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The title compound, [Zn4(C2H2N3)3(NCS)3S]n, is a three-dimensional coordination polymer consisting of tetra­hedral SZn4 clusters bridged by triazole ligands. In the tetra­hedral unit, three Zn atoms are connected to six bridging triazolate ligands, whereas the fourth Zn atom (site symmetry 3m) is bonded to three terminal thio­cyanate anions that protrude into the void space created by the Zn–triazolate network. The network prototype is simple cubic, but a strong distortion along a body diagonal and the imposition of a polar direction by the arrangement of the mol­ecular constituents lead to the trigonal space group R3m. This study demonstrates the use of the 3-mercapto-1,2,4-triazole ligand as an effective source for sulfide ions in the synthesis of sulfide-based coordination polymers.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270108027327/gd3237sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270108027327/gd3237Isup2.hkl
Contains datablock I

CCDC reference: 707195

Comment top

Research into organic–inorganic hybrid solids has resulted in a tremendous number of new and interesting structures in recent years (Cheetham et al., 2006; Férey, 2008; Suh et al., 2008). Many of these have been investigated for potential applications in gas storage, catalysis, magnetism, luminescence etc. (Maspoch et al. 2007; Morris & Wheatley, 2008). While a wide variety of organic ligands are available for the construction of coordination polymers, polyazaheterocyclic compounds, such as pyrazole, imidazole and triazole, have been extensively applied as organic linkers due to their ability to form multi-dimensional frameworks through multiple metal-binding sites. For example, a new class of zeolitic imidazolate frameworks (ZIFs) have recently been found to have exceptional stability and structrual similarities to traditional zeolites (Huang et al., 2006; Park et al., 2006; Hayashi et al., 2007). There are also a number of compounds containing triazole-type ligands (Haasnoot, 2000; Zhang & Chen, 2006; Park et al., 2007; Ouellette et al., 2006, 2007). The ZnF(AmTAZ) (AmTAZ = 3-amino-1,2,4-triazole) coordination polymer forms an especially interesting hollow tubular architecture (Su et al., 2004).

In addition to their fascinating framework architectures, polyazaheterocycle-based compounds are of interest as functional materials, since they can possess interesting photoluminescence properties when d10 metal ions such as Cu+, Zn2+ and Cd2+ are present (Ouellette et al., 2007; Zhao et al., 2008). Although there are many known sulfide-based inorganic frameworks, coordination polymers based on metal–sulfur linkages are still quite uncommon. Recent developments by Feng and co-workers have resulted in a number of transition metal–sulfide clusters linked by organic ligands (Xie et al., 2005; Zhang, Lin et al., 2008; Zhang, Liu et al., 2008). These materials contain tetrahedral M4S (M = Zn or Cd) units which are connected to each other via substituted phenylthiolates in order to create a three-dimensional open framework. The single-crystal growth of these materials depends on the slow release of sulfide from the decomposition of thiourea. There is only one example of a sulfide-based metal–triazolate complex known in the literature to date (Schlueter et al., 2006). In that case, the sulfide is generated by the slow thermal decomposition of thiocyanate. The basic building block for the [Zn6(AmTAZ)6S2](NO3)3(H3O)(H2O)x structure is a sulfide-centered triangle of Zn atoms. The assembly of eight of these building units results in the formation of a three-dimensional cage structure. In this report, we describe a new zinc triazole–thiolate coordination polymer, the title compound, (I). To our knowledge, the crystallization of (I) is the first example whereby 3-mercapto-1,2,4-trizole undergoes a gradual in situ dethiolation process to generate both the triazolate ligand and the sulfide anion during the solvothermal reaction.

The atom-numbering scheme of (I) is shown in Fig. 1. The structure is based on the [SZn3(triazole)3]+ secondary building unit (SBU) which has a Zn3S core. The central S2 sulfide ion of the [SZn3(triazole)3]+ SBU is bonded to three Zn1 atoms and Zn2 of the [Zn(NCS)3]- anion. Atom Zn1 is further bound to one N2 atom and two N3 atoms of three triazolate ligands. Atom N2 is at the 4-position of the triazole ring, while the N3 atoms are at the 1,2-positions. The Zn1—N3 bonds complete the trimeric [SZn3(triazole)3]+ SBU. A three-dimensional cage structure is formed by linking eight [SZn3(triazole)3]+ SBUs through Zn1—N2 bonds. The Zn1—N bond lengths are in the range 1.995 (2)–2.0310 (13) Å, which is consistent with the values reported for similar tetrahedral Zn2+ coordination polymers (Park et al., 2007; Ouellette et al., 2007). The resulting environment around Zn1 is a distorted tetrahedron, with N—Zn—N and N—Zn—S bond angles varying from 107.45 (5) to 125.05 (7)°. Distorted tetrahedral coordination about the S2 sulfide center is completed by coordination to the Zn2 atom of the [Zn(NCS)3]- anion [Zn2—S2 = 2.3580 (11) Å]. Atom Zn2 is also coordinated to the N atoms of three [NCS]- anions, with Zn2—N distances of 1.952 (3) Å, resulting in a stretched tetrahedral coordination.

The thiocyanate anion shows a typical linear geometry, with an N—C—S angle of 178.8 (3)°. The CN bond length is 1.151 (5) Å, and the C—S bond distance is 1.624 (4) Å. The resulting structure (Fig. 2) is a three-dimensional distorted (6,4) simple cubic net with pore dimensions of approximately 3.5 × 3.5 Å2, taking the van der Waals radii into account. However, the porosity of the structure is removed as the bulky thiocyanate ligands protrude into the void space.

In conclusion, a new sulfide-based three-dimensional Zn–triazolate coordination polymer has been prepared. This work demonstrates that the slow decomposition of 3-mercapto-1,2,4-triazole provides an effective source of sulfide ions for the crystallization of novel sulfide-based coordination complexes and framework materials. In contrast with the crystallization of [Zn6(AmTAZ)6S2](NO3)3(H3O)(H2O)x, where the sulfide is formed from the slow thermal decomposition of thiocyanate, in the case of (I), the sulfide is formed from the thermal decompositon of 3-mercapto-1,2,4-triazole, while the thiocyanate is incorporated into the crystal structure.

Related literature top

For related literature, see: Cheetham et al. (2006); Férey (2008); Flack (1983); Haasnoot (2000); Hayashi et al. (2007); Huang et al. (2006); Maspoch et al. (2007); Morris & Wheatley (2008); Ouellette et al. (2006, 2007); Park et al. (2006, 2007); Schlueter et al. (2006); Su et al. (2004); Suh et al. (2008); Xie et al. (2005); Zhang & Chen (2006); Zhang, Lin, Bu, Wu & Feng (2008); Zhang, Liu, Bu, Wu & Feng (2008); Zhao et al. (2008).

Experimental top

Zn4S(SCN)3(triazolate)3 was prepared under mild solvothermal conditions. Zinc nitrate hexahydrate (Zn(NO3)2.6H2O, 0.594 g, 2 mmol), 3-mercapto-1,2,4-triazole (C2H3N3S, 0.202 g, 2 mmol) and potassium thiocyanate (KSCN, 0.194 g, 2 mmol) were added to a solvent mixture of water (6.0 ml) and ethanol (4.0 ml) in a 23 ml Teflon-lined stainless steel autoclave. The sealed reaction vessel was heated at 423 K for 3 d. After cooling to room temperature, the product was filtered, washed with deionized water and dried in air. Colorless block-shaped crystals of (I) were recovered.

Refinement top

H atoms were positioned geometrically and treated as riding, with C—H = 0.93 Å, and with Uiso(H) = 1.2Ueq(C) [Please check added text]. The correct orientation of the structure with respect to the polar axis direction was established by means of the Flack x parameter (Flack, 1983).

Structure description top

Research into organic–inorganic hybrid solids has resulted in a tremendous number of new and interesting structures in recent years (Cheetham et al., 2006; Férey, 2008; Suh et al., 2008). Many of these have been investigated for potential applications in gas storage, catalysis, magnetism, luminescence etc. (Maspoch et al. 2007; Morris & Wheatley, 2008). While a wide variety of organic ligands are available for the construction of coordination polymers, polyazaheterocyclic compounds, such as pyrazole, imidazole and triazole, have been extensively applied as organic linkers due to their ability to form multi-dimensional frameworks through multiple metal-binding sites. For example, a new class of zeolitic imidazolate frameworks (ZIFs) have recently been found to have exceptional stability and structrual similarities to traditional zeolites (Huang et al., 2006; Park et al., 2006; Hayashi et al., 2007). There are also a number of compounds containing triazole-type ligands (Haasnoot, 2000; Zhang & Chen, 2006; Park et al., 2007; Ouellette et al., 2006, 2007). The ZnF(AmTAZ) (AmTAZ = 3-amino-1,2,4-triazole) coordination polymer forms an especially interesting hollow tubular architecture (Su et al., 2004).

In addition to their fascinating framework architectures, polyazaheterocycle-based compounds are of interest as functional materials, since they can possess interesting photoluminescence properties when d10 metal ions such as Cu+, Zn2+ and Cd2+ are present (Ouellette et al., 2007; Zhao et al., 2008). Although there are many known sulfide-based inorganic frameworks, coordination polymers based on metal–sulfur linkages are still quite uncommon. Recent developments by Feng and co-workers have resulted in a number of transition metal–sulfide clusters linked by organic ligands (Xie et al., 2005; Zhang, Lin et al., 2008; Zhang, Liu et al., 2008). These materials contain tetrahedral M4S (M = Zn or Cd) units which are connected to each other via substituted phenylthiolates in order to create a three-dimensional open framework. The single-crystal growth of these materials depends on the slow release of sulfide from the decomposition of thiourea. There is only one example of a sulfide-based metal–triazolate complex known in the literature to date (Schlueter et al., 2006). In that case, the sulfide is generated by the slow thermal decomposition of thiocyanate. The basic building block for the [Zn6(AmTAZ)6S2](NO3)3(H3O)(H2O)x structure is a sulfide-centered triangle of Zn atoms. The assembly of eight of these building units results in the formation of a three-dimensional cage structure. In this report, we describe a new zinc triazole–thiolate coordination polymer, the title compound, (I). To our knowledge, the crystallization of (I) is the first example whereby 3-mercapto-1,2,4-trizole undergoes a gradual in situ dethiolation process to generate both the triazolate ligand and the sulfide anion during the solvothermal reaction.

The atom-numbering scheme of (I) is shown in Fig. 1. The structure is based on the [SZn3(triazole)3]+ secondary building unit (SBU) which has a Zn3S core. The central S2 sulfide ion of the [SZn3(triazole)3]+ SBU is bonded to three Zn1 atoms and Zn2 of the [Zn(NCS)3]- anion. Atom Zn1 is further bound to one N2 atom and two N3 atoms of three triazolate ligands. Atom N2 is at the 4-position of the triazole ring, while the N3 atoms are at the 1,2-positions. The Zn1—N3 bonds complete the trimeric [SZn3(triazole)3]+ SBU. A three-dimensional cage structure is formed by linking eight [SZn3(triazole)3]+ SBUs through Zn1—N2 bonds. The Zn1—N bond lengths are in the range 1.995 (2)–2.0310 (13) Å, which is consistent with the values reported for similar tetrahedral Zn2+ coordination polymers (Park et al., 2007; Ouellette et al., 2007). The resulting environment around Zn1 is a distorted tetrahedron, with N—Zn—N and N—Zn—S bond angles varying from 107.45 (5) to 125.05 (7)°. Distorted tetrahedral coordination about the S2 sulfide center is completed by coordination to the Zn2 atom of the [Zn(NCS)3]- anion [Zn2—S2 = 2.3580 (11) Å]. Atom Zn2 is also coordinated to the N atoms of three [NCS]- anions, with Zn2—N distances of 1.952 (3) Å, resulting in a stretched tetrahedral coordination.

The thiocyanate anion shows a typical linear geometry, with an N—C—S angle of 178.8 (3)°. The CN bond length is 1.151 (5) Å, and the C—S bond distance is 1.624 (4) Å. The resulting structure (Fig. 2) is a three-dimensional distorted (6,4) simple cubic net with pore dimensions of approximately 3.5 × 3.5 Å2, taking the van der Waals radii into account. However, the porosity of the structure is removed as the bulky thiocyanate ligands protrude into the void space.

In conclusion, a new sulfide-based three-dimensional Zn–triazolate coordination polymer has been prepared. This work demonstrates that the slow decomposition of 3-mercapto-1,2,4-triazole provides an effective source of sulfide ions for the crystallization of novel sulfide-based coordination complexes and framework materials. In contrast with the crystallization of [Zn6(AmTAZ)6S2](NO3)3(H3O)(H2O)x, where the sulfide is formed from the slow thermal decomposition of thiocyanate, in the case of (I), the sulfide is formed from the thermal decompositon of 3-mercapto-1,2,4-triazole, while the thiocyanate is incorporated into the crystal structure.

For related literature, see: Cheetham et al. (2006); Férey (2008); Flack (1983); Haasnoot (2000); Hayashi et al. (2007); Huang et al. (2006); Maspoch et al. (2007); Morris & Wheatley (2008); Ouellette et al. (2006, 2007); Park et al. (2006, 2007); Schlueter et al. (2006); Su et al. (2004); Suh et al. (2008); Xie et al. (2005); Zhang & Chen (2006); Zhang, Lin, Bu, Wu & Feng (2008); Zhang, Liu, Bu, Wu & Feng (2008); Zhao et al. (2008).

Computing details top

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Figures top
[Figure 1] Fig. 1. The structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii. [Symmetry codes: (i) -x + y, y, z; (ii) 2/3 - y, 1/3 - x, 1/3 + z; (iii) 2/3 - y, 1/3 + x - y, 1/3 + z; (iv) -x + y, -x, z; (v) -y, x - y, z]
[Figure 2] Fig. 2. Ball-and-stick representation of the distorted (6,4) nets formed by [SZn3(triazole)3]+ secondary building units. The [Zn(NCS)3]- groups occupy the void space.
Poly[µ4-sulfido-tris(thiocyanato-κN)tris(µ3-1,2,4-triazolato- κ3N1:N2:N4)tetrazinc(II)] top
Crystal data top
[Zn4(C2H2N3)3(NCS)3S]Dx = 2.343 Mg m3
Mr = 672.10Mo Kα radiation, λ = 0.71073 Å
Hexagonal, R3mCell parameters from 2038 reflections
Hall symbol: R 3 -2"θ = 2.9–28.2°
a = 13.9947 (4) ŵ = 5.44 mm1
c = 8.4249 (3) ÅT = 298 K
V = 1428.97 (8) Å3Block, colorless
Z = 30.30 × 0.22 × 0.22 mm
F(000) = 984
Data collection top
Siemens SMART CCD area-detector
diffractometer
871 independent reflections
Radiation source: fine-focus sealed tube865 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.026
area–detector ω scansθmax = 28.3°, θmin = 2.9°
Absorption correction: integration
(SADABS; Sheldrick, 2001)
h = 1818
Tmin = 0.201, Tmax = 0.442k = 1817
4682 measured reflectionsl = 1011
Refinement top
Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.014 w = 1/[σ2(Fo2) + (0.0189P)2 + 0.264P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.034(Δ/σ)max < 0.001
S = 1.13Δρmax = 0.24 e Å3
871 reflectionsΔρmin = 0.31 e Å3
56 parametersExtinction correction: SHELXTL (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
1 restraintExtinction coefficient: 0.00071 (16)
Primary atom site location: structure-invariant direct methodsAbsolute structure: Flack (1983), with 421 Friedel pairs
Secondary atom site location: difference Fourier mapAbsolute structure parameter: 0.032 (10)
Crystal data top
[Zn4(C2H2N3)3(NCS)3S]Z = 3
Mr = 672.10Mo Kα radiation
Hexagonal, R3mµ = 5.44 mm1
a = 13.9947 (4) ÅT = 298 K
c = 8.4249 (3) Å0.30 × 0.22 × 0.22 mm
V = 1428.97 (8) Å3
Data collection top
Siemens SMART CCD area-detector
diffractometer
871 independent reflections
Absorption correction: integration
(SADABS; Sheldrick, 2001)
865 reflections with I > 2σ(I)
Tmin = 0.201, Tmax = 0.442Rint = 0.026
4682 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.014H-atom parameters constrained
wR(F2) = 0.034Δρmax = 0.24 e Å3
S = 1.13Δρmin = 0.31 e Å3
871 reflectionsAbsolute structure: Flack (1983), with 421 Friedel pairs
56 parametersAbsolute structure parameter: 0.032 (10)
1 restraint
Special details top

Experimental. The data collection nominally covered over a hemisphere of reciprocal space by a combination of four sets of exposures; each set had a different φ angle for the crystal and each exposure covered 0.3° in ω. The crystal-to-detector distance was 4.975 cm. Coverage of the unique set was 100% complete to at least 27.2° in θ, 99.9% complete to at least 28.2° in θ.

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
Zn10.082094 (10)0.16419 (2)0.542210 (18)0.01806 (9)
Zn20.00000.00000.12110 (7)0.03677 (16)
S10.18436 (4)0.36873 (8)0.06133 (12)0.04217 (19)
N10.07655 (14)0.1531 (3)0.0492 (5)0.0574 (8)
C10.12143 (15)0.2429 (3)0.0049 (4)0.0365 (6)
S20.00000.00000.40099 (11)0.0178 (2)
N20.15726 (9)0.31451 (19)0.4456 (3)0.0201 (4)
N30.18542 (11)0.46937 (12)0.33373 (18)0.0191 (3)
C20.11270 (14)0.37625 (15)0.4009 (2)0.0219 (3)
H20.03900.35540.41580.026*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Zn10.01433 (10)0.01439 (13)0.02548 (14)0.00720 (7)0.00149 (5)0.00298 (10)
Zn20.0431 (2)0.0431 (2)0.0241 (3)0.02155 (12)0.0000.000
S10.0337 (3)0.0372 (4)0.0568 (5)0.0186 (2)0.00194 (18)0.0039 (4)
N10.0680 (15)0.058 (2)0.0427 (15)0.0292 (11)0.0093 (8)0.0185 (16)
C10.0352 (10)0.0485 (18)0.0302 (14)0.0242 (9)0.0007 (6)0.0013 (13)
S20.0174 (3)0.0174 (3)0.0185 (4)0.00869 (14)0.0000.000
N20.0166 (7)0.0160 (9)0.0276 (10)0.0080 (4)0.0020 (4)0.0039 (8)
N30.0174 (7)0.0163 (7)0.0252 (7)0.0096 (6)0.0015 (5)0.0010 (6)
C20.0163 (7)0.0199 (8)0.0295 (9)0.0089 (6)0.0027 (6)0.0014 (6)
Geometric parameters (Å, º) top
Zn1—N21.995 (2)N1—C11.150 (5)
Zn1—N3i2.0309 (13)N2—C21.348 (2)
Zn1—S22.3185 (6)N3—C21.314 (2)
Zn2—N11.952 (3)N3—N3ii1.379 (3)
Zn2—S22.3580 (11)C2—H20.9300
S1—C11.624 (4)
N2—Zn1—N3i107.45 (5)Zn1—S2—Zn2120.88 (2)
N3i—Zn1—N3iii116.40 (8)C2—N2—C2ii103.1 (2)
N2—Zn1—S2125.05 (7)C2—N2—Zn1128.39 (10)
N3iii—Zn1—S2100.51 (4)C2—N3—N3ii106.17 (9)
N1iv—Zn2—N1110.83 (14)C2—N3—Zn1vi132.18 (12)
N1—Zn2—S2108.07 (14)N3ii—N3—Zn1vi120.60 (4)
C1—N1—Zn2179.1 (4)N3—C2—N2112.27 (15)
N1—C1—S1178.9 (4)N3—C2—H2123.9
Zn1v—S2—Zn196.03 (3)N2—C2—H2123.9
C2ii—N2—C2—N30.1 (3)
Symmetry codes: (i) y+2/3, x+1/3, z+1/3; (ii) x+y, y, z; (iii) x+y1/3, x+1/3, z+1/3; (iv) x+y, x, z; (v) y, xy, z; (vi) y+1/3, x+2/3, z1/3.

Experimental details

Crystal data
Chemical formula[Zn4(C2H2N3)3(NCS)3S]
Mr672.10
Crystal system, space groupHexagonal, R3m
Temperature (K)298
a, c (Å)13.9947 (4), 8.4249 (3)
V3)1428.97 (8)
Z3
Radiation typeMo Kα
µ (mm1)5.44
Crystal size (mm)0.30 × 0.22 × 0.22
Data collection
DiffractometerSiemens SMART CCD area-detector
Absorption correctionIntegration
(SADABS; Sheldrick, 2001)
Tmin, Tmax0.201, 0.442
No. of measured, independent and
observed [I > 2σ(I)] reflections
4682, 871, 865
Rint0.026
(sin θ/λ)max1)0.667
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.014, 0.034, 1.13
No. of reflections871
No. of parameters56
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.24, 0.31
Absolute structureFlack (1983), with 421 Friedel pairs
Absolute structure parameter0.032 (10)

Computer programs: SMART (Bruker, 1998), SAINT (Bruker, 2001), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Selected geometric parameters (Å, º) top
Zn1—N21.995 (2)Zn2—N11.952 (3)
Zn1—N3i2.0309 (13)Zn2—S22.3580 (11)
Zn1—S22.3185 (6)
N2—Zn1—N3i107.45 (5)N3ii—Zn1—S2100.51 (4)
N3i—Zn1—N3ii116.40 (8)N1iii—Zn2—N1110.83 (14)
N2—Zn1—S2125.05 (7)N1—Zn2—S2108.07 (14)
Symmetry codes: (i) y+2/3, x+1/3, z+1/3; (ii) x+y1/3, x+1/3, z+1/3; (iii) x+y, x, z.
 

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