(2,2′-Di­amino-4,4′-bi-1,3-thia­zole-κ²N³,N^3′)(oxy­diacetato-κ³O,O′,O′′)­copper(II) monohydrate

The title compound, [Cu(C₄H₄O₅)(C₆H₆N₄S₂)]·H₂O, displays a square-pyramidal coordination geometry. The tridentate oxy­di­acetate dianion chelates the Cu^II atom in the facial mode. The large difference [0.487 (4) Å] between the longest Cu—O distance in the basal plane and that in the apical direction correlates with the small displacement of the Cu^II atom [0.0576 (13) Å] from the basal plane towards the apex of the square pyramid. The intermolecular hydrogen-bonding network results in a closely overlapped arrangement of the coordination basal plane and the thia­zole ring of a neighboring mol­ecule.

S1. Comment

Transition metal complexes with 2,2'-diamino-4,4'-bithiazole (DABT) or its derivatives have shown interesting properties and potential applications in many fields (Waring, 1981; Fisher et al., 1985). A series of metal complexes with DABT has been prepared in our laboratory (Liu et al., 2001). As part of this investigation, the Cu^II complex with DABT and oxydiacetate (ODA) has recently been prepared, and its X-ray structure is presented here.

The molecular structure of (I) is illustrated in Fig. 1. Two N atoms of a DABT molecule and two O atoms from the carboxyl groups of an ODA ligand form a basal coordination plane, with the maximum deviation being 0.0017 (12) Å for atom N3, while atom O5 of the ODA ligand occupies on the apical position to complete the square-pyramidal coordination geometry around the Cu^II atom. The Cu—O distance of 2.442 (3) Å in the apical direction is longer than those in the basal plane by 0.512 (4) and 0.487 (4) Å. The larger difference in Cu—O distances correlates with the small displacement of the Cu^II atom [0.0576 (13) Å] from the basal plane towards the apex. This configuration is similar to the situation found in Cu^II complexes with a square-pyramidal geometry. For example, the larger difference of 0.478 (6) Å in Cu—O distances correlated with the smaller Cu^II displacement of 0.0919 (9) Å in an acetato(aqua)copper(II) complex (Christou et al., 1990), whereas the smaller difference of 0.314 (7) Å in Cu—O distances correlated with the larger Cu^II displacement of 0.1963 (8) Å in an aqua(isonicotinato)copper(II) complex (Xu et al., 1998).

The tridentate ODA ligand chelates to the Cu^II atom in the facial coordination mode, and two O atoms from the carboxyl groups of an ODA ligand coordinate to the Cu^II atom in a cis configuration. A search of the Cambridge Structure Database (Allen, 2002) indicated that the facial mode is a rare configuration for ODA in transition metal complexes. Only one Cu^II complex, namely aqua-(2,2'-bipyridyl)-(oxydiacetato)-copper(II), has been found previously to exhibit the facial mode (Bonomo et al., 1981). The Cu—O5 bond distance of 2.442 (3) Å in the title complex is almost identical to the equivalent bond length of 2.458 (4) Å found in this referenced Cu^II complex. Both the Cu—O5—C12 [102.47 (19)°] and the Cu—O5—C14 angles [100.32 (19)°] in the title complex are much smaller than that found in transition metal complexes with ODA in a usual meridional mode (120 °; Bresciani-Pahor et al., 1983; Hatfield et al., 1987; Powell et al., 1992).

Water atom O6 forms a hydrogen bond to the uncoordinated carboxyl atom O2 but does not coordinate to the Cu^II atom as a sixth donor (Fig. 1). In the expected sixth coordination site, there is a thiazole ring from the adjacent complex molecule (see Fig. 2). This thiazole ring is nearly parallel to the coordination basal plane of the Cu atom [dihedral angle 7.39 (10) °] and the perpendicular out-of-plane distance for the Cu atom is 3.474 (6) Å. A similar observation was made for the tyrosinato-copper(II) complex and was interpreted as a weak interaction between the π-electron system of the aromatic ring and the neighboring Cu^II atom (Van der Helm & Tatsch, 1972). However, in the title complex, the shortest separation of 3.383 (4) Å (Cu···C5'ⁱ) between the Cu atom and the thiazole ring is slightly larger than the sum of the van der Waals radii of the Cu and C atoms (Rodgers, 1994). Therefore, it can be assumed that the normal van der Waals contact occurs between the Cu atom and the neighboring thiazole ring.

The DABT molecule chelates the Cu^II atom in a cis configuration. The thiazole rings form a dihedral angle of 6.52 (9)°, while an angle of 8.44 (8)° is found in a DABT complex of Cd^II (Liu et al., 2003) and 7.91 (9)° is found in a DABT complex of Ni^II (Baker & Goodwin, 1985).

An intermolecular hydrogen-bonding network occurs in the crystal structure, as shown in Fig. 2 and Table 2. Lattice water molecules bridge complex molecules via hydrogen bonds, and the complex molecules also link directly to one another via hydrogen bonds between the carboxyl and amine groups of adjacent molecules. Weak C—H···O hydrogen bonding occurs between a carboxyl group and the thiazole ring. This extensive hydrogen bonding results in a closely overlapped arrangement of the coordination basal plane and thiazole ring of the neighboring molecule.

S2. Experimental

An aqueous solution (20 ml) containing CuCl₂·2H₂O (0.086 g, 0.5 mmol), oxydiacetic acid hydrate (0.076 g, 0.5 mmol) and NaOH (0.04 g, 1 mmol) was refluxed for 5 h. Heating of the reaction mixture was stopped, and DABT (0.10 g, 0.5 mmol) was added to the solution. The DABT dissolved quickly in the hot solution, and the product precipitated shortly afterwards. The hot solution was filtered immediately, and then the filtrate was cooled to room temperature and filtered again. The final filtrate was kept at room temperature, and green crystals of suitable size were obtained after 5 d.

S3. Refinement

H atoms attached to C atoms were placed in calculated positions, with C—H distances of 0.97 or 0.93 Å, and were included in the final cycles of refinement in riding mode with U_iso(H) values equal to 1.2U_eq of the carrier atoms. Other H atoms were located in a difference Fourier map and included in the structure-factor calculations with fixed positional and isotropic displacement parameters [U_iso(H) = 0.06 Ų].

Computing details

Data collection: MSC/AFC diffractometer control (Molecular Structure Corporation, 1992); cell refinement: MSC/AFC diffractometer control; data reduction: TEXSAN (Molecular Structure Corporation, 1992); 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), XP (Siemens, 1994); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. The molecular structure of (I), with displacement ellipsoids shown at the 50% probability level. Dashed lines indicate the intramolecular hydrogen bonding.
	Fig. 2. The hydrogen-bonding network and the thiazole ring located beneath the basal plane of the Cu atom. [Symmetry code: (i)1 − x,1 − y,1 − z.]

(I)

Crystal data

[Cu(C4H4O5)(C6H6N4S2)]·H2O	Z = 2
Mr = 411.93	F(000) = 418
Triclinic, P1	Dx = 1.820 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 9.688 (4) Å	Cell parameters from 25 reflections
b = 9.720 (4) Å	θ = 5.1–12.8°
c = 9.831 (4) Å	µ = 1.77 mm^−1
α = 68.64 (3)°	T = 298 K
β = 62.33 (3)°	Prism, green
γ = 71.74 (3)°	0.20 × 0.18 × 0.16 mm
V = 751.8 (6) Å^3

Data collection

Rigaku AFC-7S diffractometer	Rint = 0.014
ω/2θ scans	θmax = 26.0°, θmin = 2.3°
Absorption correction: psi scan (North et al., 1968)	h = −11→11
Tmin = 0.702, Tmax = 0.761	k = −11→0
3116 measured reflections	l = −12→11
2932 independent reflections	3 standard reflections every 150 reflections
2166 reflections with I > 2σ(I)	intensity decay: 0.3%

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)] = 0.032	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.093	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0397P)^2 + 0.1631P] where P = (Fo^2 + 2Fc^2)/3
2932 reflections	(Δ/σ)max < 0.001
208 parameters	Δρmax = 0.55 e Å^−3
0 restraints	Δρmin = −0.43 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
Cu	0.30135 (5)	0.33907 (4)	0.58615 (4)	0.02803 (13)
S1	0.19100 (12)	0.46545 (11)	1.03376 (10)	0.0443 (2)
S1'	0.34944 (11)	0.82311 (9)	0.29968 (10)	0.0391 (2)
O1	0.3450 (3)	0.2827 (3)	0.3965 (3)	0.0363 (5)
O2	0.2720 (3)	0.1715 (3)	0.2866 (3)	0.0456 (6)
O3	0.2925 (3)	0.1323 (2)	0.7062 (3)	0.0353 (5)
O4	0.1581 (3)	−0.0541 (3)	0.8472 (3)	0.0543 (7)
O5	0.0407 (3)	0.3108 (3)	0.6308 (3)	0.0376 (5)
O6	0.5872 (3)	0.1679 (4)	0.0592 (3)	0.0573 (7)
N2	0.2469 (4)	0.1919 (3)	0.9934 (3)	0.0421 (7)
N2'	0.3838 (4)	0.5852 (3)	0.2032 (3)	0.0423 (7)
N3'	0.3217 (3)	0.5529 (3)	0.4736 (3)	0.0294 (6)
N3	0.2706 (3)	0.4035 (3)	0.7717 (3)	0.0305 (6)
C2	0.2412 (4)	0.3380 (4)	0.9243 (4)	0.0316 (7)
C2'	0.3529 (4)	0.6350 (4)	0.3241 (4)	0.0308 (7)
C4	0.2578 (4)	0.5584 (4)	0.7390 (4)	0.0331 (7)
C4'	0.2951 (4)	0.6400 (4)	0.5716 (4)	0.0313 (7)
C5	0.2141 (5)	0.6104 (4)	0.8638 (4)	0.0449 (9)
H5	0.1983	0.7110	0.8597	0.054*
C5'	0.3072 (4)	0.7840 (4)	0.4998 (4)	0.0406 (8)
H5'	0.2945	0.8540	0.5505	0.049*
C11	0.2417 (4)	0.2388 (4)	0.3848 (4)	0.0321 (7)
C12	0.0697 (4)	0.2828 (5)	0.4874 (4)	0.0478 (9)
H12A	0.0248	0.3724	0.4254	0.057*
H12B	0.0140	0.2034	0.5134	0.057*
C13	0.1665 (4)	0.0766 (4)	0.7715 (4)	0.0334 (7)
C14	0.0163 (4)	0.1818 (4)	0.7628 (4)	0.0464 (9)
H14A	−0.0484	0.1266	0.7580	0.056*
H14B	−0.0425	0.2146	0.8599	0.056*
H2A	0.2931	0.1174	0.9310	0.060*
H2B	0.2328	0.1634	1.0985	0.060*
H2C	0.3843	0.4821	0.2254	0.060*
H2D	0.4000	0.6547	0.0961	0.060*
H6A	0.6576	0.1386	0.1136	0.060*
H6B	0.4836	0.1690	0.1464	0.060*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu	0.0318 (2)	0.0271 (2)	0.0289 (2)	−0.00779 (15)	−0.01368 (16)	−0.00685 (15)
S1	0.0621 (6)	0.0422 (5)	0.0338 (4)	−0.0089 (4)	−0.0195 (4)	−0.0148 (4)
S1'	0.0434 (5)	0.0298 (4)	0.0422 (5)	−0.0116 (4)	−0.0195 (4)	0.0005 (4)
O1	0.0377 (13)	0.0439 (14)	0.0333 (12)	−0.0126 (11)	−0.0107 (10)	−0.0165 (10)
O2	0.0572 (16)	0.0526 (15)	0.0392 (13)	−0.0134 (13)	−0.0208 (12)	−0.0197 (12)
O3	0.0382 (13)	0.0287 (11)	0.0436 (13)	−0.0070 (10)	−0.0222 (11)	−0.0054 (10)
O4	0.0588 (17)	0.0302 (13)	0.0687 (18)	−0.0139 (12)	−0.0262 (15)	−0.0007 (13)
O5	0.0363 (13)	0.0372 (13)	0.0330 (12)	−0.0016 (10)	−0.0129 (10)	−0.0074 (10)
O6	0.0498 (16)	0.0740 (19)	0.0373 (13)	−0.0172 (15)	−0.0180 (12)	0.0035 (13)
N2	0.066 (2)	0.0355 (16)	0.0314 (14)	−0.0165 (14)	−0.0253 (14)	−0.0013 (12)
N2'	0.0524 (18)	0.0432 (17)	0.0319 (14)	−0.0162 (14)	−0.0165 (14)	−0.0043 (13)
N3'	0.0309 (14)	0.0282 (13)	0.0318 (13)	−0.0062 (11)	−0.0152 (11)	−0.0060 (11)
N3	0.0364 (15)	0.0293 (13)	0.0295 (13)	−0.0076 (11)	−0.0158 (11)	−0.0065 (11)
C2	0.0325 (16)	0.0376 (18)	0.0311 (16)	−0.0073 (14)	−0.0151 (13)	−0.0113 (14)
C2'	0.0241 (15)	0.0325 (16)	0.0344 (16)	−0.0081 (13)	−0.0120 (13)	−0.0040 (13)
C4	0.0372 (17)	0.0300 (16)	0.0367 (17)	−0.0080 (14)	−0.0176 (14)	−0.0079 (13)
C4'	0.0330 (16)	0.0294 (16)	0.0367 (17)	−0.0047 (13)	−0.0167 (14)	−0.0110 (13)
C5	0.063 (2)	0.0338 (18)	0.043 (2)	−0.0089 (17)	−0.0212 (18)	−0.0141 (16)
C5'	0.048 (2)	0.0316 (18)	0.047 (2)	−0.0092 (15)	−0.0229 (17)	−0.0073 (15)
C11	0.0402 (18)	0.0305 (16)	0.0269 (15)	−0.0082 (14)	−0.0176 (14)	−0.0014 (13)
C12	0.039 (2)	0.069 (3)	0.042 (2)	−0.0092 (19)	−0.0206 (17)	−0.0155 (19)
C13	0.0433 (19)	0.0310 (17)	0.0288 (16)	−0.0090 (14)	−0.0152 (14)	−0.0076 (13)
C14	0.0381 (19)	0.047 (2)	0.042 (2)	−0.0105 (17)	−0.0144 (16)	0.0016 (17)

Geometric parameters (Å, º)

Cu—O3	1.930 (2)	N2—H2B	0.921
Cu—O1	1.955 (2)	N2'—C2'	1.317 (4)
Cu—O5	2.442 (3)	N2'—H2C	0.944
Cu—N3'	1.990 (3)	N2'—H2D	0.992
Cu—N3	2.005 (3)	N3'—C2'	1.331 (4)
S1—C5	1.721 (4)	N3'—C4'	1.393 (4)
S1—C2	1.743 (3)	N3—C2	1.326 (4)
S1'—C5'	1.728 (4)	N3—C4	1.397 (4)
S1'—C2'	1.746 (3)	C4—C5	1.333 (5)
O1—C11	1.268 (4)	C4—C4'	1.465 (5)
O2—C11	1.234 (4)	C4'—C5'	1.333 (5)
O3—C13	1.276 (4)	C5—H5	0.930
O4—C13	1.222 (4)	C5'—H5'	0.930
O5—C12	1.416 (4)	C11—C12	1.512 (5)
O5—C14	1.424 (4)	C12—H12A	0.970
O6—H6A	0.969	C12—H12B	0.970
O6—H6B	0.971	C13—C14	1.513 (5)
N2—C2	1.328 (4)	C14—H14A	0.970
N2—H2A	0.983	C14—H14B	0.970
O3—Cu—O1	89.27 (10)	N2'—C2'—N3'	125.7 (3)
O3—Cu—N3'	174.53 (10)	N2'—C2'—S1'	121.3 (2)
O1—Cu—N3'	94.86 (11)	N3'—C2'—S1'	113.0 (2)
O3—Cu—N3	93.14 (11)	C5—C4—N3	115.7 (3)
O1—Cu—N3	175.90 (10)	C5—C4—C4'	129.4 (3)
N3'—Cu—N3	82.53 (11)	N3—C4—C4'	115.0 (3)
O5—Cu—O1	77.50 (9)	C5'—C4'—N3'	115.6 (3)
O5—Cu—O3	77.19 (9)	C5'—C4'—C4	129.9 (3)
O5—Cu—N3	106.27 (10)	N3'—C4'—C4	114.5 (3)
O5—Cu—N3'	107.18 (10)	C4—C5—S1	110.6 (3)
C5—S1—C2	89.99 (17)	C4—C5—H5	124.7
C5'—S1'—C2'	89.51 (16)	S1—C5—H5	124.7
C11—O1—Cu	121.6 (2)	C4'—C5'—S1'	110.9 (3)
C13—O3—Cu	122.9 (2)	C4'—C5'—H5'	124.6
Cu—O5—C12	102.47 (19)	S1'—C5'—H5'	124.6
Cu—O5—C14	100.32 (19)	O2—C11—O1	123.9 (3)
C12—O5—C14	113.6 (3)	O2—C11—C12	117.7 (3)
H6A—O6—H6B	102.4	O1—C11—C12	118.1 (3)
C2—N2—H2A	121.8	O5—C12—C11	115.6 (3)
C2—N2—H2B	115.4	O5—C12—H12A	108.4
H2A—N2—H2B	120.5	C11—C12—H12A	108.4
C2'—N2'—H2C	116.6	O5—C12—H12B	108.4
C2'—N2'—H2D	120.9	C11—C12—H12B	108.4
H2C—N2'—H2D	122.4	H12A—C12—H12B	107.5
C2'—N3'—C4'	111.0 (3)	O4—C13—O3	124.1 (3)
C2'—N3'—Cu	134.8 (2)	O4—C13—C14	118.2 (3)
C4'—N3'—Cu	114.2 (2)	O3—C13—C14	117.6 (3)
C2—N3—C4	110.9 (3)	O5—C14—C13	114.7 (3)
C2—N3—Cu	135.5 (2)	O5—C14—H14A	108.6
C4—N3—Cu	113.0 (2)	C13—C14—H14A	108.6
N3—C2—N2	126.1 (3)	O5—C14—H14B	108.6
N3—C2—S1	112.8 (2)	C13—C14—H14B	108.6
N2—C2—S1	121.1 (2)	H14A—C14—H14B	107.6
O3—Cu—O1—C11	67.7 (3)	Cu—N3—C4—C4'	−9.7 (3)
N3'—Cu—O1—C11	−115.9 (2)	C2'—N3'—C4'—C5'	−0.7 (4)
O1—Cu—O3—C13	−86.5 (2)	Cu—N3'—C4'—C5'	−179.7 (2)
N3—Cu—O3—C13	96.8 (2)	C2'—N3'—C4'—C4	179.3 (3)
O1—Cu—N3'—C2'	0.2 (3)	Cu—N3'—C4'—C4	0.2 (3)
N3—Cu—N3'—C2'	177.0 (3)	C5—C4—C4'—C5'	6.0 (6)
N3—Cu—N3'—C4'	−4.3 (2)	N3—C4—C4'—C5'	−173.8 (3)
O3—Cu—N3—C2	−5.2 (3)	C5—C4—C4'—N3'	−173.9 (3)
N3'—Cu—N3—C2	178.2 (3)	N3—C4—C4'—N3'	6.3 (4)
O3—Cu—N3—C4	−175.7 (2)	N3—C4—C5—S1	1.8 (4)
N3'—Cu—N3—C4	7.7 (2)	C4'—C4—C5—S1	−178.0 (3)
C4—N3—C2—N2	−178.4 (3)	C2—S1—C5—C4	−0.6 (3)
Cu—N3—C2—N2	11.0 (5)	N3'—C4'—C5'—S1'	1.4 (4)
C4—N3—C2—S1	1.9 (3)	C4—C4'—C5'—S1'	−178.6 (3)
Cu—N3—C2—S1	−168.80 (18)	C2'—S1'—C5'—C4'	−1.3 (3)
C5—S1—C2—N3	−0.8 (3)	Cu—O1—C11—O2	−163.3 (2)
C5—S1—C2—N2	179.5 (3)	Cu—O1—C11—C12	22.1 (4)
C4'—N3'—C2'—N2'	179.7 (3)	C14—O5—C12—C11	−91.4 (4)
Cu—N3'—C2'—N2'	−1.6 (5)	O2—C11—C12—O5	158.9 (3)
C4'—N3'—C2'—S1'	−0.3 (3)	O1—C11—C12—O5	−26.2 (5)
Cu—N3'—C2'—S1'	178.39 (17)	Cu—O3—C13—O4	179.5 (3)
C5'—S1'—C2'—N2'	−179.1 (3)	Cu—O3—C13—C14	−4.4 (4)
C5'—S1'—C2'—N3'	0.9 (3)	C12—O5—C14—C13	80.8 (4)
C2—N3—C4—C5	−2.4 (4)	O4—C13—C14—O5	−157.7 (3)
Cu—N3—C4—C5	170.5 (3)	O3—C13—C14—O5	26.0 (5)
C2—N3—C4—C4'	177.4 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2A···O3	0.98	2.16	2.894 (4)	130
N2—H2B···O2^i	0.92	2.09	2.935 (4)	153
N2′—H2C···O1	0.94	2.06	2.891 (4)	147
N2′—H2D···O6^ii	0.99	1.83	2.781 (4)	159
O6—H6A···O4^iii	0.97	1.87	2.796 (5)	159
O6—H6B···O2	0.97	1.86	2.824 (4)	170
C5—H5···O4^iv	0.93	2.16	3.088 (5)	179

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