Di­aqua­(2,2′-di­amino-4,4′-bi-1,3-thia­zole)­oxo­sulfato­vanadium(IV) tetrahydrate

The title compound, [VO(SO₄)(C₆H₆N₄S₂)(H₂O)₂]·4H₂O, displays a distorted octahedral coordination geometry. The 2,2′-di­amino-4,4′-bi­thia­zole ligand is present in the usual chelating bidentate mode. The sulfate ligand coordinates in a monodentate fashion to the V atom. A large displacement of the V atom from the equatorial plane towards the oxo group correlates with the strong V=O double bond. In the crystal structure, a three-dimensional supramolecular network is formed by hydrogen bonds.

S1. Comment

Some transition metal complexes with 2,2'-diamino-4,4'-bithiazole (DABT) or its derivatives have been found to be effective inhibitors of DNA synthesis in tumor cells (Fisher et al., 1985; Waring, 1981). Vanadium plays an important role in various biological processes (Rehder, 1991) and shows potential application in the pharmaceutical area (Sakurai et al., 2002), which has received increased attention in recent years (Butler & Carrano, 1991; Robson et al., 1986; Soedjak & Butler, 1990). As part of an investigation of a series of metal complexes with DABT (Wu et al., 2003), the oxovanadium complex with DABT, (I), has recently been prepared and its X-ray structure is presented here.

The molecular structure of (I) is shown in Fig. 1. The title compound contains a vanadium(IV) complex and four solvent water molecules. The octahedral geometry around the vanadium ion is defined by {VO₂(H₂O)₂N₂}, with the V^IV center coordinated to a terminal oxo group, the two coordinated water molecules at cis positions, two N donor atoms from a chelating DABT ligand and an O-atom donor from a monodentate SO₄²⁻ ligand. The apical positions of the octahedron are occupied by the terminal oxo group (O1) and one coordinated water molecule (O1W); the O1–V1–O1W angle is 172.97 (7)° (Table 1). The equatorial plane is formed by the rest of the coordinated atoms with a maximum deviation of 0.0538 (8) Å (N2). A large displacement of 0.3287 (9) Å of the V atom from the equatorial plane towards the oxo group is observed; it is correlated with the short V1—O1 distance of 1.5858 (16) Å that indicates a substantial V═O double bond and a elongated V1—O1W bond length of 2.2319 (15) Å.

The DABT is present in the usual chelating bidentate mode, forming a five-membered ring with V—N bond lengths of 2.0990 (19) and 2.1170 (18) Å and N2–V1–N4 bond angles of 79.00 (7)°. The dihedral angle between the planes of the two thiazole rings is 2.91 (12)°.

The SO₄²⁻ ligand adopts a monodentate mode coordinating to the V^IV center with a V1—O2 bond length of 2.0113 (15) Å. The V1—O2—S2—O3,O4,O5 torsion angles are 75.40 (15), −44.64 (17) and −166.03 (14)°, respectively. The S2—O2—V1 angle is 136.69 (9)°. The S2—O2 bond is longer than the bonds to noncoordinated O atoms in the SO₄²⁻ tetrahedron, which were also observed in some similar compounds (Doedens et al., 2002; Dong et al., 2000; Khan et al., 1999; Triantafillou et al., 2004). The overall geometry around atom S2 is a distorted tetrahedron.

In the crystal structure, a three-dimensional supramolecular hydrogen-bonding network is observed (Table 2). As illustrated in Fig. 2, via hydrogen bonds between atom O2W, the sulfate group and the amine groups on the bithiazole moiety, the complexes are linked to one another and extend along the of [110] direction. These chains are assembled into a two-dimensional layer structure parallel to the (001) crystal plane by solvent water molecules (O4W, O5W and O6W) forming hydrogen bonds to the coordinated water molecules and sulfate groups of the complexes. Through intralayer hydrogen bonds involving atom O3W, a three-dimensional hydrogen-bonding structure is completed (Fig. 3).

The molecular packing is shown in Fig. 3. The crystal has two distinct regions; one contains the DABT ligands and the other contains intimately hydrogen-bonded sulfates and water molcules as described above. In the region of the ligands, neighboring thiazole rings, related by the symmetry operation (−x + 2, −y, −z + 1), are nearly parallel; the separations of 3.4970 (32) Å (C3) to 3.5979 (22) Å (S3) suggests π–π stacking between the ligands.

S2. Experimental

DABT (0.10 g, 0.5 mmol) was added to an aqueous solution containing VOSO₄ (0.08 g, 0.5 mmol); the mixture was stirred quickly until the DABT dissolved. The solution was filtered immediately and the filtrate was kept at room temperature. Green crystals (yield 0.16 g, 67.5%) of suitable size were obtained after 2 h.

S3. Refinement

H atoms of water molecules were located in a difference Fourier map and included in structure-factor calculation with fixed positional and displacement parameters (0.08 Ų); H atoms of aromatic rings and terminal amino group were placed in calculated positions, with C—H = 0.93 Å and N—H = 0.86 Å, and were included in the final cycles of refinement in the riding mode, with U_iso(H) values equal to 1.2U_eq of the carrier atoms.

Computing details

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and CAMERON (Watkin, et al., 1993); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. A view of (I). Displacement ellipsoids are drawn at the 30% probability level. Dashed lines indicate hydrogen bonds.
	Fig. 2. A two-dimensional hydrogen-bonding structure parallel to the (001) plane. The hydrogen-bond linkage among the complex molecules extend along [110]. [Symmetry codes: (A) −x + 2, −y, −z; (B) x + 1, y + 1, z; (C) −x + 1, −y, −z; (D) x − 1, y, z; (E) −x + 2, −y + 1, −z.]
	Fig. 3. A molecular packing diagram, showing the hydrogen bonds involving O3W and the two distinct regions within the structure. In the region of the DABT ligand, there is π–π stacking between the thiazole rings related by the operation (−x + 2, −y, −z + 1). [Symmetry code: (i) x − 1, y, z; (ii) −x + 2, −y + 1, −z + 1.]

Diaqua(2,2'-diamino-4,4'-bi-1,3-thiazole)oxosulfatovanadium tetrahydrate

Crystal data

[VO(SO4)(C6H6N4S2)(H2O)2]·4H2O	Z = 2
Mr = 469.36	F(000) = 482
Triclinic, P1	Dx = 1.765 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.9043 (16) Å	Cell parameters from 3780 reflections
b = 10.230 (2) Å	θ = 2.2–27.5°
c = 12.597 (3) Å	µ = 0.98 mm^−1
α = 102.32 (3)°	T = 296 K
β = 102.61 (3)°	Chunk, blue
γ = 110.50 (3)°	0.28 × 0.22 × 0.20 mm
V = 883.1 (3) Å^3

Data collection

Bruker APEX area-detector diffractometer	4015 independent reflections
Radiation source: fine-focus sealed tube	3573 reflections with I > 2/s(I)
Graphite monochromator	Rint = 0.016
ϕ and ω scans	θmax = 27.5°, θmin = 1.8°
Absorption correction: multi-scan (SADABS; Bruker, 2002)	h = −10→10
Tmin = 0.772, Tmax = 0.829	k = −13→11
8440 measured reflections	l = −16→16

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)] = 0.031	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.089	H-atom parameters constrained
S = 1.09	w = 1/[σ^2(Fo^2) + (0.0472P)^2 + 0.4813P] where P = (Fo^2 + 2Fc^2)/3
4015 reflections	(Δ/σ)max = 0.001
226 parameters	Δρmax = 0.64 e Å^−3
0 restraints	Δρmin = −0.40 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
V1	0.93524 (4)	0.08832 (3)	0.24812 (3)	0.02433 (9)
O1	1.0989 (2)	0.03140 (18)	0.25991 (14)	0.0380 (3)
O1W	0.6844 (2)	0.14440 (16)	0.21230 (13)	0.0323 (3)
H1WA	0.6916	0.2060	0.1722	0.080*
H1WB	0.5802	0.0791	0.1770	0.080*
O2W	0.7848 (2)	−0.04916 (16)	0.08169 (12)	0.0328 (3)
H2WA	0.7393	−0.0187	0.0260	0.080*
H2WB	0.8472	−0.0976	0.0503	0.080*
S2	1.17296 (7)	0.31067 (5)	0.12801 (4)	0.02631 (11)
O2	1.0403 (2)	0.26338 (16)	0.19537 (12)	0.0319 (3)
O3	1.0705 (2)	0.22654 (19)	0.00590 (13)	0.0410 (4)
O4	1.3387 (2)	0.2814 (2)	0.16737 (16)	0.0494 (4)
O5	1.2233 (3)	0.46667 (18)	0.14634 (17)	0.0498 (4)
S1	1.14155 (9)	0.41820 (6)	0.61634 (4)	0.04024 (14)
N1	1.2495 (3)	0.4547 (2)	0.43399 (17)	0.0451 (5)
H1A	1.2462	0.4257	0.3640	0.054*
H1B	1.3267	0.5425	0.4775	0.054*
N2	1.0110 (2)	0.22656 (18)	0.41594 (14)	0.0279 (3)
C1	1.1357 (3)	0.3641 (2)	0.47481 (17)	0.0314 (4)
C2	0.9173 (3)	0.1605 (2)	0.48555 (17)	0.0304 (4)
C3	0.9702 (3)	0.2461 (3)	0.59469 (19)	0.0395 (5)
H3	0.9213	0.2166	0.6506	0.047*
S3	0.51609 (9)	−0.24520 (6)	0.37459 (5)	0.04363 (15)
N3	0.5707 (3)	−0.2831 (2)	0.17027 (18)	0.0478 (5)
H3A	0.6258	−0.2554	0.1221	0.057*
H3B	0.4824	−0.3704	0.1505	0.057*
N4	0.7554 (2)	−0.05404 (18)	0.31591 (14)	0.0294 (3)
C4	0.6221 (3)	−0.1906 (2)	0.27541 (19)	0.0334 (4)
C5	0.7767 (3)	0.0105 (2)	0.43067 (17)	0.0309 (4)
C6	0.6616 (3)	−0.0762 (3)	0.4755 (2)	0.0398 (5)
H6	0.6608	−0.0486	0.5506	0.048*
O3W	0.5463 (2)	0.26994 (19)	0.38688 (14)	0.0441 (4)
H3WA	0.4670	0.2822	0.3334	0.080*
H3WB	0.6065	0.2272	0.3447	0.080*
O4W	0.3382 (3)	−0.0817 (2)	0.07216 (18)	0.0562 (5)
H4WA	0.3581	−0.1533	0.0361	0.080*
H4WB	0.2172	−0.1228	0.0807	0.080*
O5W	0.6417 (2)	0.3216 (2)	0.08582 (16)	0.0461 (4)
H5WA	0.7380	0.4034	0.1030	0.080*
H5WB	0.5496	0.3377	0.1085	0.080*
O6W	0.9489 (3)	0.5826 (2)	0.14037 (16)	0.0532 (5)
H6WA	1.0515	0.5579	0.1397	0.080*
H6WB	0.9454	0.6409	0.0958	0.080*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
V1	0.02317 (16)	0.02500 (17)	0.02201 (16)	0.00757 (13)	0.00677 (12)	0.00671 (12)
O1	0.0334 (8)	0.0418 (8)	0.0406 (8)	0.0187 (7)	0.0104 (7)	0.0125 (7)
O1W	0.0274 (7)	0.0341 (7)	0.0338 (7)	0.0121 (6)	0.0081 (6)	0.0108 (6)
O2W	0.0361 (8)	0.0321 (7)	0.0254 (7)	0.0126 (6)	0.0088 (6)	0.0038 (6)
S2	0.0248 (2)	0.0276 (2)	0.0246 (2)	0.00789 (18)	0.00936 (17)	0.00811 (18)
O2	0.0333 (7)	0.0318 (7)	0.0333 (7)	0.0112 (6)	0.0172 (6)	0.0129 (6)
O3	0.0416 (9)	0.0493 (9)	0.0269 (7)	0.0182 (7)	0.0098 (6)	0.0045 (7)
O4	0.0327 (8)	0.0772 (13)	0.0495 (10)	0.0277 (9)	0.0160 (7)	0.0304 (9)
O5	0.0535 (10)	0.0275 (8)	0.0674 (12)	0.0080 (7)	0.0318 (9)	0.0153 (8)
S1	0.0462 (3)	0.0386 (3)	0.0251 (2)	0.0122 (2)	0.0091 (2)	0.0009 (2)
N1	0.0487 (12)	0.0324 (10)	0.0327 (9)	−0.0026 (8)	0.0136 (9)	0.0016 (8)
N2	0.0280 (8)	0.0283 (8)	0.0233 (7)	0.0084 (7)	0.0073 (6)	0.0070 (6)
C1	0.0320 (10)	0.0321 (10)	0.0249 (9)	0.0115 (8)	0.0061 (8)	0.0051 (8)
C2	0.0319 (10)	0.0348 (10)	0.0272 (9)	0.0142 (8)	0.0112 (8)	0.0129 (8)
C3	0.0464 (13)	0.0418 (12)	0.0281 (10)	0.0147 (10)	0.0141 (9)	0.0110 (9)
S3	0.0449 (3)	0.0368 (3)	0.0492 (3)	0.0078 (2)	0.0239 (3)	0.0206 (3)
N3	0.0544 (13)	0.0305 (10)	0.0398 (10)	−0.0020 (9)	0.0160 (9)	0.0077 (8)
N4	0.0296 (8)	0.0278 (8)	0.0277 (8)	0.0075 (7)	0.0085 (7)	0.0113 (7)
C4	0.0337 (10)	0.0303 (10)	0.0372 (11)	0.0102 (8)	0.0125 (9)	0.0166 (9)
C5	0.0325 (10)	0.0346 (10)	0.0286 (9)	0.0143 (9)	0.0111 (8)	0.0142 (8)
C6	0.0449 (13)	0.0404 (12)	0.0374 (11)	0.0143 (10)	0.0203 (10)	0.0175 (10)
O3W	0.0456 (9)	0.0459 (9)	0.0317 (8)	0.0146 (8)	0.0105 (7)	0.0040 (7)
O4W	0.0335 (9)	0.0572 (11)	0.0653 (12)	0.0105 (8)	0.0054 (8)	0.0205 (10)
O5W	0.0421 (9)	0.0490 (10)	0.0502 (10)	0.0192 (8)	0.0176 (8)	0.0184 (8)
O6W	0.0618 (12)	0.0553 (11)	0.0504 (10)	0.0272 (10)	0.0207 (9)	0.0243 (9)

Geometric parameters (Å, º)

V1—O1	1.5858 (16)	C2—C3	1.346 (3)
V1—O2	2.0113 (15)	C2—C5	1.444 (3)
V1—O1W	2.2319 (15)	C3—H3	0.9300
V1—O2W	2.0662 (18)	S3—C6	1.720 (3)
V1—N2	2.0990 (19)	S3—C4	1.733 (2)
V1—N4	2.1170 (18)	C4—N4	1.324 (3)
O1W—H1WA	0.8824	C4—N3	1.332 (3)
O1W—H1WB	0.8062	N3—H3A	0.8600
O2W—H2WA	0.8834	N3—H3B	0.8600
O2W—H2WB	0.9044	N4—C5	1.401 (3)
S2—O2	1.5041 (14)	C5—C6	1.344 (3)
S2—O3	1.4716 (17)	C6—H6	0.9300
S2—O4	1.4513 (17)	O3W—H3WA	0.8769
S2—O5	1.4548 (17)	O3W—H3WB	0.9259
S1—C3	1.724 (3)	O4W—H4WA	0.858
S1—C1	1.736 (2)	O4W—H4WB	0.9409
C1—N1	1.324 (3)	O5W—H5WA	0.8554
C1—N2	1.329 (3)	O5W—H5WB	0.8905
N1—H1A	0.8600	O6W—H6WA	0.931
N1—H1B	0.8600	O6W—H6WB	0.9052
N2—C2	1.400 (2)
O1—V1—O2	102.46 (8)	C1—N1—H1A	120.0
O1—V1—O2W	93.86 (8)	C1—N1—H1B	120.0
O2—V1—O2W	92.05 (7)	H1A—N1—H1B	120.0
O1—V1—N2	101.30 (8)	C1—N2—C2	110.70 (17)
O2—V1—N2	90.89 (7)	C1—N2—V1	134.48 (14)
O2W—V1—N2	163.55 (6)	C2—N2—V1	114.75 (13)
O1—V1—N4	99.21 (8)	C3—C2—N2	115.33 (19)
O2—V1—N4	157.53 (6)	C3—C2—C5	128.8 (2)
O2W—V1—N4	92.40 (7)	N2—C2—C5	115.84 (18)
N2—V1—N4	79.00 (7)	C2—C3—S1	110.50 (17)
O1—V1—O1W	172.97 (7)	C2—C3—H3	124.8
O2—V1—O1W	79.66 (6)	S1—C3—H3	124.8
O2W—V1—O1W	79.31 (6)	C6—S3—C4	90.01 (11)
N2—V1—O1W	85.31 (7)	N4—C4—N3	125.7 (2)
N4—V1—O1W	79.54 (6)	N4—C4—S3	113.51 (17)
V1—O1W—H1WA	114.33	N3—C4—S3	120.76 (16)
V1—O1W—H1WB	118.84	C4—N3—H3A	120.0
H1WA—O1W—H1WB	101.83	C4—N3—H3B	120.0
V1—O2W—H2WA	123.03	H3A—N3—H3B	120.0
V1—O2W—H2WB	113.97	C4—N4—C5	110.77 (18)
H2WA—O2W—H2WB	102.59	C4—N4—V1	135.47 (15)
O4—S2—O5	112.14 (12)	C5—N4—V1	113.74 (13)
O4—S2—O3	110.15 (11)	C6—C5—N4	115.2 (2)
O5—S2—O3	110.16 (11)	C6—C5—C2	128.2 (2)
O4—S2—O2	109.26 (9)	N4—C5—C2	116.60 (18)
O5—S2—O2	106.62 (10)	C5—C6—S3	110.54 (17)
O3—S2—O2	108.39 (10)	C5—C6—H6	124.7
S2—O2—V1	136.69 (9)	S3—C6—H6	124.7
C3—S1—C1	89.99 (11)	H3WA—O3W—H3WB	101.60
N1—C1—N2	125.38 (19)	H4WA—O4W—H4WB	107.0
N1—C1—S1	121.14 (17)	H5WA—O5W—H5WB	109.7
N2—C1—S1	113.47 (16)	H6WA—O6W—H6WB	108.7
O3—S2—O2—V1	75.40 (15)	O5—S2—O2—V1	−166.03 (14)
O4—S2—O2—V1	−44.64 (17)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O2	0.86	2.24	2.942 (3)	139
N1—H1B···O3W^i	0.86	2.03	2.854 (3)	161
N3—H3A···O2W	0.86	2.27	2.994 (3)	141
N3—H3B···O5^ii	0.86	2.12	2.928 (3)	156
O1W—H1WA···O5W	0.8824	1.8510	2.714 (2)	165.21
O1W—H1WB···O4W	0.8062	1.969	2.769 (3)	172.05
O2W—H2WA···O4W^iii	0.8834	1.900	2.773 (3)	169.25
O2W—H2WB···O3^iv	0.9044	1.7515	2.640 (2)	166.68
O3W—H3WA···O4^v	0.8769	2.1127	2.940 (3)	157.02
O3W—H3WB···O1W	0.9259	2.0221	2.916 (2)	161.77
O4W—H4WA···O5W^iii	0.858	2.049	2.887 (3)	165.10
O4W—H4WB···O3^iii	0.9409	2.0543	2.870 (3)	144.08
O5W—H5WA···O6W	0.8554	1.873	2.729 (3)	179.93
O5W—H5WB···O4^v	0.8905	1.9261	2.743 (2)	151.69
O6W—H6WA···O5	0.931	1.8957	2.808 (3)	165.90
O6W—H6WB···O3^vi	0.9052	2.0704	2.975 (3)	178.28

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