[μ-4,7-Dioxa-1,10-diazaoctane-1,1,10,10-tetra­acetat0-1κ⁴O¹,O^1′,N¹,O⁴:2κ⁴O⁷,N¹⁰,O¹⁰,O^10′]bis[aquanickel(II)] dihydrate

The Ni atom in the title complex, [Ni₂(C₁₄H₂₀N₂O₁₀)(H₂O)₂]·2H₂O or {[Ni₂(egta)·2H₂O]·2H₂O}] [egtaH4 is 3,12-bis­(car­boxy­meth­yl)-6,9-dioxa-3,12-diaza­tetra­deca­nedioic acid], has a square-pyramidal coordination geometry. Both Ni^II centres are penta­coordinated by one N atom and three O atoms of egta, forming the basal plane, and one O donor water mol­ecule in the apical position. The dinuclear complex is arranged around an inversion centre. The solvent water mol­ecules and coordinated water mol­ecules are involved in hydrogen bonds with uncoordinated O atoms of carboxyl­ate groups, which link the complex mol­ecules to form a three-dimensional supra­molecular network structure.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.024
• wR factor = 0.060
• Data-to-parameter ratio = 12.8

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Ni1    -   O1      ..       6.23 su
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Ni1    -   O6      ..       7.24 su
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Ni1    -   N1      ..       5.09 su
PLAT417_ALERT_2_C Short Inter D-H..H-D       H1W    ..  H4W     ..       2.12 Ang.

Alert level G
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          6

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

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

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S1. Comment

The coordination of multipyridine and multi-carboxylate ligands to metal centers has proved to be an excellent tool in the assembly process and has been highly influenced by the structural characterizations of tectonic spacers. Polydentate amino-polycarboxylate acid [H4egta=3,12-bis (carboxymethyl)-6, 9-dioxa-3, 12-diazatetradecanedioic acid], being extensively used as a calcium buffer in biological research, possesses symmetrical four potential coordinating sites and renders it an appropriate candidate to improve the extension of the ferrimagnetic lattice from one dimensional (one-dimensional) systems to two-dimensional and three-dimensional networks (Bomas-Almenar et al., 1993). In this paper, we report the synthesis and crystal structure of the title complex,(I).

As illustrated in Fig. 1, the neutral dinuclear molecule, lies on a centre of symmetry. Both nickel(II) centers are pentacoordinated to one N atom and three O atoms of egta, forming the basal plane, and one O donors of water molecule being in axial position, then leading to a distorted square-pyramid environment. The structural components are connected through O—H···O hydrogen bonding involving the lattice water molecules as donors and the uncoordinated O atoms as acceptors thus forming a three dimensionnal supramolecular network structure (Table 1).

Related literature

For related literature, see: Bomas-Almenar et al. (1993).

S2. Experimental

The title complex was prepared by the addition of a stoichiometric amount of nickel chloride (1 mmol) to a hot methanol solution (10 ml) of egtaH4 (1 mmol). The resulting solution was filtered, and pale green blocky crystals were obtained on slow evaporation of the solvent over several days at room temperature.

S3. Refinement

Carbon-bound H atoms were placed at calculated positions and were treated as riding on the parent C atoms with C—H= 97Å and with U_iso(H) = 1.2U_eq(C). H atoms attached to water molecules were found in a difference map and their positions were refined using restraints (O—H= 0.84 (2)Å and H···H= 1.38 Å) with U_iso(H) = 1.5U_eq(O).

Computing details

Data collection: APEX2 (Bruker, 1998); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT (Bruker, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPIII (Burnett & Johnson, 1996); ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXTL (Ref??).

Figures

Fig. 1. The structure of (I), showing the atom-numbering scheme and displacement ellipsoids drawn at the 30% probability level. Free water molecule has been omitted for clarity. [Symmetry code: (i) 1 - x, 1 - y, 1 - z].

[µ-4,7-dioxa-1,10-diazaoctane-1,1,10,10-tetraacetato- 1κ⁴O¹,O^1',N¹,O⁴:2κ⁴O⁷,N¹⁰,O¹⁰,O^10'] bis[aquanickel(II)] dihydrate

Crystal data

[Ni2(C14H20N2O10)(H2O)2]·2H2O	F(000) = 1176
Mr = 565.80	Dx = 1.748 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 2007 reflections
a = 21.031 (2) Å	θ = 2.9–25.5°
b = 7.5299 (9) Å	µ = 1.83 mm^−1
c = 13.5789 (16) Å	T = 298 K
β = 90.464 (1)°	Block, green
V = 2150.3 (4) Å^3	0.34 × 0.12 × 0.04 mm
Z = 4

Data collection

Bruker APEXII area-detector diffractometer	2007 independent reflections
Radiation source: fine-focus sealed tube	1756 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.027
φ and ω scans	θmax = 25.5°, θmin = 2.9°
Absorption correction: multi-scan SADABS (Sheldrick, 1996)	h = −25→25
Tmin = 0.580, Tmax = 0.931	k = −9→9
7928 measured reflections	l = −16→15

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)] = 0.024	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.060	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	w = 1/[σ^2(Fo^2) + (0.0294P)^2 + 0.9421P] where P = (Fo^2 + 2Fc^2)/3
2007 reflections	(Δ/σ)max = 0.002
157 parameters	Δρmax = 0.34 e Å^−3
6 restraints	Δρmin = −0.19 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	0.628725 (12)	0.21993 (3)	0.564464 (18)	0.02584 (10)
O1	0.67589 (7)	0.37797 (18)	0.47843 (11)	0.0328 (3)
O2	0.74168 (7)	0.3724 (2)	0.35187 (12)	0.0412 (4)
O3	0.60468 (7)	0.02307 (18)	0.64666 (10)	0.0352 (4)
O4	0.62324 (9)	−0.2649 (2)	0.66266 (12)	0.0497 (5)
O5	0.53305 (7)	0.28393 (19)	0.47083 (11)	0.0336 (4)
O6	0.61807 (8)	0.3871 (2)	0.67071 (12)	0.0383 (4)
H1W	0.6396 (12)	0.354 (3)	0.7181 (16)	0.057*
H2W	0.6247 (12)	0.492 (2)	0.6580 (18)	0.057*
O7	0.70120 (9)	0.2874 (2)	0.80982 (13)	0.0453 (4)
H3W	0.7178 (12)	0.385 (3)	0.828 (2)	0.068*
H4W	0.7255 (12)	0.239 (3)	0.7706 (19)	0.068*
N1	0.63903 (8)	0.0375 (2)	0.45889 (11)	0.0250 (4)
C1	0.70315 (10)	0.2990 (3)	0.40776 (16)	0.0290 (5)
C2	0.68935 (9)	0.1023 (3)	0.39122 (15)	0.0282 (5)
H2A	0.6757	0.0840	0.3236	0.034*
H2B	0.7280	0.0344	0.4020	0.034*
C3	0.65593 (10)	−0.1272 (3)	0.51335 (15)	0.0306 (5)
H3A	0.7018	−0.1353	0.5206	0.037*
H3B	0.6414	−0.2300	0.4765	0.037*
C4	0.62514 (10)	−0.1259 (3)	0.61503 (15)	0.0318 (5)
C5	0.57655 (10)	0.0158 (3)	0.40651 (15)	0.0315 (5)
H5A	0.5477	−0.0502	0.4482	0.038*
H5B	0.5829	−0.0522	0.3467	0.038*
C6	0.54713 (10)	0.1921 (3)	0.38073 (16)	0.0346 (5)
H6A	0.5764	0.2617	0.3416	0.042*
H6B	0.5084	0.1742	0.3426	0.042*
C7	0.51520 (11)	0.4654 (3)	0.45390 (16)	0.0399 (6)
H7A	0.4855	0.4729	0.3991	0.048*
H7B	0.5524	0.5357	0.4382	0.048*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni1	0.03413 (17)	0.01904 (16)	0.02442 (16)	−0.00075 (11)	0.00398 (11)	−0.00223 (11)
O1	0.0396 (8)	0.0230 (8)	0.0360 (8)	−0.0019 (6)	0.0064 (7)	−0.0023 (6)
O2	0.0463 (10)	0.0303 (9)	0.0472 (10)	−0.0061 (7)	0.0184 (8)	0.0033 (7)
O3	0.0509 (9)	0.0244 (8)	0.0305 (8)	−0.0004 (7)	0.0112 (7)	−0.0017 (6)
O4	0.0880 (14)	0.0262 (9)	0.0349 (9)	0.0034 (9)	0.0107 (9)	0.0057 (7)
O5	0.0361 (9)	0.0321 (8)	0.0326 (8)	0.0080 (7)	0.0034 (7)	0.0013 (6)
O6	0.0560 (11)	0.0231 (8)	0.0358 (9)	0.0043 (8)	0.0001 (8)	−0.0041 (7)
O7	0.0633 (12)	0.0324 (9)	0.0404 (10)	−0.0015 (8)	0.0109 (9)	−0.0031 (8)
N1	0.0269 (9)	0.0236 (9)	0.0247 (9)	−0.0006 (7)	0.0034 (7)	0.0001 (7)
C1	0.0274 (11)	0.0259 (11)	0.0336 (12)	0.0016 (9)	−0.0005 (9)	0.0032 (9)
C2	0.0288 (11)	0.0267 (11)	0.0293 (11)	−0.0013 (9)	0.0066 (9)	−0.0014 (9)
C3	0.0390 (12)	0.0225 (11)	0.0306 (11)	0.0030 (9)	0.0043 (9)	−0.0015 (9)
C4	0.0390 (13)	0.0285 (12)	0.0279 (11)	−0.0033 (9)	0.0005 (9)	0.0008 (10)
C5	0.0318 (12)	0.0320 (12)	0.0308 (11)	−0.0044 (9)	0.0027 (9)	−0.0060 (9)
C6	0.0325 (12)	0.0442 (14)	0.0273 (12)	0.0036 (10)	0.0003 (9)	−0.0013 (10)
C7	0.0415 (13)	0.0351 (13)	0.0433 (14)	0.0119 (10)	0.0036 (10)	0.0064 (11)

Geometric parameters (Å, º)

Ni1—O3	1.9255 (14)	N1—C5	1.498 (3)
Ni1—O6	1.9293 (15)	C1—C2	1.525 (3)
Ni1—O1	1.9451 (14)	C2—H2A	0.9700
Ni1—N1	1.9986 (16)	C2—H2B	0.9700
O1—C1	1.270 (2)	C3—C4	1.530 (3)
O2—C1	1.244 (2)	C3—H3A	0.9700
O3—C4	1.277 (2)	C3—H3B	0.9700
O4—C4	1.231 (3)	C5—C6	1.505 (3)
O5—C7	1.436 (3)	C5—H5A	0.9700
O5—C6	1.438 (2)	C5—H5B	0.9700
O6—H1W	0.823 (16)	C6—H6A	0.9700
O6—H2W	0.821 (16)	C6—H6B	0.9700
O7—H3W	0.847 (16)	C7—C7^i	1.503 (4)
O7—H4W	0.826 (16)	C7—H7A	0.9700
N1—C3	1.486 (2)	C7—H7B	0.9700
N1—C2	1.489 (2)
O3—Ni1—O6	92.08 (7)	N1—C3—C4	110.04 (16)
O3—Ni1—O1	163.08 (6)	N1—C3—H3A	109.7
O6—Ni1—O1	96.47 (7)	C4—C3—H3A	109.7
O3—Ni1—N1	85.25 (6)	N1—C3—H3B	109.7
O6—Ni1—N1	177.32 (7)	C4—C3—H3B	109.7
O1—Ni1—N1	86.04 (6)	H3A—C3—H3B	108.2
C1—O1—Ni1	113.76 (13)	O4—C4—O3	123.9 (2)
C4—O3—Ni1	112.98 (13)	O4—C4—C3	118.98 (19)
C7—O5—C6	112.13 (16)	O3—C4—C3	117.09 (18)
Ni1—O6—H1W	108.7 (19)	N1—C5—C6	111.81 (17)
Ni1—O6—H2W	116.7 (19)	N1—C5—H5A	109.3
H1W—O6—H2W	111 (2)	C6—C5—H5A	109.3
H3W—O7—H4W	108 (2)	N1—C5—H5B	109.3
C3—N1—C2	114.36 (16)	C6—C5—H5B	109.3
C3—N1—C5	110.52 (16)	H5A—C5—H5B	107.9
C2—N1—C5	111.58 (15)	O5—C6—C5	108.25 (17)
C3—N1—Ni1	104.10 (11)	O5—C6—H6A	110.0
C2—N1—Ni1	107.40 (12)	C5—C6—H6A	110.0
C5—N1—Ni1	108.41 (12)	O5—C6—H6B	110.0
O2—C1—O1	123.58 (19)	C5—C6—H6B	110.0
O2—C1—C2	117.76 (18)	H6A—C6—H6B	108.4
O1—C1—C2	118.65 (18)	O5—C7—C7^i	108.0 (2)
N1—C2—C1	111.27 (16)	O5—C7—H7A	110.1
N1—C2—H2A	109.4	C7^i—C7—H7A	110.1
C1—C2—H2A	109.4	O5—C7—H7B	110.1
N1—C2—H2B	109.4	C7^i—C7—H7B	110.1
C1—C2—H2B	109.4	H7A—C7—H7B	108.4
H2A—C2—H2B	108.0

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
O6—H1W···O7	0.82 (2)	1.86 (2)	2.671 (3)	169 (3)
O6—H2W···O4^ii	0.82 (2)	1.83 (2)	2.625 (2)	162 (3)
O7—H3W···O2^iii	0.85 (2)	1.92 (2)	2.758 (2)	168 (3)
O7—H4W···O2^iv	0.83 (2)	1.99 (2)	2.785 (2)	161 (3)

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