Complexes of 1,2,4-Triazoles, Part XVII
The Crystal Structure of Tris-/«-(4-ethyl-l,2,4-triazole-Nl,N2)(4-ethyl-l,2,4-triazole-N1 )-aquo-bis [bis(thiocyanato-N)nickel(II)]hydrate, Ni2(C4N3H7)4(H20)(NCS)4 *H 2 0 (x ~ 2.5)
Ger Vos*, Anthonie J. de Kok, and Gerrit C. Verschoor
Department of Chemistry, Gorlaeus Laboratories, State University Leiden,
P.O. Box 9502, 2300 RA Leiden, The Netherlands
Z. Naturforsch. 36 b, 809-813 (1981); received April 2, 1981
4-Ethyl-l,2,4-triazole, Binuclear Compound, Hydrogen Bonding
The crystal structure of Ni2(C4N3H7)4(H20)(NCS)4 • 2.5 H 2 0 has been determined by
X-ray diffraction techniques. The compound crystallizes in the monoclinic space group
P2i/n with a — 15.121(4), 6 = 13.237(2), c= 18.069(3), ß = 94.71(2)° and Z = 4; R = 0.040
(Rm = 0.051). The compound consists of dimeric units in which two Ni ions are bridged by
three ethyltriazole (Ettrz) groups. For one Ni, two N donating NCS" groups and an Ettrz
coordinating by only one N atom complete the NiNe octahedron. The other Ni atom,
which is also octahedrally coordinated, has a coordinated water molecule instead of a
monodentate Ettrz.
Introduction
The Et-group on the 4-position of the triazole
ring rules out the possibility of 2,4-bi-co-ordination
of the ligand, as found in the layered structures of
/?-Ni(trz)2(NCS)2 and related compounds with Mn,
Fe, Co and Zn [1, 2]. It is to be expected, that
4-ethyl-l,2,4-triazole gives rise to complexes with
1,2 bridging Ettrz units or to compounds with Ettrz
coordinating by only one N atom. 1,2 bridging
triazoles occur in CuCl2 • trz [3] and in
Ni3(trz)6(H20)6(N03)6 • H 2 0 [4]. Triazole units coordinating by only one N atom are known for the
compound Mn(trz)(H20)4 • SO4 [5]. Both monodentate and bidentate coordinating ligands were
found for the complex Mn2(4-Metrz)5(NCS)4 [6].
The results of magnetic susceptibility measurements of the title compound strongly suggest, that
either linear chains of bridged Ni atoms are present,
or that the compound is built up of linear clusters
containing an even number of Ni atoms [7]. Based
on infrared data and on stoichiometric grounds a
dimeric structure was thought to be the most
acceptable possibility. To test the validity of this
idea, a crystal structure determination of this compound was undertaken.
Experimental
Starting materials
Ettrz was prepared as described elsewhere [8, 9].
Commercially available chemicals were used without
further purification.
* Reprint requests to Drs. G. Vos.
0340-5087/81/0700-0809/$ 01.00/0
Preparation of Ni2( Ettrz)a(H20) (NCS)A • 2.5 H20
5 mmol of Ni-nitrate were dissolved in about
15 ml of H 2 0. A solution of NH4SCN (10 mmol) in
H2O (15 ml) was added rapidly. The metal salt
solution was slightly acidified with HN0 3 . Ettrz
(10 mmol), dissolved in H 2 0 (10 ml) was added
slowly to the boiling solution of the metal salt. The
complex crystallized after standing for several days.
X-ray data collection
A single crystal of good quality was selected and
mounted on an Enraf-Nonius CAD-4 diffractometer.
MoKa radiation, monochromated by graphite, was
used to determine the unit cell parameters and the
space group as well as to measure the reflexion
intensities. The diffraction data are listed in Table I.
The data were corrected for Lorentz and polarization effects and for ab3orption [10]. After reduction
of the intensities to structure factors a Wilson plot
Table I. Diffraction data for
Ni2(Ettrz)4(H20)(NCS)4 • 2.5 H 2 0 .
Space group
Lattice constants
p2i/w
a [A]
b[ a ]
15.121(4)
13.237(2)
18.069(3)
c [A]
94.71(2)
ß [°]
4
z
0.47 x 0.15 x 0.45
Crystal dimensions [mm]
2.5-25
0 range [°]
6932
Measured reflexions
6621
Independent reflexions
4427
Significant reflexions
1.45
Experimental density (kg • m - 3 )
1.43
Calculated density (kg • m - 3 )
0.040 (0.051)
Final R (Re)
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was calculated to obtain starting values for the
scale factor and the initial thermal parameter B.
The experimental density was determined in a
mixture of CCI4 and toluene.
Table II. Fractional coordinates ( X 104), multiplicities
and isotropic temperature factors (A 2 ) of the nonhydrogen atoms.
Solution and Refinement 0 ! the Structure
The function minimized during the least-squares
refinement was 2w(|F0| — |FC|)2 with the weighting
scheme to = crF~2. Discrepancy indices are defined as
£ = 2|JF|/2|Fo| and £«, =
F^/ZcoFo 2 ] 1 / 2 .
Scattering factors and anomalous-dispersion corrections were taken from International Tables for
X-ray Crystallography [11].
A three dimensional Patterson synthesis revealed
the positions of the Ni-ions. The positions of some
of the non-hydrogen atoms were located by the
usual Fourier techniques and refined by blockdiagonal least-squares. Hoeever, not all non-hydrogen atoms could be located by this method. Therefore the program NORMAL was used to calculate
the strongest E values, making use of the positions
of the Ni-ions. A structure in which two Ni-ions are
bridged by three Ettrz groups was found by using
the program MULTAN. The S atoms of the isothiocyanate groups appeared to be in disorder. The
oxygens of the non-coordinating H2O molecules and
C7 of triazole ring 2 could not be located by this
procedure. Seven cycles of isotropic refinement
yielded R = 0.138 (£„> = 0.193). The other nonhydrogen atoms were located by Fourier methods.
C7 of triazole ring 2 as well as the oxygens of the
non-coordinating H2O molecules appeared to be in
disorder. After seven cycles of isotropic refinement,
including all non-hydrogen atoms, R decreased to
0.107 ( 5 . = 0.140). Six cycles of anisotropic refinement yielded £ = 0.064 ( £ „ = 0.087). Only two
H-atoms could be located from a difference Fourier
syntheses. Apart from the hydrogens attached to
C(2,6) and C(2,7) and the water hydrogens, the
hydrogens were placed at calculated positions. Nine
cycles of anisotropic refinement led finally to
£ = 0.040 ( £ „ = 0.051) (significant reflexions only).
Three cycles including all reflexions yielded £ = 0.062
( £ „ = 0.051).
The positional parameters of the non-hydrogen
atoms are listed in Table II*.
* Further details of the investigations on crystal
structures may be received at: "Fachinformationszentrum Energie, Physik, Mathematik, GmbH,
D-7514 Eggenstein-Leopoldshafen 2 " .
The Registry-Nr., CSD 50013, the name of the
author, and the reference should be given.
Ni(l)
Ni(2)
N(l)
C(l)
S(1 A)
S(1B)
N(2)
C(2)
S(2 A)
S(2B)
N(3)
0(3)
S(3A)
S(3B)
N(4)
0(4)
S(4A)
S(4B)
N(l,l)
N(l,2)
C(l,3)
N(l,4)
C(l,5)
0(1,6)
0(1,7)
N(2,l)
N(2,2)
C(2,3)
N(2,4)
C(2,5)
C(2,6)
C(2,7 A)
0(2,7B)
N(3,l)
N(3,2)
C(3,3)
N(3,4)
C(3,5)
C(3,6)
C(3,7)
N(4,l)
N(4,2)
C(4,3)
N(4,4)
C(4,5)
C(4,6)
0(4,7)
0(1)
0(2 A)
0(2B)
0 ( 3 A)
0(3B)
0(4)
X
y
z
Mult.
3801.1(3)
6170.3(3)
3317(2)
3221(2)
3227(2)
3020(1)
2700(2)
2114(2)
1384(1)
1115(2)
7130(2)
7533(2)
8038(1)
8200(3)
6487(2)
6460(2)
6320(2)
6535(2)
4939(1)
5800(1)
6305(2)
5825(2)
4970(2)
6157(3)
6342(3)
4349(1)
5209(1)
5283(3)
4514(2)
3961(2)
4328(4)
4468(9)
4404(7)
4409(1)
5269(1)
5378(2)
4636(1)
4050(2)
4477(3)
4187(3)
3171(2)
3540(2)
2912(3)
2148(2)
2342(3)
1243(3)
1035(3)
7136(1)
6572(4)
6813(8)
5321(3)
5219(6)
5531(9)
4383.1(5)
3465.7(5)
5690(2)
6446(3)
7604(2)
7476(2)
3588(2)
3192(3)
2434(2)
2913(2)
4188(2)
4687(3)
5536(2)
5113(4)
2063(2)
1235(3)
— 5(2)
87(2)
5179(2)
4861(2)
5578(2)
6366(2)
6072(2)
7303(3)
7172(5)
3092(2)
2765(2)
1951(3)
1732(2)
2461(3)
863(5)
60(8)
1128(6)
4013(2)
3668(2)
3503(2)
3732(2)
4041(2)
3618(3)
2569(4)
4739(2)
4701(2)
4950(3)
5099(3)
4962(4)
5313(5)
6329(4)
3294(2)
3312(5)
2697(9)
4673(5)
4102(8)
1367(17)
7138.7(3)
7052.8(3)
6635(2)
6335(2)
6053(2)
5830(1)
6727(2)
6426(2)
5990(1)
5977(2)
6528(2)
6182(2)
5673(1)
5586(3)
6666(2)
6496(2)
6398(2)
6135(2)
7533(1)
7482(2)
7753(2)
7979(2)
7835(2)
8348(2)
9155(3)
7666(2)
7641(2)
8045(2)
8329(2)
8084(2)
8818(3)
8717(7)
9545(5)
6167(1)
6141(1)
5440(2)
5007(1)
5487(2)
4206(2)
4002(2)
8089(2)
8808(2)
9222(2)
8818(2)
8110(2)
9087(3)
9052(3)
7956(2)
9351(3)
9371(6)
9362(3)
9429(5)
2668(8)
2.00
2.00
2.00
2.00
0.66
1.34
2.00
2.00
1.20
0.80
2.00
2.00
1.40
0.60
2.00
2.00
0.94
1.06
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
0.83
1.17
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
1.34
0.66
1.60
0.40
0.49
Biso
2.56(2)
2.63(2)
3.6(2)
3.5(2)
5.1(1)
5.1(1)
3.9(2)
3.7(2)
5.5(1)
5.5(1)
3.8(2)
3.9(2)
7.1(1)
7.1(1)
4.1(2)
4.8(2)
8.7(1)
8.7(1)
2.7(2)
2.7(2)
3.6(2)
3.6(2)
3.4(2)
5.5(3)
8.5(3)
3.0(2)
3.1(2)
4.7(2)
6.0(2)
4.5(2)
10.4(4)
7.4(4)
7.4(4)
2.6(1)
2.6(1)
3.0(2)
2.9(2)
3.0(2)
3.7(2)
7.1(3)
3.5(2)
4.3(2)
5.2(2)
5.5(2)
5.5(2)
9.1(4)
10.2(4)
4.6(2)
9.5(4)
9.5(4)
9.6(3)
9.6(3)
13 (1)
Description of the Structure
Intramolecular distances and bond angles with
their e.s.d's are listed in Table III and IV. The
stereochemistry of one unit Ni2(Ettrz)4(Ü20)(NCS)4
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Table III. Intramolecular distances (A) and angles (°) in Ni2(Ettrz)4(H20)(NCS)4 • 2.5 H2O except Ettrz rings
(e.s.d.'s include errors in the cell parameters).
Ni(l)
Ni(l)
Ni(l)
Ni(l)
Ni(l)
Ni(l)
Ni(l)
Ni(2)
Ni(2)
Ni(2)
Ni(2)
Ni(2)
Ni(2)
- Ni(2)
-N(l)
-N(2)
-N(l,l)
- N(2,l)
- N(3,l)
— N(4,l)
-N(3)
-N(4)
- N(l,2)
- N(2,2)
- N(3,2)
-0(1)
3.801(1)
2.060(3)
2.059(3)
2.092(2)
2.093(3)
2.106(2)
2.082(4)
2.063(3)
2.053(3)
2.098(3)
2.088(3)
2.067(2)
2.109(3)
N(l)
N(2)
N(3)
N(4)
C(l)
C(l)
C(2)
C(2)
C(3)
C(3)
C(4)
C(4)
-C(l)
-C(2)
-C(3)
-C(4)
-S(1A)
-S(1B)
-S(2A)
- S(2B)
- S(3A)
- S(3B)
— S(4A)
— S(4B)
N(3)
Ni(2)
Ni(2)
Ni(2)
Ni(2)
Ni(2)
Ni(2)
Ni(2)
Ni(2)
Ni(2)
Ni(2)
Ni(2)
Ni(2)
Ni(2)
Ni(2)
Ni(2)
- N i ( l ) - N(2)
- N i ( l ) - N(l,l)
- N i ( l ) - N(2,l)
- N i ( l ) - N(3,l)
- N i ( l ) - N(4,l)
N(2) - N i ( l ) - N ( l , l )
- N i ( l ) - N(2,l)
- Ni(l) - N(3,l)
- Ni(l) - N(4,l)
N ( l , l ) - Ni(l) - N(2,l)
- N i ( l ) - N(3,l)
- N i ( l ) - N(4,l)
N(2,l) - N i ( l ) - N(3,l)
- Ni(l) - N(4,l)
N(3,l) - N i ( l ) - N(4,l)
91.2 (1)
88.9 (1)
177.4 (1)
89.4 (1)
90.2 (1)
178.5 (1)
91.4 (1)
88.6 (1)
90.1 (1)
88.47(9)
89.88(7)
91.4 (1)
90.4 (1)
90.0 (1)
178.6 (1)
N(4) N(l,2) N(2,2) N(3,2) -
Ni(l) - N ( l )
Ni(l) - N ( 2 )
Ni(2) - N ( 3 )
Ni(2) - N ( 4 )
N(l) - C ( l )
N(l) - C ( l )
N(2) - C ( 2 )
N(2) - C ( 2 )
N(3) - C ( 3 )
N(3) - C ( 3 )
N(4) - C ( 4 )
N(4) - C ( 4 )
166.5
172.3
167.4
163.4
168.1
173.7
169.7
164.4
173.3
164.0
168.8
169.6
N(l,l)
N(l,2)
N(2,l)
N(2,2)
N(3,l)
N(3,2)
N(4,2)
C(l,3)
C(l,5)
C(2,3)
C(2,5)
C(3,3)
C(3,5)
C(4,5)
N(l)
-
C(l)
C(2)
C(3)
C(4)
S(1A)
S(1B)
S(2A)
S(2B)
S(3A)
S(3B)
S(4A)
S(4B)
(3)
(3)
(3)
(3)
(3)
(3)
(4)
(4)
(3)
(4)
(4)
(4)
- N(4)
- N(l,2)
- N(2,2)
- N(3,2)
- O(l)
- N(l,2)
- N(2,2)
- N(3,2)
- O(l)
- N(2,2)
- N(3,2)
- O(l)
- N(3,2)
- 0(1)
- 0(1)
- N(l,2) - Ni(2)
-N(l,l) -Ni(l)
- N(2,2) - Ni(2)
- N(2,l) - N i ( l )
- N(3,2) - Ni(2)
-N(3,l) -Ni(l)
— N(4,l) - N i ( l )
- N ( l , 2 ) - Ni(2)
-N(l,l) -Ni(l)
- N(2,2) - Ni(2)
- N(2,l) - N i ( l )
- N(3,2) - Ni(2)
-N(3,l) -Ni(l)
- N(4,l) - N i ( l )
1.143(5)
1.125(4)
1.124(5)
1.139(5)
1.618(5)
1.653(5)
1.647(4)
1.699(4)
1.674(4)
1.647(6)
1.664(5)
1.664(5)
94.0 (1)
88.9 (1)
177.1 (1)
90.8 (1)
86.6 (1)
177.1 (1)
88.0 (1)
90.2 (1)
90.0 (1)
89.1 (1)
90.1 (1)
89.8 (1)
91.3 (1)
91.3 (1)
177.41(9)
125.2
125.3
125.2
125.6
125.1
125.5
126.4
128.3
126.9
128.5
127.7
128.6
127.2
126.1
(2)
(2)
(2)
(2)
(1)
(1)
(2)
(2)
(2)
(2)
(2)
(2)
(2)
(3)
Table IV. Bond lengths (A) and angles (°) in the Ettrz rings in Ni 2 (Ettrz)4(H 2 0)(NCS)4 • 2.5 H 2 0 .
N ( l ) - N(2)
N(2)-C(3)
C(3) — N(4)
N(4)-C(5)
C(5) - N ( l )
N(4)-C(6)
C(6) - C(7)
N ( l ) - N(2) N(2)-C(3) C(3) - N(4) N(4) - C(5) C(5) - N ( l ) C(3) — N(4) C(5) - N(4) N(4)-C(6) -
C(3)
C(4)
C(5)
N(l)
N(2)
C(6)
C(6)
C(7)
Ring 1
Ring 2
Ring 3
Ring 4
1.378(2)
1.289(4)
1.352(4)
1.357(4)
1.299(4)
1.478(5)
1.472(7)
1.377(2)
1.302(5)
1.340(6)
1.327(5)
1.299(5)
1.498(7)
1.09 (1)
1.20 (1)
106.3(3)
110.8(3)
105.1(3)
111.1(3)
106.8(3)
127.3(4)
127.6(4)
126.7(8)
107.8(6)
1.384(2)
1.309(4)
1.346(4)
1.354(4)
1.300(4)
1.454(4)
1.491(7)
1.378(5)
1.300(6)
1.323(5)
1.354(5)
1.289(6)
1.519(6)
1.375(8)
106.3(2)
111.2(3)
104.6(2)
110.8(2)
107.2(2)
128.0(3)
127.4(3)
111.5(3)
105.8(3)
111.8(3)
104.6(3)
110.4(3)
107.3(3)
128.4(4)
127.0(4)
112.3(5)
106.5(3)
111.5(3)
104.3(3)
110.1(3)
107.7(2)
127.8(3)
127.8(3)
112.2(4)
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Fig. 1. Perspective view of the binuclear unit of Ni2(Ettrz)4(H20)(NCS)4 • 2.5 H2O. The H atoms and the noncoordinating H2O molecules have been omitted.
is shown in Fig. 1, with the labeling of the atoms,
used in Table II, III and IV.
The structure consists of dimeric units in which
two Ni-ions are bridged by three 1,2-bicoordinating
Ettrz groups. Two N donating NCS - groups and an
Ettrz coordinating by only one N atom complete
the NiNe octahedron around one Ni-atom. For the
second Ni-ion, which is also coordinated octahedrally, the monodentate coordinating Ettrz is
replaced by a H2O molecule.
possible scheme for hydrogen bonding in the structure is proposed (Fig. 3). The water molecules form
hydrogen bridges with other H2O molecules and
with the sulfur atoms of the isothiocyanates. 0(4),
with multiplicity 0.49 has rather high standard
deviations. The presence of this H2O molecule may
be doubtful, but nevertheless it was included in the
refinement.
The positions of the binuclear units in the unit
cell are depicted in Fig. 2.
There is a reasonable agreement between the
geometries of the trz rings, described in the literature [4, 6], and those of the Ettrz rings 1, 2, 3 and 4.
The deviating distances in triazole ring 2 are
probably caused by the disordering of the Etgroup.
The asymmetrical coordination around the Niions, which is very remarkable, is probably stabilized
by hydrogen bonding. Thermoanalytical experiments already showed that hydrogen bonding is
expected to play an important role in the stability
of this compound [7]. The disorder, present in the
structure, hinders the location of the hydrogen
atoms belonging to the H2O molecules. However, a
Fig. 2. Positions of the Ni(II) ions in the dimeric units
in Ni 2 (Ettrz) 4 (H 2 0)(NCS)4 • 2.5 H 2 0 . The points halfway the Ni ions have been indicated. The empty
circles correspond to the Ni ions located outside the
unit cell.
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Final Remarks
The title compound is, to our knowledge, the first
synthesized binuclear Ni compound with 3 bridging
triazoles. The structure shows much resemblance
with the structure of Mn2(4-Metrz)5(NCS)4 [6]. Only
in the latter case the coordinated H 2 0 molecule is
replaced by a Metrz unit, which implies a much
more symmetrical coordination.
The related compounds with Mn, Fe and Co are
X-ray isomorphous with the title compound [7].
Further investigations on the coordination chemistry of 4-substituted, 1,2,4-triazoles will also deal
with other substituents, namely J-butyl and allyl.
[1] D. W . Engelfriet and W . L. Groeneveld, Z. Naturforsch. 33 a, 848 (1978).
[2] D. W . Engelfriet, J. G. Haasnoot, and W . L.
Groeneveld, Z. Naturforsch. 32a, 783 (1977).
[3] J. A. J. Jarvis, Acta Crystallogr. 15, 964 (1962).
[4] C. W . Reimann and M. Zocchi, Acta Crystallogr.
B 27, 682 (1971).
[5] S. Gorter and D. W . Engelfriet, Acta Crystallogr.
B (1981), accepted for publication.
[6] D. W . Engelfriet, G. C. Verschoor, and W. J.
Vermin, Acta Crystallogr. B 35, 2927 (1979).
This class of compounds is particularly interesting
from a magnetochemistry point of view, because of
the occurrence of well-separated dimeric units.
. All calculations were carried out on the Leiden
University I.B.M. 370-158 computers, using a set
of computer programs written or modified by Mrs.
E. W. Rutten-Keulemans and Dr. R. A. G. de
Graaff. The authors are indebted to Prof. Dr. C.
Romers, Prof. Dr. J. Reedijk, Dr. R. A. G. de Graaff
and Dr. J. Hoogendorp for their stimulating interest
in this study. The investigations were supported in
part by the Netherlands Organization for Chemical
Research (SON), with financial aid of the Netherlands Organization for the Advancement of Pure
Research (ZWO).
[7] G. Vos, J. G. Haasnoot, and W . L. Groeneveld,
Z. Naturforsch. 36 b, 802 (1981).
[8] U. S. Patent 3,821,376, June 28, 1974.
[9] S. African Patent 70,04,373, June 25, 1971.
[10] R. A. G. de Graaff, Acta Crystallogr. A 29, 298
(1973).
[11] International Tables for X-ray Crystallography
(1974). Vol. IV,pp. 71-151. Birmingham: Kynoch
Press.
Unauthenticated
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