4,17,25,26-Tetraaza-6,9,12,15-tetra­oxa-2,19,21,24-tetrathiatricyclo[18.4.1^1,4.1^17,20]hexacosa-1(25),20(26)-diene-3,5,16,18-tetraone

The title compound, C₁₄H₁₆N₄O₈S₄, has crystallographic C₂ symmetry with half a molecule in the asymmetric unit and a dihedral angle of 58.7 (1)° between the two planar 1,3,4-thiadiazole five-membered rings of the macrocyclic, giving the molecule a twisted conformation.

S1. Comment

The determination of the structure of the title compound, (I), is part of our continuing study of the molecular structures of macrocycles containing 1,3,4-thiadiazole subunits (Cho, Park & Hwang, 1999; Cho et al., 1999). These compounds are of interest because of their potential activity as artificial receptors of transition metals and other small organic molecules.

Half a molecule of (I) belongs to the asymmetric unit and a molecule is completed by the crystallographic twofold axis (see Fig. 1). The S—C bond lengths range from 1.739 (3) to 1.800 (3) Å, with a mean value of 1.766 (2) Å, which is similar to that found in the International Tables for Crystallography (Vol. C). The C2—S2—C3 angle of 99.55 (17)° is similar to that found in (2S,4S,5R)-(-)-3,4-dimethyl-5-phenyl-2-(1,3-thiazol-2-yl)-1,3-oxazolidine (Fitzsimons & Gallagher, 1999). The bond lengths O2—C4 of 1.188 (4) Å, O4—C3 of 1.193 (4) Å and N1—C2 of 1.285 (4) Å all show clearly double-bond character; the remainder of the bonds are single bonds. The five-membered ring, 5-mercapto-3H-1,3,4-thiadiazolin-2-one, is planar to within 0.008 (2) Å. The dihedral angle between the two five-membered rings of the molecule is 58.7 (1)°. The two half molecules are twisted around the twofold axis with torsion angles S1—C1—C1ⁱ—S1ⁱ of 82.9 (3)° [symmetry code: (i) 1 − x, y, 1.5 − z] and O1—C7—C7ⁱ—O1ⁱ of −76.2 (5)°, so that O3···O3ⁱ = 6.984 (5), N1···N1ⁱ = 5.706 (6) Å and N1···O3ⁱ = 6.661 (4) Å. The atoms S1, N1, O3 and O1 in an asymmetric unit lie in a plane within 0.042 (4) Å, and C1 and C7 in ether groups deviate by −0.595 (4) and 0.194 (5) Å, respectively, from the best plane.

S2. Experimental

The macrocycle is derived from α,α'-bis[(5-oxa-2,3-dihydro-1,3,4-thiadiazol-2-yl)thio]ethane (Cho et al., 1999). The details of the synthesis will be reported elsewhere.

S3. Refinement

All H atoms were placed in calculated positions and allowed to ride upon their parent C atom with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: CAD-4 EXPRESS (Enraf Nonius, 1994); cell refinement: CAD-4 EXPRESS; data reduction: CAD-4 EXPRESS; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1998); molecular graphics: ORTEP-3 for Windows (Farrugia, 1998); software used to prepare material for publication: WinGX publication routines (Farrugia, 1998).

Figures

Fig. 1. ORTEP (Farrugia, 1998) diagram, drawn with 40% probability displacement ellipsoids, showing the twisted conformation of (I). Only the asymmetric unit is labelled and H atoms are omitted for clarity.

(I)

Crystal data

C14H16N4O8S4	F(000) = 1024
Mr = 496.55	Dx = 1.635 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71069 Å
a = 15.151 (3) Å	Cell parameters from 25 reflections
b = 12.739 (3) Å	θ = 9.9–14.1°
c = 10.5509 (13) Å	µ = 0.52 mm^−1
β = 97.888 (13)°	T = 291 K
V = 2017.1 (7) Å^3	Block, colourless
Z = 4	0.20 × 0.17 × 0.12 mm

Data collection

Enraf-Nonius CAD-4 diffractometer	1059 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.054
Graphite monochromator	θmax = 25.0°, θmin = 2.1°
non–profiled ω/2θ scans	h = −17→17
Absorption correction: empirical (using intensity measurements) (Harms & Wocadlo, 1995)	k = −15→15
Tmin = 0.904, Tmax = 0.942	l = 0→12
3616 measured reflections	3 standard reflections every 624 reflections
1772 independent reflections	intensity decay: 2%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.044	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.092	H atoms treated by a mixture of independent and constrained refinement
S = 1.02	w = 1/[σ^2(Fo^2) + (0.0299P)^2] where P = (Fo^2 + 2Fc^2)/3
1772 reflections	(Δ/σ)max < 0.001
136 parameters	Δρmax = 0.24 e Å^−3
0 restraints	Δρmin = −0.20 e Å^−3

Special details

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.

Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane)

10.6361 (0.0167) x + 6.2429 (0.0119) y − 6.4170 (0.0112) z = 2.6608 (0.0095)

* 0.0069 (0.0015) S2 * 0.0038 (0.0021) N1 * 0.0033 (0.0020) N2 * −0.0075 (0.0020) C2 * −0.0064 (0.0018) C3 − 0.0455 (0.0048) S1 − 0.0181 (0.0050) O4 0.1365 (0.0051) C4 0.1197 (0.0057) O2 0.2698 (0.0047) O3

Rms deviation of fitted atoms = 0.0058

− 10.6361 (0.0167) x + 6.2429 (0.0119) y + 6.4170 (0.0112) z = 1.6503 (0.0219)

Angle to previous plane (with approximate e.s.d.) = 58.69 (0.10)

* 0.0069 (0.0015) S2_$1 * 0.0038 (0.0021) N1_$1 * 0.0033 (0.0020) N2_$1 * −0.0075 (0.0020) C2_$1 * −0.0064 (0.0018) C3_$1

Rms deviation of fitted atoms = 0.0058

9.1286 (0.0142) x + 3.8048 (0.0064) y − 8.6075 (0.0081) z = 0.2685 (0.0120)

Angle to previous plane (with approximate e.s.d.) = 48.77 (0.10)

* −0.0150 (0.0009) S1 * 0.0329 (0.0020) N1 * −0.0241 (0.0015) O3 * 0.0062 (0.0004) O1 0.7801 (0.0038) S2 0.2924 (0.0043) N2 − 0.6045 (0.0039) C1 0.1923 (0.0054) C7

Rms deviation of fitted atoms = 0.0220

− 9.1286 (0.0142) x + 3.8048 (0.0064) y + 8.6075 (0.0081) z = 4.0512 (0.0138)

Angle to previous plane (with approximate e.s.d.) = 34.76 (0.10)

* −0.0150 (0.0009) S1_$1 * 0.0329 (0.0020) N1_$1 * −0.0241 (0.0015) O3_$1 * 0.0062 (0.0004) O1_$1

Rms deviation of fitted atoms = 0.0220

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
S1	0.51955 (6)	0.12805 (8)	0.57815 (9)	0.0524 (3)
S2	0.38530 (6)	0.12037 (8)	0.34000 (10)	0.0529 (3)
O1	0.40995 (16)	0.6166 (2)	0.6754 (2)	0.0572 (8)
O2	0.21839 (16)	0.4178 (2)	0.3351 (3)	0.0577 (8)
O3	0.31823 (17)	0.4490 (2)	0.5076 (2)	0.0604 (8)
O4	0.24763 (17)	0.2271 (2)	0.2195 (2)	0.0576 (8)
N1	0.39481 (18)	0.2723 (2)	0.5040 (3)	0.0392 (7)
N2	0.32378 (17)	0.2952 (2)	0.4087 (3)	0.0375 (7)
C1	0.5349 (2)	0.2234 (3)	0.7051 (3)	0.0416 (9)
HC1A	0.5927	0.2115	0.7553	0.050*
HC1B	0.5363	0.2927	0.6672	0.050*
C2	0.4306 (2)	0.1844 (3)	0.4797 (3)	0.0390 (9)
C3	0.3050 (2)	0.2230 (3)	0.3089 (3)	0.0425 (9)
C4	0.2802 (2)	0.3933 (3)	0.4111 (3)	0.0386 (9)
C5	0.2846 (3)	0.5552 (3)	0.5240 (4)	0.0576 (12)
HC5A	0.2494	0.5565	0.5942	0.069*
HC5B	0.2469	0.5773	0.4468	0.069*
C6	0.3618 (3)	0.6269 (3)	0.5513 (4)	0.0566 (11)
HC6A	0.4021	0.6142	0.4891	0.068*
HC6B	0.3408	0.6986	0.5401	0.068*
C7	0.4731 (2)	0.5348 (3)	0.6846 (4)	0.0712 (14)
HC7A	0.5123	0.5441	0.6201	0.085*
HC7B	0.4428	0.4680	0.6693	0.085*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0551 (6)	0.0481 (6)	0.0490 (6)	0.0168 (5)	−0.0103 (5)	−0.0080 (5)
S2	0.0571 (6)	0.0518 (6)	0.0450 (6)	0.0069 (5)	−0.0095 (5)	−0.0132 (5)
O1	0.0581 (17)	0.0623 (18)	0.0487 (17)	0.0159 (15)	−0.0017 (13)	−0.0079 (15)
O2	0.0470 (15)	0.0624 (18)	0.0571 (17)	0.0122 (14)	−0.0161 (14)	−0.0027 (15)
O3	0.0771 (19)	0.0434 (16)	0.0512 (17)	0.0204 (14)	−0.0246 (15)	−0.0107 (15)
O4	0.0494 (15)	0.073 (2)	0.0438 (16)	0.0020 (14)	−0.0159 (13)	−0.0128 (15)
N1	0.0410 (17)	0.0422 (19)	0.0308 (16)	0.0049 (15)	−0.0082 (14)	0.0006 (14)
N2	0.0396 (17)	0.0386 (18)	0.0313 (17)	0.0022 (13)	−0.0057 (14)	−0.0009 (14)
C1	0.038 (2)	0.046 (2)	0.037 (2)	−0.0015 (16)	−0.0079 (16)	−0.0027 (18)
C2	0.041 (2)	0.042 (2)	0.032 (2)	0.0019 (18)	−0.0004 (17)	0.0007 (18)
C3	0.043 (2)	0.047 (2)	0.037 (2)	−0.0035 (18)	0.0051 (19)	−0.0012 (19)
C4	0.039 (2)	0.044 (2)	0.032 (2)	0.0010 (18)	0.0026 (18)	0.0034 (19)
C5	0.068 (3)	0.049 (3)	0.050 (3)	0.019 (2)	−0.011 (2)	−0.003 (2)
C6	0.079 (3)	0.044 (2)	0.046 (2)	0.014 (2)	0.007 (2)	0.006 (2)
C7	0.058 (3)	0.065 (3)	0.083 (4)	0.007 (2)	−0.020 (2)	−0.011 (3)

Geometric parameters (Å, º)

S1—C2	1.739 (3)	O4—C3	1.193 (4)
S1—C1	1.800 (3)	N1—C2	1.285 (4)
S2—C2	1.741 (3)	N1—N2	1.399 (3)
S2—C3	1.785 (4)	N2—C3	1.398 (4)
O1—C7	1.408 (4)	N2—C4	1.415 (4)
O1—C6	1.414 (4)	C1—C1^i	1.514 (6)
O2—C4	1.188 (4)	C5—C6	1.482 (5)
O3—C4	1.307 (4)	C7—C7^i	1.504 (7)
O3—C5	1.465 (4)
C2—S1—C1	100.16 (17)	S1—C2—S2	119.7 (2)
C2—S2—C3	89.55 (17)	O4—C3—N2	128.2 (3)
C7—O1—C6	113.0 (3)	O4—C3—S2	125.5 (3)
C4—O3—C5	118.0 (3)	N2—C3—S2	106.3 (2)
C2—N1—N2	110.0 (3)	O2—C4—O3	127.3 (3)
C3—N2—N1	117.4 (3)	O2—C4—N2	123.1 (3)
C3—N2—C4	123.2 (3)	O3—C4—N2	109.6 (3)
N1—N2—C4	119.1 (3)	O3—C5—C6	108.3 (3)
C1^i—C1—S1	115.8 (2)	O1—C6—C5	114.6 (3)
N1—C2—S1	123.6 (3)	O1—C7—C7^i	109.9 (3)
N1—C2—S2	116.7 (3)
C2—N1—N2—C3	−0.1 (4)	C2—S2—C3—O4	−179.1 (3)
C2—N1—N2—C4	−174.3 (3)	C2—S2—C3—N2	1.0 (2)
C2—S1—C1—C1^i	73.3 (3)	C5—O3—C4—O2	−2.3 (6)
N2—N1—C2—S1	−178.6 (2)	C5—O3—C4—N2	177.9 (3)
N2—N1—C2—S2	1.0 (4)	C3—N2—C4—O2	7.6 (5)
C1—S1—C2—N1	1.3 (3)	N1—N2—C4—O2	−178.5 (3)
C1—S1—C2—S2	−178.3 (2)	C3—N2—C4—O3	−172.6 (3)
C3—S2—C2—N1	−1.2 (3)	N1—N2—C4—O3	1.3 (4)
C3—S2—C2—S1	178.4 (2)	C4—O3—C5—C6	−134.8 (3)
N1—N2—C3—O4	179.4 (3)	C7—O1—C6—C5	83.5 (4)
C4—N2—C3—O4	−6.6 (6)	O3—C5—C6—O1	−73.2 (4)
N1—N2—C3—S2	−0.7 (4)	C6—O1—C7—C7^i	175.0 (3)
C4—N2—C3—S2	173.2 (3)

Symmetry code: (i) −x+1, y, −z+3/2.