Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270102019820/fr1398sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270102019820/fr1398Isup2.hkl |
CCDC reference: 201259
[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 continuous 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).
The positional parameters of the H atoms were obtained geometrically with fixed C—H distances (0.93 Å for Csp2 and 0.96 Å for Csp3) and refined as riding atoms on their respective C atoms with a isotropic temperature factor of 1.2 times the value of the attached Csp2 and 1.5 times of the value of the attached Csp3 atom, respectively. The methyl group was refined as a rigid group with the rotation around the N11—C1 bond as a free variable.
Data collection: CAD-4 EXPRESS (Enraf-Nonius, 1994); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).
Fig. 1. Perspective view of (I). Displacement ellipsoids are drawn at the 50% probability level and H atoms have been omitted for clarity. |
[Ni(C7H7N4O3)2(C5H5N)2] | F(000) = 628 |
Mr = 607.22 | Dx = 1.506 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 25 reflections |
a = 10.473 (2) Å | θ = 2.0–25.0° |
b = 14.961 (3) Å | µ = 0.78 mm−1 |
c = 8.569 (2) Å | T = 294 K |
β = 94.028 (10)° | Prism, red |
V = 1339.4 (5) Å3 | 0.30 × 0.20 × 0.10 mm |
Z = 2 |
Enraf-Nonius CAD-4 diffractometer | 1888 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.036 |
Graphite monochromator | θmax = 25.0°, θmin = 2.0° |
θ/2θ scans | h = −12→12 |
Absorption correction: ψ scan (Spek, 1990) | k = −15→17 |
Tmin = 0.799, Tmax = 0.926 | l = −10→10 |
8301 measured reflections | 3 standard reflections every 60 min |
2373 independent reflections | intensity decay: <1% |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.031 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.076 | H-atom parameters constrained |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0333P)2 + 0.4419P] where P = (Fo2 + 2Fc2)/3 |
2373 reflections | (Δ/σ)max < 0.001 |
188 parameters | Δρmax = 0.17 e Å−3 |
0 restraints | Δρmin = −0.25 e Å−3 |
[Ni(C7H7N4O3)2(C5H5N)2] | V = 1339.4 (5) Å3 |
Mr = 607.22 | Z = 2 |
Monoclinic, P21/c | Mo Kα radiation |
a = 10.473 (2) Å | µ = 0.78 mm−1 |
b = 14.961 (3) Å | T = 294 K |
c = 8.569 (2) Å | 0.30 × 0.20 × 0.10 mm |
β = 94.028 (10)° |
Enraf-Nonius CAD-4 diffractometer | 1888 reflections with I > 2σ(I) |
Absorption correction: ψ scan (Spek, 1990) | Rint = 0.036 |
Tmin = 0.799, Tmax = 0.926 | 3 standard reflections every 60 min |
8301 measured reflections | intensity decay: <1% |
2373 independent reflections |
R[F2 > 2σ(F2)] = 0.031 | 0 restraints |
wR(F2) = 0.076 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.17 e Å−3 |
2373 reflections | Δρmin = −0.25 e Å−3 |
188 parameters |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Mean-plane data from final SHELXL refinemente run:- Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane) 6.8993 (0.0073) x + 1.4234 (0.0141) y - 6.7760 (0.0048) z = 0.8488 (0.0106) * -0.0089 (0.0016) C11 * 0.0010 (0.0016) C12 * 0.0076 (0.0016) C13 * -0.0081 (0.0017) C14 * -0.0001 (0.0017) C15 * 0.0086 (0.0017) C16 Rms deviation of fitted atoms = 0.0068 - 7.4104 (0.0075) x + 0.6649 (0.0205) y + 6.4544 (0.0053) z = 0.1639 (0.0175) Angle to previous plane (with approximate e.s.d.) = 8.80 (0.12) * -0.0030 (0.0005) N13 * 0.0063 (0.0011) N12 * -0.0066 (0.0012) N11 * 0.0034 (0.0006) O1 Rms deviation of fitted atoms = 0.0051 6.7324 (0.0391) x + 2.8434 (0.0403) y - 6.7301 (0.0210) z = 1.8962 (0.0305) Angle to previous plane (with approximate e.s.d.) = 14.13 (0.40) * 0.0000 (0.0000) O11 * 0.0000 (0.0000) N1 * 0.0000 (0.0000) O12 Rms deviation of fitted atoms = 0.0000 6.8993 (0.0073) x + 1.4234 (0.0141) y - 6.7760 (0.0048) z = 0.8488 (0.0106) Angle to previous plane (with approximate e.s.d.) = 5.52 (0.43) * -0.0089 (0.0016) C11 * 0.0010 (0.0016) C12 * 0.0076 (0.0016) C13 * -0.0081 (0.0017) C14 * -0.0001 (0.0017) C15 * 0.0086 (0.0017) C16 Rms deviation of fitted atoms = 0.0068 - 2.1139 (0.0104) x + 14.6376 (0.0030) y + 0.5107 (0.0088) z = 6.5018 (0.0095) Angle to previous plane (with approximate e.s.d.) = 85.76 (0.08) * -0.0030 (0.0015) N21 * 0.0003 (0.0017) C22 * 0.0037 (0.0018) C23 * -0.0051 (0.0019) C24 * 0.0024 (0.0018) C25 * 0.0016 (0.0017) C26 Rms deviation of fitted atoms = 0.0031 |
x | y | z | Uiso*/Ueq | ||
Ni1 | 0.5000 | 0.5000 | 0.5000 | 0.03241 (13) | |
O1 | 0.60940 (14) | 0.56821 (9) | 0.66704 (16) | 0.0376 (3) | |
O11 | −0.02789 (18) | 0.73477 (14) | 0.0008 (2) | 0.0755 (6) | |
O12 | 0.0165 (2) | 0.86365 (14) | 0.0997 (3) | 0.0993 (8) | |
N1 | 0.0386 (2) | 0.78362 (16) | 0.0879 (3) | 0.0595 (6) | |
N11 | 0.59752 (17) | 0.65562 (11) | 0.6428 (2) | 0.0388 (4) | |
N12 | 0.51464 (17) | 0.69104 (12) | 0.5460 (2) | 0.0403 (4) | |
N13 | 0.44106 (16) | 0.63173 (11) | 0.4662 (2) | 0.0358 (4) | |
N21 | 0.64413 (16) | 0.52527 (11) | 0.3362 (2) | 0.0367 (4) | |
C1 | 0.6857 (3) | 0.71331 (17) | 0.7350 (3) | 0.0581 (7) | |
H1A | 0.6712 | 0.7744 | 0.7041 | 0.087* | |
H1B | 0.7721 | 0.6969 | 0.7176 | 0.087* | |
H1C | 0.6718 | 0.7067 | 0.8439 | 0.087* | |
C11 | 0.34630 (19) | 0.67329 (14) | 0.3701 (2) | 0.0359 (5) | |
C12 | 0.2651 (2) | 0.61908 (15) | 0.2746 (3) | 0.0438 (5) | |
H12 | 0.2782 | 0.5576 | 0.2747 | 0.053* | |
C13 | 0.1663 (2) | 0.65466 (16) | 0.1805 (3) | 0.0461 (6) | |
H13 | 0.1136 | 0.6177 | 0.1168 | 0.055* | |
C14 | 0.1461 (2) | 0.74590 (16) | 0.1814 (3) | 0.0442 (5) | |
C15 | 0.2251 (2) | 0.80148 (16) | 0.2724 (3) | 0.0495 (6) | |
H15 | 0.2111 | 0.8629 | 0.2710 | 0.059* | |
C16 | 0.3250 (2) | 0.76616 (15) | 0.3653 (3) | 0.0461 (6) | |
H16 | 0.3789 | 0.8040 | 0.4255 | 0.055* | |
C22 | 0.6116 (2) | 0.52614 (16) | 0.1831 (3) | 0.0485 (6) | |
H22 | 0.5267 | 0.5150 | 0.1499 | 0.058* | |
C23 | 0.6970 (2) | 0.54260 (18) | 0.0715 (3) | 0.0550 (7) | |
H23 | 0.6698 | 0.5429 | −0.0342 | 0.066* | |
C24 | 0.8221 (2) | 0.55843 (17) | 0.1183 (3) | 0.0532 (6) | |
H24 | 0.8820 | 0.5689 | 0.0453 | 0.064* | |
C25 | 0.8576 (2) | 0.55860 (18) | 0.2750 (3) | 0.0542 (6) | |
H25 | 0.9420 | 0.5699 | 0.3105 | 0.065* | |
C26 | 0.7665 (2) | 0.54176 (16) | 0.3791 (3) | 0.0456 (6) | |
H26 | 0.7917 | 0.5419 | 0.4853 | 0.055* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Ni1 | 0.0364 (2) | 0.0295 (2) | 0.0305 (2) | −0.00083 (16) | −0.00346 (14) | −0.00118 (16) |
O1 | 0.0461 (8) | 0.0289 (8) | 0.0368 (8) | −0.0024 (6) | −0.0048 (6) | 0.0010 (6) |
O11 | 0.0591 (12) | 0.0746 (14) | 0.0885 (15) | −0.0037 (10) | −0.0256 (11) | 0.0165 (11) |
O12 | 0.0965 (17) | 0.0580 (14) | 0.136 (2) | 0.0248 (12) | −0.0460 (15) | 0.0118 (14) |
N1 | 0.0497 (13) | 0.0601 (15) | 0.0672 (15) | 0.0059 (11) | −0.0059 (11) | 0.0201 (12) |
N11 | 0.0467 (11) | 0.0323 (10) | 0.0365 (10) | −0.0043 (8) | −0.0027 (8) | −0.0012 (8) |
N12 | 0.0488 (11) | 0.0325 (10) | 0.0392 (10) | −0.0029 (8) | 0.0002 (9) | 0.0005 (8) |
N13 | 0.0386 (10) | 0.0336 (10) | 0.0348 (10) | −0.0007 (8) | −0.0013 (8) | −0.0002 (8) |
N21 | 0.0403 (10) | 0.0337 (10) | 0.0353 (10) | −0.0025 (7) | −0.0026 (8) | −0.0011 (7) |
C1 | 0.0675 (17) | 0.0437 (14) | 0.0598 (16) | −0.0148 (12) | −0.0188 (13) | −0.0042 (12) |
C11 | 0.0395 (12) | 0.0365 (12) | 0.0323 (11) | 0.0033 (9) | 0.0063 (9) | 0.0038 (9) |
C12 | 0.0463 (13) | 0.0352 (13) | 0.0492 (13) | 0.0032 (10) | −0.0013 (11) | 0.0030 (10) |
C13 | 0.0425 (13) | 0.0483 (14) | 0.0466 (14) | −0.0024 (10) | −0.0026 (10) | 0.0061 (11) |
C14 | 0.0402 (13) | 0.0470 (14) | 0.0456 (13) | 0.0069 (10) | 0.0031 (10) | 0.0127 (11) |
C15 | 0.0544 (15) | 0.0369 (13) | 0.0570 (15) | 0.0086 (11) | 0.0015 (12) | 0.0069 (11) |
C16 | 0.0510 (14) | 0.0372 (13) | 0.0496 (14) | 0.0033 (10) | −0.0010 (11) | 0.0006 (11) |
C22 | 0.0452 (13) | 0.0609 (15) | 0.0386 (13) | −0.0122 (11) | −0.0035 (10) | 0.0022 (11) |
C23 | 0.0650 (17) | 0.0628 (17) | 0.0366 (13) | −0.0167 (13) | 0.0006 (12) | −0.0014 (12) |
C24 | 0.0541 (15) | 0.0557 (15) | 0.0509 (15) | −0.0150 (12) | 0.0109 (12) | −0.0033 (12) |
C25 | 0.0416 (13) | 0.0659 (17) | 0.0548 (16) | −0.0107 (12) | 0.0012 (12) | −0.0029 (13) |
C26 | 0.0430 (13) | 0.0529 (14) | 0.0398 (13) | −0.0031 (11) | −0.0039 (11) | −0.0008 (11) |
Ni1—O1 | 2.0427 (13) | C12—C13 | 1.374 (3) |
Ni1—N13 | 2.0794 (16) | C12—H12 | 0.9300 |
Ni1—N21 | 2.1652 (18) | C13—C14 | 1.382 (3) |
O1—N11 | 1.329 (2) | C13—H13 | 0.9300 |
O11—N1 | 1.226 (3) | C14—C15 | 1.376 (3) |
O12—N1 | 1.225 (3) | C15—C16 | 1.374 (3) |
N1—C14 | 1.449 (3) | C15—H15 | 0.9300 |
N11—N12 | 1.273 (2) | C16—H16 | 0.9300 |
N11—C1 | 1.455 (3) | C22—C23 | 1.377 (3) |
N12—N13 | 1.332 (2) | C22—H22 | 0.9300 |
N13—C11 | 1.391 (3) | C23—C24 | 1.364 (3) |
N21—C26 | 1.331 (3) | C23—H23 | 0.9300 |
N21—C22 | 1.332 (3) | C24—C25 | 1.367 (3) |
C1—H1A | 0.9600 | C24—H24 | 0.9300 |
C1—H1B | 0.9600 | C25—C26 | 1.375 (3) |
C1—H1C | 0.9600 | C25—H25 | 0.9300 |
C11—C12 | 1.398 (3) | C26—H26 | 0.9300 |
C11—C16 | 1.407 (3) | ||
O1i—Ni1—O1 | 180 | H1B—C1—H1C | 109.5 |
O1i—Ni1—N13 | 103.27 (6) | N13—C11—C12 | 117.82 (19) |
O1—Ni1—N13 | 76.73 (6) | N13—C11—C16 | 124.32 (19) |
O1i—Ni1—N13i | 76.73 (6) | C12—C11—C16 | 117.84 (19) |
O1—Ni1—N13i | 103.27 (6) | C13—C12—C11 | 121.4 (2) |
N13—Ni1—N13i | 180 | C13—C12—H12 | 119.3 |
O1i—Ni1—N21 | 90.88 (6) | C11—C12—H12 | 119.3 |
O1—Ni1—N21 | 89.12 (6) | C12—C13—C14 | 119.3 (2) |
N13—Ni1—N21 | 87.59 (7) | C12—C13—H13 | 120.4 |
N13i—Ni1—N21 | 92.41 (7) | C14—C13—H13 | 120.4 |
O1i—Ni1—N21i | 89.12 (6) | C15—C14—C13 | 120.9 (2) |
O1—Ni1—N21i | 90.88 (6) | C15—C14—N1 | 119.4 (2) |
N13—Ni1—N21i | 92.41 (7) | C13—C14—N1 | 119.7 (2) |
N13i—Ni1—N21i | 87.59 (7) | C16—C15—C14 | 119.9 (2) |
N21—Ni1—N21i | 180 | C16—C15—H15 | 120.0 |
N11—O1—Ni1 | 109.92 (11) | C14—C15—H15 | 120.0 |
O12—N1—O11 | 122.0 (2) | C15—C16—C11 | 120.6 (2) |
O12—N1—C14 | 118.6 (2) | C15—C16—H16 | 119.7 |
O11—N1—C14 | 119.4 (2) | C11—C16—H16 | 119.7 |
N12—N11—O1 | 124.29 (16) | N21—C22—C23 | 123.5 (2) |
N12—N11—C1 | 118.95 (18) | N21—C22—H22 | 118.2 |
O1—N11—C1 | 116.76 (17) | C23—C22—H22 | 118.2 |
N11—N12—N13 | 113.61 (17) | C24—C23—C22 | 118.9 (2) |
N12—N13—C11 | 111.66 (17) | C24—C23—H23 | 120.5 |
N12—N13—Ni1 | 113.86 (13) | C22—C23—H23 | 120.5 |
C11—N13—Ni1 | 134.31 (14) | C23—C24—C25 | 118.6 (2) |
C26—N21—C22 | 116.4 (2) | C23—C24—H24 | 120.7 |
C26—N21—Ni1 | 123.71 (15) | C25—C24—H24 | 120.7 |
C22—N21—Ni1 | 119.89 (15) | C24—C25—C26 | 118.9 (2) |
N11—C1—H1A | 109.5 | C24—C25—H25 | 120.5 |
N11—C1—H1B | 109.5 | C26—C25—H25 | 120.5 |
H1A—C1—H1B | 109.5 | N21—C26—C25 | 123.6 (2) |
N11—C1—H1C | 109.5 | N21—C26—H26 | 118.2 |
H1A—C1—H1C | 109.5 | C25—C26—H26 | 118.2 |
N13—Ni1—O1—N11 | −10.38 (12) | N12—N13—C11—C12 | 177.47 (18) |
N13i—Ni1—O1—N11 | 169.62 (12) | Ni1—N13—C11—C12 | 2.7 (3) |
N21—Ni1—O1—N11 | 77.35 (13) | N12—N13—C11—C16 | −4.0 (3) |
N21i—Ni1—O1—N11 | −102.65 (13) | Ni1—N13—C11—C16 | −178.82 (16) |
Ni1—O1—N11—N12 | 10.5 (2) | N13—C11—C12—C13 | 177.6 (2) |
Ni1—O1—N11—C1 | −169.79 (17) | C16—C11—C12—C13 | −0.9 (3) |
O1—N11—N12—N13 | −1.6 (3) | C11—C12—C13—C14 | −0.6 (4) |
C1—N11—N12—N13 | 178.7 (2) | C12—C13—C14—C15 | 1.5 (4) |
N11—N12—N13—C11 | 175.80 (17) | C12—C13—C14—N1 | −177.2 (2) |
N11—N12—N13—Ni1 | −8.3 (2) | O12—N1—C14—C15 | −4.3 (4) |
O1i—Ni1—N13—N12 | −169.55 (13) | O11—N1—C14—C15 | 176.3 (2) |
O1—Ni1—N13—N12 | 10.45 (13) | O12—N1—C14—C13 | 174.4 (3) |
N21—Ni1—N13—N12 | −79.21 (14) | O11—N1—C14—C13 | −5.1 (4) |
N21i—Ni1—N13—N12 | 100.79 (14) | C13—C14—C15—C16 | −0.7 (4) |
O1i—Ni1—N13—C11 | 5.1 (2) | N1—C14—C15—C16 | 177.9 (2) |
O1—Ni1—N13—C11 | −174.9 (2) | C14—C15—C16—C11 | −0.9 (4) |
N21—Ni1—N13—C11 | 95.48 (19) | N13—C11—C16—C15 | −176.8 (2) |
N21i—Ni1—N13—C11 | −84.52 (19) | C12—C11—C16—C15 | 1.7 (3) |
O1i—Ni1—N21—C26 | −155.89 (17) | C26—N21—C22—C23 | 0.2 (4) |
O1—Ni1—N21—C26 | 24.11 (17) | Ni1—N21—C22—C23 | 179.28 (19) |
N13—Ni1—N21—C26 | 100.86 (17) | N21—C22—C23—C24 | 0.4 (4) |
N13i—Ni1—N21—C26 | −79.14 (17) | C22—C23—C24—C25 | −0.9 (4) |
O1i—Ni1—N21—C22 | 25.12 (18) | C23—C24—C25—C26 | 0.8 (4) |
O1—Ni1—N21—C22 | −154.88 (18) | C22—N21—C26—C25 | −0.4 (3) |
N13—Ni1—N21—C22 | −78.13 (18) | Ni1—N21—C26—C25 | −179.37 (18) |
N13i—Ni1—N21—C22 | 101.87 (18) | C24—C25—C26—N21 | −0.2 (4) |
Symmetry code: (i) −x+1, −y+1, −z+1. |
Experimental details
Crystal data | |
Chemical formula | [Ni(C7H7N4O3)2(C5H5N)2] |
Mr | 607.22 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 294 |
a, b, c (Å) | 10.473 (2), 14.961 (3), 8.569 (2) |
β (°) | 94.028 (10) |
V (Å3) | 1339.4 (5) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.78 |
Crystal size (mm) | 0.30 × 0.20 × 0.10 |
Data collection | |
Diffractometer | Enraf-Nonius CAD-4 diffractometer |
Absorption correction | ψ scan (Spek, 1990) |
Tmin, Tmax | 0.799, 0.926 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8301, 2373, 1888 |
Rint | 0.036 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.031, 0.076, 1.03 |
No. of reflections | 2373 |
No. of parameters | 188 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.17, −0.25 |
Computer programs: CAD-4 EXPRESS (Enraf-Nonius, 1994), CAD-4 EXPRESS, XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).
Ni1—O1 | 2.0427 (13) | N1—C14 | 1.449 (3) |
Ni1—N13 | 2.0794 (16) | N11—N12 | 1.273 (2) |
Ni1—N21 | 2.1652 (18) | N11—C1 | 1.455 (3) |
O1—N11 | 1.329 (2) | N12—N13 | 1.332 (2) |
O11—N1 | 1.226 (3) | N13—C11 | 1.391 (3) |
O12—N1 | 1.225 (3) | ||
O1i—Ni1—O1 | 180 | N11—O1—Ni1 | 109.92 (11) |
O1—Ni1—N13 | 76.73 (6) | O12—N1—O11 | 122.0 (2) |
N13—Ni1—N13i | 180 | N12—N11—O1 | 124.29 (16) |
O1—Ni1—N21 | 89.12 (6) | N11—N12—N13 | 113.61 (17) |
N13—Ni1—N21 | 87.59 (7) | N12—N13—Ni1 | 113.86 (13) |
N21—Ni1—N21i | 180 |
Symmetry code: (i) −x+1, −y+1, −z+1. |
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 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 hexacoordinated mononuclear NiII complex, with deprotonated 1-methyl-3-(p-nitrophenyl)triazenide 1-oxide ions and neutral pyridine molecules as ligands. Compound (I) is the first example of a triazenide 1-oxide complex with a hexacoordinated Ni2+ ion and two different kinds of ligands (Fig. 1).
Deviations from the normal N—N and N—Caryl bond lengths underline the delocalization of the π electrons over the N—N═N chain of the N13—N12—N11—O1 group and the p-nitrophenyl substituent. The bond length N13—N12 [1.332 (2) Å] is longer than a normal double bond (1.24 Å), N12—N11 [1.273 (2) Å] is shorter than a normal single bond (1.44 Å) (International Tables for X-ray Crystallography, 1985, Vol. III, p. 270) and N13—C11 [1.391 (3) Å] is shorter than expected for an N—Caryl single bond. The N—N bond lengths in complex (I) are almost identical to those of non-coordinated triazene 1-oxide molecules; N13—N12 = 1.323 (2), 1.327 (4) and 1.332 (4) Å, and N12—N11 = 1.263 (2), 1.264 (3) and 1.270 (4) Å (Samanta et al., 1997, 1998).
A typical feature of the coordinated deprotonated triazenide 1-oxide ligand is the lengthening of the N—O bond (comparative values for neutral non-coordinated triazene 1-oxides are given in square brackets): N11—O1 = 1.329 (2) Å [1.288 (3) and 1.288 (2) Å; Samanta et al., 1997, 1998]. The N—N and N—O 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 et al., 1991), hereafter (II) [N—N = 1.260 (3) and 1.337 (2) Å, and N—O = 1.340 (3) Å], while the bonds Ni1—N13 of 2.0794 (16) Å [1.871 (2) Å in (II)] and Ni1—O1 of 2.0427 (13) Å [1.828 (3) Å in (II)] are significantly longer (Ciunik et al., 1991). These significant differences between the Ni—N and Ni—O 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 Ni—N and Ni—O bond distances observed in other NiII complexes with octahedral coordination, such as [{H3CN(O)NNC6H4S(CH2)3SC6H4NN(O)NCH3}Ni] [Ni—N = 1.984 (8) and 1.993 (8) Å, and Ni—O = 2.060 (7) and 2.075 (8) Å] and [{nPrN(O)NNC6H4SMe}2Ni] [Ni—N = 1.972 (4) and 1.970 (4) Å and Ni—O = 2.048 (4) and 2.051 (4) Å] (Karmakar et al., 1993a,b).
Due to the strong π-acidity of the nitro group, which favours the delocalization of the π electrons and the conjugation 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 pyridine 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 N12—N13—C11—C16 torsion anle of 27.5 (3)° (Ciunik et al., 1991). The C11–C16 phenyl ring (r.m.s. = 0.0068 Å) and the N21/C22–C2 pyridine ring (r.m.s. = 0.0031 Å) are planar within experimental error. The Ni1—N21 bond distance of 2.1652 (18) may be compared with the values found in the related complex cis-[Ni{O2NC6H4NC(OEt)NC(O)C6H5}2(C5H5N)2] (Ni—Npy = 2.150 and 2.131 Å; Beyer et al., 1999). The nitro O atoms show a large thermal motion, indicated by their elongated displacement ellipsoids (Fig. 1). Split peaks for these atoms were not observed, and consequently a disorder model was not used.