper Á
Triazole Á Topology
Experimental
Materials and Methods
Introduction
The CHN microanalyses were carried out with a Flash
EA1112 elemental analyzer. IR spectra were recorded on a
Nicolet NEXUS 470-FTIR instrument as KBr pellets in the
Chen et al. recently reported a series of binary copper(I)
3,5-disubstituted 1,2,4-triazolates (Cu(3,5-R2tz); tz =
triazolate, R = hydrogen (H), methyl (Me), ethyl (Et),
propyl (Pr), phenyl (Ph), 2-/4-pyridyl (2-/4-py)), prepared
by in situ solvothermal reaction of organonitriles, ammonia
and Cu(II) salts [1–6]. The triazolate components were
believed to be formed from copper-mediated oxidative
cycloaddition of nitriles and ammonia. However, while
valeronitrile was used, the targeted binary copper(I)
3,5-dibutyl triazolate—Cu(3,5-Bu2tz) can not be obtained.
Instead a 3D metal–organic network [Cu5CN(3,5-Bu2tz)4]
was formed; cyanide ion was possibly generated by the C–C
bond cleavage of nitriles mediated by metals [2]. As far as
we know, the binary triazolate—Cu(3,5-Bu2tz) remains
1
range of 400–4,000 cm-1. H NMR spectra were recorded
on a Bruker DPX-400 spectrometer. Thermogravimetry
and differential scanning calorimetry were measured on a
NETZSCH STA 409 PC system in static air at a scanning
rate of 10 °C min-1. All reagents were purchased from
commercial sources.
Synthesis of 4-Amino-3,5-dibutyl-4H-1,2,4-triazole
(4-NH2-3,5-Bu2tz)
Valeric acid (0.02 mol, 2.5 mL) and 80% hydrazine
(0.02 mol, 1.5 mL) were sealed in a Teflon-lined autoclave
and heated in an oven at 180 °C for 72 h. The resulted
viscous liquid was neutralized with diluted HCl until
pH & 7 and white precipitate formed. The solid was dis-
solved in CH2Cl2 and then the solution was washed with
water. After evaporation of CH2Cl2, the resulted solid was
recrystallized from MeOH–water (v:v = 1:2) to afford
colorless sheets in 66% yield. M.p. 146–148 °C. Anal.
Calcd (%) for C10H20N4: C, 61.19; H, 10.27; N, 28.54.
Electronic supplementary material The online version of this
article (doi:10.1007/s10870-010-9961-x) contains supplementary
material, which is available to authorized users.
Y.-H. Wang Á H. Xu Á G. Yang (&) Á H.-W. Hou
Department of Chemistry, Zhengzhou University,
Zhengzhou 450001, China
e-mail: yang@zzu.edu.cn
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435
N
water, 160 oC
Hydrothermal
Table 1 Crystal data and structure refinement parameters for Cu(3,5-
Bu2tz)
Cu(3,5-Bu2tz)
+ Cu(NO3)2
N
NH
(3,5-Bu2tzH)
Compound
Cu(3,5-Bu2tz)
CCDC deposit no.
Formula
737909
Scheme 1 Synthesis of Cu(3,5-Bu2tz)
C10H18CuN3
243.81
Found: C, 61.14; H, 10.26; N, 28.50. 1HNMR (ppm,
CDCl3): d = 0.99 (t, 6H, –CHd3), 1.43 (m, 4H, –CH2c–),
1.73 (m, 4H, –CHb2–), 2.74 (t, 4H, –CHa2–), 4.51 (s, 2H,
NH2).
Formula weight
Crystal system
Space group
Tetragonal
I41/a
˚
a (A)
17.622 (3)
17.622 (3)
15.842 (3)
4919.8 (14)
16
˚
b (A)
˚
c (A)
Synthesis of 3,5-Dibutyl-1H-1,2,4-triazole
(3,5-Bu2tzH)
3
V (A )
˚
Z
4-NH2-3,5-Bu2tz (4.3 g, 22 mmol) was dissolved in aque-
ous HCl (3 M, 10 mL). An aqueous solution of NaNO2
(1.5 g, 22 mmol) was added slowly with the temperature
being maintained at 20 °C. After the addition of NaNO2
was completed, the mixture was stirred for another 1 h at
the same temperature until the bubbles of N2 ceased to
form. Then the pH of the obtained solution was adjusted to
ca. 7 by a diluted solution of NaOH. The solution became
turbid and was extracted with CH2Cl2 (3 9 50 mL). After
removal of CH2Cl2 by a rotary evaporator, a white sticky
residue was obtained, which was firstly recrystallized from
MeOH–H2O (v:v = 1:1) and then from diethyl ether–
petroleum ether (v:v = 3:1) to afford colorless club-shaped
crystals in 45% yield. M.p. 33–35 °C. Anal. Calcd (%) for
C10H19N3: C, 66.26; H, 10.56; N, 23.18. Found: C, 66.12;
H, 10.61; N, 23.27. 1HNMR (ppm, CDCl3): d = 0.98
(t, 6H, –CHd3), 1.36 (m, 4H, –CH2c–), 1.62 (m, 4H, –CHb2–),
2.77 (t, 4H, –CHa2–).
qcalc (mg/m3)
1.317
l (mm-1
)
1.745
Reflections collected
Reflections unique
h range (°)
Data/restraints/parameters
R1, wR2 (I [ 2r(I))
R1, wR2 (all data)
GOF
32776
3318 (Rint = 0.0480)
1.73–29.13
3318/0/130
0.0794, 0.1914
0.0881, 0.2012
1.328
-3
˚
Dqmax (e A
)
0.726
SHELXL program [7]. All non-hydrogen atoms were
refined with anisotropic displacement parameters; hydro-
gen atoms were treated as riding. Crystal data are sum-
marized in Table 1; selected bond distances and angles are
listed in Table 2.
Synthesis of Cu(3,5-Bu2tz)
Results and Discussions
Cu(NO3)2Á3H2O (24.2 mg, 0.1 mmol) and 3,5-Bu2tzH
(18.1 mg, 0.1 mmol) were dissolved in 4 mL of water. The
mixture was sealed in a 15-mL Teflon-lined autoclave and
heated in an oven at 160 °C for 72 h and then slowly
cooled to room temperature. Colorless prismatic crystals of
Cu(3,5-Bu2tz) were obtained in 75% yield. Anal. Calcd
(%) for C10H18CuN3: C, 49.26; H, 7.44; N, 17.23. Found:
C, 49.10; H, 7.20; N, 16.95. IR (KBr pellet, cm-1): 2957s,
2930s, 2872w, 1715w, 1630m, 1506s, 1457s, 1384s, 1275s,
1105w, 1079m, 933w, 789w, 729m.
Using 3,5-dibutyl-1H-1,2,4-triazole instead of valeronitrile
and ammonia as starting reagent, we successfully prepared
binary copper(I) 3,5-di-butyl-1,2,4-triazolate under hydro-
thermal condition. The advantage of our method lies in
exclusion of the possible cleavage of organonitriles [2] and
therefore no cyanide ions in the final product, as we
expected.
Cu(3,5-Bu2tz) crystallizes in tetragonal space group
I41/a and exhibits a 3D metal–organic framework (MOF)
structure. In the asymmetric unit, there are one Cu(I) atom
and one 3,5-Bu2tz ligand. Cu(I) atom adopts a planar
triangular coordination geometry and triazolate acts as
l3-N1,N2,N4 bridge (Fig. 1).
X-ray Crystallography
The 3D structure can be derived from a Cu2tz2-SBU
(secondary building unit), which is further linked with
neighboring four Cu2tz2-SBUs from its two Cu atom and
two triazole N4 positions (Fig. 2). From the topological
viewpoint, the Cu2tz2-SBU can be taken as a planar
X-ray single-crystal diffraction data were collected on a
Rikagu Saturn 724 CCD diffractometer, with graphite-
monochromated Mo-Ka radiation and corrected by ‘‘multi-
scan’’ absorption corrections. The structure was solved by
direct methods and refined by least-squares on F2 using the
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J Chem Crystallogr (2011) 41:434–437
˚
Table 2 Selected bond lengths (A) and angles (°)
N
Cu(1)–N(3)
Cu(1)–N(1)
Cu(1)–N(2)
1.949 (3)
1.989 (3)
1.998 (3)
N(3)–Cu(1)–N(1)
N(3)–Cu(1)–N(2)
N(1)–Cu(1)–N(2)
127.10 (14)
117.01 (13)
114.69 (14)
N
N
Cu
Cu
lvt
N
N3
N
N2
N
Cu1
N
N1
N
N
lvt-a
Cu
Cu
N
N
N2a
N3b
N
Fig. 1 ORTEP drawing of a fragment of 3D Cu(3,5-Bu2tz), showing
the coordination geometry around Cu atom. Symmetry codes:
(a) y - 1/4, -x ? 5/4, -z ? 1/4; (b) -y ? 3/4, x ? 1/4, z ? 1/4
Scheme 2 Two ways to simplify the structure of Cu(3,5-Bu2tz)
interconnection of helices via Cu–N2/N1 bonds gives rise to
the 3D structure (Fig. 2). If the Cu(I) atom and the triaz-
olate are chosen as planar three-connected nodes, the
¨
topology now is lvt-a (4.8.10 in Schlafli symbol)
(Scheme 2) [8–17]. The lvt-a net is uninodal, that means
the Cu(I) and triazolate nodes are topologically identical
under this circumstance. The lvt net is related to lvt-a
net by augmentation, namely replacement of each four-
connected node in lvt by four three-connected nodes [8].
In the crystal of Cu(3,5-Bu2tz), CuI-tz skeleton forms
channels along the a-, b- and c-axes, which are, however,
occupied by the butyl substituents (Fig. 2). PLATON
analysis shows no solvent accessible void is found for this
complex [18].
The structure of Cu(3,5-Bu2tz) is similar to that of
a-Cu(3,5-Me2tz) [4]. However, while the former is non-
interpenetrating, the latter consists of two identical, trans-
lational nets, and therefore is twofold interpenetrating. The
twofold interpenetration results in 42 axes along c-direction
of the crystal structure and therefore the space group
P42/n for a-Cu(3,5-Me2tz). The larger size of the substit-
uents (Bu vs. Me) might account for the non-interpene-
tration observed in Cu(3,5-Bu2tz).
Fig. 2 Packing diagram of Cu(3,5-Bu2tz) viewing down the c axis.
The two arrows show the positions and handedness of the two
interconnected 41 helices. The butyl groups have been omitted for
clarity
rectangular four-connected node, and the net underlying
2
4
¨
Cu(3,5-Bu2tz) is lvt, namely 4 .8 net in Schlafli symbol
(Scheme 2) [8–17].
TG/DSC measurement indicates that Cu(3,5-Bu2tz) is
stable up to 250 °C under air. Above 250 °C, this complex
experiences successive weight losses with three exothermic
events at 278.3, 415.6 and 465.0 °C, corresponding to the
decomposition of the triazolato ligand. The final residue at
500 °C accords with a product with composition of
Furthermore, the 3D structure of Cu(3,5-Bu2tz) can also
be derived from 41 helices extending parallel to the c-axis,
which are formed by Cu(I) atoms and triazolates utilizing
N1/N2 and N4 positions. Each 41 helix is of the oppo-
site handedness than its four nearest neighbours; further
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J Chem Crystallogr (2011) 41:434–437
437
Acknowledgments This work has been supported by NSF of China
(No. 21071126), the Scientific Research Foundation for the Returned
Overseas Chinese Scholars, State Education Ministry and the
Education Department of Henan Province, China.
Cu(OH)2ÁCuCO3, based on the residual weight percentage
(observed 45.8%; calculated 45.4%).
The structural characterization of Cu(3,5-Bu2tz) adds
one more member to the family of binary copper(I) triazo-
lates and provides a better opportunity to conduct a com-
parable study on the effect of 3,5-substituents of triazole on
the structure of Cu(3,5-R2tz). We noticed that when R are
H or alkyl groups, all the hitherto known structures of
Cu(3,5-R2tz) actually can be derived from the Cu2tz2-SBU.
However, while Cu(3,5-Bu2tz) and a-Cu(3,5-Me2tz) have
the same topology of lvt (or lvt-a); Cu(3,5-Et2tz) and
Cu(3,5-Pr2tz) are isoreticular to each other, both having
nbo topology [2]. As discussed by Chen et al., the size/
shape of the 3,5-substituents is an important factor to deter-
mine the dihedral angles between adjacent Cu2tz2-SBUs,
and therefore the structures and topologies of Cu(3,5-R2tz)
[2]. A parallel study has revealed that the same factor also
plays an important role in dictating the structures of
Ag(3,5-R2tz)—the silver counterpart of Cu(3,5-R2tz); the
substituents might act as the ‘‘template’’ to organize the
silver triazolate skeletons [19]. Obviously, the structural
role of the 3,5-substituents has not yet been fully under-
stood; more work is needed to address this issue.
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Supplemental Material
1HNMR spectra of 4-NH2-3,5-Bu2tz and 3,5-Bu2tzH,
TG-DSC curves of Cu(3,5-Bu2tz), schematic diagrams of
lvt and lvt-a net are provided as supplementary material.
CCDC-737909 contains the supplementary crystallographic
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, by emailing
data_request@ccdc.cam.ac.uk, or by contacting The
Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: ?44(0)1223-336033.
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