A dimeric zinc(II) complex: bis­[μ-1,2-bis­(1,2,4-triazol-4-yl)ethane-κ2 N 1:N 1′]bis­[dinitritozinc(II)]

Rongxian Zhang; Qiuyun Chen; Jing Gao; Xiangyang Wu

doi:10.1107/S1600536810034203

. 2010 Sep 4;66(Pt 10):m1208. doi: 10.1107/S1600536810034203

A dimeric zinc(II) complex: bis[μ-1,2-bis(1,2,4-triazol-4-yl)ethane-κ² N ¹:N ^1′]bis[dinitritozinc(II)]

Rongxian Zhang ^a,^*, Qiuyun Chen ^a, Jing Gao ^b, Xiangyang Wu ^a

PMCID: PMC2983239 PMID: 21587367

Abstract

The coordination geometry of the Zn^II atom in the title complex, [Zn₂(NO₂)₄(C₆H₈N₆)₂], is distorted octahedral, in which the Zn^II atom is coordinated by two N atoms from the triazole rings of two symmetry-related 1,2-bis(1,2,4-triazol-4-yl)ethane ligands and four O atoms from two nitrite ligands. Two Zn^II atoms are bridged by two organic ligands, forming a centrosymmetric dimer. Weak C—H⋯N and C—H⋯O hydrogen bonds play an important role in the intermolecular packing.

Related literature

For background to 1,2,4-triazole and its derivatives, see: Haasnoot (2000 ▶). For a related structure, see: Habit et al. (2009 ▶). For hydrogen bonding, see: Mascal (1998 ▶).

Experimental

Crystal data

[Zn₂(NO₂)₄(C₆H₈N₆)₂]
M _r = 643.15
Monoclinic,
a = 20.491 (4) Å
b = 6.7087 (13) Å
c = 17.289 (4) Å
β = 97.125 (5)°
V = 2358.3 (8) Å³
Z = 4
Mo Kα radiation
μ = 2.11 mm⁻¹
T = 293 K
0.60 × 0.20 × 0.20 mm

Data collection

Rigaku Mercury CCD diffractometer
Absorption correction: multi-scan (Blessing, 1995 ▶, 1997 ▶) T _min = 0.364, T _max = 0.678
10892 measured reflections
2144 independent reflections
1945 reflections with I > 2σ(I)
R _int = 0.036

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.104
S = 1.06
2144 reflections
172 parameters
H-atom parameters constrained
Δρ_max = 0.47 e Å⁻³
Δρ_min = −0.61 e Å⁻³

Data collection: CrystalClear (Rigaku, 2000 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; 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.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810034203/bv2153sup1.cif

e-66-m1208-sup1.cif^{(18.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810034203/bv2153Isup2.hkl

e-66-m1208-Isup2.hkl^{(105.5KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected bond lengths (Å).

Zn1—N4ⁱ	2.002 (3)
Zn1—O1	2.031 (3)
Zn1—N1	2.036 (3)
Zn1—O3	2.046 (3)
Zn1—O2	2.477 (3)
Zn1—O4	2.488 (3)

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Symmetry code: (i) Inline graphic .

Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1B⋯O2ⁱⁱ	0.97	2.53	3.396 (5)	149
C2—H2A⋯O1ⁱⁱⁱ	0.97	2.49	3.417 (4)	160
C3—H3A⋯O2ⁱⁱ	0.93	2.66	3.412 (5)	139
C6—H6A⋯N2^iv	0.93	2.39	3.314 (4)	176

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Symmetry codes: (ii) Inline graphic ; (iii) ; (iv) .

supplementary crystallographic information

Comment

1,2,4-Triazole and its derivatives are very interesting ligands, because they combine the coordination geometry of both pyrazole and imidazole with regard to the arrangement of their three heteroatoms. A large number of mononuclear, oligonuclear and polynuclear transition metal complexes of 1,2,4-triazole derivatives have been synthesized and characterized because of their magnetic properties and novel topologies (Haasnoot, 2000).

In the present work, we report here the preparation and crystal structure of a dimeric zinc^II complex, namely, [Zn(btre)NO₂)₂]₂ (I) (btre = 1,2-bis(1,2,4-triazol-4-yl)ethane.

In the complex (I), the coordination geometry of the zinc^II atom in the title complex, [Zn(C₆H₈N₆)(NO₂)₂]₂ or [Zn(btre)(NO₂)₂]₂, where btre is µ-[1,2-bis(1,2,4-triazol-4-yl)ethane], is a distorted octahedron, in which the Zn^II atom is coordinated by two N atoms from the triazole rings of two symmetry-related btre ligands and four O atoms from two NO₂^- ligands. Two Zn^II atoms are bridged by two organic ligands to form a dimer. Each NO₂^- anion acts as a chelating coordination mode.

The crystal structure of (I) is built up from a neutral dimeric metallocycle. The dimer is centrosymmetric. As shown in Fig.1, in each dimer, two zinc^II centres are connected by two btre ligands resulting in a discrete Zn₂(btre)₂ 18-membered binuclear metallocycle.

Each zinc^II centre is six-coordinated by two N atoms of btre ligands and four O atoms from two NO₂^- ligands (Table 1), forming a distorted octahedral geometry. Each btre exhibits a gauche conformation in (I). The N3—C1—C2—N6 torsion angle is 64.9 (4)°. The dihedral angle between the two triazole ring is 40.1 (2)°. The Zn···Zn separation via the bridging btre ligand is 7.809 (2)Å in (I), compared with the corresponding values 7.8750 (2)Å in [Zn(btre)Cl₂]₂ and 7.7980 (5)Å in [Zn(btre)I₂]₂ (Habit et al., 2009).

Weak hydrogen bonds play an important role in the formation of the crystal structure. The intermolecular packing is organized by C—H···N and C—H···O hydrogen bonds (Table 2 and Figure 2; Mascal 1998).

Experimental

A 10 ml aqueous solution of Zn(NO₂)₂ (1 mmol) was added to a tube, and a 10 ml MeOH solution of 1,2-bis(1,2,4-triazol-4-yl)ethane (btre) (1.0 mmol) was carefully added above the aqueous solution. Colourless crystal were obtained after about two weeks. Anal. Calcd. for C₁₂H₁₆N₁₆O₈Zn₂: C, 22.41; H, 2.51; N, 34.85%. Found: C, 22.36; H, 2.44; N, 34.69%.