Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270105026260/ob1242sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270105026260/ob1242Isup2.hkl |
CCDC reference: 285649
2-Hydroxy-1-naphthaldehyde (0.1 mmol, 17.2 mg) and 2-aminomethylpyridine (0.1 mmol, 10.8 mg) were dissolved in MeOH (10 ml). The mixture was stirred at room temperature for 10 min to give a yellow solution. To this solution was added an aqueous solution (3 ml) of NaN3 (0.1 mmol, 6.5 mg) and an MeOH solution (5 ml) of Zn(CH3COO)2·4H2O (0.1 mmol, 25.6 mg), with stirring. The mixture was stirred for another 10 min at room temperature. After keeping the filtrate in air for 17 d, colourless block-shaped crystals of (I) were formed (yield 72.3%, on the basis of the Schiff base used).
All H atoms were placed in geometrically idealized positions and allowed to ride on their parent atoms, with C—H distances in the range 0.93–0.97 Å and with Uiso(H) = 1.2Ueq(C).
Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXTL.
[Zn2(C17H13N2O)2(N3)2] | F(000) = 752 |
Mr = 737.39 | Dx = 1.600 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 7.587 (1) Å | Cell parameters from 2253 reflections |
b = 14.746 (2) Å | θ = 2.7–23.4° |
c = 13.692 (2) Å | µ = 1.62 mm−1 |
β = 92.53 (2)° | T = 298 K |
V = 1530.3 (4) Å3 | Block, colourless |
Z = 2 | 0.25 × 0.21 × 0.17 mm |
Bruker SMART CCD area-detector diffractometer | 3406 independent reflections |
Radiation source: fine-focus sealed tube | 2491 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.031 |
ω scans | θmax = 27.5°, θmin = 2.0° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −9→9 |
Tmin = 0.688, Tmax = 0.770 | k = −19→13 |
8467 measured reflections | l = −17→15 |
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)] = 0.046 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.120 | H-atom parameters constrained |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0656P)2] where P = (Fo2 + 2Fc2)/3 |
3406 reflections | (Δ/σ)max < 0.001 |
217 parameters | Δρmax = 0.55 e Å−3 |
0 restraints | Δρmin = −0.25 e Å−3 |
[Zn2(C17H13N2O)2(N3)2] | V = 1530.3 (4) Å3 |
Mr = 737.39 | Z = 2 |
Monoclinic, P21/c | Mo Kα radiation |
a = 7.587 (1) Å | µ = 1.62 mm−1 |
b = 14.746 (2) Å | T = 298 K |
c = 13.692 (2) Å | 0.25 × 0.21 × 0.17 mm |
β = 92.53 (2)° |
Bruker SMART CCD area-detector diffractometer | 3406 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 2491 reflections with I > 2σ(I) |
Tmin = 0.688, Tmax = 0.770 | Rint = 0.031 |
8467 measured reflections |
R[F2 > 2σ(F2)] = 0.046 | 0 restraints |
wR(F2) = 0.120 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.55 e Å−3 |
3406 reflections | Δρmin = −0.25 e Å−3 |
217 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. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
Zn1 | 0.28270 (5) | 0.02511 (2) | 0.48926 (3) | 0.03900 (15) | |
O1 | 0.2176 (3) | −0.05608 (14) | 0.58940 (15) | 0.0421 (5) | |
N1 | 0.1394 (3) | 0.12139 (16) | 0.54036 (18) | 0.0374 (6) | |
N2 | 0.3156 (3) | 0.11495 (18) | 0.38190 (17) | 0.0377 (6) | |
N3 | 0.4231 (3) | −0.07074 (17) | 0.42703 (18) | 0.0399 (6) | |
N4 | 0.3887 (3) | −0.1492 (2) | 0.43811 (18) | 0.0418 (6) | |
N5 | 0.3600 (5) | −0.2250 (2) | 0.4454 (2) | 0.0694 (10) | |
C1 | 0.0354 (4) | 0.04268 (19) | 0.6822 (2) | 0.0344 (7) | |
C2 | 0.1264 (4) | −0.03955 (19) | 0.6652 (2) | 0.0358 (7) | |
C3 | 0.1202 (4) | −0.1095 (2) | 0.7363 (2) | 0.0460 (8) | |
H3 | 0.1805 | −0.1634 | 0.7262 | 0.055* | |
C4 | 0.0293 (5) | −0.1000 (2) | 0.8179 (2) | 0.0505 (8) | |
H4 | 0.0315 | −0.1468 | 0.8635 | 0.061* | |
C5 | −0.1698 (5) | −0.0125 (3) | 0.9213 (3) | 0.0590 (10) | |
H5 | −0.1709 | −0.0601 | 0.9658 | 0.071* | |
C6 | −0.2633 (5) | 0.0629 (3) | 0.9387 (3) | 0.0630 (10) | |
H6 | −0.3271 | 0.0672 | 0.9950 | 0.076* | |
C7 | −0.2644 (5) | 0.1340 (3) | 0.8726 (3) | 0.0575 (9) | |
H7 | −0.3288 | 0.1862 | 0.8846 | 0.069* | |
C8 | −0.1703 (4) | 0.1274 (2) | 0.7895 (2) | 0.0470 (8) | |
H8 | −0.1743 | 0.1754 | 0.7453 | 0.056* | |
C9 | −0.0686 (4) | 0.0511 (2) | 0.7689 (2) | 0.0376 (7) | |
C10 | −0.0692 (5) | −0.0211 (2) | 0.8363 (2) | 0.0444 (8) | |
C11 | 0.0467 (4) | 0.1168 (2) | 0.6175 (2) | 0.0384 (7) | |
H11 | −0.0195 | 0.1678 | 0.6318 | 0.046* | |
C12 | 0.1348 (5) | 0.2054 (2) | 0.4849 (2) | 0.0508 (8) | |
H12A | 0.1801 | 0.2545 | 0.5259 | 0.061* | |
H12B | 0.0139 | 0.2196 | 0.4647 | 0.061* | |
C13 | 0.2437 (4) | 0.1971 (2) | 0.3965 (2) | 0.0409 (7) | |
C14 | 0.2656 (4) | 0.2675 (2) | 0.3328 (3) | 0.0505 (8) | |
H14 | 0.2156 | 0.3238 | 0.3446 | 0.061* | |
C15 | 0.3632 (4) | 0.2542 (3) | 0.2505 (2) | 0.0527 (9) | |
H15 | 0.3805 | 0.3014 | 0.2069 | 0.063* | |
C16 | 0.4326 (5) | 0.1710 (3) | 0.2351 (2) | 0.0549 (9) | |
H16 | 0.4955 | 0.1602 | 0.1795 | 0.066* | |
C17 | 0.4100 (4) | 0.1029 (2) | 0.3015 (2) | 0.0456 (8) | |
H17 | 0.4613 | 0.0467 | 0.2909 | 0.055* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Zn1 | 0.0439 (2) | 0.0327 (2) | 0.0410 (2) | 0.00130 (16) | 0.00916 (16) | 0.00069 (15) |
O1 | 0.0507 (13) | 0.0288 (10) | 0.0481 (12) | 0.0037 (10) | 0.0178 (10) | 0.0009 (10) |
N1 | 0.0434 (14) | 0.0309 (13) | 0.0385 (14) | 0.0023 (11) | 0.0093 (11) | 0.0036 (11) |
N2 | 0.0379 (13) | 0.0399 (15) | 0.0354 (13) | −0.0008 (11) | 0.0019 (11) | 0.0046 (11) |
N3 | 0.0506 (15) | 0.0285 (13) | 0.0416 (14) | 0.0001 (12) | 0.0129 (12) | 0.0010 (11) |
N4 | 0.0465 (15) | 0.0480 (17) | 0.0319 (13) | 0.0064 (13) | 0.0123 (11) | −0.0061 (12) |
N5 | 0.109 (3) | 0.0324 (17) | 0.069 (2) | −0.0026 (17) | 0.0337 (19) | −0.0023 (15) |
C1 | 0.0335 (15) | 0.0335 (16) | 0.0367 (15) | −0.0030 (12) | 0.0054 (12) | −0.0028 (12) |
C2 | 0.0362 (16) | 0.0298 (16) | 0.0418 (16) | −0.0055 (12) | 0.0058 (13) | −0.0020 (12) |
C3 | 0.0533 (19) | 0.0293 (16) | 0.056 (2) | 0.0035 (14) | 0.0119 (16) | 0.0036 (15) |
C4 | 0.062 (2) | 0.0397 (19) | 0.0505 (19) | −0.0017 (16) | 0.0154 (17) | 0.0100 (15) |
C5 | 0.072 (3) | 0.065 (2) | 0.041 (2) | −0.002 (2) | 0.0169 (18) | 0.0048 (17) |
C6 | 0.068 (2) | 0.079 (3) | 0.044 (2) | 0.002 (2) | 0.0219 (18) | −0.008 (2) |
C7 | 0.059 (2) | 0.061 (2) | 0.053 (2) | 0.0122 (19) | 0.0111 (17) | −0.0167 (19) |
C8 | 0.0523 (19) | 0.0439 (19) | 0.0456 (18) | 0.0058 (16) | 0.0096 (15) | −0.0045 (15) |
C9 | 0.0372 (16) | 0.0384 (17) | 0.0372 (16) | −0.0036 (13) | 0.0023 (13) | −0.0072 (14) |
C10 | 0.0483 (19) | 0.0428 (19) | 0.0423 (18) | −0.0065 (15) | 0.0057 (14) | −0.0013 (15) |
C11 | 0.0393 (16) | 0.0302 (15) | 0.0459 (17) | 0.0027 (13) | 0.0050 (13) | −0.0057 (13) |
C12 | 0.064 (2) | 0.0346 (18) | 0.055 (2) | 0.0090 (16) | 0.0150 (16) | 0.0091 (15) |
C13 | 0.0399 (17) | 0.0405 (18) | 0.0421 (17) | −0.0019 (14) | −0.0006 (13) | 0.0071 (14) |
C14 | 0.0491 (19) | 0.044 (2) | 0.059 (2) | 0.0034 (16) | 0.0015 (16) | 0.0158 (16) |
C15 | 0.0514 (19) | 0.055 (2) | 0.052 (2) | −0.0012 (17) | 0.0010 (16) | 0.0225 (18) |
C16 | 0.052 (2) | 0.075 (3) | 0.0378 (17) | −0.0045 (19) | 0.0079 (15) | 0.0159 (18) |
C17 | 0.0454 (18) | 0.050 (2) | 0.0416 (17) | 0.0006 (15) | 0.0044 (14) | 0.0038 (15) |
Zn1—O1 | 1.902 (2) | C5—H5 | 0.9300 |
Zn1—N1 | 1.938 (2) | C6—C7 | 1.384 (5) |
Zn1—N2 | 2.003 (2) | C6—H6 | 0.9300 |
Zn1—N3 | 1.985 (2) | C7—C8 | 1.373 (5) |
Zn1—N3i | 2.554 (2) | C7—H7 | 0.9300 |
O1—C2 | 1.296 (4) | C8—C9 | 1.401 (4) |
N1—C11 | 1.297 (4) | C8—H8 | 0.9300 |
N1—C12 | 1.452 (4) | C9—C10 | 1.409 (4) |
N2—C13 | 1.347 (4) | C11—H11 | 0.9300 |
N2—C17 | 1.352 (4) | C12—C13 | 1.500 (4) |
N3—N4 | 1.197 (4) | C12—H12A | 0.9700 |
C1—C11 | 1.412 (4) | C12—H12B | 0.9700 |
C1—C2 | 1.420 (4) | C13—C14 | 1.371 (4) |
C1—C9 | 1.459 (4) | C14—C15 | 1.389 (5) |
C2—C3 | 1.421 (4) | C14—H14 | 0.9300 |
C3—C4 | 1.345 (4) | C15—C16 | 1.355 (5) |
C3—H3 | 0.9300 | C15—H15 | 0.9300 |
C4—C10 | 1.412 (5) | C16—C17 | 1.370 (4) |
C4—H4 | 0.9300 | C16—H16 | 0.9300 |
C5—C6 | 1.345 (6) | C17—H17 | 0.9300 |
C5—C10 | 1.425 (5) | N4—N5 | 1.144 (4) |
O1—Zn1—N1 | 91.89 (10) | C8—C7—C6 | 120.0 (3) |
O1—Zn1—N3 | 91.30 (10) | C8—C7—H7 | 120.0 |
N1—Zn1—N3 | 175.74 (10) | C6—C7—H7 | 120.0 |
O1—Zn1—N2 | 172.02 (10) | C7—C8—C9 | 122.3 (3) |
N1—Zn1—N2 | 82.55 (10) | C7—C8—H8 | 118.8 |
N3—Zn1—N2 | 93.98 (11) | C9—C8—H8 | 118.8 |
O1—Zn1—N3i | 95.28 (10) | C8—C9—C10 | 117.2 (3) |
N1—Zn1—N3i | 97.94 (11) | C8—C9—C1 | 123.7 (3) |
N2—Zn1—N3i | 91.17 (11) | C10—C9—C1 | 119.1 (3) |
N3—Zn1—N3i | 84.56 (11) | C9—C10—C4 | 119.2 (3) |
Zn1—N3—Zn1i | 95.44 (10) | C9—C10—C5 | 119.0 (3) |
C2—O1—Zn1 | 128.62 (19) | C4—C10—C5 | 121.8 (3) |
C11—N1—C12 | 118.0 (3) | N1—C11—C1 | 127.0 (3) |
C11—N1—Zn1 | 126.1 (2) | N1—C11—H11 | 116.5 |
C12—N1—Zn1 | 115.90 (19) | C1—C11—H11 | 116.5 |
C13—N2—C17 | 118.2 (3) | N1—C12—C13 | 110.6 (3) |
C13—N2—Zn1 | 114.9 (2) | N1—C12—H12A | 109.5 |
C17—N2—Zn1 | 126.8 (2) | C13—C12—H12A | 109.5 |
N4—N3—Zn1 | 120.6 (2) | N1—C12—H12B | 109.5 |
N4—N3—Zn1i | 112.9 (2) | C13—C12—H12B | 109.5 |
C11—C1—C2 | 121.0 (3) | H12A—C12—H12B | 108.1 |
C11—C1—C9 | 119.6 (3) | N2—C13—C14 | 121.6 (3) |
C2—C1—C9 | 119.4 (3) | N2—C13—C12 | 115.7 (3) |
O1—C2—C1 | 124.9 (3) | C14—C13—C12 | 122.6 (3) |
O1—C2—C3 | 116.6 (3) | C13—C14—C15 | 119.6 (3) |
C1—C2—C3 | 118.5 (3) | C13—C14—H14 | 120.2 |
C4—C3—C2 | 121.8 (3) | C15—C14—H14 | 120.2 |
C4—C3—H3 | 119.1 | C16—C15—C14 | 118.6 (3) |
C2—C3—H3 | 119.1 | C16—C15—H15 | 120.7 |
C3—C4—C10 | 122.0 (3) | C14—C15—H15 | 120.7 |
C3—C4—H4 | 119.0 | C15—C16—C17 | 120.0 (3) |
C10—C4—H4 | 119.0 | C15—C16—H16 | 120.0 |
C6—C5—C10 | 121.6 (4) | C17—C16—H16 | 120.0 |
C6—C5—H5 | 119.2 | N2—C17—C16 | 122.0 (3) |
C10—C5—H5 | 119.2 | N2—C17—H17 | 119.0 |
C5—C6—C7 | 119.9 (3) | C16—C17—H17 | 119.0 |
C5—C6—H6 | 120.1 | N5—N4—N3 | 177.1 (3) |
C7—C6—H6 | 120.1 |
Symmetry code: (i) −x+1, −y, −z+1. |
Experimental details
Crystal data | |
Chemical formula | [Zn2(C17H13N2O)2(N3)2] |
Mr | 737.39 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 298 |
a, b, c (Å) | 7.587 (1), 14.746 (2), 13.692 (2) |
β (°) | 92.53 (2) |
V (Å3) | 1530.3 (4) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 1.62 |
Crystal size (mm) | 0.25 × 0.21 × 0.17 |
Data collection | |
Diffractometer | Bruker SMART CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.688, 0.770 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8467, 3406, 2491 |
Rint | 0.031 |
(sin θ/λ)max (Å−1) | 0.650 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.046, 0.120, 1.03 |
No. of reflections | 3406 |
No. of parameters | 217 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.55, −0.25 |
Computer programs: SMART (Bruker, 1998), SAINT (Bruker, 1998), SAINT, SHELXS97 (Sheldrick, 1997a), SHELXL97 (Sheldrick, 1997a), SHELXTL (Sheldrick, 1997b), SHELXTL.
Zn1—O1 | 1.902 (2) | Zn1—N3 | 1.985 (2) |
Zn1—N1 | 1.938 (2) | Zn1—N3i | 2.554 (2) |
Zn1—N2 | 2.003 (2) | ||
O1—Zn1—N1 | 91.89 (10) | N1—Zn1—N3i | 97.94 (11) |
O1—Zn1—N3 | 91.30 (10) | N2—Zn1—N3i | 91.17 (11) |
N1—Zn1—N3 | 175.74 (10) | N3—Zn1—N3i | 84.56 (11) |
O1—Zn1—N2 | 172.02 (10) | Zn1—N3—Zn1i | 95.44 (10) |
N1—Zn1—N2 | 82.55 (10) | N4—N3—Zn1 | 120.6 (2) |
N3—Zn1—N2 | 93.98 (11) | N4—N3—Zn1i | 112.9 (2) |
O1—Zn1—N3i | 95.28 (10) | N5—N4—N3 | 177.1 (3) |
Symmetry code: (i) −x+1, −y, −z+1. |
Subscribe to Acta Crystallographica Section C: Structural Chemistry
The full text of this article is available to subscribers to the journal.
- Information on subscribing
- Sample issue
- Purchase subscription
- Reduced-price subscriptions
- If you have already subscribed, you may need to register
Metal–organic complexes containing bridging ligands are of current interest because of their interesting molecular topologies and crystal packing motifs, as well as the fact that they may be designed with specific functionalities (Supriya et al., 2005; Batten & Robson, 1998; Colacio et al., 2005; Abourahma et al., 2002; Konar et al., 2002). In addition to being robust and thermally stable, some possess photoluminescent properties, a feature that has contributed to d10 metal polynuclear complexes being investigated in the search for new materials (Weidenbruch et al., 1989; Kunkely & Vogler, 1990; Bertoncello et al., 1992). Among the ZnII and CdII complexes of this class, most possess photoluminescent properties (Sang & Xu, 2005; Wang et al., 2003).
Due to the versatile coordination modes of the ambidentate azide ligand, this pseudohalide ligand has become one of the most extensively studied building blocks in the field of polynuclear complexes (Woodward et al., 2005; Mukherjee et al., 2001; Goher et al., 2002). A major obstacle to a more comprehensive study of such azide-based complexes is the lack of rational synthetic procedures since, with the present state of knowledge, it is hardly possible to determine which coordination mode will be adopted by the azide ligand and whether the sought-after alternating chain structure will finally be formed (Tercero et al., 2002; Ribas et al., 1999; Liu et al., 2003).
Our work is aimed at obtaining polynuclear complexes. Based on the above considerations, the author has already reported an azide-bridged polynuclear copper(II) complex, viz. catena-poly[{4-bromo-2-[2-(dimethylamino)ethyliminomethyl]phenolato} (µ-azido)copper(II)], [Cu(bdmp)(N3)]n, (II) (You, 2005). In (II), the bridging azide ligand coordinates to two metal atoms via the same terminal N atom. The [Cu(bdmp)] moieties are linked by the bridging azide ligands, forming polymeric chains. In order to study the effects of Schiff base ligands in the construction of polynuclear complexes with the azide ligand, we have designed and synthesized a rigid tridentate ligand, 1-(pyridin-2-ylmethyliminomethyl)naphthalen-2-ol (Hpmmn), which is different from the flexible tridentate ligand, 4-bromo-2-[2-(dimethylamino)ethyliminomethyl]phenol (Hbdmp), used in the preparation of (II). The title complex, [Zn2(pmmn)2(N3)2], (I), formed by the reaction of Hpmmn, sodium azide, and zinc(II) acetate, is reported here.
Complex (I) is an azide-bridged dinuclear zinc(II) compound (Fig. 1) which has inversion symmetry. The ZnII atom is in a square-pyramidal coordination, with atoms O1, N1 and N2 of the pmmn ligand and the terminal N atom (N3) of a bridging azide ligand defining the basal plane, and one terminal N atom (N3i) of another bridging azide ligand occupying the apical position [symmetry code: (i) 1 − x, −y, 1 − z]. These are similar to the coordination modes of the Schiff base ligand and the bridging azide anion observed in (II). However, (I) and (II) are dinuclear and polynuclear complexes, respectively. The difference between the two structures is very likely caused by the hindrance effects of the Schiff bases. In (I), the rigid pmmn ligand is kept almost coplanar when coordinated to the metal ions, with a mean deviation from the plane of 0.057 (3) Å. The basal least-squares planes of the two adjacent ZnII centres are parallel to each other, making it possible for the two azide anions to be coordinated to the same two zinc(II) atoms. In contrast, in (II), the bdmp is a flexible Schiff base ligand. The basal least-squares planes of the two adjacent CuII centres in (II) are not parallel to each other and form a dihedral angle of 43.5 (2)°. This configuration makes it difficult for the other azide ligand to coordinate to the same two metal atoms as the first azide ligand from the other side. However, the other bridging azide has no choice but to coordinate to the third metal atom via the low-hindrance side of (II). Thus, complex (II) forms an infinite chain structure. The bond lengths around the metal centre are comparable in (I) and (II), although the metal centres are ZnII and CuII, respectively. The different configurations lead to an M—N—M bond angle of 95.44 (10)° in (I), much smaller than the corresponding value of 129.1 (2)° observed in (II), and the M···M distance in (I) [3.380 (2) Å] is much shorter than the corresponding value [4.196 (2) Å] in (II).
The bond lengths subtended at atom Zn1 in the basal plane are comparable with those observed in other Schiff base zinc(II) complexes (Gross & Vahrenkamp, 2005; Chen et al., 2005), and as expected, the bond involving the pyridine atom N2 [2.003 (2) Å] is longer than that involving the imino atom N1 [1.938 (2) Å] (Mondal et al., 2001). The bridging NNN group is nearly linear and shows bent coordination modes with the metal atoms (Table 1).