2,2′-Di­amino-4,4′-bi-1,3-thia­zolium fumarate

The title compound, C₆H₈N₄S₂²⁺·C₄H₂O₄²⁻, consists of a di­amino­bi­thia­zole (DABT) cation and a fumarate anion. The cation and anion are both located on inversion centers. Both ions display a planar configuration and link to each other through hydrogen bonding between carboxyl and amino groups, as well as through weak C—H...O hydrogen bonding between thia­zole and carboxyl groups. The C—N(amino) bond distance of 1.323 (4) Å suggests the existence of electron delocalization between the thia­zole ring and the amino group.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.050
• wR factor = 0.137
• Data-to-parameter ratio = 14.9

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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S1. Comment

Transition metal complexes with 2,2'-diamine-4,4'-bithiazole (DABT) or its derivatives have shown interesting properties and potential application in any fields (Waring, 1981; Fisher et al., 1985). A series of metal complexes with BADT has been prepared in our laboratory (Liu et al., 2001). As a part of this investigation, the X-ray structure of the title BADT fumarate, (I), is presented here.

The structure of (I) is shown in Fig. 1 and consists of a protonated DABT cation and a fumarate anion, both being located around an individual crystallographic inversion center. The DABT cation displays a planar trans configuration, which agrees with that found in 2,2'-diamino-4,4'-1,3-thiazolium dichloride (Liu et al., 2002), but differs from the cis configuration found in DABT metal complexes (Tian et al., 1996; Liu et al., 2001). The N3—C2 distance of 1.333 (4) Å within the DABT cation is identical to the values of 1.335 (6) and 1.322 (3) Å found in the dichloride (Liu et al., 2002) and the Cu^II complex (Liu et al., 2001), respectively, but significantly longer than the distance of 1.309 (2) Å in the neutral DABT molecule (Liu et al., 2003). The N2—C2 bond distance of 1.323 (4) Å suggests the existence of the electron delocalization between the thiazole ring and the amino group.

The carboxyl groups of the fumarate anion are coplanar with the carbon skeleton, the maximum atomic deviation from the mean plane defined by all atoms of the fumarate being 0.0806 (14) Å (O1). The fumarate anions link with DABT cations through classic hydrogen bonding between the carboxyl and amino groups and weak C—H···O hydrogen bonding between the carboxyl and thiazole ring, forming a three-dimensional supramolecular structure, as shown in Fig. 2.

S2. Experimental

Fine crystals of DABT were obtained in the manner reported by Erlenmeyer (1948). Single crystals of (I) were obtained from an aqueous solution, as a by-product, during the preparation of a BADT complex of Mn^II bridged by fumarate.

S3. Refinement

Amine H atoms were located in a difference Fourier map and were included in the final cycles of refinement, with fixed positional parameters and U_iso of values of 0.04 Ų. Other H atoms were placed in calculated positions, with C—H = 0.93 Å and N—H = 0.86 Å, and included in the final cycles of refinement as riding, with U_iso(H) = 1.2U_eq of the carrier atoms.

Computing details

Data collection: PROCESS-AUTO (Rigaku Corporation, 1998); cell refinement: PROCESS-AUTO; data reduction: CrystalStructure (Rigaku/MSC and Rigaku, 2002); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and XP (Siemens, 1994); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. The molecular structure of (I), shown with 50% probability displacement ellipsoids, with dashed lines indicating the hydrogen bonding. [Symmetry codes: (i) 2 − x, −y, −z; (ii) −x, 1 − y, −z.]
	Fig. 2. A molecular packing of (I), with dashed lines showing the hydrogen bonding.

(I)

Crystal data

C6H8N4S2^2+·C4H2O4^2^−	F(000) = 324
Mr = 314.34	Dx = 1.750 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.7107 Å
Hall symbol: -P 2ybc	Cell parameters from 3028 reflections
a = 5.2834 (17) Å	θ = 3.2–26.5°
b = 7.936 (3) Å	µ = 0.47 mm^−1
c = 14.370 (5) Å	T = 298 K
β = 98.164 (6)°	Prism, colorless
V = 596.4 (4) Å^3	0.32 × 0.28 × 0.20 mm
Z = 2

Data collection

Rigaku R-AXIS-RAPID diffractometer	1359 independent reflections
Radiation source: fine-focus sealed tube	874 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.095
Detector resolution: 10.00 pixels mm^-1	θmax = 27.5°, θmin = 2.9°
ω scans	h = −5→6
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	k = −10→9
Tmin = 0.86, Tmax = 0.91	l = −18→18
3650 measured reflections

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)] = 0.050	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.137	H-atom parameters constrained
S = 1.06	w = 1/[σ^2(Fo^2) + (0.062P)^2 + 0.0525P] where P = (Fo^2 + 2Fc^2)/3
1359 reflections	(Δ/σ)max < 0.001
91 parameters	Δρmax = 0.58 e Å^−3
0 restraints	Δρmin = −0.68 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.

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

	x	y	z	Uiso*/Ueq
S1	0.99312 (15)	−0.11891 (9)	0.21681 (5)	0.0211 (3)
C7	0.0974 (6)	0.4669 (4)	−0.0178 (2)	0.0191 (7)
H7	0.1063	0.4840	−0.0813	0.023*
C5	1.1150 (6)	−0.1190 (4)	0.1112 (2)	0.0190 (7)
H5	1.2537	−0.1834	0.0990	0.023*
N2	0.6014 (5)	0.0968 (3)	0.22327 (17)	0.0214 (6)
C2	0.7659 (6)	0.0298 (3)	0.1725 (2)	0.0177 (7)
C4	0.9820 (6)	−0.0132 (4)	0.04877 (19)	0.0185 (7)
O1	0.4498 (4)	0.2836 (3)	−0.00883 (15)	0.0216 (5)
N3	0.7857 (5)	0.0730 (3)	0.08446 (16)	0.0169 (6)
H3	0.6885	0.1461	0.0529	0.020*
C6	0.3048 (6)	0.3654 (3)	0.0386 (2)	0.0181 (7)
O2	0.3233 (4)	0.3637 (3)	0.12609 (14)	0.0229 (5)
H21	0.4960	0.1676	0.1995	0.040*
H22	0.5855	0.0593	0.2780	0.040*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0264 (5)	0.0203 (4)	0.0167 (4)	0.0048 (3)	0.0030 (3)	0.0013 (3)
C7	0.028 (2)	0.0133 (14)	0.0161 (14)	−0.0003 (12)	0.0019 (13)	−0.0011 (11)
C5	0.0217 (18)	0.0178 (15)	0.0182 (15)	0.0029 (12)	0.0055 (13)	−0.0022 (12)
N2	0.0276 (16)	0.0204 (13)	0.0168 (12)	0.0047 (11)	0.0054 (11)	0.0026 (10)
C2	0.0210 (17)	0.0133 (14)	0.0177 (15)	−0.0008 (12)	−0.0010 (12)	−0.0015 (11)
C4	0.0181 (16)	0.0172 (15)	0.0195 (15)	−0.0033 (12)	0.0000 (13)	−0.0028 (12)
O1	0.0218 (13)	0.0212 (12)	0.0219 (11)	0.0045 (9)	0.0040 (9)	−0.0020 (9)
N3	0.0190 (15)	0.0153 (13)	0.0162 (12)	0.0023 (10)	0.0016 (11)	0.0003 (9)
C6	0.0244 (18)	0.0118 (14)	0.0188 (15)	−0.0035 (12)	0.0054 (13)	−0.0012 (11)
O2	0.0248 (13)	0.0242 (12)	0.0186 (11)	0.0071 (9)	−0.0004 (9)	−0.0006 (9)

Geometric parameters (Å, º)

S1—C5	1.731 (3)	N2—H21	0.829
S1—C2	1.738 (3)	N2—H22	0.856
C7—C7^i	1.322 (6)	C2—N3	1.330 (4)
C7—C6	1.501 (4)	C4—N3	1.399 (4)
C7—H7	0.930	C4—C4^ii	1.456 (6)
C5—C4	1.351 (4)	O1—C6	1.273 (4)
C5—H5	0.930	N3—H3	0.860
N2—C2	1.323 (4)	C6—O2	1.248 (3)
C5—S1—C2	90.18 (14)	N2—C2—S1	123.0 (2)
C7^i—C7—C6	123.5 (3)	N3—C2—S1	112.3 (2)
C7^i—C7—H7	118.2	C5—C4—N3	113.8 (3)
C6—C7—H7	118.2	C5—C4—C4^ii	127.0 (4)
C4—C5—S1	111.0 (2)	N3—C4—C4^ii	119.2 (3)
C4—C5—H5	124.5	C2—N3—C4	112.7 (3)
S1—C5—H5	124.5	C2—N3—H3	123.7
C2—N2—H21	120.0	C4—N3—H3	123.7
C2—N2—H22	121.6	O2—C6—O1	124.5 (3)
H21—N2—H22	117.8	O2—C6—C7	119.8 (3)
N2—C2—N3	124.6 (3)	O1—C6—C7	115.7 (2)

Symmetry codes: (i) −x, −y+1, −z; (ii) −x+2, −y, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H21···O2	0.83	2.02	2.831 (3)	164
N2—H22···O2^iii	0.86	2.09	2.832 (3)	145
N3—H3···O1	0.86	1.80	2.658 (3)	172
C5—H5···O1^ii	0.93	2.31	3.181 (4)	155

Symmetry codes: (ii) −x+2, −y, −z; (iii) −x+1, y−1/2, −z+1/2.