metal-organic compounds
trans-Bis[acetone (2-hydroxybenzoyl)hydrazonato-κ2N′,O]bis(pyridine-κN)zinc(II)
aCollege of Chemistry and Materials Science, Fujian Normal University, Fuzhou, Fujian 350007, People's Republic of China, and bState Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, People's Republic of China
*Correspondence e-mail: shenlin@fjnu.edu.cn
In the title compound, [Zn(C10H11N2O2)2(C5H5N)2], the ZnII atom lies on an inversion centre, and is coordinated in a distorted octahedral geometry by two carbonyl O atoms and two imino N atoms from two anionic bidentate acetone (2-hydroxybenzoyl)hydrazone ligands and by two N atoms from two pyridine molecules. The hydroxyl group acts as a donor, forming an intramolecular O—H⋯N hydrogen bond.
Related literature
For general background, see: Bai et al. (2006); Gao et al. (1998); Grove et al. (2004); Liu & Gao (1998); Ma et al. (1989). For related structures, see: Chen & Liu (2004); Domiano et al. (1975); Hu et al. (2006, 2007); Li et al. (2006); Liu et al. (1999); Samanta et al. (2007); Wen et al. (2000); Wu et al. (2006); Xiao et al. (2000).
Experimental
Crystal data
|
Data collection
|
Refinement
|
|
|
Data collection: PROCESS-AUTO (Rigaku, 1998); cell PROCESS-AUTO; data reduction: PROCESS-AUTO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.
Supporting information
10.1107/S1600536809001949/hy2173sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536809001949/hy2173Isup2.hkl
All reagents were commercially available and of analytical grade. To a solution of Zn(CH3COO)2.2H2O (0.110 g, 0.5 mmol) in pyridine (5 ml) was slowly added a suspension of acetone-N-salicyloylhydrazone (0.192 g, 1.0 mmol) in DMF(5 ml). The resulting red solution was stirred for 20 min and then filtered. After standing for 5 d, yellow crystals were separated from the filtrate.
H atoms bonded to C atoms were positioned geometrically and refined as riding atoms, with C—H = 0.93 (aromatic) and 0.96 (CH3) Å and with Uiso(H) = xUeq(C), where x=1.2 for aromatic and 1.5 for methyl H atoms. H atom of the hydroxyl group was located in difference Fourier map and refined isotropically with its coordinates fixed.
Data collection: PROCESS-AUTO (Rigaku, 1998); cell
PROCESS-AUTO (Rigaku, 1998); data reduction: PROCESS-AUTO (Rigaku, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).Fig. 1. Molecular structure of the title compound. Displacement ellipsoids are drawn at the 30% probability level. Hydrogen bonds are shown as dashed lines. [Symmetry code: (i) 1 - x, -y, -z.] |
[Zn(C10H11N2O2)2(C5H5N)2] | F(000) = 632 |
Mr = 605.99 | Dx = 1.370 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 3282 reflections |
a = 7.8225 (8) Å | θ = 2.3–27.5° |
b = 10.0381 (10) Å | µ = 0.88 mm−1 |
c = 18.8201 (18) Å | T = 293 K |
β = 96.21 (4)° | Block, yellow |
V = 1469.1 (3) Å3 | 0.35 × 0.26 × 0.15 mm |
Z = 2 |
Rigaku R-AXIS RAPID diffractometer | 2334 reflections with I > 2σ(I) |
Radiation source: 18 kW rotation anode | Rint = 0.034 |
Graphite monochromator | θmax = 27.5°, θmin = 2.3° |
ω scans | h = 0→10 |
13028 measured reflections | k = 0→13 |
3282 independent reflections | l = −24→24 |
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)] = 0.033 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.097 | H-atom parameters constrained |
S = 0.98 | w = 1/[σ2(Fo2) + (0.058P)2] where P = (Fo2 + 2Fc2)/3 |
3282 reflections | (Δ/σ)max < 0.001 |
188 parameters | Δρmax = 0.38 e Å−3 |
0 restraints | Δρmin = −0.33 e Å−3 |
[Zn(C10H11N2O2)2(C5H5N)2] | V = 1469.1 (3) Å3 |
Mr = 605.99 | Z = 2 |
Monoclinic, P21/n | Mo Kα radiation |
a = 7.8225 (8) Å | µ = 0.88 mm−1 |
b = 10.0381 (10) Å | T = 293 K |
c = 18.8201 (18) Å | 0.35 × 0.26 × 0.15 mm |
β = 96.21 (4)° |
Rigaku R-AXIS RAPID diffractometer | 2334 reflections with I > 2σ(I) |
13028 measured reflections | Rint = 0.034 |
3282 independent reflections |
R[F2 > 2σ(F2)] = 0.033 | 0 restraints |
wR(F2) = 0.097 | H-atom parameters constrained |
S = 0.98 | Δρmax = 0.38 e Å−3 |
3282 reflections | Δρmin = −0.33 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. |
x | y | z | Uiso*/Ueq | ||
Zn1 | 0.5000 | 0.0000 | 0.0000 | 0.04214 (12) | |
O1 | 0.4610 (2) | 0.49143 (15) | 0.11896 (11) | 0.0690 (5) | |
H1 | 0.5171 | 0.4215 | 0.0926 | 0.113 (11)* | |
O2 | 0.35166 (17) | 0.09309 (14) | 0.06705 (8) | 0.0492 (3) | |
N1 | 0.5358 (2) | 0.27234 (16) | 0.06295 (8) | 0.0423 (4) | |
N2 | 0.6294 (2) | 0.19207 (16) | 0.02003 (8) | 0.0433 (4) | |
N3 | 0.6638 (2) | −0.09222 (17) | 0.09654 (9) | 0.0469 (4) | |
C1 | 0.2948 (2) | 0.2914 (2) | 0.12902 (10) | 0.0435 (4) | |
C2 | 0.3302 (3) | 0.4273 (2) | 0.14421 (11) | 0.0525 (5) | |
C3 | 0.2284 (4) | 0.4958 (3) | 0.18860 (14) | 0.0694 (7) | |
H3A | 0.2484 | 0.5859 | 0.1977 | 0.083* | |
C4 | 0.1004 (4) | 0.4326 (3) | 0.21861 (15) | 0.0755 (8) | |
H4A | 0.0372 | 0.4790 | 0.2496 | 0.091* | |
C5 | 0.0628 (4) | 0.3007 (3) | 0.20383 (15) | 0.0753 (7) | |
H5A | −0.0267 | 0.2587 | 0.2237 | 0.090* | |
C6 | 0.1600 (3) | 0.2321 (2) | 0.15905 (12) | 0.0567 (5) | |
H6A | 0.1342 | 0.1433 | 0.1487 | 0.068* | |
C7 | 0.3987 (2) | 0.21174 (19) | 0.08292 (10) | 0.0397 (4) | |
C8 | 0.7671 (3) | 0.2453 (2) | 0.00115 (12) | 0.0511 (5) | |
C9 | 0.8255 (3) | 0.3833 (2) | 0.02229 (16) | 0.0741 (7) | |
H9A | 0.7457 | 0.4226 | 0.0515 | 0.111* | |
H9B | 0.8308 | 0.4364 | −0.0198 | 0.111* | |
H9C | 0.9374 | 0.3792 | 0.0487 | 0.111* | |
C10 | 0.8761 (3) | 0.1689 (3) | −0.04426 (17) | 0.0835 (9) | |
H10A | 0.8262 | 0.0826 | −0.0543 | 0.125* | |
H10B | 0.9893 | 0.1587 | −0.0195 | 0.125* | |
H10C | 0.8833 | 0.2159 | −0.0883 | 0.125* | |
C11 | 0.7532 (3) | −0.0149 (2) | 0.14528 (13) | 0.0584 (6) | |
H11A | 0.7448 | 0.0771 | 0.1401 | 0.070* | |
C12 | 0.8567 (3) | −0.0653 (3) | 0.20266 (13) | 0.0659 (7) | |
H12A | 0.9172 | −0.0082 | 0.2352 | 0.079* | |
C13 | 0.8699 (3) | −0.2014 (3) | 0.21143 (13) | 0.0647 (6) | |
H13A | 0.9398 | −0.2380 | 0.2496 | 0.078* | |
C14 | 0.7773 (3) | −0.2813 (2) | 0.16238 (13) | 0.0624 (6) | |
H14A | 0.7824 | −0.3735 | 0.1667 | 0.075* | |
C15 | 0.6764 (3) | −0.2228 (2) | 0.10655 (12) | 0.0549 (5) | |
H15A | 0.6134 | −0.2781 | 0.0739 | 0.066* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Zn1 | 0.04131 (17) | 0.03917 (18) | 0.04726 (19) | −0.01003 (14) | 0.01086 (12) | −0.00788 (15) |
O1 | 0.0754 (11) | 0.0435 (8) | 0.0881 (12) | −0.0109 (8) | 0.0086 (10) | −0.0158 (9) |
O2 | 0.0496 (7) | 0.0406 (7) | 0.0606 (9) | −0.0129 (6) | 0.0201 (6) | −0.0087 (7) |
N1 | 0.0429 (8) | 0.0400 (8) | 0.0437 (8) | −0.0079 (7) | 0.0031 (7) | −0.0041 (7) |
N2 | 0.0410 (8) | 0.0441 (9) | 0.0447 (9) | −0.0106 (7) | 0.0046 (7) | −0.0030 (7) |
N3 | 0.0466 (9) | 0.0486 (10) | 0.0449 (9) | −0.0068 (8) | 0.0024 (7) | −0.0018 (8) |
C1 | 0.0495 (10) | 0.0437 (10) | 0.0360 (9) | 0.0032 (9) | −0.0008 (8) | −0.0007 (8) |
C2 | 0.0589 (12) | 0.0486 (12) | 0.0476 (12) | 0.0048 (11) | −0.0056 (10) | −0.0054 (10) |
C3 | 0.0841 (17) | 0.0553 (14) | 0.0669 (15) | 0.0167 (14) | −0.0013 (13) | −0.0165 (13) |
C4 | 0.0821 (18) | 0.0784 (19) | 0.0683 (16) | 0.0286 (16) | 0.0177 (14) | −0.0098 (14) |
C5 | 0.0811 (17) | 0.0750 (18) | 0.0756 (17) | 0.0154 (15) | 0.0344 (14) | 0.0028 (14) |
C6 | 0.0617 (13) | 0.0532 (13) | 0.0582 (13) | 0.0043 (11) | 0.0201 (10) | 0.0016 (11) |
C7 | 0.0435 (9) | 0.0391 (9) | 0.0355 (9) | −0.0050 (8) | −0.0003 (7) | −0.0001 (8) |
C8 | 0.0447 (10) | 0.0505 (12) | 0.0587 (12) | −0.0168 (9) | 0.0076 (9) | 0.0020 (10) |
C9 | 0.0645 (14) | 0.0572 (15) | 0.102 (2) | −0.0289 (12) | 0.0137 (14) | 0.0001 (14) |
C10 | 0.0660 (15) | 0.0813 (19) | 0.111 (2) | −0.0259 (14) | 0.0433 (15) | −0.0134 (17) |
C11 | 0.0641 (13) | 0.0516 (13) | 0.0571 (13) | −0.0078 (11) | −0.0041 (11) | −0.0051 (10) |
C12 | 0.0678 (15) | 0.0684 (16) | 0.0573 (14) | −0.0087 (13) | −0.0130 (12) | −0.0074 (12) |
C13 | 0.0652 (14) | 0.0717 (16) | 0.0536 (13) | −0.0039 (13) | −0.0107 (11) | 0.0098 (12) |
C14 | 0.0699 (15) | 0.0526 (13) | 0.0626 (14) | −0.0059 (12) | −0.0032 (12) | 0.0078 (12) |
C15 | 0.0588 (12) | 0.0526 (12) | 0.0511 (12) | −0.0104 (11) | −0.0039 (10) | −0.0007 (10) |
Zn1—O2i | 2.0319 (14) | C4—H4A | 0.9300 |
Zn1—O2 | 2.0319 (14) | C5—C6 | 1.379 (3) |
Zn1—N2 | 2.1912 (16) | C5—H5A | 0.9300 |
Zn1—N2i | 2.1912 (16) | C6—H6A | 0.9300 |
Zn1—N3i | 2.3013 (18) | C8—C10 | 1.485 (3) |
Zn1—N3 | 2.3013 (18) | C8—C9 | 1.498 (3) |
O1—C2 | 1.338 (3) | C9—H9A | 0.9600 |
O1—H1 | 0.99 | C9—H9B | 0.9600 |
O2—C7 | 1.273 (2) | C9—H9C | 0.9600 |
N1—C7 | 1.322 (2) | C10—H10A | 0.9600 |
N1—N2 | 1.402 (2) | C10—H10B | 0.9600 |
N2—C8 | 1.286 (2) | C10—H10C | 0.9600 |
N3—C15 | 1.326 (3) | C11—C12 | 1.374 (3) |
N3—C11 | 1.339 (3) | C11—H11A | 0.9300 |
C1—C6 | 1.384 (3) | C12—C13 | 1.379 (4) |
C1—C2 | 1.415 (3) | C12—H12A | 0.9300 |
C1—C7 | 1.485 (3) | C13—C14 | 1.369 (3) |
C2—C3 | 1.396 (3) | C13—H13A | 0.9300 |
C3—C4 | 1.359 (4) | C14—C15 | 1.375 (3) |
C3—H3A | 0.9300 | C14—H14A | 0.9300 |
C4—C5 | 1.378 (4) | C15—H15A | 0.9300 |
O2i—Zn1—O2 | 180.00 (6) | C6—C5—H5A | 120.5 |
O2i—Zn1—N2 | 103.14 (6) | C5—C6—C1 | 122.0 (2) |
O2—Zn1—N2 | 76.86 (6) | C5—C6—H6A | 119.0 |
O2i—Zn1—N2i | 76.86 (6) | C1—C6—H6A | 119.0 |
O2—Zn1—N2i | 103.14 (6) | O2—C7—N1 | 125.93 (18) |
N2—Zn1—N2i | 180.00 (9) | O2—C7—C1 | 118.57 (17) |
O2i—Zn1—N3i | 90.07 (6) | N1—C7—C1 | 115.49 (17) |
O2—Zn1—N3i | 89.93 (6) | N2—C8—C10 | 119.64 (19) |
N2—Zn1—N3i | 89.38 (6) | N2—C8—C9 | 123.4 (2) |
N2i—Zn1—N3i | 90.62 (6) | C10—C8—C9 | 116.92 (19) |
O2i—Zn1—N3 | 89.93 (6) | C8—C9—H9A | 109.5 |
O2—Zn1—N3 | 90.07 (6) | C8—C9—H9B | 109.5 |
N2—Zn1—N3 | 90.62 (6) | H9A—C9—H9B | 109.5 |
N2i—Zn1—N3 | 89.38 (6) | C8—C9—H9C | 109.5 |
N3i—Zn1—N3 | 180.00 (10) | H9A—C9—H9C | 109.5 |
C2—O1—H1 | 103.6 | H9B—C9—H9C | 109.5 |
C7—O2—Zn1 | 113.95 (12) | C8—C10—H10A | 109.5 |
C7—N1—N2 | 112.91 (15) | C8—C10—H10B | 109.5 |
C8—N2—N1 | 115.16 (17) | H10A—C10—H10B | 109.5 |
C8—N2—Zn1 | 134.68 (15) | C8—C10—H10C | 109.5 |
N1—N2—Zn1 | 110.16 (11) | H10A—C10—H10C | 109.5 |
C15—N3—C11 | 116.73 (19) | H10B—C10—H10C | 109.5 |
C15—N3—Zn1 | 122.43 (14) | N3—C11—C12 | 123.0 (2) |
C11—N3—Zn1 | 120.83 (15) | N3—C11—H11A | 118.5 |
C6—C1—C2 | 118.3 (2) | C12—C11—H11A | 118.5 |
C6—C1—C7 | 119.76 (18) | C11—C12—C13 | 119.3 (2) |
C2—C1—C7 | 121.98 (19) | C11—C12—H12A | 120.4 |
O1—C2—C3 | 118.9 (2) | C13—C12—H12A | 120.4 |
O1—C2—C1 | 122.2 (2) | C14—C13—C12 | 118.2 (2) |
C3—C2—C1 | 119.0 (2) | C14—C13—H13A | 120.9 |
C4—C3—C2 | 120.8 (2) | C12—C13—H13A | 120.9 |
C4—C3—H3A | 119.6 | C13—C14—C15 | 118.9 (2) |
C2—C3—H3A | 119.6 | C13—C14—H14A | 120.6 |
C3—C4—C5 | 121.0 (3) | C15—C14—H14A | 120.6 |
C3—C4—H4A | 119.5 | N3—C15—C14 | 123.9 (2) |
C5—C4—H4A | 119.5 | N3—C15—H15A | 118.0 |
C4—C5—C6 | 118.9 (3) | C14—C15—H15A | 118.0 |
C4—C5—H5A | 120.5 |
Symmetry code: (i) −x+1, −y, −z. |
Experimental details
Crystal data | |
Chemical formula | [Zn(C10H11N2O2)2(C5H5N)2] |
Mr | 605.99 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 293 |
a, b, c (Å) | 7.8225 (8), 10.0381 (10), 18.8201 (18) |
β (°) | 96.21 (4) |
V (Å3) | 1469.1 (3) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.88 |
Crystal size (mm) | 0.35 × 0.26 × 0.15 |
Data collection | |
Diffractometer | Rigaku R-AXIS RAPID diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 13028, 3282, 2334 |
Rint | 0.034 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.033, 0.097, 0.98 |
No. of reflections | 3282 |
No. of parameters | 188 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.38, −0.33 |
Computer programs: PROCESS-AUTO (Rigaku, 1998), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
Acknowledgements
This work was supported by the National Natural Science Foundation of China (grant No. 20771024), the Natural Science Foundation of Fujian Province (grant No. 2008 J0142) and the Foundation of the State Key Laboratory of Structural Chemistry (grant No. 070032).
References
Bai, Y., Dang, D.-B., Cao, X., Duan, C.-Y. & Meng, Q.-J. (2006). Inorg. Chem. Commun. 9, 86–89. Web of Science CSD CrossRef CAS Google Scholar
Chen, X.-H. & Liu, S.-X. (2004). Chin. J. Struct. Chem. 23, 33–37. CAS Google Scholar
Domiano, P., Musatti, A., Nardelli, M., Pelizzi, C. & Predieri, G. (1975). J. Chem. Soc. Dalton Trans. pp. 2357–2360. CSD CrossRef Web of Science Google Scholar
Gao, S., Weng, Z.-Q. & Liu, S.-X. (1998). Polyhedron, 17, 3595–3606. Web of Science CSD CrossRef CAS Google Scholar
Grove, H., Kelly, T. L., Thompson, L. K., Zhao, L., Xu, Z., Abedin, T. S. M., Miller, D. O., Goeta, A. E., Wilson, C. & Howard, J. A. K. (2004). Inorg. Chem. 43, 4278–4288. Web of Science CrossRef PubMed CAS Google Scholar
Hu, Z.-Q., Shi, S.-M., He, H.-W., Yu, D. & Jia, B. (2007). Chin. J. Inorg. Chem. 23, 323–328. CAS Google Scholar
Hu, X., Zhang, L., Liu, L., Liu, G.-F., Jia, D.-Z. & Xu, G.-C. (2006). Inorg. Chim. Acta, 359, 633–641. Web of Science CrossRef CAS Google Scholar
Li, M.-X., Zhou, J., Yan, L. & Wang, J.-P. (2006). Acta Cryst. E62, m2321–m2322. Web of Science CSD CrossRef IUCr Journals Google Scholar
Liu, S.-X. & Gao, S. (1998). Polyhedron, 17, 81–84. CSD CrossRef Web of Science Google Scholar
Liu, B., Hu, R.-X., Liang, H. & Yu, K.-B. (1999). Chin. J. Struct. Chem. 18, 414–417. CAS Google Scholar
Ma, Y.-X., Ma, Z.-Q., Zhao, G., Ma, Y. & Yang, M. (1989). Polyhedron, 8, 2105–2108. CAS Google Scholar
Rigaku (1998). PROCESS-AUTO. Rigaku Corporation, Tokyo, Japan. Google Scholar
Samanta, B., Chakraborty, J., Shit, S., Batten, S. R., Jensen, P., Masuda, J. D. & Mitra, S. (2007). Inorg. Chim. Acta, 360, 2471–2481. Web of Science CSD CrossRef CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Wen, X., Lu, Z.-L., Wang, X.-J., Su, C.-Y., Yu, K.-B., Liu, H.-Q. & Kang, B. (2000). Polyhedron, 19, 1295–1304. Google Scholar
Wu, Y., Shi, S.-M., Jia, B. & Hu, Z.-Q. (2006). Acta Cryst. E62, m648–m649. Web of Science CSD CrossRef IUCr Journals Google Scholar
Xiao, G.-C., Feng, Y.-L. & Liu, S.-X. (2000). Chin. J. Struct. Chem. 19, 177–180. CAS Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
Hydrazones have been attracting much attention by chemists in recent years because of their biological activities, chemical and industrial versatility, and strong tendency to chelate transition metals (Bai et al., 2006; Grove et al., 2004), lanthanide metals (Ma et al., 1989) and main group metals (Gao et al., 1998; Liu & Gao, 1998). In particular, salicyloylhydrazone can be very flexible and finely tuned at the molecular level to take versatile bonding modes. It can act as a bi-, tri-, tetra- and even pentadentate ligand. A number of zinc(II) complexes with salicyloylhydrazone ligands have been studied (Hu et al., 2006; Hu et al., 2007; Li et al., 2006; Samanta et al., 2007; Wu et al., 2006). As an extension of the work on the structural characterization of salicyloylhydrazone complexes, the preparation and crystal structure of the title zinc(II) complex are reported here.
The molecular structure of the title compound is shown in Fig. 1. The ZnII atom lies on an inversion centre and has an axially elongated octahedral coordination geometry. The two carbonyl O atoms and the two imino N atoms make up the equatorial plane and the two N atoms of two pyridine molecules occupy the axial positions at longer distances (Table 1). Double-bond character is present in C7—N1 and C8—N2, as judged from their bond lengths [1.322 (2) and 1.286 (2) Å] (Domiano et al., 1975; Liu et al., 1999; Xiao et al., 2000). The C7—O2 bond length of 1.273 (2) Å approaches the value of 1.263 Å expected for an enolic form of the hydrazone ligand (Chen & Liu, 2004; Wen et al., 2000). The data suggest enolization and deprotonation of the hydrazone groups, which is different from the analogous ZnII complex with the same ligand (Li et al., 2006). There exists an intramolecular O—H···N hydrogen bond (Table 2).