Tris(ethyl­ene­diamine)­nickel(II) bis­[2-cyano-2-(oxidoimino)­acetamidato]­nickelate(II) monohydrate

The title compound, [Ni(C₂H₈N₂)₃][Ni(C₃HN₃O₂)₂]·H₂O, appears to be a modular associate consisting of two complex counter-ions, containing bivalent nickel as the central atom in both cases, and a solvent water mol­ecule. The Ni^II ion in the complex cation lies on the C₂ crystallographic axis. Its coordination environment is formed by six N atoms of three ethyl­ene­diamine (en) mol­ecules, representing a distorted octa­hedral geometry. The Ni^II ion in the complex anion occupies a position at the center of inversion. It exhibits a distorted square-planar coordination geometry formed by four N atoms belonging to the deprotonated oxidoimine and amide groups of the two doubly charged 2-cyano-2-(oxidoimino)acetamidate anions, situated in trans positions with respect to each other. In the crystal packing, the complex anions are linked by water mol­ecules via hydrogen bonds between the amide O atoms and water H atoms, forming chains translated along the a direction. The [Ni(en)₃]²⁺ cations fill empty spaces between the translational chains, connecting them by hydrogen bonds between the oxime and amide O atoms of the anions and the amine H atoms of the cations, forming layers along the ac plane. The water mol­ecules provide connection between layers through N atoms of the cations, thus forming a three-dimensional modular structure.

S1. Comment

Mononuclear complexes of transition metals containing additional vacant donor sets are of current interest as convenient blocks for the building of polynuclear systems widely used in bioinorganic modeling, electron transfer and molecular magnetism (Kahn, 1993 or ?? 1994). Polydentate ligands containing the oxime groups attract particular attention owing to the possibility that these groups may provide a bridging mode of coordination and mediate very strong magnetic exchange interaction between metal ions (Colacio et al., 1994, and references therein). 2-Cyano-2-(oxidoimino)acetamide is an efficient chelating ligand for Cu^II and Ni^II ions (Sliva, Duda et al., 1997). It exhibits either N,O-chelation [via the oxime N atom and amide O atom forming a five-membered chelate ring (Skopenko et al., 1983; Gerasimchuk et al., 1993)] or N,N-chelation [via the oxime and amide N atoms (Sliva, Duda et al., 1997; Mokhir et al., 1998)] forming mononuclear complexes. Bridging coordination modes have been reported by Skopenko et al. (1997) (the 2-carbamoyl-cyanoketoximato-O,O'-bridging mode) and Price et al. (2003) (the carbamoyl-µ₂-cyanketoximato-N,O-bridging mode]. In the case of spatial difficulties the monodentate coordination mode via the oxime O atom (Domasevitch et al., 1995) and the amide O atom (Domasevitch et al., 1998) is realised. To the best of our knowledge, no structural characterization of modular complexes of the corresponding ligand has been reported to date. We present here the synthesis and X-ray crystal structure of the title modular associate, (I), containing Ni^II ions in both coordination spheres.

An ORTEP-3 (Farrugia, 1997) view of (1) and packing diagrams are shown in Figs. 1–3, and geometric parameters are given in Tables 1 and 2. The title compound consists of two discrete modules, each containing an Ni atom in a different coordination environment.

In the complex cation, the Ni^II ion lies on the C₂ crystallography axis. The coordination environment is formed by six N atoms of three ethylenediamine molecules, providing a distorted octahedral geometry. The axial Ni—N distances [Ni1—N5 = 2.113 (2) Å] are a little shorter than those in the equatorial plane [2.125 (2) Å for Ni1—N6 and 2.124 (2) Å for Ni1—N4]. The values of bond angles around the central atom slightly deviate from ideal octahedral geometry.

The structure of the anion is analogous to those reported by Sliva, Duda et al. (1997) and Mokhir et al. (1998). It consists of the central atom and two doubly deprotonated residues of 2-cyano-2-(oxidoimino)acetamide coordinated via four N atoms belonging to the deprotonated oxidoimino and oxime groups to provide a slightly distorted square-planar geometry. The ligands are situated in trans-position with respect to each other, while in the case of the related ligand containing the same coordination set [2-(hydroximino)propanamide (Sliva, Kowalik-Jankowska et al., 1997)] the two molecules of the ligand are situated in cis-position due to the intramolecular hydrogen bond between the two oxime O atoms. This bond is not observed in the case of 2-cyano-2-(oxidoimino)acetamide owing to the increased acidity of the oxidoimino group (Sliva, Duda et al., 1997). The coordination bond lengths Ni—N_oxime and Ni—N_amide are 1.881 (2) Å and 1.858 (2) Å, respectively. The fact that the angles around the central atom are slightly distorted from an ideal square-planar configuration [N2—Ni2—N1ⁱⁱ = 96.58 (9)° and N2ⁱⁱ—Ni2—N1ⁱⁱ = 83.42 (9)°] can be explained by the formation of the five-membered chelate rings, which in fact have ill-defined envelope conformation [the deviation of atom Ni2 from the plane defined by the four N atoms is -0.088 (4) Å].

The N1—O1 and N1—C2 distances are 1.286 (3) and 1.329 (3) Å, respectively, close to those reported for the N-coordinated deprotonated oxime group (Fritsky et al., 1993). This indicates the existance of the CNO– grouping in the nitroso form (Domasevitch et al., 1995)

It is woth noting the different function of the solvent water molecules in the early reported structure of tetramethylammonium bis(2-oximinocyanacetamidato)nickelate(II) (Sliva, Duda et al., 1997) and in (I). In the former case, the water molecules bind the anion through oxime atom O1 and the amide H atom, forming a closed pseudo-macrocyclic system, while in (I) the water molecule is linked to the anion only via amide atom O2, forming translational chains. In both cases, the water molecules provide intermolecular hydrogen-bonding interaction between anions.

In the crystal packing, the anion molecules are connected by the water molecules via an O1W—H14···O2 hydrogen bond forming zigzag-like chains translated along the x direction (Table 2). The [Ni(en)₃]²⁺ cations occupy empty spaces between the chains and interact with them via N—H···O hydrogen bonds through the oxime O1 atom and also the amide O2 atom (Table 2) to form cationic and anionic layers spread along the xz plane (Fig. 2). Interaction between layers is realised only via N—H···O1W hydrogen bonds (Table 2), forming a three-dimensional modular structure (Fig. 3).

S2. Experimental

The initial complex [N(CH₃)₄]₂[Ni(C₃HN₃O₂)₂]·2H₂O (0.928 g, 0.2 mmol), prepared according to the method described by Sliva et al. (1997) [which ref?], was dissolved in water, and then Ni(NO₃)₂·H₂O (0.058 g, 0.2 mmol) and ethylenediamine (0.040 ml, 0.036 g, 0.6 mmol) in ethanol solution were added. Red crystals obtained after evaporation of the solvent were filtered and washed with cool water. Finally, red cubic crystals suitable for X-ray analysis were obtained by diffusion of 2-propanol into a methanol solution of the product at room temperature. Analysis calculated for C₁₂H₂₈N₁₂Ni₂O₅: C 26.80, H 5.25, N 31.25%; found: C 26.40, H 5.32, N 31.09%. IR (KBr pellet, cm^-1): ν(C≡N) 2220, ν(C═N) 1665, ν(N—O) 1305.

S3. Refinement

C-bound H atoms were placed in calculated positions, with C—H = 0.97 Å and U_iso(H) = 1.2U_eq(C), and treated using the riding-model approximation. Other H atoms were observed in a difference Fourier map and were refined freely

Computing details

Data collection: KM-4 CCD Software (Kuma Diffraction, 1999); cell refinement: SAINT (Bruker, 1999); 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); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. A view of compound (I), with displacement ellipsoids shown at the 40% probability level. H atoms are drawn as spheres of arbitrary radii. Hydrogen bonds are represented as dashed lines [Symmetry codes: (i) 1 - x, y, 1/2 - z; (ii) -x, 1 - y, -z.]
	Fig. 2. A packing diagram for (I). Hydrogen bonds are indicated by dashed lines. All H atoms not included in hydrogen bonding have been omitted for clarity.
	Fig. 3. A view of the packing for (I), shown along the xz plane to represent connection between layers. All H atoms not included in hydrogen bonding have been omitted for clarity.

Tris(ethylenediamine)nickel(II) bis[2-cyano-2-(oxidoimino)acetamide]nickelate(II) monohydrate

Crystal data

[Ni(C2H8N2)3][Ni(C3HN3O2)2]·H2O	F(000) = 1120
Mr = 537.88	Dx = 1.703 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 6962 reflections
a = 10.119 (2) Å	θ = 3.6–28.5°
b = 11.212 (2) Å	µ = 1.85 mm^−1
c = 19.170 (4) Å	T = 100 K
β = 105.26 (3)°	Prism, red
V = 2098.2 (8) Å^3	0.27 × 0.16 × 0.11 mm
Z = 4

Data collection

Manufacturer? Model? CCD area-detector diffractometer	2655 independent reflections
Radiation source: fine-focus sealed tube	2202 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.038
ω scans	θmax = 28.5°, θmin = 3.6°
Absorption correction: ψ scan (North et al., 1968)	h = −8→13
Tmin = 0.696, Tmax = 0.820	k = −14→14
6962 measured reflections	l = −24→25

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)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.082	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	w = 1/[σ^2(Fo^2) + (0.0291P)^2 + 6.5482P] where P = (Fo^2 + 2Fc^2)/3
2413 reflections	(Δ/σ)max < 0.001
175 parameters	Δρmax = 1.08 e Å^−3
0 restraints	Δρmin = −0.44 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
Ni1	0.5000	0.41116 (4)	0.2500	0.01624 (11)
Ni2	0.0000	0.5000	0.0000	0.02037 (12)
O1W	0.0000	0.4511 (3)	−0.2500	0.0296 (6)
O1	0.23211 (17)	0.59723 (18)	0.09913 (9)	0.0276 (4)
O2	0.20598 (17)	0.56339 (17)	−0.14606 (9)	0.0249 (4)
N1	0.17459 (19)	0.5694 (2)	0.03303 (11)	0.0227 (4)
N2	0.0360 (2)	0.5123 (2)	−0.08990 (11)	0.0243 (4)
N3	0.4865 (2)	0.6645 (3)	0.01552 (13)	0.0373 (6)
N4	0.4840 (2)	0.2869 (2)	0.33100 (12)	0.0271 (5)
N5	0.7115 (2)	0.3950 (2)	0.30063 (12)	0.0244 (4)
N6	0.5318 (2)	0.5547 (2)	0.18384 (12)	0.0236 (4)
C1	0.1580 (2)	0.5527 (2)	−0.09195 (12)	0.0208 (5)
C2	0.2393 (2)	0.5861 (2)	−0.01821 (12)	0.0213 (5)
C3	0.3756 (2)	0.6310 (2)	−0.00121 (13)	0.0254 (5)
C4	0.6149 (3)	0.2920 (3)	0.38694 (14)	0.0339 (6)
H4A	0.6235	0.2237	0.4189	0.041*
H4B	0.6194	0.3640	0.4155	0.041*
C5	0.7279 (3)	0.2913 (3)	0.34976 (15)	0.0337 (6)
H5A	0.8160	0.2953	0.3853	0.040*
H5B	0.7247	0.2180	0.3224	0.040*
C6	0.5509 (3)	0.6645 (2)	0.22742 (15)	0.0300 (6)
H6A	0.5365	0.7338	0.1960	0.036*
H6B	0.6435	0.6678	0.2586	0.036*
H1	0.597 (4)	0.542 (3)	0.171 (2)	0.044 (10)*
H2	0.759 (4)	0.383 (3)	0.2687 (19)	0.045 (10)*
H3	0.477 (3)	0.213 (3)	0.3157 (16)	0.022 (7)*
H5	0.746 (3)	0.465 (3)	0.3282 (18)	0.035 (8)*
H7	0.460 (3)	0.565 (3)	0.1495 (18)	0.031 (8)*
H8	−0.015 (3)	0.486 (3)	−0.1295 (19)	0.038 (9)*
H12	0.412 (4)	0.299 (3)	0.3512 (19)	0.045 (10)*
H14	0.059 (4)	0.502 (3)	−0.225 (2)	0.047 (11)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni1	0.01414 (19)	0.0200 (2)	0.01696 (19)	0.000	0.00820 (14)	0.000
Ni2	0.01275 (19)	0.0325 (3)	0.0171 (2)	−0.00279 (16)	0.00630 (15)	−0.00390 (17)
O1W	0.0367 (15)	0.0320 (14)	0.0173 (11)	0.000	0.0024 (11)	0.000
O1	0.0232 (8)	0.0452 (11)	0.0136 (7)	−0.0032 (8)	0.0037 (6)	−0.0056 (7)
O2	0.0203 (8)	0.0394 (10)	0.0167 (7)	−0.0026 (7)	0.0080 (6)	−0.0016 (7)
N1	0.0164 (9)	0.0340 (11)	0.0173 (9)	−0.0012 (8)	0.0037 (7)	−0.0042 (8)
N2	0.0157 (9)	0.0402 (13)	0.0178 (9)	−0.0037 (8)	0.0057 (7)	−0.0051 (9)
N3	0.0237 (11)	0.0507 (15)	0.0362 (12)	−0.0112 (10)	0.0057 (9)	0.0005 (12)
N4	0.0312 (11)	0.0302 (12)	0.0217 (10)	−0.0068 (9)	0.0102 (9)	0.0011 (9)
N5	0.0170 (9)	0.0315 (12)	0.0265 (10)	0.0075 (8)	0.0088 (8)	0.0069 (9)
N6	0.0151 (9)	0.0282 (11)	0.0265 (10)	−0.0022 (8)	0.0036 (8)	0.0066 (9)
C1	0.0171 (10)	0.0292 (12)	0.0168 (10)	0.0010 (9)	0.0056 (8)	−0.0022 (9)
C2	0.0176 (10)	0.0291 (12)	0.0177 (10)	−0.0023 (9)	0.0055 (8)	−0.0039 (10)
C3	0.0237 (12)	0.0323 (13)	0.0197 (10)	−0.0025 (10)	0.0051 (9)	−0.0013 (10)
C4	0.0431 (15)	0.0331 (14)	0.0249 (12)	−0.0007 (12)	0.0077 (11)	0.0070 (11)
C5	0.0306 (13)	0.0353 (15)	0.0328 (13)	0.0109 (11)	0.0040 (11)	0.0057 (12)
C6	0.0245 (12)	0.0239 (12)	0.0369 (14)	−0.0057 (10)	−0.0005 (10)	0.0055 (11)

Geometric parameters (Å, º)

Ni1—N5^i	2.113 (2)	N4—H3	0.88 (3)
Ni1—N5	2.113 (2)	N4—H12	0.92 (4)
Ni1—N4^i	2.124 (2)	N5—C5	1.478 (3)
Ni1—N4	2.124 (2)	N5—H2	0.88 (4)
Ni1—N6^i	2.125 (2)	N5—H5	0.96 (4)
Ni1—N6	2.125 (2)	N6—C6	1.472 (4)
Ni2—N2	1.858 (2)	N6—H1	0.78 (4)
Ni2—N2^ii	1.858 (2)	N6—H7	0.85 (3)
Ni2—N1	1.881 (2)	C1—C2	1.484 (3)
Ni2—N1^ii	1.881 (2)	C2—C3	1.423 (3)
O1W—H14	0.86 (4)	C4—C5	1.499 (4)
O1—N1	1.286 (3)	C4—H4A	0.9700
O2—C1	1.262 (3)	C4—H4B	0.9700
N1—C2	1.329 (3)	C5—H5A	0.9700
N2—C1	1.325 (3)	C5—H5B	0.9700
N2—H8	0.85 (4)	C6—C6^i	1.510 (5)
N3—C3	1.146 (3)	C6—H6A	0.9700
N4—C4	1.470 (3)	C6—H6B	0.9700
N5^i—Ni1—N5	170.18 (13)	Ni1—N5—H2	112 (2)
N5^i—Ni1—N4^i	82.60 (9)	C5—N5—H5	109 (2)
N5—Ni1—N4^i	90.95 (9)	Ni1—N5—H5	111.3 (19)
N5^i—Ni1—N4	90.95 (9)	H2—N5—H5	108 (3)
N5—Ni1—N4	82.60 (9)	C6—N6—Ni1	108.22 (16)
N4^i—Ni1—N4	98.00 (13)	C6—N6—H1	110 (3)
N5^i—Ni1—N6^i	92.56 (8)	Ni1—N6—H1	109 (3)
N5—Ni1—N6^i	94.88 (9)	C6—N6—H7	106 (2)
N4^i—Ni1—N6^i	170.31 (9)	Ni1—N6—H7	110 (2)
N4—Ni1—N6^i	90.44 (9)	H1—N6—H7	113 (3)
N5^i—Ni1—N6	94.88 (9)	O2—C1—N2	128.3 (2)
N5—Ni1—N6	92.56 (8)	O2—C1—C2	121.5 (2)
N4^i—Ni1—N6	90.44 (9)	N2—C1—C2	110.21 (19)
N4—Ni1—N6	170.31 (9)	N1—C2—C3	121.1 (2)
N6^i—Ni1—N6	81.58 (13)	N1—C2—C1	114.2 (2)
N2—Ni2—N2^ii	180.0	C3—C2—C1	124.6 (2)
N2—Ni2—N1	83.42 (9)	N3—C3—C2	176.8 (3)
N2^ii—Ni2—N1	96.58 (9)	N4—C4—C5	107.9 (2)
N2—Ni2—N1^ii	96.58 (9)	N4—C4—H4A	110.1
N2^ii—Ni2—N1^ii	83.42 (9)	C5—C4—H4A	110.1
N1—Ni2—N1^ii	180.0	N4—C4—H4B	110.1
O1—N1—C2	120.70 (19)	C5—C4—H4B	110.1
O1—N1—Ni2	125.00 (15)	H4A—C4—H4B	108.4
C2—N1—Ni2	114.28 (16)	N5—C5—C4	109.1 (2)
C1—N2—Ni2	117.67 (17)	N5—C5—H5A	109.9
C1—N2—H8	116 (2)	C4—C5—H5A	109.9
Ni2—N2—H8	126 (2)	N5—C5—H5B	109.9
C4—N4—Ni1	106.28 (16)	C4—C5—H5B	109.9
C4—N4—H3	104.8 (19)	H5A—C5—H5B	108.3
Ni1—N4—H3	113.0 (19)	N6—C6—C6^i	108.53 (16)
C4—N4—H12	110 (2)	N6—C6—H6A	110.0
Ni1—N4—H12	115 (2)	C6^i—C6—H6A	110.0
H3—N4—H12	107 (3)	N6—C6—H6B	110.0
C5—N5—Ni1	106.88 (16)	C6^i—C6—H6B	110.0
C5—N5—H2	109 (2)	H6A—C6—H6B	108.4
N2—Ni2—N1—O1	177.9 (2)	N4^i—Ni1—N6—C6	−170.72 (17)
N2^ii—Ni2—N1—O1	−2.1 (2)	N6^i—Ni1—N6—C6	14.80 (12)
N2—Ni2—N1—C2	−3.73 (19)	Ni2—N2—C1—O2	176.7 (2)
N2^ii—Ni2—N1—C2	176.27 (19)	Ni2—N2—C1—C2	−2.9 (3)
N1—Ni2—N2—C1	3.8 (2)	O1—N1—C2—C3	2.3 (4)
N1^ii—Ni2—N2—C1	−176.2 (2)	Ni2—N1—C2—C3	−176.14 (19)
N5^i—Ni1—N4—C4	−169.44 (18)	O1—N1—C2—C1	−178.4 (2)
N5—Ni1—N4—C4	17.99 (18)	Ni2—N1—C2—C1	3.1 (3)
N4^i—Ni1—N4—C4	107.91 (19)	O2—C1—C2—N1	−179.8 (2)
N6^i—Ni1—N4—C4	−76.87 (18)	N2—C1—C2—N1	−0.2 (3)
N4^i—Ni1—N5—C5	−85.64 (18)	O2—C1—C2—C3	−0.6 (4)
N4—Ni1—N5—C5	12.30 (17)	N2—C1—C2—C3	179.0 (2)
N6^i—Ni1—N5—C5	102.12 (18)	Ni1—N4—C4—C5	−45.1 (3)
N6—Ni1—N5—C5	−176.13 (17)	Ni1—N5—C5—C4	−40.8 (3)
N5^i—Ni1—N6—C6	106.67 (16)	N4—C4—C5—N5	59.0 (3)
N5—Ni1—N6—C6	−79.75 (17)	Ni1—N6—C6—C6^i	−41.5 (3)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N6—H1···O2^iii	0.78 (4)	2.47 (4)	3.214 (3)	161 (4)
N4—H3···O1W^iv	0.88 (3)	2.28 (3)	3.113 (4)	160 (3)
N5—H5···O1^i	0.96 (4)	2.00 (4)	2.929 (3)	160 (3)
N6—H7···O1	0.85 (3)	2.28 (3)	3.077 (3)	156 (3)
O1W—H14···O2	0.86 (4)	1.96 (4)	2.777 (2)	158 (3)

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