Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536802014034/ww6026sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536802014034/ww6026Isup2.hkl |
CCDC reference: 198326
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (C-C) = 0.003 Å
- R factor = 0.035
- wR factor = 0.097
- Data-to-parameter ratio = 14.8
checkCIF results
No syntax errors found ADDSYM reports no extra symmetry
Alert Level C:
ABSTY_02 Alert C An _exptl_absorpt_correction_type has been given without a literature citation. This should be contained in the _exptl_absorpt_process_details field. Absorption correction given as empirical General Notes
ABSTM_02 When printed, the submitted absorption T values will be replaced by the scaled T values. Since the ratio of scaled T's is identical to the ratio of reported T values, the scaling does not imply a change to the absorption corrections used in the study. Ratio of Tmax expected/reported 0.901 Tmax scaled 0.815 Tmin scaled 0.725
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
1 Alert Level C = Please check
CuBr (0.5 mmol) and C3H4N2S2 (0.5 mmol) were stirred in a mixed solvent of alcohol (5 ml), acetonitrile (10 ml), and tetrahydropyran (5 ml) at room temperature. Yellow crystals of the title compound were obtained after a few days.
The H atoms on the ligands were located at geometrically calculated positions with H-atom parameters constrained.
Data collection: SMART (Siemens, 1995); cell refinement: SMART; data reduction: SAINT (Siemens, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Sheldrick, 1996); software used to prepare material for publication: SHELXL97.
Fig. 1. A view of the molecule of (I), shown with 50% probability displacement ellipsoids. | |
Fig. 2. A view of the molecule of (II), shown with 50% probability displacement ellipsoids. |
C6H6N4S4 | F(000) = 536 |
Mr = 262.39 | Dx = 1.625 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
a = 8.5647 (6) Å | Cell parameters from 1505 reflections |
b = 6.9212 (6) Å | θ = 3.8–25.0° |
c = 18.2692 (15) Å | µ = 0.85 mm−1 |
β = 98.074 (1)° | T = 293 K |
V = 1072.23 (15) Å3 | Cube, yellow |
Z = 4 | 0.40 × 0.40 × 0.24 mm |
Siemens SMART CCD diffractometer | 948 independent reflections |
Radiation source: fine-focus sealed tube | 807 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.021 |
ω scans | θmax = 25.0°, θmin = 3.8° |
Absorption correction: empirical (using intensity measurements) ? | h = −10→7 |
Tmin = 0.805, Tmax = 0.905 | k = −8→4 |
1847 measured reflections | l = −21→18 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.035 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.097 | H-atom parameters constrained |
S = 1.04 | w = 1/[σ2(Fo2) + (0.0581P)2 + 0.4258P] where P = (Fo2 + 2Fc2)/3 |
948 reflections | (Δ/σ)max = 0.001 |
64 parameters | Δρmax = 0.32 e Å−3 |
0 restraints | Δρmin = −0.28 e Å−3 |
C6H6N4S4 | V = 1072.23 (15) Å3 |
Mr = 262.39 | Z = 4 |
Monoclinic, C2/c | Mo Kα radiation |
a = 8.5647 (6) Å | µ = 0.85 mm−1 |
b = 6.9212 (6) Å | T = 293 K |
c = 18.2692 (15) Å | 0.40 × 0.40 × 0.24 mm |
β = 98.074 (1)° |
Siemens SMART CCD diffractometer | 948 independent reflections |
Absorption correction: empirical (using intensity measurements) ? | 807 reflections with I > 2σ(I) |
Tmin = 0.805, Tmax = 0.905 | Rint = 0.021 |
1847 measured reflections |
R[F2 > 2σ(F2)] = 0.035 | 0 restraints |
wR(F2) = 0.097 | H-atom parameters constrained |
S = 1.04 | Δρmax = 0.32 e Å−3 |
948 reflections | Δρmin = −0.28 e Å−3 |
64 parameters |
Geometry. Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane) 3.1535 (0.0073) x + 3.9961 (0.0033) y + 12.2368 (0.0083) z = 11.4708 (0.0030) * 0.0494 (0.0016) C1 * −0.0061 (0.0021) C2 * −0.0488 (0.0018) C3 * 0.0038 (0.0017) N1 * −0.0251 (0.0016) N2 * −0.0422 (0.0012) S1 * 0.0689 (0.0011) S2 Rms deviation of fitted atoms = 0.0415 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. |
x | y | z | Uiso*/Ueq | ||
S2 | 0.60982 (8) | 0.15497 (9) | 0.73527 (4) | 0.0511 (3) | |
S1 | 0.45955 (8) | 0.51058 (9) | 0.64879 (4) | 0.0525 (3) | |
N2 | 0.7220 (3) | 0.3574 (3) | 0.63259 (12) | 0.0527 (6) | |
N1 | 0.7063 (3) | 0.5180 (3) | 0.58654 (13) | 0.0534 (6) | |
C3 | 0.6028 (3) | 0.3380 (3) | 0.66769 (12) | 0.0394 (5) | |
C2 | 0.5768 (3) | 0.6104 (3) | 0.58890 (12) | 0.0418 (6) | |
C1 | 0.5333 (3) | 0.7907 (4) | 0.54579 (15) | 0.0544 (7) | |
H1A | 0.6142 | 0.8213 | 0.5163 | 0.082* | |
H1B | 0.5225 | 0.8953 | 0.5792 | 0.082* | |
H1C | 0.4351 | 0.7714 | 0.5142 | 0.082* |
U11 | U22 | U33 | U12 | U13 | U23 | |
S2 | 0.0579 (5) | 0.0462 (4) | 0.0536 (4) | 0.0147 (3) | 0.0228 (3) | 0.0122 (3) |
S1 | 0.0449 (4) | 0.0562 (5) | 0.0616 (5) | 0.0183 (3) | 0.0259 (3) | 0.0189 (3) |
N2 | 0.0516 (13) | 0.0536 (12) | 0.0578 (13) | 0.0174 (10) | 0.0243 (10) | 0.0134 (10) |
N1 | 0.0531 (14) | 0.0568 (13) | 0.0556 (13) | 0.0173 (10) | 0.0267 (10) | 0.0161 (10) |
C3 | 0.0406 (12) | 0.0395 (12) | 0.0398 (12) | 0.0070 (9) | 0.0122 (9) | −0.0003 (9) |
C2 | 0.0439 (13) | 0.0447 (13) | 0.0395 (12) | 0.0069 (10) | 0.0157 (10) | 0.0028 (10) |
C1 | 0.0591 (16) | 0.0528 (14) | 0.0559 (15) | 0.0132 (13) | 0.0243 (12) | 0.0135 (13) |
S2—C3 | 1.764 (2) | N1—C2 | 1.286 (3) |
S2—S2i | 2.0280 (13) | C2—C1 | 1.495 (3) |
S1—C3 | 1.712 (2) | C1—H1A | 0.9600 |
S1—C2 | 1.730 (2) | C1—H1B | 0.9600 |
N2—C3 | 1.287 (3) | C1—H1C | 0.9600 |
N2—N1 | 1.389 (3) | ||
C3—S2—S2i | 104.11 (8) | N1—C2—S1 | 113.74 (18) |
C3—S1—C2 | 86.73 (11) | C1—C2—S1 | 122.86 (17) |
C3—N2—N1 | 111.64 (19) | C2—C1—H1A | 109.5 |
C2—N1—N2 | 112.9 (2) | C2—C1—H1B | 109.5 |
N2—C3—S1 | 115.04 (17) | H1A—C1—H1B | 109.5 |
N2—C3—S2 | 118.15 (17) | C2—C1—H1C | 109.5 |
S1—C3—S2 | 126.53 (14) | H1A—C1—H1C | 109.5 |
N1—C2—C1 | 123.4 (2) | H1B—C1—H1C | 109.5 |
Symmetry code: (i) −x+1, y, −z+3/2. |
Experimental details
Crystal data | |
Chemical formula | C6H6N4S4 |
Mr | 262.39 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 293 |
a, b, c (Å) | 8.5647 (6), 6.9212 (6), 18.2692 (15) |
β (°) | 98.074 (1) |
V (Å3) | 1072.23 (15) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.85 |
Crystal size (mm) | 0.40 × 0.40 × 0.24 |
Data collection | |
Diffractometer | Siemens SMART CCD diffractometer |
Absorption correction | Empirical (using intensity measurements) |
Tmin, Tmax | 0.805, 0.905 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 1847, 948, 807 |
Rint | 0.021 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.035, 0.097, 1.04 |
No. of reflections | 948 |
No. of parameters | 64 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.32, −0.28 |
Computer programs: SMART (Siemens, 1995), SMART, SAINT (Siemens, 1995), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Sheldrick, 1996), SHELXL97.
(I) | (II) | ||
S1—C2 | 1.730 (2) | 1.742 (2) | |
S1—C3 | 1.712 (2) | 1.738 (2) | |
S2—C3 | 1.764 (2) | 1.665 (2) | |
N1—N2 | 1.389 (3) | 1.382 (3) | |
N1—C2 | 1.286 (3) | 1.295 (3) | |
N2—C3 | 1.287 (3) | 1.331 (3) | |
C1—C2 | 1.495 (3) | 1.479 (3) | |
C3—S1—C2 | 86.73 (11) | 90.35 (12) | |
C2—N1—N2 | 112.9 (2) | 109.77 (19) | |
C3—N2—N1 | 111.64 (19) | 119.09 (18) | |
N1—C2—C1 | 123.4 (2) | 122.6 (2) | |
N1—C2—S1 | 113.74 (18) | 113.70 (18) | |
C1—C2—S1 | 122.86 (17) | 123.62 (19) | |
N2—C3—S2 | 118.15 (17) | 125.91 (18) | |
S2—C3—S1 | 126.53 (14) | 127.02 (16) | |
N2—C3—S1 | 115.04 (17) | 107.07 (17) |
Triazole and its derivative ligands are versatile chelating ligands that can bridge a wide range of metal atoms into dimers, oligomers, and polymeric chains through multidendate donor atoms (Steel, 1990; Inoue & Kubo, 1976; Maekawa et al., 1999). The combined effects of deprotonation and coordination are found to cause significant changes to the bond lengths and angles in these ligands (Chen et al., 1993; Tandon et al., 1994). In a recent effort to investigate the dependence of optical properties of coinage metal complexes on the molecular structures and metal–metal interactions (Ford et al., 1999; Zhou et al.,2002), the title molecule, (I), was isolated as a dimerized structure of parent 1,3,4-triazole through S—S bonding (see Scheme). In this paper, we report the synthesis and crystal structure of (I).
As shown in Fig. 1, the dimerized structure is formed through the S—S connection of parent 2-mercapto-5-methyl-1,3,4-thiadiazole moieties following the deprotonation of thiol groups. The observed S2—S2' distance in the present disulfide structure is 2.028 (1) Å, very close to the sum of the atomic radius (1.035 Å) or single-bond covalent radius (1.04 Å) of the element. The S—S single-bond character is further confirmed by the associated S2—C3 distance of 1.764 (2) Å, which is only slightly smaller than the sum of single–bond radii (1.81 Å). The S1···S1' non-bonding distance is 3.666 Å. The torsion angle of C3—S2—S2'—C3' is −84.45 (16)°. The 2-mercapto-5-methyl-1,3,4-thiadiazole ring in the molecule remains planar, with an r.m.s deviation of 0.042 Å. The two ring planes make a dihedral angle of 70.5 (1) Å, related by a crystallographic twofold rotation symmetry through the middle of the S—S bond.
Table 1 lists important bond distances and angles for (I), as well as for the parent 2-mercapto-5-methyl-1,3,4-thiadiazole ligand, which has also been determined [C3H4N2S2, (II), space group Pbca, a = 10.5107 (6), b = 20.398 (1), c = 9.1157 (5) Å, V = 1121.6 (1) Å3, R1/wR = 0.0383/0.1307, S = 1.152) (Song et al., 2002)]. To facilitate the comparison between dimerized (I) and parent (II), the molecular picture of the latter is also shown in Fig. 2. The bond distances in the structure are subjected to small variations upon the deprotonation and dimerization. Such effect was previously observed when the ligand is deprotonated and then coordinated to metal atoms (Chen et al., 1993; Tandon et al., 1994). The N—N distance is slightly lengthened, 1.382 (3) Å in (II) to 1.389 (3) Å in (I), in spite of an insignificant deviation within 3° σ, but both are comparable to the single-bond distance of 1.40 Å. Accordingly, the C—N bond distances are slightly shortened from 1.331 (3) Å in (II) to 1.286 (3) Å in (I), sufficiently short to suggest partial double-bond character (Senda et al., 1986; Mathew & Palenik, 1974). The cyclic C—S bond distances are also shortened from 1.742 (2) Å in (II) to 1.712 (2) Å in (I), both are slightly shorter than the value of 1.77 Å for a Csp2—S single bond (Mathew & Palenik, 1974). In contrast, the exocyclic C—S bond distances are significantly lengthened from 1.665 (2) Å in (II) with thiols, to 1.764 (2) Å in (I) with disulfur units. The structural effect of deprotonation is evident.