[1,3-Bis(4-nitrophenyl)triazenido]-(triphenylphosphine)gold(I)

Article abstract of DOI:10.1107/S0108270103018481

In the title complex, [Au(C₁₂H₈N₅O ₄)(C₁₈H₁₅P)], the coordination geometry about the Au_I ion is linear, with one deprotonated l,3-bis(4-nitrophenyl)triazenide ion, [O₂NC₆H ₄N= N-NC₆H₄NO₂]^-, acting as a monodentate ligand (two-electron donor), and one neutral triphenylphosphine molecule completing the metal coordination. The triazenide ligand is almost planar (r.m.s. deviation = 0.0767 A), with the largest interplanar angle being 11.6 (7)° between the phenyl ring of one of the terminal 4-nitrophenyl substituents and the plane defined by the N=N - N triad. The Au - N and Au - P distances are 2.108 (5) and 2.2524 (13) A, respectively. Pairs of molecules generated by centrosymmetry are associated into a supramolecular array via intermolecular C - H...O interactions, and N...C and N...O π-π interactions.

Full text of DOI:10.1107/S0108270103018481

metal-organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
(Immirzi et al., 1976), cis-bis(triphenylphosphine)bis(1,3-di-
phenyltriazenido)platinum(II) benzene solvate (Brown et al.,
1976), trans-carbonyl(1,3-di-p-tolyltriazenido)bis(triphenyl-
phosphine)iridium(I) (Immirzi et al., 1980) and trans-[1,3-
bis(4-¯uorophenyl)-1-triazenato-N](2-methylphenyl)bis(tri-
ethylphosphine)nickel(II) (Peregudov et al., 2000).
ISSN 0108-2701
[1,3-Bis(4-nitrophenyl)triazenido]-
(triphenylphosphine)gold(I)
Recently, the analogy between the isolobal species
[(Ph3P)Au]+ and H+ was connected with the formal zwitter-
ionic bond structure of the complex N-(triphenylphosphine-
gold)-N-(5-methoxyquinolyl-8)-2,4,6-trinitroaniline, compar-
ed with the structure of free N-(5-methoxyquinol-8-yl)-2,4,6-
trinitroaniline obtained by ab initio quantum-chemical calcul-
ations (Kuz'mina et al., 2001).
Based on the fact that [(Ph3P)Au]+ and H+ are isolobal
particles, and on the potential of triazenes for sigmatropic
migration of the H atom on the nitrogen triad, our goal was to
investigate the title complex, (I), resulting from the substitu-
tion of H+ on the diazoamine group of 1,3-bis-(4-nitro-
phenyl)triazene by the [(Ph3P)Au]+ cation, and the results are
presented here.
Manfredo Horner,a* Ivan Carlos Casagrande,a Herton
È
Fenner,a Jorg Danielsb and Johannes Beckb
È
aDepartamento de Quimica, Universidade Federal de Santa Maria, Caixa Postal
5071, 97110-970 Santa Maria±RS, Brazil, and bInstitut fur Anorganische Chemie,
È
Universitat Bonn, Gerhard-Domagk-Straûe 1, D-53121 Bonn, Germany
È
Correspondence e-mail: hoerner@base.ufsm.br
Received 30 June 2003
Accepted 18 August 2003
Online 30 September 2003
In the title complex, [Au(C12H8N5O4)(C18H15P)], the coordi-
nation geometry about the AuI ion is linear, with one depro-
tonated 1,3-bis(4-nitrophenyl)triazenide ion, [O2NC6H4N
N±NC6H4NO2] , acting as a monodentate ligand (two-
electron donor), and one neutral triphenylphosphine molecule
completing the metal coordination. The triazenide ligand is
Ê
almost planar (r.m.s. deviation = 0.0767 A), with the largest
interplanar angle being 11.6 (7)ꢀ between the phenyl ring of
one of the terminal 4-nitrophenyl substituents and the plane
de®ned by the N NÐN triad. The AuÐN and AuÐP
Ê
distances are 2.108 (5) and 2.2524 (13) A, respectively. Pairs of
The crystal structure of (I) reveals discrete asymmetric two-
coordinate mononuclear AuI complexes. The deprotonated
1,3-bis(4-nitrophenyl)triazenide ion acts as an N1-ꢂ1 mono-
dentate (two-electron donor) ligand, while one neutral tri-
phenylphosphine molecule completes the coordination
environment of the metal ion to an almost linear arrangement
(Fig. 1).
Deviations from normal NÐN and NÐCaryl bond lengths in
(I) (Table 1) provide evidence for the delocalization of the ꢀ
electrons on the NÐN N group towards the terminal aryl
molecules generated by centrosymmetry are associated into a
supramolecular array via intermolecular CÐHÁ Á ÁO inter-
actions, and NÁ Á ÁC and NÁ Á ÁO ꢀ±ꢀ interactions.
Comment
Although metal complexes with 1,3-diaryl-substituted tri-
azenide ligands, [ArNNNAr] , have been extensively inves-
tigated in the past, only a few reports of mononuclear gold(I)
complexes with monodentate triazenide ligands are found in
the literature. More recently, monodentate diaryltriazenide
complexes have received attention in connection with the
¯uxional behaviour of such compounds, in which transition
metal fragments MLn, such as AuPPh3, show N1±N3 ꢁ±ꢁ
migration on the nitrogen chain (Peregudov et al., 1998, 2000).
Besides the AuPPh3 group, to date only six monodentate di-
aryltriazenide complexes incorporating MLn fragments
(where L is phosphine) have been characterized by single-
crystal X-ray diffraction: cis-chlorobis(triphenylphos-
phine)(1,3-di-p-tolyltriazenido)palladium(II) and cis-chloro-
bis(triphenylphosphine)(1,3-di-p-tolyltriazenido)platinum(II)
chloroform solvate (Bombieri et al., 1976), trans-hydridobis-
(triphenylphosphine)(1,3-di-p-tolyltriazenido)platinum(II)
Ê
substituents. The N2 N3 bond [1.290 (7) A] is longer than
Ê
the typical value for a double bond (1.24 A), while N1ÐN2
Ê
[1.324 (6) A] is shorter than the characteristic value for a
Ê
single bond (1.44 A; International Tables for X-ray Crystal-
Ê
lography, 1985, Vol. III, p. 270). Both N1ÐC1B [1.390 (8) A]
Ê
and N3ÐC1A [1.402 (7) A] are shorter than expected for an
Ê
NÐCaryl single bond (1.452 A for secondary amines, NHR2,
with R = Csp2; Orpen et al., 1989). These values are in good
agreement with the distances found in the related compound
trans-[1,3-bis(4-¯uorophenyl)-1-triazenato-N](2-methylphen-
Ê
yl)bis(triethylphosphine)nickel(II) [N1 N2 = 1.298 (7) A
Ê
and N2ÐN3 = 1.326 (7) A; Peregudov et al., 2000].
Ê
The AuÐN1 bond distance of 2.108 (5) A in (I) is close to
Ê
the sum of the covalent radii (2.144 A; Allen et al., 1987;
Teatum et al., 1960) and corresponds to a covalent single bond.
m424 # 2003 International Union of Crystallography
DOI: 10.1107/S0108270103018481
Acta Cryst. (2003). C59, m424±m426

metal-organic compounds
This value is longer than that observed in the related
compound [Au(RN1 N2ÐN3ÐN4 N5R)(PPh3)], herein-
Ê
after (II) [where R is p-tolyl; AuÐN3 = 2.082 (5) A; Beck,
1988], suggesting that the 1,3-bis(4-nitrophenyl)triazenide ion
possesses minor basicity compared with the 1,5-ditolyl-1,4-
pentazadienide ion, [(tolN5tol)] , as a consequence of the ꢀ
acidity of both terminal 4-nitrophenyl substituents. On the
Ê
other hand, the AuÐP bond distance of 2.2524 (13) A in (I) is
signi®cantly shorter than the sum of the covalent radii
Ê
(2.530 A; Allen et al., 1987; Teatum et al., 1960) and is in good
Ê
agreement with that found in (II) [Au1ÐP1 = 2.234 (3) A].
The coordination angle of the AuI ion in (I) [N1ÐAuÐP =
178.70 (13)ꢀ] deviates only slightly from the ideal value of 180ꢀ
and is very close to that found in (II) [N3ÐAu1ÐP1 =
178.35ꢀ]. Due to the delocalization of the ꢀ electrons over the
nitro groups and the C1A±C6A and C1B±C6B phenyl rings
towards the N1ÐN2 N3 chain, the triazenide ligand is nearly
planar, with interplanar angles as follows: 5 (1)ꢀ between the
O1A/N6/O2A plane and the C1A±C6A ring, 3.5 (7)ꢀ between
the C1A±C6A ring and N1ÐN2 N3, 11.6 (7)ꢀ between the
C1B±C6B ring and N1ÐN2 N3, 3 (1)ꢀ between the O1B/N5/
O2B plane and the C1B±C6B ring, and 8.9 (4)ꢀ between the
C1A±C6A and C1B±C6B rings.
Figure 2
The unit cell of (I) in a view inclined slightly towards [010]. The
intermolecular NÁ Á ÁO ꢀ±ꢀ interactions are shown as dashed lines
[symmetry code: (iii)
x
1, 1 y, z].
The crystal structure of (I) reveals pairs of molecules
generated by centrosymmetry, which are associated into a
supramolecular array via intermolecular CÐHÁ Á ÁO interac-
tions (Table 2), and NÁ Á ÁC and NÁ Á ÁO ꢀ±ꢀ interactions (Fig. 2),
Zhang et al., 1999]. On the other hand, simultaneous weak
intermolecular N6Á Á ÁC6Bi and N3Á Á ÁC6Bii contacts hinder the
coplanarity of the C1B±C6B phenyl ring with the plane
de®ned by the N1ÐN2 N3 group [interplanar angle =
11.6 (7)ꢀ]. All phenyl rings in (I) are planar within experi-
with N6Á Á ÁC6Bi
=
3.282 (8), N3Á Á ÁC6Bii
= 3.357 (8),
N6Á Á ÁO1Biii = 3.136 (9) and O1AÁ Á ÁN5iii = 3.234 (9) A
Ê
[symmetry codes: (i) x, 1 + y, z; (ii) x, 1 y, z; (iii)
1
x
1,
y, z]. These values are similar to those for ꢀ±ꢀ contacts
Ê
mental error (average r.m.s. deviation = 0.0062 A).
found in free 1,3-bis(3-nitrophenyl)triazene [NÁ Á ÁC
=
Ê
Ê
3.387 (3) A, and NÁ Á ÁO = 2.992 (2), 3.304 (3) and 3.023 (2) A;
Experimental
1,3-Bis(4-nitrophenyl)triazene (28.7 mg, 0.1 mmol) was dissolved in
absolute tetrahydrofuran (20 ml) and treated with small portions of
metallic sodium powder until H2 evolution stopped. The resulting
intense-red mixture was ®ltered over a sintered-glass frit to remove
excess metallic sodium. A solution of Ph3PAuCl (49.5 mg, 0.1 mmol)
in absolute tetrahydrofuran was added slowly with continuous stir-
ring. After stirring at room temperature for 1 h, the yellow precipitate
of the title complex was ®ltered off and dried in vacuo. Red prism-
shaped crystals of (I) suitable for X-ray diffraction were obtained by
slow evaporation at room temperature of a solution of the complex in
pyridine (yield: 41 mg, 55%; m.p. 506±507 K).
Crystal data
3
[Au(C12H8N5O4)(C18H15P)]
Mr = 745.47
Triclinic, P1
Dx = 1.701 Mg m
Mo Kꢃ radiation
Cell parameters from 11 145
re¯ections
Ê
a = 10.2034 (4) A
b = 10.7550 (2) A
ꢆ = 1.0±27.5ꢀ
ꢇ = 5.15 mm
T = 296 (2) K
Ê
Ê
1
c = 14.0941 (5) A
ꢃ = 93.987 (2)ꢀ
ꢄ = 102.148 (2)ꢀ
ꢅ = 103.930 (2)ꢀ
V = 1455.73 (8) A
Z = 2
Figure 1
Prism, red
0.30 Â 0.20 Â 0.10 mm
The molecular structure of (I) with the atom-numbering scheme.
Displacement ellipsoids are drawn at the 50% probability and H atoms
have been omitted for clarity.
3
Ê
ꢁ
Acta Cryst. (2003). C59, m424±m426
Manfredo Horner et al. [Au(C12H8N5O4)(C18H15P)] m425
È

metal-organic compounds
Data collection
(Fig. 1). Splitpeaks for these atoms were not observed and conse-
quently a disorder model was not used in the re®nement.
Nonius KappaCCD area-detector
diffractometer
' and ! scans
Absorption correction: analytical
(Alcock, 1970)
Tmin = 0.438, Tmax = 0.648
15 644 measured re¯ections
6639 independent re¯ections
5647 re¯ections with I > 2ꢁ(I)
Rint = 0.034
Data collection: COLLECT (Nonius, 1997±2000); cell re®nement:
HKL SCALEPACK (Otwinowski & Minor, 1997); data reduction:
HKL DENZO (Otwinowski & Minor, 1997) and SCALEPACK;
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) and
DIAMOND (Brandenburg, 1996); software used to prepare material
for publication: WinGX (Farrugia, 1999).
ꢆ
max = 27.5ꢀ
h = 13 ! 13
k = 13 ! 11
l = 18 ! 17
Re®nement
Re®nement on F2
R(F) = 0.047
wR(F2) = 0.133
S = 1.09
6639 re¯ections
370 parameters
H-atom parameters constrained
w = 1/[ꢁ2(Fo2) + (0.0698P)2
+ 3.1565P]
This work received partial support from CNPq (Proc.
475734/01-7). CNPq (MH) and CAPES (ICC) are thanked for
grants.
where P = (Fo2 + 2Fc2)/3
(Á/ꢁ)max = 0
3
Ê
Áꢈmax = 1.27 e A
3
Ê
1.20 e A
Áꢈmin
=
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: SQ1026). Services for accessing these data are
described at the back of the journal.
Table 1
Selected geometric parameters (A, ).
References
ꢀ
Ê
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S. R. Hall & C. P. Huber, p. 271. Copenhagen: Munksgaard.
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AuÐP
2.108 (5)
2.2524 (13)
1.324 (6)
1.390 (8)
1.290 (7)
1.402 (7)
1.466 (8)
1.211 (9)
N6ÐO2A
C4BÐN5
N5ÐO1B
N5ÐO2B
PÐC1C
1.227 (9)
1.467 (9)
1.198 (12)
1.209 (12)
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C4AÐN6
N6ÐO1A
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ꢀ
Ê
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DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
C4CÐH4CÁ Á ÁO1Bi
0.93
0.93
2.55
2.53
3.304 (9)
3.330 (8)
139
144
C5DÐH5DÁ Á ÁO1Aii
Symmetry codes: (i) 1 ‡ x; 1 ‡ y; 1 ‡ z; (ii) 1 ‡ x; y 1; z.
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Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of
The positional parameters of the H atoms were obtained geome-
2
trically, with the CÐH distances ®xed (0.93 A for Csp ), and these
È
Ê
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atoms were re®ned as riding on their respective C atoms, with
Uiso(H) = 1.2Ueq(Csp2). The nitro O atoms show a large thermal
motion, indicated by their elongated displacement ellipsoids
ꢁ
m426 Manfredo Horner et al.
[Au(C12H8N5O4)(C18H15P)]
Acta Cryst. (2003). C59, m424±m426
È