The heterobifunctional ligand 5-[4-(1,2,4-triazol-4-yl)phen­yl]-1H-tetra­zole and its role in the construction of a Cd^II metal–organic chain structure

5-[4-(1,2,4-Triazol-4-yl)phen­yl]-1H-tetra­zole, C₉H₇N₇, (I), an asymmetric heterobifunctional organic ligand containing triazole (tr) and tetra­zole (tz) termini linked directly through a 1,4-phenyl­ene spacer, crystallizes in the polar space group Pc. The heterocyclic functions, serving as single hydrogen-bond donor (tz) or acceptor (tr) units, afford hydrogen-bonded zigzag chains with no crystallographic centre of inversion. In the structure of catena-poly[[di­aqua­cad­mium(II)]bis{μ₂-5-[4-(1,2,4-triazol-4-yl)phenyl]tetra­zol-1-ido-κ²N¹:N^1′}], [Cd(C₉H₆N₇)₂(H₂O)₂]_n, (II), the Cd^II dication resides on a centre of in­version in an octa­hedral {N₄O₂} environment. In the equatorial plane, the Cd^II polyhedron is built up from four N atoms of two kinds, namely of trans-coordinating tr and tz fragments [Cd—N = 2.2926 (17) and 2.3603 (18) Å], and the coordinating aqua ligands occupy the two apical sites. The metal centres are separated at a distance of 11.1006 (7) Å by means of the double-bridging tetra­zolate anion, L⁻, forming a chain structure. The water ligands and tz fragments inter­act with one another, like a double hydrogen-bond donor–acceptor synthon, leading to a hydrogen-bonded three-dimensional array.

S1. Comment

The ligand-design approach has proved to be a crucial starting point and attractive design tool for the rapid development of metal–organic frameworks (MOFs), as well as for modulating their properties (Elsevier et al., 2003). An interesting perspective may be focused on the screening of heterobitopic ligands consisting of parent azole heterocycles [e.g. 1,2,4-triazole/tetrazole (Aromí et al., 2011) or their close 1,2,4-triazole/pyrazole analogues etc.], each of which represents a widely known class of organic bridges. The introduction of asymmetry into the bridging-ligand topology may be considered as an interesting supramolecular design tool for engineering acentric and chiral coordination solids (Zhang et al., 2008). On the other hand, the presence of neutral and acidic heterofunctional donors can also provide specificity towards the preferential coordination of metal ions via the formation of M–[N—N]–M linkages. As mentioned earlier by Colombo et al. (2011), the strength of the resulting M—N bonds correlates well with the pK_a values for the deprotonation of the N—H bond in the azole heterocycle. This may be one of the reasons why tetrazolide-based MOFs demonstrate relatively low thermal stability and water sensitivity, which significantly limits their application in hydrogen storage (Dinca et al., 2006) and Lewis acid catalysis (Horike et al., 2008). Thus, azolide–MOF stability can be optimized and increased through the introduction of heterobifunctional N-donor groups. Recently, Bondar et al. (2008) described a 1,2,4-triazole/tetrazole ligand linked by a p-phenylene spacer, which shows promise for the production of microporous coordination polymers prepared in aqueous media under hydrothermal conditions. Another interesting example, demonstrating the heterobitopic ligand concept in the construction of porous heterometallic Cd/{Cu₆(OH)₆} frameworks, was provided by Govor et al. (2011). 4-(3,5-Dimethylpyrazol-4-yl)-1,2,4-triazole was utilized in the self-assembly of halide-incorporating nanocluster {Cu₆(OH)₆} container molecules for halogenated hydrocarbone sorption applications, and their rational integration into polymeric solids was realised using a `step-by-step' approach. These findings have stimulated our interest in heterobitopic ligands. In this paper, we report the crystal structures of the title heterobifunctional ligand, HL, (I), which contains both 1,2,4-triazole and tetrazole functions, and its cadmium complex, [CdL₂(H₂O)₂], (II).

The organic ligand (I), crystallizing in the polar space group Pc, is a dipolar molecule in which two different functions (tr and tz) are separated by a 1,4-phenylene (ph) spacer. Its asymmetric unit contains a whole molecule of 5-[4-(1,2,4-triazol-4-yl)phenyl]-1H-tetrazole (Fig. 1). Similar to simple 5-phenyl-1H-tetrazole (Krygowski & Cyranski, 1996), in (I) the C1—N4 [1.325 (4) Å] and especially the N2—N3 [1.291 (5) Å] bonds of the tetrazole ring are shorter than the other three, suggesting that the compound exists as the 1H-tautomer. It is known that, in solution and in the gas phase, 5-substituted tetrazoles appear in two tautomeric forms, 1H and 2H, while in the solid state 1H-tetrazole is preferred (Kiselev et al., 2011). This could be the reason for the angular directed intermolecular (tz)NH—N(tr) bonding vectors, leading preferentially to zigzag orientated chains of (I), in which the molecular dipoles interact accurately in the donor–acceptor sequence [N1—H1···N5ⁱ; Fig. 2 and Table 2]. Additionally, the packing motifs are supported by weaker C—H···N contacts (C3—H3···N4ⁱⁱ and C8—H8···N4ⁱⁱⁱ, Table 2), affording a three-dimensional hydrogen-bonding net (Desiraju & Steiner, 1999). These interactions cause the tz–benzene pair to be even more coplanar than the opposite side of (I) [the C3—N7—C7—C8 and N4—C1—C4—C5 torsion angles are 24.8 (6) and 10.1 (6)°, respectively]. Also, this packing mode eliminates the presence of a crystallographic centre of inversion and the individual molecular dipoles are not cancelled out in the crystal structure.

In the cadmium complex, (II), the asymmetric unit consists of a deprotonated organic ligand, a water molecule and a Cd^II cation. This last lies on an inversion centre and adopts a slightly distorted octahedral {N₄O₂} environment involving four N atoms of singly coordinated tetrazolide [Cd—N(tz) = 2.3603 (18) Å] and triazole [Cd—N(tr) = 2.2926 (17) Å] donor groups in a 1:1 ratio, and two O atoms of the coordinated water molecules [Cd1—O1 = 2.3960 (15) Å] (Fig. 3). These three donors occupy trans dispositions in the coordination environment of the Cd^II centres. The significant differences observed for the Cd—N distances may indicate a more ionic character of the Cd—N(tz) bond than the Cd—N(tr) bond. The organic ligands, utilizing one N1(tr) [No N1 in triazole] and one N1(tz) atom, act as a bidentate double-bridge between adjacent Cd^II cations [related by symmetry code (1 + x, 1 + y, 1 + z)], connecting them at a distance of 11.1006 (7) Å into a linear chain running almost perpendicular to the [112] plane.

The partially coordinated tetrazolide can be considered as a scaffold with multiple H-acceptor sites (through peripheral atoms N3 and N4), whereas the bound water molecule is a double H donor. Two water molecules and two tz fragments interact with one another, leading to a ten-membered {H—O—H—[N—N]—}₂ synthon in the ab plane [O1···N4ⁱⁱ = 2.900 (3) and O1···N3ⁱⁱⁱ = 2.920 (2) Å, Fig. 4]. In terms of graph-set analysis, these cyclic rings can be identified as R₄⁴(10) (Etter et al., 1990). Indeed, the {H—O—H—[N—N]—}₂ motifs are very characteristic and essential to controlling the organisation of the extended structures of molecular diaqua-bis[5-(2-pyridyl)tetrazolato]copper(II) (Mukhopadhyay et al., 2009) and the related diaquabis[4-(4H-1,2,4-triazol-4-yl)benzoato-k²O,O']cobalt(II), cadmium(II) and copper(II) analogues (Lukashuk et al., 2007).

Thus, the [Cd(C₉H₆N₇)₂(H₂O)₂] chains of (I) are tightly packed in a three-dimensional hydrogen-bonded network, which is additionally stabilized by means of numerous weak (tr)C—H—N(tz) interactions (Table 4).

In complex (II), it is interesting to note that the N^tr,N^tz coordinating ligand possesses an arc-shaped configuration that may be a consequence of the close interligand disposition in the polymeric chain (Fig. 5). A similar deformation effect for a tetradentate ligand was previously observed in the three-dimensional framework structure of [Cu₂(µ₄-L)₃]Cl.12H₂O (Bondar et al., 2008).

Summarizing, we have shown that 5-[4-(1,2,4-triazol-4-yl)phenyl]-1H-tetrazole is a prospective heterobifunctional asymmetric ligand for the controlled construction of acentric solids and coordination polymers utilizing triazole and tetrazolide donor moieties. The singly coordinated tetrazolide group tends to be involved in the formation of a cyclic hydrogen-bonded {H—O—H—[N—N]—}₂ synthon, which may be an important component for the organization of the crystal structures of coordination polymers.

Related literature

For related literature, see: Aromí et al. (2011); Bondar et al. (2008); Colombo et al. (2011); Desiraju & Steiner (1999); Dinca et al. (2006); Elsevier et al. (2003); Etter et al. (1990); Govor et al. (2011); Horike et al. (2008); Kiselev et al. (2011); Krygowski & Cyranski (1996); Lukashuk et al. (2007); Mukhopadhyay et al. (2009); Zhang et al. (2008).

S2. Experimental

All materials were of reagent grade and used as received. The organic ligand, 5-[4-(1,2,4-triazol-4-yl)phenyl]-1H-tetrazole (HL), (I), was prepared according to a previously described procedure (Bondar et al., 2008). Colourless prismatic monocrystals of HL suitable for X-ray analysis were grown by recrystallization from a hot aqueous solution.

For the synthesis of [CdL₂(H₂O)₂], (II), HL (10.6 mg, 49.7 µmol) was placed in a 50 ml test tube and dissolved in hot water (25 ml). To this solution was added Cd(NO₃)₂.4H₂O (0.0308 mg, 99.8 µmol) in water (5 ml). The test-tube was closed, placed into a 2 l Dewar flask filled with hot water and allowed to cool slowly to ambient temperature over period of 48 h. The yellowish [Colourless in CIF tables - please clarify] prisms of (II) which formed were collected and dried at room temperature (yield 8.1 mg, 56%).

S3. Refinement

All H atoms were located in difference maps and then refined as riding, with O—H = 0.85, N—H = 0.88 or C—H = 0.95 Å, and with U_iso(H) = 1.2U_eq(C) or U_iso(H) = 1.5U_eq(N,O).

Computing details

For both compounds, data collection: SMART-NT (Bruker, 1998); cell refinement: SAINT-NT (Bruker, 1999); data reduction: SAINT-NT (Bruker, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. The molecule of HL, (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. The hydrogen-bonding motif of (I), showing the zigzag packing of the HL molecules. The ligand dipoles are aligned in a parallel mode, forming layers. [Symmetry codes: (i) x - 1, -y + 1, z + 1/2; (ii) x + 1, y + 1, z; (iii) x, y + 1, z.]
	Fig. 3. A fragment of the structure of (II), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry codes: (i) -x + 1, -y + 1, -z + 1; (ii) x - 1, y - 1, z - 1; (iii) -x, -y, -z; (iv) x +1, y + 1, z + 1.]
	Fig. 4. Projections of the structure of (II), showing the formation of (a) the cyclic hydrogen-bonded {H—O—H—[N—N]—}2 synthon and (b) the hydrogen-bonded network. Hydrogen bonds are shown as dashed lines. [Symmetry codes: (ii) -x + 1, -y, -z; (iii) x, y + 1, z; (iv) -x + 1, -y, -z + 1.]
	Fig. 5. The packing of (II), showing the O—H···N(tz) interchain interactions that lead to the three-dimensional hydrogen-bonded framework. Hydrogen bonds are represented as dashed lines. [Symmetry code: (ii) -x + 1, -y, -z.]

(I) 5-[4-(1,2,4-Triazol-4-yl)phenyl]-1H-tetrazole

Crystal data

C9H7N7	F(000) = 220
Mr = 213.22	Dx = 1.562 Mg m^−3
Monoclinic, Pc	Mo Kα radiation, λ = 0.71073 Å
a = 3.7413 (7) Å	Cell parameters from 2647 reflections
b = 7.8684 (9) Å	θ = 2.6–26.2°
c = 15.4092 (13) Å	µ = 0.11 mm^−1
β = 91.54 (3)°	T = 153 K
V = 453.39 (11) Å^3	Prism, colourless
Z = 2	0.28 × 0.25 × 0.25 mm

Data collection

Bruker APEXII area-detector diffractometer	1317 independent reflections
Radiation source: fine-focus sealed tube	956 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.052
ω scans	θmax = 26.2°, θmin = 2.6°
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996)	h = −4→3
Tmin = 0.970, Tmax = 0.974	k = −9→8
2647 measured reflections	l = −19→18

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.049	H-atom parameters constrained
wR(F^2) = 0.104	w = 1/[σ^2(Fo^2) + (0.0469P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.99	(Δ/σ)max < 0.001
1317 reflections	Δρmax = 0.20 e Å^−3
146 parameters	Δρmin = −0.19 e Å^−3
2 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.029 (7)

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
N1	0.2057 (10)	0.0201 (4)	0.4166 (2)	0.0397 (10)
H1	0.1568	0.1172	0.4421	0.059*
N2	0.1482 (10)	−0.1347 (5)	0.4501 (2)	0.0491 (12)
N3	0.2613 (11)	−0.2436 (4)	0.3944 (3)	0.0491 (10)
N4	0.3861 (9)	−0.1614 (4)	0.3234 (2)	0.0415 (10)
N5	0.9698 (11)	0.6829 (5)	0.0076 (3)	0.0527 (11)
N6	1.0454 (11)	0.7764 (4)	0.0823 (3)	0.0536 (11)
N7	0.8134 (8)	0.5311 (4)	0.1196 (2)	0.0331 (9)
C1	0.3488 (10)	0.0032 (5)	0.3388 (3)	0.0303 (10)
C2	0.8341 (13)	0.5384 (6)	0.0331 (3)	0.0464 (12)
H2	0.7595	0.4497	−0.0050	0.056*
C3	0.9542 (13)	0.6819 (5)	0.1474 (3)	0.0462 (11)
H3	0.9821	0.7139	0.2067	0.055*
C4	0.4573 (10)	0.1405 (4)	0.2812 (3)	0.0276 (10)
C5	0.5620 (11)	0.1047 (5)	0.1973 (3)	0.0361 (11)
H5	0.5544	−0.0092	0.1768	0.043*
C6	0.6765 (10)	0.2322 (5)	0.1436 (3)	0.0344 (11)
H6	0.7462	0.2072	0.0862	0.041*
C7	0.6888 (11)	0.3960 (5)	0.1742 (3)	0.0302 (10)
C8	0.5793 (11)	0.4361 (5)	0.2564 (3)	0.0399 (12)
H8	0.5832	0.5506	0.2760	0.048*
C9	0.4645 (11)	0.3083 (5)	0.3097 (3)	0.0351 (10)
H9	0.3893	0.3348	0.3665	0.042*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.050 (2)	0.032 (2)	0.038 (2)	−0.0069 (18)	0.0162 (19)	−0.0039 (17)
N2	0.066 (3)	0.042 (2)	0.040 (3)	−0.012 (2)	0.009 (2)	0.005 (2)
N3	0.067 (3)	0.037 (2)	0.043 (2)	−0.003 (2)	0.015 (2)	0.0077 (19)
N4	0.061 (3)	0.029 (2)	0.035 (2)	0.0046 (18)	0.0164 (19)	−0.0033 (16)
N5	0.057 (2)	0.048 (2)	0.054 (3)	−0.005 (2)	0.023 (2)	0.008 (2)
N6	0.061 (3)	0.048 (2)	0.053 (3)	−0.004 (2)	0.007 (2)	0.007 (2)
N7	0.040 (2)	0.0288 (19)	0.031 (2)	−0.0005 (17)	0.0030 (17)	−0.0005 (17)
C1	0.030 (2)	0.031 (2)	0.030 (3)	−0.0002 (19)	0.010 (2)	−0.0021 (18)
C2	0.059 (3)	0.047 (3)	0.035 (3)	0.001 (2)	0.014 (2)	0.002 (2)
C3	0.056 (3)	0.043 (3)	0.040 (3)	−0.015 (2)	−0.001 (2)	0.002 (2)
C4	0.031 (2)	0.024 (2)	0.028 (2)	0.0046 (17)	0.0031 (18)	−0.0002 (17)
C5	0.048 (3)	0.026 (2)	0.035 (3)	0.004 (2)	0.006 (2)	−0.0054 (19)
C6	0.043 (2)	0.036 (2)	0.025 (3)	0.003 (2)	0.011 (2)	−0.0020 (18)
C7	0.032 (2)	0.032 (2)	0.027 (2)	−0.0010 (18)	0.0045 (19)	0.0056 (19)
C8	0.051 (3)	0.034 (3)	0.035 (3)	−0.005 (2)	0.013 (2)	−0.004 (2)
C9	0.046 (2)	0.037 (2)	0.023 (3)	0.002 (2)	0.008 (2)	−0.0026 (19)

Geometric parameters (Å, º)

N1—C1	1.333 (5)	C2—H2	0.9500
N1—N2	1.342 (4)	C3—H3	0.9500
N1—H1	0.8800	C4—C5	1.390 (5)
N2—N3	1.291 (5)	C4—C9	1.391 (5)
N3—N4	1.364 (5)	C5—C6	1.376 (5)
N4—C1	1.325 (4)	C5—H5	0.9500
N5—C2	1.310 (5)	C6—C7	1.373 (5)
N5—N6	1.389 (6)	C6—H6	0.9500
N6—C3	1.303 (5)	C7—C8	1.379 (6)
N7—C2	1.337 (5)	C8—C9	1.374 (5)
N7—C3	1.363 (5)	C8—H8	0.9500
N7—C7	1.442 (5)	C9—H9	0.9500
C1—C4	1.463 (5)
C1—N1—N2	109.1 (4)	N7—C3—H3	124.4
C1—N1—H1	125.4	C5—C4—C9	118.8 (3)
N2—N1—H1	125.4	C5—C4—C1	120.3 (3)
N3—N2—N1	106.7 (4)	C9—C4—C1	120.9 (4)
N2—N3—N4	110.1 (3)	C6—C5—C4	120.8 (3)
C1—N4—N3	106.2 (3)	C6—C5—H5	119.6
C2—N5—N6	106.4 (4)	C4—C5—H5	119.6
C3—N6—N5	106.5 (4)	C7—C6—C5	119.1 (4)
C2—N7—C3	104.2 (3)	C7—C6—H6	120.5
C2—N7—C7	129.9 (4)	C5—C6—H6	120.5
C3—N7—C7	125.9 (4)	C6—C7—C8	121.5 (4)
N4—C1—N1	107.8 (4)	C6—C7—N7	120.0 (4)
N4—C1—C4	125.5 (4)	C8—C7—N7	118.5 (4)
N1—C1—C4	126.7 (4)	C9—C8—C7	119.1 (4)
N5—C2—N7	111.7 (4)	C9—C8—H8	120.5
N5—C2—H2	124.1	C7—C8—H8	120.5
N7—C2—H2	124.1	C8—C9—C4	120.7 (4)
N6—C3—N7	111.2 (4)	C8—C9—H9	119.7
N6—C3—H3	124.4	C4—C9—H9	119.7
C1—N1—N2—N3	1.3 (5)	N4—C1—C4—C9	−168.7 (4)
N1—N2—N3—N4	−1.4 (6)	N1—C1—C4—C9	9.2 (6)
N2—N3—N4—C1	0.9 (6)	C9—C4—C5—C6	1.1 (6)
C2—N5—N6—C3	0.6 (5)	C1—C4—C5—C6	−177.7 (4)
N3—N4—C1—N1	−0.1 (5)	C4—C5—C6—C7	0.5 (6)
N3—N4—C1—C4	178.2 (4)	C5—C6—C7—C8	−1.9 (6)
N2—N1—C1—N4	−0.8 (5)	C5—C6—C7—N7	179.0 (4)
N2—N1—C1—C4	−179.0 (4)	C2—N7—C7—C6	20.9 (7)
N6—N5—C2—N7	0.4 (6)	C3—N7—C7—C6	−156.1 (4)
C3—N7—C2—N5	−1.2 (5)	C2—N7—C7—C8	−158.2 (5)
C7—N7—C2—N5	−178.7 (4)	C3—N7—C7—C8	24.8 (6)
N5—N6—C3—N7	−1.4 (5)	C6—C7—C8—C9	1.8 (7)
C2—N7—C3—N6	1.6 (5)	N7—C7—C8—C9	−179.1 (4)
C7—N7—C3—N6	179.3 (4)	C7—C8—C9—C4	−0.2 (7)
N4—C1—C4—C5	10.1 (6)	C5—C4—C9—C8	−1.2 (6)
N1—C1—C4—C5	−172.0 (4)	C1—C4—C9—C8	177.6 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···N5^i	0.88	2.01	2.875 (6)	170
C3—H3···N4^ii	0.95	2.52	3.353 (6)	147
C8—H8···N4^iii	0.95	2.50	3.414 (5)	162

Symmetry codes: (i) x−1, −y+1, z+1/2; (ii) x+1, y+1, z; (iii) x, y+1, z.

(II) catena-poly[[diaquacadmium(II)]bis{µ₂-5-[4-(1,2,4-triazol-4- yl)phenyl]tetrazol-1-ato-κ²N¹:N^1'}]

Crystal data

[Cd(C9H6N7)2(H2O)2]	Z = 1
Mr = 572.85	F(000) = 286
Triclinic, P1	Dx = 1.897 Mg m^−3
a = 7.6554 (5) Å	Mo Kα radiation, λ = 0.71073 Å
b = 7.8589 (7) Å	Cell parameters from 5552 reflections
c = 9.0762 (8) Å	θ = 2.3–26.4°
α = 98.926 (2)°	µ = 1.14 mm^−1
β = 98.066 (3)°	T = 296 K
γ = 108.354 (2)°	Prism, pale yellow
V = 501.47 (7) Å^3	0.24 × 0.23 × 0.20 mm

Data collection

Bruker APEXII area-detector diffractometer	2037 independent reflections
Radiation source: fine-focus sealed tube	1968 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.026
ω scans	θmax = 26.4°, θmin = 2.3°
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996)	h = −9→9
Tmin = 0.771, Tmax = 0.804	k = −9→9
5552 measured reflections	l = −11→11

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.024	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.050	H-atom parameters constrained
S = 1.10	w = 1/[σ^2(Fo^2) + (0.0209P)^2 + 0.1279P] where P = (Fo^2 + 2Fc^2)/3
2037 reflections	(Δ/σ)max < 0.001
160 parameters	Δρmax = 0.32 e Å^−3
0 restraints	Δρmin = −0.35 e Å^−3

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Cd1	0.0000	0.0000	0.0000	0.02171 (8)
O1	0.1967 (2)	0.2477 (2)	−0.09102 (18)	0.0302 (4)
H1W	0.2944	0.2382	−0.1206	0.045*
H2W	0.2169	0.3605	−0.0564	0.045*
N1	0.2390 (3)	−0.1184 (2)	0.0725 (2)	0.0253 (4)
N2	0.1788 (3)	−0.2991 (2)	0.0089 (2)	0.0279 (4)
N3	0.3029 (3)	−0.3682 (2)	0.0608 (2)	0.0279 (4)
N4	0.4485 (3)	−0.2359 (2)	0.1607 (2)	0.0266 (4)
N5	0.9402 (3)	0.8268 (2)	0.7588 (2)	0.0255 (4)
N6	0.9261 (3)	0.9092 (2)	0.6358 (2)	0.0302 (5)
N7	0.8147 (2)	0.6093 (2)	0.55559 (19)	0.0219 (4)
C1	0.4042 (3)	−0.0840 (3)	0.1654 (2)	0.0210 (5)
C2	0.8748 (3)	0.6495 (3)	0.7085 (2)	0.0248 (5)
H2	0.8701	0.5634	0.7688	0.030*
C3	0.8520 (3)	0.7760 (3)	0.5173 (3)	0.0273 (5)
H3	0.8273	0.7924	0.4182	0.033*
C4	0.5182 (3)	0.0953 (3)	0.2636 (2)	0.0213 (5)
C5	0.6397 (3)	0.1085 (3)	0.3974 (3)	0.0256 (5)
H5	0.6543	0.0027	0.4222	0.031*
C6	0.7391 (3)	0.2763 (3)	0.4940 (3)	0.0256 (5)
H6	0.8196	0.2834	0.5834	0.031*
C7	0.7180 (3)	0.4335 (3)	0.4565 (2)	0.0206 (5)
C8	0.5989 (3)	0.4239 (3)	0.3232 (2)	0.0255 (5)
H8	0.5848	0.5299	0.2984	0.031*
C9	0.5018 (3)	0.2556 (3)	0.2279 (2)	0.0243 (5)
H9	0.4234	0.2493	0.1375	0.029*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cd1	0.02407 (13)	0.01785 (12)	0.02010 (13)	0.00692 (9)	0.00001 (9)	−0.00038 (9)
O1	0.0299 (9)	0.0188 (8)	0.0405 (10)	0.0069 (7)	0.0087 (7)	0.0040 (7)
N1	0.0239 (10)	0.0175 (9)	0.0301 (11)	0.0060 (8)	−0.0004 (8)	0.0000 (8)
N2	0.0294 (11)	0.0176 (9)	0.0317 (11)	0.0055 (8)	0.0019 (9)	−0.0003 (8)
N3	0.0311 (11)	0.0196 (9)	0.0309 (11)	0.0081 (8)	0.0051 (9)	0.0019 (8)
N4	0.0271 (10)	0.0221 (9)	0.0283 (10)	0.0083 (8)	0.0022 (8)	0.0021 (8)
N5	0.0301 (11)	0.0236 (10)	0.0201 (10)	0.0079 (8)	0.0024 (8)	0.0024 (8)
N6	0.0405 (12)	0.0220 (10)	0.0247 (10)	0.0085 (9)	0.0013 (9)	0.0043 (8)
N7	0.0240 (10)	0.0183 (9)	0.0194 (9)	0.0048 (8)	0.0004 (8)	0.0015 (7)
C1	0.0225 (11)	0.0193 (10)	0.0215 (11)	0.0075 (9)	0.0044 (9)	0.0042 (8)
C2	0.0304 (12)	0.0213 (11)	0.0201 (11)	0.0064 (9)	0.0021 (10)	0.0046 (9)
C3	0.0363 (13)	0.0196 (11)	0.0235 (12)	0.0077 (10)	0.0005 (10)	0.0060 (9)
C4	0.0193 (11)	0.0198 (10)	0.0226 (11)	0.0049 (9)	0.0042 (9)	0.0023 (9)
C5	0.0289 (12)	0.0190 (11)	0.0306 (13)	0.0118 (9)	0.0034 (10)	0.0054 (9)
C6	0.0256 (12)	0.0254 (11)	0.0237 (12)	0.0097 (10)	−0.0018 (10)	0.0031 (9)
C7	0.0196 (11)	0.0191 (10)	0.0200 (11)	0.0045 (8)	0.0032 (9)	0.0007 (8)
C8	0.0295 (12)	0.0205 (11)	0.0250 (12)	0.0076 (9)	0.0018 (10)	0.0061 (9)
C9	0.0244 (12)	0.0244 (11)	0.0200 (11)	0.0071 (9)	−0.0029 (9)	0.0028 (9)

Geometric parameters (Å, º)

Cd1—N5^i	2.2926 (17)	N7—C2	1.353 (3)
Cd1—N5^ii	2.2926 (17)	N7—C3	1.361 (3)
Cd1—N1	2.3603 (18)	N7—C7	1.432 (3)
Cd1—N1^iii	2.3603 (18)	C1—C4	1.470 (3)
Cd1—O1	2.3960 (15)	C2—H2	0.9300
Cd1—O1^iii	2.3960 (15)	C3—H3	0.9300
O1—H1W	0.8500	C4—C9	1.387 (3)
O1—H2W	0.8500	C4—C5	1.390 (3)
N1—C1	1.341 (3)	C5—C6	1.381 (3)
N1—N2	1.349 (2)	C5—H5	0.9300
N2—N3	1.303 (3)	C6—C7	1.382 (3)
N3—N4	1.356 (2)	C6—H6	0.9300
N4—C1	1.336 (3)	C7—C8	1.385 (3)
N5—C2	1.304 (3)	C8—C9	1.377 (3)
N5—N6	1.382 (3)	C8—H8	0.9300
N5—Cd1^iv	2.2926 (17)	C9—H9	0.9300
N6—C3	1.296 (3)
N5^i—Cd1—N5^ii	180	C2—N7—C7	128.60 (18)
N5^i—Cd1—N1	90.69 (6)	C3—N7—C7	126.93 (18)
N5^ii—Cd1—N1	89.31 (6)	N4—C1—N1	111.01 (18)
N5^i—Cd1—N1^iii	89.31 (6)	N4—C1—C4	124.4 (2)
N5^ii—Cd1—N1^iii	90.69 (6)	N1—C1—C4	124.56 (19)
N1—Cd1—N1^iii	180	N5—C2—N7	110.04 (19)
N5^i—Cd1—O1	93.04 (6)	N5—C2—H2	125.0
N5^ii—Cd1—O1	86.96 (6)	N7—C2—H2	125.0
N1—Cd1—O1	95.31 (6)	N6—C3—N7	111.7 (2)
N1^iii—Cd1—O1	84.69 (6)	N6—C3—H3	124.1
N5^i—Cd1—O1^iii	86.96 (6)	N7—C3—H3	124.1
N5^ii—Cd1—O1^iii	93.04 (6)	C9—C4—C5	118.26 (19)
N1—Cd1—O1^iii	84.69 (6)	C9—C4—C1	120.6 (2)
N1^iii—Cd1—O1^iii	95.31 (6)	C5—C4—C1	121.10 (19)
O1—Cd1—O1^iii	180	C6—C5—C4	121.1 (2)
Cd1—O1—H1W	119.3	C6—C5—H5	119.4
Cd1—O1—H2W	124.5	C4—C5—H5	119.4
H1W—O1—H2W	108.3	C5—C6—C7	119.4 (2)
C1—N1—N2	105.42 (17)	C5—C6—H6	120.3
C1—N1—Cd1	145.03 (14)	C7—C6—H6	120.3
N2—N1—Cd1	108.93 (13)	C6—C7—C8	120.6 (2)
N3—N2—N1	108.92 (17)	C6—C7—N7	121.01 (19)
N2—N3—N4	110.09 (17)	C8—C7—N7	118.39 (19)
C1—N4—N3	104.55 (18)	C9—C8—C7	119.3 (2)
C2—N5—N6	108.23 (17)	C9—C8—H8	120.4
C2—N5—Cd1^iv	130.92 (15)	C7—C8—H8	120.4
N6—N5—Cd1^iv	119.03 (13)	C8—C9—C4	121.4 (2)
C3—N6—N5	105.74 (17)	C8—C9—H9	119.3
C2—N7—C3	104.24 (18)	C4—C9—H9	119.3
N5^i—Cd1—N1—C1	−29.8 (3)	C7—N7—C2—N5	−173.7 (2)
N5^ii—Cd1—N1—C1	150.2 (3)	N5—N6—C3—N7	0.5 (3)
O1—Cd1—N1—C1	63.3 (3)	C2—N7—C3—N6	−0.9 (3)
O1^iii—Cd1—N1—C1	−116.7 (3)	C7—N7—C3—N6	173.9 (2)
N5^i—Cd1—N1—N2	139.03 (14)	N4—C1—C4—C9	157.8 (2)
N5^ii—Cd1—N1—N2	−40.97 (14)	N1—C1—C4—C9	−24.6 (3)
O1—Cd1—N1—N2	−127.84 (13)	N4—C1—C4—C5	−24.6 (3)
O1^iii—Cd1—N1—N2	52.16 (13)	N1—C1—C4—C5	153.0 (2)
C1—N1—N2—N3	−0.4 (2)	C9—C4—C5—C6	1.2 (3)
Cd1—N1—N2—N3	−173.80 (14)	C1—C4—C5—C6	−176.4 (2)
N1—N2—N3—N4	0.3 (2)	C4—C5—C6—C7	−0.3 (3)
N2—N3—N4—C1	0.0 (2)	C5—C6—C7—C8	−0.2 (3)
C2—N5—N6—C3	0.2 (3)	C5—C6—C7—N7	178.35 (19)
Cd1^iv—N5—N6—C3	−166.14 (16)	C2—N7—C7—C6	−27.1 (3)
N3—N4—C1—N1	−0.2 (2)	C3—N7—C7—C6	159.4 (2)
N3—N4—C1—C4	177.64 (19)	C2—N7—C7—C8	151.6 (2)
N2—N1—C1—N4	0.4 (2)	C3—N7—C7—C8	−22.0 (3)
Cd1—N1—C1—N4	169.44 (18)	C6—C7—C8—C9	−0.1 (3)
N2—N1—C1—C4	−177.47 (19)	N7—C7—C8—C9	−178.74 (19)
Cd1—N1—C1—C4	−8.4 (4)	C7—C8—C9—C4	1.1 (3)
N6—N5—C2—N7	−0.8 (3)	C5—C4—C9—C8	−1.6 (3)
Cd1^iv—N5—C2—N7	163.34 (15)	C1—C4—C9—C8	176.0 (2)
C3—N7—C2—N5	1.0 (3)

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x−1, y−1, z−1; (iii) −x, −y, −z; (iv) x+1, y+1, z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1W···N4^v	0.85	2.06	2.900 (3)	172
O1—H2W···N3^vi	0.85	2.08	2.920 (2)	169
C2—H2···N3^vii	0.93	2.56	3.386 (3)	149

Symmetry codes: (v) −x+1, −y, −z; (vi) x, y+1, z; (vii) −x+1, −y, −z+1.