Bis[N-amino­carbonyl-N′-(3-pyridylmethyl­ene-κN)hydrazine]diaqua­bis(thio­cyanato-κN)zinc(II)

The Zn atom of the title complex, [Zn(NCS)₂(C₇H₈N₄O)₂(H₂O)₂] or [Zn(SCN)₂(H-Pysc)₂(H₂O)₂] [H-Pysc = N-amino­carbonyl-N′-(3-pyridylmethyl­ene)hydrazine], derived from the condensation of pyridine-3-carbaldehyde and semicarbazone, is located at a crystallographic centre of inversion and is octa­hedrally coordinated by two thio­cyanate anions, two aqua mol­ecules and two mol­ecules of the neutral Schiff base ligand H-Pysc. The Schiff base mol­ecules act as monodentate ligands coordinating the metal through the pyridyl N atom, whereas the amide O and imine N atoms remain uncoordinated. The crystal packing is stabilized by inter­molecular hydrogen bonds involving H-Pysc ligands, thio­cyanate anions and water mol­ecules.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.032
• wR factor = 0.107
• Data-to-parameter ratio = 13.6

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT152_ALERT_1_C Supplied and Calc Volume s.u. Inconsistent .....          ?
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal  (x 10000)        200 Deg.
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Zn1    -   N5      ..       6.64 su
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.19
PLAT420_ALERT_2_C D-H Without Acceptor       N4     -   H4A    ...          ?

Alert level G
PLAT794_ALERT_5_G Check Predicted Bond Valency for Zn1         (2)       1.80

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   5 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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S1. Comment

Metal complexes based on Schiff base ligands being synthesized by condensation of pyridine-3-carbaldehydehyde and thiosemicarbazone, semicarbazone and other amines (Mendes et al., 2001; Li et al., 2006) have attracted numerous chemists and biologists due to their antimicrobial, cytotoxic and antioxidant activities. Structurally characterized metal-organic complexes of Schiff bases derived from the condensation of pyridine- 3-carbaldehydehyde and semicarbazone have been reported during the last several years. (Chen, Zhou, Liang et al., 2004; Chen, Zhou, Li et al., 2004; Beraldo et al. 2001). As a consecutive work of our studies, we report herein the synthesis and crystal structure of the title compound, (I).

The title compound, (I) (Fig. 1), is isostructural with the manganese derivative of the same ligand (Zhong et al., 2007). The central Zn atom is situated at an crystallographic center of inversion and is hexa-coordinated by two O atoms of water molecules and four N atoms, two of which come from two thiocyanate anions and the others from H-Pysc ligands (Fig. 1), forming a slightly distorted octahedral geometry. The molecules are held together by intermolecular hydrogen bonding interactions forming a three- dimensional supramolecular network. The coordinated water molecules (O2) donate H atoms to the terminal O1 atom and thiocyanate S atoms to form O—H···Oⁱⁱ and O—H···Sⁱⁱⁱ hydrogen bonds, respectively [symmetry codes ii = -1 + x, y, -1 + z; iii = 1 + x, y, z]. The O1 atoms also accept H atom from N to form N—H···O^iv hydrogen bonds [symmetry codes iv = 3 - x, 1 - y, 2 - z] (Table 1, Fig. 2).

Related literature

For related literature, see: Beraldo et al. (2001); Chen, Zhou, Liang et al. (2004); Chen, Zhou, Li et al. (2004); Li et al. (2006); Mendes et al. (2001); Zhong et al. (2007).

S2. Experimental

1.0 mmol H-Pysc and 0.5 mmol Zn(Ac)₂ × 4H₂O were dissolved in a water-methanol mixture (1:1 v/v; 10 ml) at room temperature. After stirring for ca 1 h, 10 ml of the same mixture solvent containing 1.0 mmol of (NH₄)SCN was added, then the mixture was further stirred for another 1 h. The resulting filtrate was left to stand for slow evaporation at room temperature. Colorless single crystals of (I) suitable for X-ray structure analysis were obtained after two weeks (yield 85%).

S3. Refinement

Hydrogen atoms attached to carbon atoms and nitrogen atoms were positioned geometrically refined using a riding model, with C—H = 0.95 Å, N—H = 0.88 Å, and U_iso(H) = 1.2U_eq(C or N). Water Hydrogen atoms were located in difference maps and constrained to ride at the as-found O—H distances (0.85 Å), with U_iso(H) = 1.5U_eq(O).

Computing details

Data collection: SMART (Bruker, 2004); cell refinement: SMART (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXTL (Sheldrick, 1997b).

Figures

	Fig. 1. The structure of (I), showing 50% probability displacement ellipsoids and the atom-labeling scheme. [symmetry code: (i) 1 - x, 1 - y, 1 - z.]
	Fig. 2. Three-dimensional supramolecular network constructed by hydrogen bonding interactions (dashed lines).

Bis[N-aminocarbonyl-N'-(3-pyridylmethylene-κN)hydrazine]diaquabis(thiocyanato- κN)zinc(II)

Crystal data

[Zn(NCS)2(C7H8N4O)2(H2O)2]	V = 559.4 (2) Å^3
Mr = 545.91	Z = 1
Triclinic, P1	F(000) = 280
Hall symbol: -P 1	Dx = 1.621 Mg m^−3
a = 6.661 (1) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.251 (2) Å	θ = 2.2–26.0°
c = 10.328 (2) Å	µ = 1.33 mm^−1
α = 65.765 (2)°	T = 173 K
β = 82.438 (2)°	Block, white
γ = 74.637 (2)°	0.36 × 0.30 × 0.22 mm

Data collection

Bruker SMART CCD area-detector diffractometer	2169 independent reflections
Radiation source: fine-focus sealed tube	2028 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.073
φ and ω scans	θmax = 26.0°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −8→8
Tmin = 0.626, Tmax = 0.742	k = −11→11
4371 measured reflections	l = −10→12

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) = 0.107	H atoms treated by a mixture of independent and constrained refinement
S = 1.01	w = 1/[σ^2(Fo^2) + (0.0572P)^2 + 0.0984P] where P = (Fo^2 + 2Fc^2)/3
2169 reflections	(Δ/σ)max < 0.001
159 parameters	Δρmax = 0.74 e Å^−3
0 restraints	Δρmin = −0.58 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
Zn1	0.5000	0.5000	0.5000	0.01975 (16)
C1	0.9145 (3)	0.3158 (3)	0.8704 (2)	0.0194 (4)
C2	0.8475 (3)	0.1800 (3)	0.9697 (2)	0.0230 (5)
H2	0.9054	0.1234	1.0614	0.028*
C3	0.6960 (4)	0.1300 (3)	0.9317 (2)	0.0280 (5)
H3	0.6530	0.0346	0.9956	0.034*
C4	0.6054 (4)	0.2192 (3)	0.7997 (2)	0.0248 (5)
H4	0.4991	0.1837	0.7761	0.030*
C5	0.8161 (3)	0.3982 (3)	0.7395 (2)	0.0215 (4)
H5	0.8609	0.4910	0.6719	0.026*
C6	1.0788 (4)	0.3762 (3)	0.8988 (2)	0.0232 (5)
H6	1.1187	0.4698	0.8285	0.028*
C7	1.4282 (4)	0.2913 (3)	1.1602 (2)	0.0231 (5)
N1	0.6620 (3)	0.3537 (2)	0.70405 (18)	0.0191 (4)
N2	1.1687 (3)	0.3027 (2)	1.01843 (19)	0.0222 (4)
N3	1.3182 (3)	0.3681 (2)	1.03825 (19)	0.0245 (4)
H3A	1.3433	0.4593	0.9726	0.029*
N4	1.3754 (4)	0.1569 (3)	1.2579 (2)	0.0365 (5)
H4A	1.4414	0.1037	1.3386	0.044*
H4B	1.2748	0.1218	1.2414	0.044*
O1	1.5688 (3)	0.3483 (2)	1.17600 (17)	0.0269 (4)
O2	0.7266 (3)	0.3584 (2)	0.40154 (18)	0.0262 (4)
H2A	0.672 (5)	0.331 (4)	0.355 (3)	0.038 (8)*
H2B	0.819 (5)	0.276 (4)	0.455 (3)	0.034 (8)*
N5	0.3130 (3)	0.3310 (3)	0.5528 (2)	0.0286 (4)
C8	0.2314 (3)	0.2262 (3)	0.5733 (2)	0.0217 (5)
S1	0.11985 (9)	0.07746 (7)	0.60024 (7)	0.02934 (19)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.0215 (2)	0.0237 (2)	0.0187 (2)	−0.00941 (15)	−0.00541 (14)	−0.00894 (17)
C1	0.0178 (10)	0.0241 (11)	0.0205 (10)	−0.0042 (8)	−0.0029 (8)	−0.0126 (9)
C2	0.0232 (11)	0.0272 (11)	0.0198 (10)	−0.0048 (9)	−0.0049 (8)	−0.0098 (9)
C3	0.0296 (12)	0.0293 (12)	0.0245 (11)	−0.0137 (9)	−0.0049 (9)	−0.0046 (9)
C4	0.0254 (11)	0.0275 (12)	0.0258 (11)	−0.0105 (9)	−0.0050 (9)	−0.0108 (10)
C5	0.0238 (11)	0.0234 (11)	0.0200 (10)	−0.0076 (8)	−0.0038 (8)	−0.0090 (9)
C6	0.0255 (11)	0.0254 (11)	0.0217 (10)	−0.0084 (9)	−0.0061 (9)	−0.0090 (9)
C7	0.0261 (11)	0.0275 (11)	0.0195 (10)	−0.0021 (9)	−0.0064 (9)	−0.0137 (9)
N1	0.0178 (8)	0.0243 (9)	0.0194 (8)	−0.0053 (7)	−0.0031 (7)	−0.0117 (7)
N2	0.0219 (9)	0.0266 (9)	0.0237 (9)	−0.0060 (7)	−0.0063 (7)	−0.0136 (8)
N3	0.0262 (10)	0.0268 (10)	0.0243 (9)	−0.0087 (8)	−0.0106 (8)	−0.0095 (8)
N4	0.0436 (13)	0.0440 (13)	0.0234 (10)	−0.0202 (10)	−0.0125 (9)	−0.0051 (9)
O1	0.0285 (9)	0.0323 (9)	0.0265 (8)	−0.0067 (7)	−0.0114 (7)	−0.0152 (7)
O2	0.0291 (9)	0.0309 (9)	0.0235 (8)	−0.0049 (7)	−0.0093 (7)	−0.0144 (7)
N5	0.0314 (11)	0.0318 (10)	0.0262 (10)	−0.0125 (8)	−0.0105 (8)	−0.0087 (8)
C8	0.0229 (11)	0.0254 (11)	0.0179 (10)	−0.0060 (9)	−0.0079 (8)	−0.0073 (8)
S1	0.0290 (3)	0.0257 (3)	0.0373 (4)	−0.0123 (3)	−0.0048 (3)	−0.0115 (3)

Geometric parameters (Å, º)

Zn1—N5	2.109 (2)	C5—N1	1.343 (3)
Zn1—N5^i	2.109 (2)	C5—H5	0.9500
Zn1—O2^i	2.1611 (16)	C6—N2	1.280 (3)
Zn1—O2	2.1611 (16)	C6—H6	0.9500
Zn1—N1	2.2182 (18)	C7—O1	1.247 (3)
Zn1—N1^i	2.2182 (18)	C7—N4	1.340 (3)
C1—C2	1.396 (3)	C7—N3	1.364 (3)
C1—C5	1.400 (3)	N2—N3	1.369 (3)
C1—C6	1.463 (3)	N3—H3A	0.8800
C2—C3	1.373 (3)	N4—H4A	0.8800
C2—H2	0.9500	N4—H4B	0.8800
C3—C4	1.391 (3)	O2—H2A	0.79 (4)
C3—H3	0.9500	O2—H2B	0.87 (3)
C4—N1	1.344 (3)	N5—C8	1.167 (3)
C4—H4	0.9500	C8—S1	1.641 (2)
N5—Zn1—N5^i	180.0	C3—C4—H4	118.7
N5—Zn1—O2^i	90.68 (8)	N1—C5—C1	123.8 (2)
N5^i—Zn1—O2^i	89.32 (8)	N1—C5—H5	118.1
N5—Zn1—O2	89.32 (8)	C1—C5—H5	118.1
N5^i—Zn1—O2	90.68 (8)	N2—C6—C1	119.9 (2)
O2^i—Zn1—O2	180.000 (1)	N2—C6—H6	120.1
N5—Zn1—N1	90.02 (7)	C1—C6—H6	120.1
N5^i—Zn1—N1	89.98 (7)	O1—C7—N4	123.7 (2)
O2^i—Zn1—N1	90.58 (6)	O1—C7—N3	119.6 (2)
O2—Zn1—N1	89.42 (6)	N4—C7—N3	116.8 (2)
N5—Zn1—N1^i	89.98 (7)	C5—N1—C4	117.08 (18)
N5^i—Zn1—N1^i	90.02 (7)	C5—N1—Zn1	121.60 (14)
O2^i—Zn1—N1^i	89.42 (6)	C4—N1—Zn1	121.28 (15)
O2—Zn1—N1^i	90.58 (6)	C6—N2—N3	116.5 (2)
N1—Zn1—N1^i	180.0	C7—N3—N2	119.70 (19)
C2—C1—C5	117.9 (2)	C7—N3—H3A	120.1
C2—C1—C6	122.8 (2)	N2—N3—H3A	120.1
C5—C1—C6	119.3 (2)	C7—N4—H4A	120.0
C3—C2—C1	118.5 (2)	C7—N4—H4B	120.0
C3—C2—H2	120.8	H4A—N4—H4B	120.0
C1—C2—H2	120.8	Zn1—O2—H2A	111 (2)
C2—C3—C4	120.0 (2)	Zn1—O2—H2B	118.7 (19)
C2—C3—H3	120.0	H2A—O2—H2B	110 (3)
C4—C3—H3	120.0	C8—N5—Zn1	170.6 (2)
N1—C4—C3	122.7 (2)	N5—C8—S1	178.9 (2)
N1—C4—H4	118.7

Symmetry code: (i) −x+1, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2A···O1^ii	0.79 (3)	1.99 (3)	2.723 (3)	155 (3)
O2—H2B···S1^iii	0.87 (3)	2.49 (3)	3.355 (2)	170 (3)
N3—H3A···O1^iv	0.88	1.98	2.862 (3)	174

Symmetry codes: (ii) x−1, y, z−1; (iii) x+1, y, z; (iv) −x+3, −y+1, −z+2.