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In the crystal structure of the title complex, [Zn(N3)2(C6H8N6)]n or [Zn(N3)2(bte)]n, where bte is [mu]-1,2-bis(1,2,4-triazol-1-yl)­ethane, each Zn atom is pentacoordinated in a distorted trigonal-bipyramidal coordination environment involving two N atoms from two bte ligands and three N atoms from three azide ligands. The Zn atoms are bridged by [mu]-1,1-azide groups and bte ligands around a centre of inversion, forming an infinite one-dimensional chain containing both four-membered Zn([mu]-1,1-N3)2Zn and 18-membered Zn(gauche-bte)2Zn rings.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270104005542/tr1078sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270104005542/tr1078Isup2.hkl
Contains datablock I

CCDC reference: 237920

Comment top

Interest in the crystal engineering of coordinated frameworks stems not only from their potential applications as zeolite-like materials in molecular selection, ion exchange and catalysis but also from their intriguing variety of architectures and topologies (Robson et al., 1992). The design of coordination polymers is highly influenced by several factors, such as the metal-coordination preference, the structural characteristics of the polydentate organic ligand, the metal–ligand ratio, the solvent system and the counter-ion (Batten & Murray, 2003; Riggio et al., 2001). The most widely used ligands are rigid rod-like organic building blocks, such as 4,4'-bipyridine (Fujita et al., 1994) and 4,4'-azobispyridine (Li et al., 2001). Relatively few studies of flexible ligands have been reported, but bis(1,2,4-triazole-1-yl)ethane (Li et al., 1999a, 1999b, 2003) is an excellent flexible ligand candidate for further research.

The pseudohalide azide has been demonstrated to be an extremely versatile ligand. It may provide end-to-end (EE or 1,3), end-on (EO or 1,1) or terminal coordination modes. Thus a large number of azide-bridged polymers have been synthesized and magneto-structurally characterized (Ribas et al., 1999). However, azide-bridged Zn polymers are relatively rare (Krischner et al., 1986; Pan et al., 1999; Chen & Chen, 2002). In the present work, we report the preparation and crystal structure of [Zn(bte)(N3)2]n, (I), which exhibits a novel one-dimensional chain with both four-membered Zn(µ-1,1-N3)2Zn and 18-membered Zn(gauche-bte)2Zn rings.

The molecular structure of (I) is shown in Fig. 1, and Table 1 gives selected structural parameters. Each Zn atom is pentacoordinated in a distorted trigonal-bipyramidal coordination environment. The trigonal base plane is defined by two N atoms [N3 and N6i; symmetry code: (i) 1 − x, 1 − y, 2 − z] from two bridging bte ligands and one N atom (N10) from an azide ligand. The Zn—Nbte bond lengths are shorter than those found in [Zn(dca)2(bte)2]n (Li et al., 2003). Two azide N atoms [N7 and N10ii; symmetry code: (ii) −x, 1 − y, 2 − z] occupy the axial positions. Atoms Zn1, N7 and N10ii deviate from the trigonal base plane by 0.2809 (9), 2.2874 (20) and −2.1934 (24) Å, respectively. One azide ligand is monodentate; the other acts as a bridging ligand linking two Zn atoms in an end-on (EO or 1,1) coordination mode [Zn1—N10—Zn1ii = 105.32 (7)°], generating a four-membered Zn(µ-1,1-N3)2Zn ring, with an intraring Zn···Zn distance of 3.5830 (9) Å.

Compound (I) develops into an infinite one-dimensional chain extending along the a axis and constructed from alternate interconnection of four-membered Zn(µ-1,1-N3)2Zn and 18-membered Zn(gauche-bte)2Zn rings (Fig. 2). The bte ligands exhibit a gauche conformation. The two triazole ring planes, viz. C1/C2/N1–N3 and C3/C4/N4–N6, are planar, with r.m.s. deviations of 0.0019 (11) and 0.0006 (10) Å, respectively. The dihedral angle between these two triazole ring planes is 51.65 (6)°. The bte ligand is twisted, the N1—C5—C6—N4 torsion angle being 62.62 (20)°.

There are four potentially coordinating N atoms in the bte ligand, but only two, at the 4-positions of the triazole rings, coordinate to Zn atoms. Two bte ligands are thus held together by two Zn atoms, forming a Zn(gauche-bte)2Zn ring around a centre of inversion, similar to that found in [Zn(dca)2(bte)2]n (Li et al., 2003). The Zn···Zn separation across the 18-membered ring is 6.7220 (18) Å, which is obviously shorter than the 8.369 (4) Å separation in [Zn(dca)2(bte)2]n. There are weak H···N interactions between the azide N atoms and alkane (triazole) H atoms of neighboring chains [N8···H6B—C6iii, 2.503 Å, and N9···H4A—C4iv, 2.274 Å; symmetry codes: (iii) −1 + x, y, −1 + z; (iv) 1 − x, 2 − y, 2 − z] linking adjacent chains in the crystal.

One example of an azide-bridged Zn polymer is [Zn(N3)2(4,4'-bipy)] (Pan et al., 1999 & Martin et al., 2001), in which the Zn/azide chain is an interesting combination of bridging types, incorporating four-membered ZnN2Zn rings, in which the azides bridge through one terminal atom, and six-membered rings, in which one of the azides coordinates to a pair of Zn atoms in an end-on fashion. Further examples are [Zn(N3)2L] (L is 2-methylpyridine, 3-methylpyridine, 4-methylpyridine, and 2,4-, 3,4- and 3,5-dimethylpyridine) (Mautner et al., 1987, 1988a, 1988b, 1992), in which each Zn atom is surrounded by four N atoms from different azide groups and one N atom from the pyridine in a distorted trigonal-bipyramidal fashion. The ZnN5 polyhedra share common edges, thus forming chains. To our knowledge, a one-dimensional chain constructed from alternate interconnection of four-membered and 18-membered rings is unusual. The structure of (I) is a successful example of synthesis of a novel polymer using the flexible bis(1,2,4-triazol-1-yl)alkane ligand.

Experimental top

A water/MeOH (1:1, v/v) solution (25 ml) of 1,2-bis(1,2,4-triazol-1-yl)ethane (0.082 g, 0.5 mmol) was added to one leg of a H-shaped tube and a water/MeOH (1:1, v/v) solution (25 ml) of NaN3 (0.078 g, 1.2 mmol) and Zn(NO3)2·6H2O (0.149 g, 0.5 mmol) was added to the other leg of the tube. Colourless crystals suitable for X-ray analysis were obtained after about three months. Analysis found: C 22.87, H 2.61, N 53.58%; calculated for C6H8N12Zn: C 22.98, H 2.57, N 53.61%.

Refinement top

H atoms were placed in idealized positions and refined as riding, with C—H distances of 0.95 (triazole) and 0.99 Å (ethane).

Computing details top

Data collection: CrystalClear (Rigaku, 2000); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1998); software used to prepare material for publication: SHELXTL & DIAMOND (Brandenburg, 2000).

Figures top
[Figure 1] Fig. 1. A view of (I), drawn at the 50% probability level. [Symmetry codes: (i) 1 − x, 1 − y, 2 − z; (ii) −x, 1 − y, 2 − z; (iii) 1 + x, y, z.]
[Figure 2] Fig. 2. The infinite one-dimensional chain of (I).
catena-Poly[[bis[µ-1,1'-ethane-1,2-diylbis(1,2,4-triazole)- κ2N4:N4']bis[azidozinc(II)]]-di-µ-azido-κ4N1:N1] top
Crystal data top
[Zn(N3)2(C6H8N6)]Z = 2
Mr = 313.61F(000) = 316
Triclinic, P1Dx = 1.805 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 7.646 (3) ÅCell parameters from 2938 reflections
b = 8.690 (3) Åθ = 3.1–27.5°
c = 9.266 (3) ŵ = 2.14 mm1
α = 95.430 (5)°T = 193 K
β = 105.054 (6)°Block, colourless
γ = 100.884 (5)°0.50 × 0.35 × 0.21 mm
V = 577.1 (3) Å3
Data collection top
Rigaku Mercury CCD
diffractometer
2575 independent reflections
Radiation source: fine-focus sealed tube2488 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.023
ω scansθmax = 27.5°, θmin = 3.1°
Absorption correction: multi-scan
(North et al., 1968)
h = 99
Tmin = 0.412, Tmax = 0.638k = 1110
6341 measured reflectionsl = 1212
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.025Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.063H-atom parameters constrained
S = 1.06 w = 1/[σ2(Fo2) + (0.0293P)2 + 0.4081P]
where P = (Fo2 + 2Fc2)/3
2575 reflections(Δ/σ)max = 0.001
172 parametersΔρmax = 0.29 e Å3
0 restraintsΔρmin = 0.41 e Å3
Crystal data top
[Zn(N3)2(C6H8N6)]γ = 100.884 (5)°
Mr = 313.61V = 577.1 (3) Å3
Triclinic, P1Z = 2
a = 7.646 (3) ÅMo Kα radiation
b = 8.690 (3) ŵ = 2.14 mm1
c = 9.266 (3) ÅT = 193 K
α = 95.430 (5)°0.50 × 0.35 × 0.21 mm
β = 105.054 (6)°
Data collection top
Rigaku Mercury CCD
diffractometer
2575 independent reflections
Absorption correction: multi-scan
(North et al., 1968)
2488 reflections with I > 2σ(I)
Tmin = 0.412, Tmax = 0.638Rint = 0.023
6341 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0250 restraints
wR(F2) = 0.063H-atom parameters constrained
S = 1.06Δρmax = 0.29 e Å3
2575 reflectionsΔρmin = 0.41 e Å3
172 parameters
Special details top

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 (Å2) top
xyzUiso*/Ueq
Zn10.13542 (3)0.67259 (2)0.95778 (2)0.01747 (8)
N10.5348 (2)0.80601 (17)1.37504 (16)0.0170 (3)
N20.5678 (2)0.94439 (18)1.31816 (18)0.0240 (3)
N30.3418 (2)0.76120 (17)1.15051 (16)0.0171 (3)
N40.8152 (2)0.61031 (17)1.41296 (16)0.0173 (3)
N50.7474 (2)0.46692 (18)1.44963 (18)0.0218 (3)
N60.8153 (2)0.43662 (17)1.22871 (16)0.0182 (3)
N70.1502 (3)0.8848 (2)0.8806 (2)0.0299 (4)
N80.0641 (2)0.97580 (17)0.82908 (17)0.0207 (3)
N90.0158 (3)1.0664 (2)0.7738 (2)0.0358 (4)
N100.1289 (2)0.58864 (18)0.95056 (19)0.0218 (3)
N110.2475 (2)0.66411 (18)0.93077 (19)0.0234 (3)
N120.3654 (3)0.7307 (3)0.9122 (3)0.0521 (6)
C10.4480 (3)0.9117 (2)1.1833 (2)0.0221 (4)
H1A0.43630.98631.11470.027*
C20.4014 (2)0.6990 (2)1.2742 (2)0.0189 (3)
H2A0.35570.59381.28850.023*
C30.7502 (2)0.3663 (2)1.3352 (2)0.0198 (3)
H3A0.71030.25481.32770.024*
C40.8546 (2)0.5909 (2)1.2821 (2)0.0189 (3)
H4A0.90310.67391.23390.023*
C50.6499 (3)0.7874 (2)1.52177 (19)0.0203 (4)
H5A0.58430.69731.55940.024*
H5B0.67010.88431.59480.024*
C60.8366 (2)0.7579 (2)1.5123 (2)0.0206 (4)
H6A0.90160.84751.47370.025*
H6B0.91410.75281.61480.025*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Zn10.01774 (12)0.01953 (12)0.01378 (11)0.00251 (8)0.00409 (8)0.00027 (7)
N10.0183 (7)0.0165 (7)0.0159 (7)0.0047 (6)0.0041 (6)0.0009 (5)
N20.0281 (8)0.0168 (7)0.0231 (8)0.0014 (6)0.0032 (7)0.0029 (6)
N30.0179 (7)0.0152 (6)0.0174 (7)0.0028 (5)0.0046 (6)0.0019 (5)
N40.0181 (7)0.0170 (7)0.0160 (7)0.0037 (6)0.0039 (6)0.0014 (5)
N50.0265 (8)0.0201 (7)0.0211 (8)0.0046 (6)0.0110 (6)0.0040 (6)
N60.0203 (7)0.0183 (7)0.0169 (7)0.0042 (6)0.0071 (6)0.0023 (6)
N70.0354 (10)0.0238 (8)0.0289 (9)0.0064 (7)0.0042 (7)0.0097 (7)
N80.0255 (8)0.0149 (7)0.0183 (7)0.0014 (6)0.0055 (6)0.0007 (6)
N90.0336 (10)0.0207 (8)0.0495 (12)0.0068 (7)0.0042 (9)0.0082 (8)
N100.0223 (8)0.0164 (7)0.0267 (8)0.0026 (6)0.0087 (6)0.0017 (6)
N110.0190 (8)0.0209 (7)0.0258 (8)0.0004 (6)0.0022 (6)0.0015 (6)
N120.0274 (10)0.0410 (11)0.0824 (18)0.0146 (9)0.0012 (11)0.0086 (11)
C10.0266 (9)0.0162 (8)0.0206 (9)0.0021 (7)0.0033 (7)0.0039 (7)
C20.0212 (8)0.0154 (8)0.0190 (8)0.0031 (7)0.0048 (7)0.0025 (6)
C30.0216 (9)0.0186 (8)0.0205 (8)0.0035 (7)0.0086 (7)0.0032 (7)
C40.0215 (9)0.0189 (8)0.0167 (8)0.0039 (7)0.0062 (7)0.0029 (6)
C50.0236 (9)0.0245 (9)0.0126 (8)0.0085 (7)0.0032 (7)0.0001 (6)
C60.0201 (8)0.0201 (8)0.0180 (8)0.0048 (7)0.0013 (7)0.0038 (7)
Geometric parameters (Å, º) top
Zn1—N32.0222 (15)N6—C31.360 (2)
Zn1—N72.0344 (18)N6—Zn1i2.0476 (15)
Zn1—N6i2.0476 (15)N7—N81.179 (2)
Zn1—N101.9964 (17)N8—N91.162 (2)
Zn1—N10ii2.4943 (17)N10—N111.203 (2)
N1—C21.327 (2)N10—Zn1ii2.4943 (17)
N1—N21.364 (2)N11—N121.145 (3)
N1—C51.457 (2)C1—H1A0.9500
N2—C11.312 (2)C2—H2A0.9500
N3—C21.324 (2)C3—H3A0.9500
N3—C11.363 (2)C4—H4A0.9500
N4—C41.327 (2)C5—C61.520 (3)
N4—N51.365 (2)C5—H5A0.9900
N4—C61.462 (2)C5—H5B0.9900
N5—C31.316 (2)C6—H6A0.9900
N6—C41.333 (2)C6—H6B0.9900
N3—Zn1—N793.69 (7)N11—N10—Zn1ii128.71 (13)
N3—Zn1—N6i121.68 (6)Zn1—N10—Zn1ii105.32 (7)
N3—Zn1—N10ii85.78 (6)N12—N11—N10177.3 (2)
N6i—Zn1—N10ii85.28 (6)N2—C1—N3113.97 (16)
N7—Zn1—N6i93.08 (7)N2—C1—H1A123.0
N7—Zn1—N10ii177.67 (6)N3—C1—H1A123.0
N10—Zn1—N3124.15 (7)N3—C2—N1109.64 (16)
N10—Zn1—N6i108.40 (6)N3—C2—H2A125.2
N10—Zn1—N7107.44 (7)N1—C2—H2A125.2
N10—Zn1—N10ii74.68 (7)N5—C3—N6113.90 (16)
C2—N1—N2110.20 (15)N5—C3—H3A123.1
C2—N1—C5128.95 (16)N6—C3—H3A123.1
N2—N1—C5120.62 (15)N4—C4—N6109.27 (15)
C1—N2—N1102.65 (15)N4—C4—H4A125.4
C2—N3—C1103.54 (15)N6—C4—H4A125.4
C2—N3—Zn1131.43 (12)N1—C5—C6111.49 (14)
C1—N3—Zn1124.94 (12)N1—C5—H5A109.3
C4—N4—N5110.40 (14)C6—C5—H5A109.3
C4—N4—C6128.55 (16)N1—C5—H5B109.3
N5—N4—C6121.05 (14)C6—C5—H5B109.3
C3—N5—N4102.73 (14)H5A—C5—H5B108.0
C4—N6—C3103.71 (14)N4—C6—C5111.59 (15)
C4—N6—Zn1i128.64 (12)N4—C6—H6A109.3
C3—N6—Zn1i127.39 (12)C5—C6—H6A109.3
N8—N7—Zn1145.03 (16)N4—C6—H6B109.3
N9—N8—N7176.8 (2)C5—C6—H6B109.3
N11—N10—Zn1124.83 (13)H6A—C6—H6B108.0
C2—N1—N2—C10.5 (2)N10ii—Zn1—N10—Zn1ii0.0
C5—N1—N2—C1175.53 (15)N1—N2—C1—N30.4 (2)
N10—Zn1—N3—C255.90 (18)C2—N3—C1—N20.1 (2)
N7—Zn1—N3—C2169.90 (17)Zn1—N3—C1—N2177.08 (13)
N6i—Zn1—N3—C294.18 (17)C1—N3—C2—N10.2 (2)
N10ii—Zn1—N3—C212.37 (16)Zn1—N3—C2—N1176.47 (12)
N10—Zn1—N3—C1120.15 (15)N2—N1—C2—N30.5 (2)
N7—Zn1—N3—C16.15 (16)C5—N1—C2—N3174.96 (16)
N6i—Zn1—N3—C189.76 (16)N4—N5—C3—N60.0 (2)
N10ii—Zn1—N3—C1171.58 (15)C4—N6—C3—N50.1 (2)
C4—N4—N5—C30.07 (19)Zn1i—N6—C3—N5174.41 (12)
C6—N4—N5—C3179.75 (15)N5—N4—C4—N60.1 (2)
N3—Zn1—N7—N8130.9 (3)C6—N4—C4—N6179.66 (16)
N6i—Zn1—N7—N8107.0 (3)C3—N6—C4—N40.1 (2)
N3—Zn1—N10—N1194.82 (17)Zn1i—N6—C4—N4174.27 (11)
N7—Zn1—N10—N1112.31 (18)C2—N1—C5—C697.0 (2)
N6i—Zn1—N10—N11111.75 (16)N2—N1—C5—C677.0 (2)
N10ii—Zn1—N10—N11168.7 (2)C4—N4—C6—C5114.3 (2)
N3—Zn1—N10—Zn1ii73.86 (8)N5—N4—C6—C565.9 (2)
N7—Zn1—N10—Zn1ii179.00 (6)N1—C5—C6—N462.6 (2)
N6i—Zn1—N10—Zn1ii79.57 (7)
Symmetry codes: (i) x+1, y+1, z+2; (ii) x, y+1, z+2.

Experimental details

Crystal data
Chemical formula[Zn(N3)2(C6H8N6)]
Mr313.61
Crystal system, space groupTriclinic, P1
Temperature (K)193
a, b, c (Å)7.646 (3), 8.690 (3), 9.266 (3)
α, β, γ (°)95.430 (5), 105.054 (6), 100.884 (5)
V3)577.1 (3)
Z2
Radiation typeMo Kα
µ (mm1)2.14
Crystal size (mm)0.50 × 0.35 × 0.21
Data collection
DiffractometerRigaku Mercury CCD
diffractometer
Absorption correctionMulti-scan
(North et al., 1968)
Tmin, Tmax0.412, 0.638
No. of measured, independent and
observed [I > 2σ(I)] reflections
6341, 2575, 2488
Rint0.023
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.025, 0.063, 1.06
No. of reflections2575
No. of parameters172
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.29, 0.41

Computer programs: CrystalClear (Rigaku, 2000), CrystalClear, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 1998), SHELXTL & DIAMOND (Brandenburg, 2000).

Selected geometric parameters (Å, º) top
Zn1—N32.0222 (15)Zn1—N101.9964 (17)
Zn1—N72.0344 (18)Zn1—N10ii2.4943 (17)
Zn1—N6i2.0476 (15)
N3—Zn1—N793.69 (7)N10—Zn1—N3124.15 (7)
N3—Zn1—N6i121.68 (6)N10—Zn1—N6i108.40 (6)
N3—Zn1—N10ii85.78 (6)N10—Zn1—N7107.44 (7)
N6i—Zn1—N10ii85.28 (6)N10—Zn1—N10ii74.68 (7)
N7—Zn1—N6i93.08 (7)Zn1—N10—Zn1ii105.32 (7)
N7—Zn1—N10ii177.67 (6)
Symmetry codes: (i) x+1, y+1, z+2; (ii) x, y+1, z+2.
 

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