μ-Oxalato-bis­[aqua­(diethyl­enetri­amine)­nickel(II)] dinitrate

The crystal structure of the title compound, [Ni₂(C₂O₄)(C₄H₁₃N₃)₂(H₂O)₂](NO₃)₂, consists of uncoordinated nitrate anions and dimeric cations, where the oxalate ligand is coordinated in a bis-bidentate fashion to centrosymmetrically related Ni^II atoms. The distorted octahedral environment of each Ni^II atom is completed by the three N atoms of the di­ethyl­enetri­amine ligand in a fac arrangement and one water O atom. Variable-temperature magnetic susceptibility measure­ments reveal a moderate intramolecular antiferromagnetic coupling.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• Disorder in main residue
• R factor = 0.032
• wR factor = 0.089
• Data-to-parameter ratio = 25.7

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



PLAT_301  Alert C Main Residue Disorder ........................       8.00 Perc.

PLAT_369  Alert C Long   C(sp2)-C(sp2) Bond  C(1)   -   C(1)a  =       1.55 Ang.


 0 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 2 Alert Level C = Please check

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S1. Comment

The design and synthesis of oxalato-bridged nickel(II) complexes have attracted much attention during the last few years due to the strong magneto-structural correlations found in this kind of complex (Román et al., 1996; Escuer et al., 1994). In the framework of our current research of polynuclear oxalato-containing first-row transition metal complexes (Castillo et al., 2000, 2001) we have obtained the compound µ-oxalato-bis[aqua(diethylenetriamine)nickel(II)] dinitrate, (I).

The crystal structure of (I) comprises NO₃^- anions and [Ni₂(C₂O₄)(C₄H₁₃N₃)₂(H₂O)₂]²⁺ binuclear cations (Fig. 1) having a symmetry centre at the midpoint of the C—C bond of the oxalate bridge. As observed in related compounds (Travnicek et al., 1997; Román et al., 1996; Escuer et al., 1994), the oxalate ion joins two adjacent coordination polyhedra with its O atoms occupying two cis positions in both polyhedra, and the diethylenetriamine group acts as a facially coordinated tridentate ligand. The coordination geometry around each metal atom is NiN₃O₃ distorted octahedral, with the O1, O2, N1 and N7 atoms in the equatorial plane [maximum deviation 0.010 (2) Å for N7]; N4 and O3W are on the axial sites. The nickel–nickel separation across the bridging oxalate is 5.487 (1) Å and the Ni–oxalato–Ni fragment is nearly planar. In the crystal structure of (I), complex cations and nitrate anions are held together by means of an extensive three-dimensional network of OW—H···O, N—H···O/OW hydrogen bonds. Magnetic susceptibility data of (I) in the temperature range 1.8–300.0 K show the occurrence of an intramolecular antiferromagnetic interaction with J = -27.2 cm^-1 and g = 2.20. The magnitude of the exchange coupling constant is within the range found for oxalate-bridged nickel(II) complexes with a NiN₃O₃ chromophore.

S2. Experimental

Ni(NO₃)₂^.6H₂O (2.670 g, 9.20 mmol) dissolved in water (20 ml) was added dropwise to a mixture of diethylenetriamine (1.0 ml, 9.20 mmol) of K₂C₂O₄^.H₂O (0.850 g, 4.60 mmol) in water (30 ml) to give an immediate blue polycrystalline powder. Blue crystals of (I) suitable for X-ray analysis were obtained by recrystallization in hot water.

S3. Refinement

The diethylenetriamine ligand shows a disordered arrangement of the C6 atom over two positions. Refinement of the site-ocupation factors revealed a partial ocupation close to 0.9 and 0.1, which were kept fixed to this value in the final refinement.

Computing details

Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

Fig. 1. The molecular structure of (I) showing the hydrogen bonds between the anions and cations. Displacement ellipsoids are shown at the 50% probability level. H atoms are shown as spheres of arbitrary radii.

µ-oxalato-bis[aqua(diethylenetriamine)nickel(II)] dinitrate

Crystal data

[Ni2(C2O4)(C4H13N3)2(H2O)2](NO3)2	F(000) = 596
Mr = 571.80	Dx = 1.765 Mg m^−3 Dm = 1.75 (1) Mg m^−3 Dm measured by flotation in a mixture of carbon tetrachloride and bromoform
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 25 reflections
a = 12.560 (2) Å	θ = 7.5–13.2°
b = 7.243 (2) Å	µ = 1.83 mm^−1
c = 13.387 (2) Å	T = 293 K
β = 117.96 (2)°	Prism, blue
V = 1075.7 (4) Å^3	0.40 × 0.40 × 0.25 mm
Z = 2

Data collection

Enraf Nonius CAD-4 diffractometer	3495 reflections with I > 2σ(I)
Radiation source: x-ray tube	Rint = 0.019
Graphite monochromator	θmax = 35.0°, θmin = 1.8°
ω/2θ scans	h = −20→17
Absorption correction: empirical (using intensity measurements) via ψ scan (North et al., 1968)	k = 0→11
Tmin = 0.494, Tmax = 0.633	l = 0→21
5512 measured reflections	2 standard reflections every 98 reflections
4732 independent reflections	intensity decay: 1%

Refinement

Refinement on F^2	13 restraints
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.033	w = 1/[σ^2(Fo^2) + (0.0487P)^2 + 0.5287P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.089	(Δ/σ)max = 0.001
S = 1.03	Δρmax = 0.58 e Å^−3
4732 reflections	Δρmin = −0.73 e Å^−3
184 parameters

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All e.s.d.'s are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement on F² for ALL reflections except for 0 with very negative F² or flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating _R_factor_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	Occ. (<1)
Ni1	0.55907 (2)	0.76308 (2)	0.178205 (14)	0.02110 (5)
O1	0.58089 (10)	1.04120 (13)	0.14506 (8)	0.0249 (2)
O2	0.47092 (10)	0.76468 (12)	−0.00044 (9)	0.0254 (2)
C1	0.53176 (11)	1.0802 (2)	0.04158 (10)	0.0200 (2)
O3W	0.71952 (11)	0.6948 (2)	0.17523 (12)	0.0360 (3)
N1	0.64163 (13)	0.8183 (2)	0.35098 (11)	0.0315 (3)
C2	0.5489 (2)	0.8330 (3)	0.38839 (14)	0.0403 (4)
H2A	0.5777 (2)	0.9115 (3)	0.45470 (14)	0.048*
H2B	0.5320 (2)	0.7118 (3)	0.40838 (14)	0.048*
C3	0.4348 (2)	0.9145 (3)	0.2931 (2)	0.0417 (4)
H3A	0.3697 (2)	0.9083 (3)	0.3128 (2)	0.05*
H3B	0.4481 (2)	1.0431 (3)	0.2822 (2)	0.05*
N4	0.40125 (12)	0.8110 (2)	0.18794 (12)	0.0295 (2)
C5	0.3425 (2)	0.6328 (3)	0.1840 (2)	0.0434 (4)
H5A	0.2557 (2)	0.6476 (3)	0.1420 (2)	0.052*	0.9
H5B	0.3626 (2)	0.5948 (3)	0.2603 (2)	0.052*	0.9
H5C	0.3074 (2)	0.6398 (3)	0.2348 (2)	0.052*	0.1
H5D	0.2769 (2)	0.6158 (3)	0.1081 (2)	0.052*	0.1
C6	0.3819 (2)	0.4853 (3)	0.1287 (2)	0.0394 (4)	0.9
H6A	0.3556 (2)	0.3651 (3)	0.1406 (2)	0.047*	0.9
H6B	0.3459 (2)	0.5074 (3)	0.0480 (2)	0.047*	0.9
N7	0.51403 (14)	0.4891 (2)	0.17864 (12)	0.0319 (3)
C6A	0.4150 (16)	0.4776 (19)	0.2122 (16)	0.042 (4)	0.1
H3C	0.3651 (16)	0.3710 (19)	0.1757 (16)	0.051*	0.1
H3D	0.4511 (16)	0.4587 (19)	0.2933 (16)	0.051*	0.1
N10	0.82822 (14)	0.8786 (2)	0.01015 (13)	0.0363 (3)
O11	0.75272 (14)	0.9460 (2)	0.03687 (13)	0.0467 (3)
O12	0.8234 (2)	0.9207 (4)	−0.07927 (15)	0.0796 (6)
O13	0.9063 (2)	0.7776 (4)	0.0781 (2)	0.0932 (8)
H31W	0.781 (2)	0.679 (4)	0.237 (2)	0.049 (7)*
H32W	0.743 (3)	0.767 (4)	0.142 (3)	0.063 (9)*
H71	0.553 (2)	0.440 (3)	0.2473 (16)	0.048 (6)*
H41	0.354 (2)	0.876 (3)	0.1313 (19)	0.059 (7)*
H72	0.532 (2)	0.431 (4)	0.133 (2)	0.054 (7)*
H11	0.682 (2)	0.920 (3)	0.365 (2)	0.051 (7)*
H12	0.695 (2)	0.736 (3)	0.394 (2)	0.052 (8)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni1	0.02101 (8)	0.02123 (8)	0.02057 (8)	−0.00034 (6)	0.00934 (6)	0.00223 (6)
O1	0.0285 (5)	0.0237 (4)	0.0193 (4)	−0.0037 (4)	0.0085 (4)	0.0000 (3)
O2	0.0331 (5)	0.0200 (4)	0.0225 (4)	−0.0025 (3)	0.0126 (4)	0.0005 (3)
C1	0.0187 (5)	0.0202 (4)	0.0211 (5)	−0.0007 (4)	0.0093 (4)	−0.0008 (4)
O3W	0.0257 (5)	0.0456 (6)	0.0374 (6)	0.0091 (5)	0.0152 (5)	0.0132 (5)
N1	0.0325 (7)	0.0330 (6)	0.0232 (5)	−0.0044 (5)	0.0082 (5)	0.0022 (5)
C2	0.0475 (10)	0.0481 (9)	0.0274 (7)	0.0034 (8)	0.0193 (7)	−0.0024 (6)
C3	0.0443 (10)	0.0440 (9)	0.0402 (9)	0.0108 (7)	0.0225 (8)	−0.0044 (7)
N4	0.0262 (6)	0.0337 (6)	0.0295 (6)	0.0027 (5)	0.0139 (5)	0.0022 (5)
C5	0.0351 (9)	0.0506 (10)	0.0511 (11)	−0.0116 (8)	0.0257 (8)	−0.0026 (8)
C6	0.0433 (10)	0.0354 (8)	0.0369 (9)	−0.0161 (8)	0.0167 (8)	−0.0040 (7)
N7	0.0410 (7)	0.0237 (5)	0.0317 (6)	0.0004 (5)	0.0177 (6)	0.0017 (4)
C6A	0.051 (11)	0.032 (7)	0.045 (10)	−0.017 (7)	0.024 (8)	−0.006 (7)
N10	0.0366 (7)	0.0385 (7)	0.0374 (7)	0.0036 (6)	0.0204 (6)	0.0003 (6)
O11	0.0522 (8)	0.0429 (7)	0.0623 (9)	0.0069 (6)	0.0412 (7)	0.0024 (6)
O12	0.0843 (14)	0.123 (2)	0.0527 (10)	0.0302 (13)	0.0494 (10)	0.0219 (11)
O13	0.087 (2)	0.109 (2)	0.091 (2)	0.0644 (14)	0.0473 (13)	0.0509 (13)

Geometric parameters (Å, º)

Ni1—O1	2.1081 (11)	N4—H41	0.85 (2)
Ni1—O2	2.1125 (12)	N7—H71	0.888 (19)
Ni1—O3W	2.0935 (17)	N7—H72	0.86 (3)
Ni1—N1	2.0822 (14)	C1—C1^i	1.5463 (17)
Ni1—N4	2.0758 (18)	C2—C3	1.522 (3)
Ni1—N7	2.0641 (15)	C5—C6	1.509 (3)
O1—C1	1.2561 (16)	C5—C6A	1.383 (17)
O2—C1^i	1.2451 (15)	C2—H2B	0.97
O3W—H32W	0.83 (4)	C2—H2A	0.97
O3W—H31W	0.83 (2)	C3—H3A	0.97
O11—N10	1.258 (3)	C3—H3B	0.97
O12—N10	1.209 (3)	C5—H5A	0.97
O13—N10	1.220 (3)	C5—H5D	0.97
N1—C2	1.471 (3)	C5—H5B	0.97
N4—C3	1.472 (2)	C5—H5C	0.97
N4—C5	1.476 (3)	C6—H6A	0.97
N7—C6A	1.51 (2)	C6—H6B	0.97
N7—C6	1.470 (3)	C6A—H3C	0.97
N1—H12	0.88 (2)	C6A—H3D	0.97
N1—H11	0.87 (2)
O1—Ni1—O2	78.89 (4)	O11—N10—O12	119.34 (19)
O1—Ni1—O3W	90.02 (6)	O11—N10—O13	118.04 (19)
O1—Ni1—N1	90.23 (5)	O1—C1—O2^i	126.01 (12)
O1—Ni1—N4	94.34 (6)	O1—C1—C1^i	116.50 (11)
O1—Ni1—N7	169.13 (5)	O2^i—C1—C1^i	117.48 (11)
O2—Ni1—O3W	88.74 (6)	N1—C2—C3	109.14 (15)
O2—Ni1—N1	168.57 (5)	N4—C3—C2	109.79 (17)
O2—Ni1—N4	93.50 (6)	N4—C5—C6A	116.5 (8)
O2—Ni1—N7	90.55 (5)	N4—C5—C6	111.32 (19)
O3W—Ni1—N1	94.82 (7)	N7—C6—C5	108.87 (17)
O3W—Ni1—N4	175.41 (6)	N7—C6A—C5	113.8 (11)
O3W—Ni1—N7	92.32 (7)	C3—C2—H2B	109.9
N1—Ni1—N4	83.75 (7)	H2A—C2—H2B	108.3
N1—Ni1—N7	100.13 (6)	C3—C2—H2A	109.8
N4—Ni1—N7	83.66 (7)	N1—C2—H2A	109.9
Ni1—O1—C1	113.68 (8)	N1—C2—H2B	109.9
Ni1—O2—C1^i	113.38 (8)	N4—C3—H3A	109.7
Ni1—O3W—H31W	117.8 (18)	N4—C3—H3B	109.7
Ni1—O3W—H32W	117 (3)	C2—C3—H3A	109.7
H31W—O3W—H32W	103 (3)	C2—C3—H3B	109.7
Ni1—N1—C2	109.30 (11)	H3A—C3—H3B	108.2
C3—N4—C5	113.18 (16)	N4—C5—H5B	109.4
Ni1—N4—C5	109.15 (13)	C6—C5—H5A	109.4
Ni1—N4—C3	106.98 (13)	N4—C5—H5C	108.3
Ni1—N7—C6	105.65 (12)	N4—C5—H5D	108.3
Ni1—N7—C6A	108.6 (5)	N4—C5—H5A	109.4
C2—N1—H12	107.9 (17)	C6A—C5—H5D	108.1
H11—N1—H12	104 (2)	H5C—C5—H5D	107.4
Ni1—N1—H11	109.9 (16)	C6—C5—H5B	109.4
Ni1—N1—H12	115.3 (15)	H5A—C5—H5B	108.0
C2—N1—H11	109.8 (17)	C6A—C5—H5C	108.0
C5—N4—H41	108.5 (16)	N7—C6—H6A	109.9
Ni1—N4—H41	108.9 (19)	N7—C6—H6B	109.9
C3—N4—H41	110.1 (15)	C5—C6—H6A	109.9
C6—N7—H72	106.5 (18)	C5—C6—H6B	109.9
Ni1—N7—H71	111.7 (14)	H6A—C6—H6B	108.3
Ni1—N7—H72	108.3 (19)	N7—C6A—H3D	109
C6—N7—H71	114.8 (17)	H3C—C6A—H3D	108
C6A—N7—H71	78.5 (19)	C5—C6A—H3C	109
C6A—N7—H72	135 (2)	C5—C6A—H3D	108.8
H71—N7—H72	110 (2)	N7—C6A—H3C	109
O12—N10—O13	122.6 (2)

Symmetry code: (i) −x+1, −y+2, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H11···O3W^ii	0.87 (2)	2.53 (2)	3.343 (2)	157 (2)
N1—H12···O11^iii	0.88 (2)	2.26 (2)	3.069 (2)	152 (2)
O3W—H31W···O1^iii	0.83 (2)	1.98 (3)	2.767 (2)	157 (3)
O3W—H32W···O11	0.83 (4)	1.96 (3)	2.764 (2)	165 (4)
O3W—H32W···O13	0.83 (4)	2.57 (4)	3.227 (3)	138 (3)
N4—H41···O11^i	0.85 (2)	2.39 (2)	3.231 (2)	170 (3)
N4—H41···O12^i	0.85 (2)	2.49 (3)	3.164 (3)	137 (2)
N7—H71···O13^iii	0.89 (2)	2.45 (2)	3.301 (3)	161 (2)
N7—H72···O2^iv	0.86 (3)	2.25 (3)	3.087 (2)	164 (3)

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