Trans-bis[1-methyl-3-(p-nitrophenyl)- triazenido 1-oxide-k2N3,O]dipyridinenickel(II)

Article abstract of DOI:10.1107/S0108270102019820

In the centrosymmetric title complex, [Ni(C₇H₇N₄O₃)₂ (C₅H₅N)₂], the coordination geometry about the Ni²⁺ ion is octahedral, with two deprotonated 1-methyl-3-(p-nitrophenyl)triazenide 1-oxide ions, viz. [O₂NC₆H₄NNN(O)CH₃]^-, acting as bidentate ligands (four-electron donors). Two neutral pyridine (py) molecules complete the coordination sphere in positions trans to each other. The triazenide 1-oxide ligand is almost planar, the largest interplanar angle of 8.80 (12)° being between the phenyl ring of the p-nitrophenyl group and the plane defined by the N₃O moiety. The Ni-N_triazenide, Ni-O and Ni-N_py distances are 2.0794 (16), 2.0427 (13) and 2.1652 (18) A, respectively.

Full text of DOI:10.1107/S0108270102019820

metal-organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
ISSN 0108-2701
trans-Bis[1-methyl-3-(p-nitrophenyl)-
triazenido 1-oxide-j2N3,O]dipyridine-
nickel(II)
Manfredo Horner,a* Julieta Saldanha de Oliveira,a
È
Jairo Bordinhaoa and Johannes Beckb
Figure 1
Perspective view of (I). Displacement ellipsoids are drawn at the 50%
probability level and H atoms have been omitted for clarity.
aDepartamento de Quimica, Universidade Federal de Santa Maria, Caixa Postal
5071, 97110-970 Santa Maria, RS, Brazil, and bInstitut fur Anorganische Chemie
È
der Rheinischen Friedrich-Wilhelms-Universitat, Gerhard-Domagk-Straûe 1,
È
D-53121 Bonn, Germany
hexacoordinated mononuclear NiII complex, with deproton-
ated 1-methyl-3-(p-nitrophenyl)triazenide 1-oxide ions and
neutral pyridine molecules as ligands. Compound (I) is the
®rst example of a triazenide 1-oxide complex with a hexa-
coordinated Ni2+ ion and two different kinds of ligands (Fig. 1).
Deviations from normal NÐN and NÐCaryl bond lengths
(Table 1) underline the delocalization of the ꢀ electrons over
the NÐNÐN chain of the N13ÐN12ÐN11ÐO1 group and
Correspondence e-mail: hoerner@base.ufsm.br
Received 24 September 2002
Accepted 30 October 2002
Online 20 November 2002
In the centrosymmetric title complex, [Ni(C7H7N4O3)2-
(C5H5N)2], the coordination geometry about the Ni2+ ion
is octahedral, with two deprotonated 1-methyl-3-(p-nitro-
phenyl)triazenide 1-oxide ions, viz. [O2NC6H4NNN(O)CH3] ,
acting as bidentate ligands (four-electron donors). Two neutral
pyridine (py) molecules complete the coordination sphere in
positions trans to each other. The triazenide 1-oxide ligand is
almost planar, the largest interplanar angle of 8.80 (12)ꢀ being
between the phenyl ring of the p-nitrophenyl group and the
plane de®ned by the N3O moiety. The NiÐNtriazenide, NiÐO
and NiÐNpy distances are 2.0794 (16), 2.0427 (13) and
Ê
the p-nitrophenyl substituent. The N13ÐN12 [1.332 (2) A]
Ê
bond length is longer than a normal double bond (1.24 A),
Ê
N12ÐN11 [1.273 (2) A] is shorter than a normal single bond
Ê
(1.44 A) (International Tables for X-ray Crystallography, 1985,
Ê
Vol. III, p. 270) and N13ÐC11 [1.391 (3) A] is shorter than
expected for an NÐCaryl single bond. The NÐN bond lengths
in complex (I) are almost identical to those of non-coordi-
nated triazene 1-oxide molecules, where N13ÐN12 =
Ê
Ê
1.323 (2), 1.327 (4) and 1.332 (4) A, and N12ÐN11 =
2.1652 (18) A, respectively.
Ê
1.263 (2), 1.264 (3) and 1.270 (4) A (Samanta et al., 1997,
1998).
A typical feature of the coordinated deprotonated triaz-
enide 1-oxide ligand is the lengthening of the NÐO bond;
Ê
N11ÐO1 = 1.329 (2) A [comparative values for neutral non-
Ê
coordinated triazene 1-oxides are 1.288 (3) and 1.288 (2) A;
Samanta et al., 1997, 1998]. The NÐN and NÐO bond lengths
in (I) are also in good agreement with those found in bis[1-
ethyl-3-(p-nitrophenyl)triazenido 1-oxide]nickel(II) (Ciunik
Comment
Despite the fact that complexes of triazene N-oxides have
been widely investigated in recent decades, the structure of
nickel(II) complexes involving deprotonated 1,3-disubstituted
triazenide 1-oxide ligands, viz. [RNNN(O)R] , continue to
attract interest (Dutta & Sharma, 1981; Ciunik et al., 1991).
However, only two examples of six-coordinate nickel(II)
complexes with triazenide 1-oxide as a ligand have been
reported in the literature. In these examples, the triazenide
1-oxide ligand is incorporated as part of a larger chelating
group (Karmakar et al., 1993a,b). As part of our investigations
Ê
et al., 1991), hereafter (II) [NÐN = 1.260 (3) and 1.337 (2) A,
Ê
and NÐO = 1.340 (3) A], while Ni1ÐN13 of 2.0794 (16) A
Ê
Ê
Ê
[1.871 (2) A in (II)] and Ni1ÐO1 of 2.0427 (13) A
Ê
[1.828 (3) A in (II)] are signi®cantly longer (Ciunik et al.,
1991). These signi®cant differences between the NiÐN and
NiÐO bond distances of both complexes can be explained by
the expansion of the coordination number of the Ni2+ ion from
four in (II) to six in (I) and the steric demand of the two
additional axial pyridine ligands in (I). This observation is in
good agreement with the NiÐN and NiÐO bond distances
observed in other NiII complexes with octahedral coordina-
tion, such as [{H3CN(O)NNC6H4S(CH2)3SC6H4NN(O)N-
of the synthesis and characterization of metal complexes
incorporating triazene 1-oxide derivatives, we report here the
structure of the title complex, (I), which is a centrosymmetric
Ê
CH3}Ni] [NiÐN = 1.984 (8) and 1.993 (8) A, and NiÐO =
n
2.060 (7) and 2.075 (8) A] and [{ PrN(O)NNC6H4SMe}2Ni]
Ê
m586 # 2002 International Union of Crystallography
DOI: 10.1107/S0108270102019820
Acta Cryst. (2002). C58, m586±m587

metal-organic compounds
Ê
[NiÐN = 1.972 (4) and 1.970 (4) A, and NiÐO = 2.048 (4) and
Data collection
Ê
2.051 (4) A] (Karmakar et al., 1993a,b).
Enraf±Nonius CAD-4
diffractometer
ꢃ/2ꢃ scans
Absorption correction: scan
(Spek, 1990)
Tmin = 0.799, Tmax = 0.926
8301 measured re¯ections
2373 independent re¯ections
1888 re¯ections with I > 2ꢅ(I)
Rint = 0.036
ꢃmax = 25.0ꢀ
h = 12 ! 12
Due to the strong ꢀ-acidity of the nitro group, which
favours the delocalization of the ꢀ electrons and the conju-
gation between the C11±C16 phenyl ring and the NNNO
moiety, the triazenide 1-oxide ligand shows only a slight
deviation from planarity [the angles between the C11±C16
phenyl ring and the O11/N1/O12 and N13/N12/N11/O1 planes
are 5.5 (4) and 8.80 (12)ꢀ, respectively]. In addition to this
electronic effect, steric interactions involving the axial pyri-
dine ligands can also be associated with the small interplanar
angle of 8.80 (12)ꢀ. In contrast, the related four-coordinated
nickel complex, (II), shows a deviation from planarity for the
ligand, characterized by an N12ÐN13ÐC11ÐC16 torsion
angle of 27.5 (3)ꢀ (Ciunik et al., 1991). The C11±C16 phenyl
k = 15 ! 17
l = 10 ! 10
3 standard re¯ections
frequency: 60 min
intensity decay: <1%
Re®nement
Re®nement on F2
R(F) = 0.031
w = 1/[ꢅ2(Fo2) + (0.0333P)2
+ 0.4419P]
wR(F2) = 0.076
S = 1.03
where P = (Fo2 + 2Fc2)/3
(Á/ꢅ)max < 0.001
3
Ê
2373 re¯ections
188 parameters
H-atom parameters constrained
Áꢆmax = 0.17 e A
3
Ê
0.25 e A
Áꢆmin
=
Ê
ring (r.m.s. deviation 0.0068 A) and the N21/C22±C26 pyridine
Ê
ring (r.m.s. deviation 0.0031 A) are planar within experimental
The positional parameters of the H atoms were obtained geomet-
3
error. The Ni1ÐN21 bond distance of 2.1652 (18) can be
compared with the values found in the related complex cis-
2
rically, the CÐH distances ®xed (0.93 A for Csp and 0.96 A for Csp
Ê
Ê
H atoms), and the atoms re®ned as riding on their respective C atoms,
with an isotropic displacement parameter of 1.2 times the Ueq value of
the attached Csp2 and 1.5 times the Ueq value of the attached Csp3
atom. The methyl group was re®ned as a rigid group, with rotation
around the N11ÐC1 bond as a free variable.
[Ni{O2NC6H4NC(OEt)NC(O)C6H5}2(C5H5N)2] (NiÐNpy
=
Ê
2.150 and 2.131 A; Beyer et al., 1999). The nitro O atoms show
a large thermal motion, indicated by their elongated displa-
cement ellipsoids (Fig. 1). Split peaks for these atoms were not
observed and consequently a disorder model was not used.
Data collection: CAD-4 EXPRESS (Enraf±Nonius, 1994); cell
re®nement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms &
Wocadlo, 1995); program(s) used to solve structure: SHELXS97
(Sheldrick, 1997); program(s) used to re®ne structure: SHELXL97
(Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows
(Farrugia, 1997); software used to prepare material for publication:
WinGX (Farrugia, 1999).
Experimental
[NiCl2(PPh3)2] (654 mg, 1 mmol) was dissolved, with heating, in a
mixture of methanol (50 ml) and ethyl acetate (25 ml). A solution of
1-methyl-3-(p-nitrophenyl)triazene 1-oxide (392 mg, 2 mmol) in
methanol (25 ml) and triethylamine (5 ml) was added under contin-
uous stirring and heating. After 10 min, pyridine (5 ml) was added to
the reaction mixture, which changed colour to deep red. Stirring was
continued for 1 h. Red plate-shaped crystals of complex (I), suitable
for X-ray analysis, were obtained by slow evaporation of the solvents
at room temperature (yield: 91 mg, 15%; m.p. 498 K).
This work has received partial support from CNPq (Proc.
475734/01-7) and FAPERGS. MH and JB thank CNPq, and
JSO thanks CAPES for grants.
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: FR1398). Services for accessing these data are
described at the back of the journal.
Crystal data
3
[Ni(C7H7N4O3)2(C5H5N)2]
Mr = 607.22
Monoclinic, P21/c
Dx = 1.506 Mg m
Mo Kꢂ radiation
Cell parameters from 25
re¯ections
Ê
a = 10.473 (2) A
b = 14.961 (3) A
References
ꢃ = 2.0±25.0ꢀ
ꢄ = 0.78 mm
T = 294 (1) K
Ê
1
Ê
Beyer, L., Richter, R., Wolf, R., Yaumseil, J., Lino-Pacheco, M. & Angulo
Cornejo, J. (1999). Inorg. Chem. Commun. 2, 184±187.
Ciunik, Z., Wolny, J. A. & Rudolf, M. F. (1991). Acta Cryst. C47, 2539±2541.
Dutta, R. L. & Sharma, R. (1981). J. Sci. Ind. Res. 40, 715±737.
Enraf±Nonius (1994). CAD-4 EXPRESS. Enraf±Nonius, Delft, The Nether-
lands.
c = 8.569 (2) A
ꢁ = 94.028 (10)ꢀ
Ê
V = 1339.4 (5) A
Z = 2
3
Prism, red
0.30 Â 0.20 Â 0.10 mm
Table 1
Selected geometric parameters (A, ).
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.
ꢀ
Ê
Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837±838.
Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.
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hedron, 12, 291±296.
Karmakar, S., Choudhury, S. B., Ray, D. & Chakravorty, A. (1993b). Poly-
hedron, 12, 2325±2329.
Ni1ÐO1
Ni1ÐN13
Ni1ÐN21
O1ÐN11
O11ÐN1
O12ÐN1
2.0427 (13)
2.0794 (16)
2.1652 (18)
1.329 (2)
1.226 (3)
1.225 (3)
N1ÐC14
N11ÐN12
N11ÐC1
N12ÐN13
N13ÐC11
1.449 (3)
1.273 (2)
1.455 (3)
1.332 (2)
1.391 (3)
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1544±1546.
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1658.
Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of
O1ÐNi1ÐN13
O1ÐNi1ÐN21
N13ÐNi1ÐN21
N11ÐO1ÐNi1
76.73 (6)
89.12 (6)
87.59 (7)
109.92 (11)
O12ÐN1ÐO11
N12ÐN11ÐO1
N11ÐN12ÐN13
N12ÐN13ÐNi1
122.0 (2)
124.29 (16)
113.61 (17)
113.86 (13)
È
Gottingen, Germany.
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ꢁ
Acta Cryst. (2002). C58, m586±m587
Manfredo Horner et al. [Ni(C7H7N4O3)2(C5H5N)2] m587
È