A monoclinic polymorph of 1,2-bis-[(1-methyl-1H-tetra-zol-5-yl)sulfan-yl]ethane (BMTTE).

The synthesis and crystal structure of a monoclinic (P21/c) polymorph of the title compound, C6H10S2N8, are reported. The mol-ecule has pseudo-twofold rotational symmetry, with the tetra-zole rings being inclined to one another by 5.50 (6)°. In the crystal, mol-ecules are linked by C-H⋯N hydrogen bonds, forming chains propagating along [101] and enclosing R22(20) ring motifs. The chains are linked by offset π-π inter-actions involving the tetra-zole rings [inter-centroid distances vary from 3.3567 (7) to 3.4227 (7) Å], forming layers parallel to the ac plane. The crystal structure of the triclinic polymorph (P [Formula: see text]) has been described previously [Li et al. (2011 ▸). Acta Cryst. E67, o1669].

Chemical context

Organic compounds such as the title compound (BMTTE) are frequently used as flexible ligands for the preparation of coordination polymers (Wang et al., 2010 ▸). A triclinic polymorph of the title compound has been described previously by Li et al., (2011 ▸). Here we describe the spectroscopic characterization and crystal structure of a new monoclinic polymorph of BMTTE, obtained by recrystallization and slow evaporation from a solution in CH3CN. Such compounds have been used in coordination chemistry (Zhao et al., 2008 ▸) and in materials design (Wang et al., 2009 ▸, 2010 ▸).

Structural commentary

The mol­ecule structure of the title compound, Fig. 1 ▸, shows N—N and C—S bond distances and S—C—C—S and C—S—C—C torsion angles similar to the values observed in the triclinic form (Li et al., 2011 ▸). As shown by the mol­ecular overlap of the two polymorphs (Fig. 2 ▸), drawn with Mercury (Macrae et al., 2008 ▸), there is only a slight difference in their geometry. The tetra­zole rings (N1–N4/C1 and N5–N8/C4) are inclined to one another by 5.50 (6)° in the title polymorph and by 1.9 (2)° in the triclinic polymorph. While there are only small differences in the geometric parameters between the two polymorphic forms, they are enough to produce a different crystal packing.

Figure 1

Mol­ecular structure of the title compound, the monoclinic polymorph of BMTTE, with atom labelling. Displacement ellipsoids are drawn at the 50% probability level.

Figure 2

A mol­ecular structure overlap (Mercury; Macrae et al., 2008 ▸) of the title monoclinic polymorph of BMTTE (blue) and the triclinic polymorph (red; Li et al., 2011 ▸).

Supra­molecular features

In the crystal, mol­ecules are linked by C—H⋯N hydrogen bonds, forming chains propagating along [101] and enclosing (20) ring motifs (Fig. 3 ▸ and Table 1 ▸). The chains are linked by offset π–π inter­actions involving the tetra­zole rings, forming layers parallel to the ac plane, as shown in Fig. 4 ▸. The numerical details of these inter­actions are: Cg1⋯Cg1i = 3.365 (1) Å, α = 0°, inter­planar distance = 3.2056 (4) Å, offset = 1.024 Å; Cg1⋯Cg2ii = 3.423 (1) Å, α = 5.5 (1)°, inter­planar distances = 3.278 (4) and 3.321 (4) Å, offset = 0.83 Å; and Cg2⋯Cg2iii = 3.4227 (7) Å, α = 0°, inter­planar distance = 3.1346 (4) Å, offset = 1.201 Å; Cg1 and Cg2 are the centroids of the tetra­zole rings N1–N4/C1 and N5–N8/C4, respectively; symmetry codes: (i) −x + 1, −y, −z; (ii) x − 1, y, z; (iii) −x + 2, −y, −z + 1.

Figure 3

A partial view of the crystal packing of the title compound, showing details of the C—H⋯N hydrogen bonds (dashed lines, see Table 1 ▸).

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C11—H11B⋯N8i	0.98	2.39	3.3533 (13)	168
C12—H12B⋯N4ii	0.98	2.36	3.3183 (13)	165

Symmetry codes: (i) ; (ii) .

Figure 4

Crystal packing of the title compound, showing details of the C—H⋯N hydrogen bonds (dashed lines, see Table 1 ▸) and examples of the π–π inter­actions (blue double-headed arrows).

As a result of these inter­actions, the mol­ecules are packed very efficiently so that the Kitaigorodskii (1973 ▸) index is 72%. The crystal packing in the crystal of the triclinic polymorph is very similar, with a Kitaigorodskii index of 69% (PLATON; Spek, 2009 ▸).

Database survey

A search of the Cambridge Structural Database (CSD; version 5.38, last update May 2017; Groom et al., 2016 ▸) for the skeleton of the title compound gave 11 hits. Apart from the crystal structure of the triclinic polymorph of the title compound (CSD refcode EVAWUU; Li et al., 2011 ▸), and that of a diphenyl substituted compound, 1,2-bis­(1-phenyl-1H-tetra­zol-5-ylsulfan­yl)ethane (IXAVUY; Wang et al., 2004 ▸), all the others involve coordination compounds of BMTTE.

Synthesis and crystallization

The title compound, (BMTTE), was synthesized by a slightly modified version of the procedure described by Li et al. (2011 ▸). 5-Mercapto-1-methyl­tetra­zole (9.29 g, 0.08 mol) was added to a solution of sodium hydroxide (3.26 g, 0.08 mol) in EtOH (110 ml). The mixture was stirred at room temperature for one day. Di­chloro­ethane (3.2 ml, 0.04 mol) in 6 ml of EtOH was then added dropwise and the mixture was refluxed for 18 h. The resulting white solid was filtered, washed with H2O and dried in vacuo (yield 88%; m.p. 417–419 K). Analysis calculated for C6H10S2N8: N 43.38, C 27.90, H 3.90%; Found: N 42.31, C 27.85, H 3.28%. IR (cm−1): 1469m, 1442m (1408m, 1391m) ν(ring); 1276m, 1222m, ω(CH–CH2); 1169m, δ(CH); 1144m, 1078m, 1026m, δ(ring); 728m, 716m, γ(CH); 698s, ν(C—S). 1H NMR (400 MHz, dmso-d 6) δ in ppm: 3.93 (s, 6H, Hb), 3.66 (s, 4H, Ha). MS–ESI: m/z (%) = 259 (100) [C6H10S2N8+H+]. Colourless prismatic crystals were obtained by slow evaporation of a solution in aceto­nitrile.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2 ▸. The C-bound H atoms were included in calculated positions and treated as riding: C—H = 0.98–0.99 Å with U iso(H) = 1.5U eq(C-meth­yl) and 1.2U eq(C) for other H atoms.

Table 2

Experimental details

Crystal data
Chemical formula	C6H10N8S2
M r	258.34
Crystal system, space group	Monoclinic, P21/c
Temperature (K)	100
a, b, c (Å)	8.2456 (10), 13.7471 (17), 9.6878 (12)
β (°)	92.643 (4)
V (Å3)	1097.0 (2)
Z	4
Radiation type	Mo Kα
μ (mm−1)	0.47
Crystal size (mm)	0.25 × 0.22 × 0.19
Data collection
Diffractometer	Bruker D8 Venture Photon 100 CMOS
Absorption correction	Multi-scan (SADABS; Bruker, 2014 ▸)
T min, T max	0.697, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	23909, 2725, 2620
R int	0.024
(sin θ/λ)max (Å−1)	0.668
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S	0.022, 0.057, 1.08
No. of reflections	2725
No. of parameters	148
H-atom treatment	H-atom parameters constrained
Δρmax, Δρmin (e Å−3)	0.36, −0.25

Computer programs: APEX3 (Bruker, 2014 ▸), SAINT (Bruker, 2014 ▸), SHELXS2014 (Sheldrick, 2008 ▸), Mercury (Macrae et al., 2008 ▸), SHELXL2014 (Sheldrick, 2015 ▸), PLATON (Spek, 2009 ▸) and publCIF (Westrip, 2010 ▸).

Crystal structure: contains datablock(s) I, Global. DOI: 10.1107/S205698901701341X/su5392sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S205698901701341X/su5392Isup2.hkl

Click here for additional data file.

Supporting information file. DOI: 10.1107/S205698901701341X/su5392Isup3.cdx

Click here for additional data file.

Supporting information file. DOI: 10.1107/S205698901701341X/su5392Isup4.cml

CCDC reference: 1575392

Additional supporting information: crystallographic information; 3D view; checkCIF report

C6H10N8S2	Dx = 1.564 Mg m−3
Mr = 258.34	Melting point: 144 K
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 8.2456 (10) Å	Cell parameters from 9507 reflections
b = 13.7471 (17) Å	θ = 2.5–28.3°
c = 9.6878 (12) Å	µ = 0.47 mm−1
β = 92.643 (4)°	T = 100 K
V = 1097.0 (2) Å3	Prism, colourless
Z = 4	0.25 × 0.22 × 0.19 mm
F(000) = 536

Bruker D8 Venture Photon 100 CMOS diffractometer	2620 reflections with I > 2σ(I)
φ and ω scans	Rint = 0.024
Absorption correction: multi-scan (SADABS; Bruker, 2014)	θmax = 28.3°, θmin = 2.5°
Tmin = 0.697, Tmax = 0.746	h = −10→11
23909 measured reflections	k = −18→18
2725 independent reflections	l = −12→12

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.022	H-atom parameters constrained
wR(F2) = 0.057	w = 1/[σ2(Fo2) + (0.0262P)2 + 0.493P] where P = (Fo2 + 2Fc2)/3
S = 1.08	(Δ/σ)max < 0.001
2725 reflections	Δρmax = 0.36 e Å−3
148 parameters	Δρmin = −0.25 e Å−3
0 restraints	Extinction correction: (SHELXL2014; Sheldrick, 2015), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0376 (18)

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

	x	y	z	Uiso*/Ueq
S1	0.46814 (3)	0.19617 (2)	0.21662 (2)	0.01218 (8)
S2	0.99483 (3)	0.22655 (2)	0.31188 (3)	0.01382 (8)
N1	0.32833 (10)	0.04027 (6)	0.08604 (8)	0.01158 (16)
N2	0.33462 (11)	−0.05843 (6)	0.08543 (9)	0.01445 (17)
N3	0.44707 (11)	−0.08272 (6)	0.17676 (9)	0.01511 (18)
N4	0.51615 (11)	−0.00275 (6)	0.23918 (9)	0.01383 (17)
N5	1.15565 (10)	0.07099 (6)	0.42528 (8)	0.01085 (16)
N6	1.16663 (10)	−0.02693 (6)	0.41075 (9)	0.01411 (17)
N7	1.06184 (11)	−0.05083 (6)	0.31273 (9)	0.01451 (17)
N8	0.98081 (11)	0.02894 (6)	0.26071 (9)	0.01352 (17)
C1	0.44014 (11)	0.07287 (7)	0.18059 (10)	0.01056 (18)
C2	0.66415 (11)	0.19192 (7)	0.31250 (10)	0.01208 (19)
H2A	0.6649	0.2392	0.3896	0.014*
H2B	0.6818	0.1262	0.3520	0.014*
C3	0.79982 (12)	0.21624 (7)	0.21671 (10)	0.01285 (19)
H3A	0.7747	0.2784	0.1687	0.015*
H3B	0.8064	0.1647	0.1458	0.015*
C4	1.04182 (11)	0.10381 (7)	0.33269 (10)	0.01087 (18)
C11	0.21707 (12)	0.09470 (7)	−0.00653 (10)	0.0147 (2)
H11A	0.1360	0.1277	0.0476	0.022*
H11B	0.1624	0.0499	−0.0721	0.022*
H11C	0.2781	0.1431	−0.0572	0.022*
C12	1.25381 (12)	0.12395 (7)	0.52931 (10)	0.0152 (2)
H12A	1.3335	0.1642	0.4838	0.023*
H12B	1.3105	0.0776	0.5914	0.023*
H12C	1.1834	0.1656	0.5827	0.023*

	U11	U22	U33	U12	U13	U23
S1	0.01044 (12)	0.00922 (12)	0.01639 (13)	0.00092 (8)	−0.00455 (8)	0.00048 (8)
S2	0.01144 (13)	0.00868 (12)	0.02066 (14)	−0.00105 (8)	−0.00666 (9)	0.00047 (8)
N1	0.0121 (4)	0.0099 (4)	0.0125 (4)	0.0000 (3)	−0.0017 (3)	0.0000 (3)
N2	0.0164 (4)	0.0100 (4)	0.0170 (4)	0.0008 (3)	0.0007 (3)	−0.0005 (3)
N3	0.0153 (4)	0.0120 (4)	0.0178 (4)	0.0002 (3)	−0.0007 (3)	0.0006 (3)
N4	0.0140 (4)	0.0111 (4)	0.0162 (4)	0.0013 (3)	−0.0020 (3)	0.0019 (3)
N5	0.0110 (4)	0.0094 (4)	0.0119 (4)	0.0003 (3)	−0.0017 (3)	0.0007 (3)
N6	0.0156 (4)	0.0100 (4)	0.0168 (4)	0.0010 (3)	0.0019 (3)	0.0010 (3)
N7	0.0161 (4)	0.0115 (4)	0.0159 (4)	−0.0002 (3)	0.0007 (3)	−0.0003 (3)
N8	0.0150 (4)	0.0109 (4)	0.0145 (4)	−0.0013 (3)	−0.0014 (3)	−0.0010 (3)
C1	0.0091 (4)	0.0114 (4)	0.0111 (4)	0.0003 (3)	−0.0007 (3)	0.0007 (3)
C2	0.0107 (4)	0.0114 (4)	0.0136 (4)	0.0000 (3)	−0.0051 (3)	0.0002 (3)
C3	0.0108 (4)	0.0120 (4)	0.0153 (4)	−0.0006 (3)	−0.0048 (3)	0.0015 (3)
C4	0.0095 (4)	0.0115 (4)	0.0114 (4)	−0.0008 (3)	−0.0006 (3)	0.0004 (3)
C11	0.0137 (5)	0.0152 (5)	0.0144 (5)	0.0018 (4)	−0.0056 (4)	0.0008 (4)
C12	0.0152 (5)	0.0157 (5)	0.0140 (4)	−0.0022 (4)	−0.0062 (4)	−0.0003 (4)

S1—C1	1.7438 (10)	N7—N8	1.3681 (12)
S1—C2	1.8276 (10)	N8—C4	1.3290 (12)
S2—C4	1.7409 (10)	C2—C3	1.5232 (14)
S2—C3	1.8218 (10)	C2—H2A	0.9900
N1—C1	1.3461 (12)	C2—H2B	0.9900
N1—N2	1.3578 (12)	C3—H3A	0.9900
N1—C11	1.4594 (12)	C3—H3B	0.9900
N2—N3	1.2956 (12)	C11—H11A	0.9800
N3—N4	1.3663 (12)	C11—H11B	0.9800
N4—C1	1.3278 (12)	C11—H11C	0.9800
N5—C4	1.3459 (12)	C12—H12A	0.9800
N5—N6	1.3569 (12)	C12—H12B	0.9800
N5—C12	1.4580 (12)	C12—H12C	0.9800
N6—N7	1.2964 (12)
C1—S1—C2	100.16 (4)	H2A—C2—H2B	108.2
C4—S2—C3	99.77 (5)	C2—C3—S2	111.39 (7)
C1—N1—N2	108.09 (8)	C2—C3—H3A	109.4
C1—N1—C11	129.71 (8)	S2—C3—H3A	109.4
N2—N1—C11	122.19 (8)	C2—C3—H3B	109.4
N3—N2—N1	106.31 (8)	S2—C3—H3B	109.4
N2—N3—N4	111.44 (8)	H3A—C3—H3B	108.0
C1—N4—N3	105.18 (8)	N8—C4—N5	108.99 (8)
C4—N5—N6	108.14 (8)	N8—C4—S2	127.81 (8)
C4—N5—C12	129.88 (8)	N5—C4—S2	123.14 (7)
N6—N5—C12	121.97 (8)	N1—C11—H11A	109.5
N7—N6—N5	106.38 (8)	N1—C11—H11B	109.5
N6—N7—N8	111.37 (8)	H11A—C11—H11B	109.5
C4—N8—N7	105.12 (8)	N1—C11—H11C	109.5
N4—C1—N1	108.98 (9)	H11A—C11—H11C	109.5
N4—C1—S1	128.32 (8)	H11B—C11—H11C	109.5
N1—C1—S1	122.69 (7)	N5—C12—H12A	109.5
C3—C2—S1	109.91 (7)	N5—C12—H12B	109.5
C3—C2—H2A	109.7	H12A—C12—H12B	109.5
S1—C2—H2A	109.7	N5—C12—H12C	109.5
C3—C2—H2B	109.7	H12A—C12—H12C	109.5
S1—C2—H2B	109.7	H12B—C12—H12C	109.5

D—H···A	D—H	H···A	D···A	D—H···A
C11—H11B···N8i	0.98	2.39	3.3533 (13)	168
C12—H12B···N4ii	0.98	2.36	3.3183 (13)	165