Tetra­aqua­bis­(pyridine-κN)nickel(II) dinitrate

In the title compound, [Ni(C₅H₅N)₂(H₂O)₄](NO₃)₂, the Ni^II ion is coordinated by two N-bonded pyridine ligands and four water mol­ecules in an octa­hedral coordination mode. The asymmetric unit consists of one Ni^II ion located on an inversion center, as well as one pyridine ligand, one nitrate anion and two water mol­ecules in general positions. In the crystal structure, the discrete complex cations and nitrate anions are connected by O—H...O and C—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.049
• wR factor = 0.129
• Data-to-parameter ratio = 21.1

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT232_ALERT_2_B Hirshfeld Test Diff (M-X)  Ni1    --  O4      ..      11.39 su
PLAT232_ALERT_2_B Hirshfeld Test Diff (M-X)  Ni1    --  O5      ..      10.40 su
PLAT420_ALERT_2_B D-H Without Acceptor       O5     -  >H3O5   ...          ?

Alert level C
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        Ni1
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600          9
PLAT913_ALERT_3_C Missing # of Very Strong Reflections in FCF ....          5
PLAT244_ALERT_4_C Low   'Solvent' Ueq as Compared to Neighbors of          N2
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600         12

Alert level G
PLAT128_ALERT_4_G Alternate Setting of Space-group P21/c   .......      P21/n
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported   _diffrn_ambient_temperature        293 K
PLAT720_ALERT_4_G Number of Unusual/Non-Standard Labels ..........          6

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

   2 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
   2 ALERT type 3 Indicator that the structure quality may be low
   4 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

Recently, we have shown that thermal decomposition reactions are an elegant route for the discovery and preparation of new ligand-deficient coordination polymers with defined magnetic properties (Wriedt & Näther, 2009a,b; Wriedt et al., 2009a,b). In our ongoing investigation on the synthesis, structures and properties of such compounds based on paramagnetic transition metal pseudo-halides and N-donor ligands, we have reacted nickel(II) dinitrate hexahydrate, sodium dicyanamide and pyridine. In this reaction single crystals of the title compound were grown.

The title compound (Fig. 1) represents a discrete complex cation, in which the Ni^II atom, lying on an inversion center, is coordinated by two pyridine ligands and four water molecules in an octahedral coordination mode. The nitrate anions are not coordinated to the metal atoms (Fig. 2). The NiN₂O₄ octahedron is slightly distorted with Ni—N_pyridine distances of 2.140 (2) Å and Ni—O_water distances of 2.113 (2) and 2.128 (2) Å (Table 1). The angles arround the metal atoms range between 85.71 (10) to 94.29 (10) and 180°. A similar coordination is found in a related structure (Halut-Desportes, 1981). The opposite pyridyl rings are coplanar due to symmetry. The shortest intermolecular Ni···Ni distance amounts to 7.3245 (4) Å.

Related literature

For general background to thermal decomposition reactions as an elegant route for the discovery and preparation of new ligand-deficient coordination polymers with defined magnetic properties, see: Wriedt & Näther (2009a,b); Wriedt et al. (2009a,b). For a related structure, see: Halut-Desportes (1981).

S2. Experimental

Ni(NO₃)₂.6H₂O (72.7 mg, 0.25 mmol), sodium dicyanamide (44.5 mg, 0.5 mmol) and pyridine (0.5 ml) obtained from Alfa Aesar were reacted in a closed test-tube at 120°C for 3 d. On cooling light green block-shaped single crystals of the title compound were grown in a mixture with unknown phases.

S3. Refinement

All H atoms were located in a difference Fourier map. H atoms bound to C atoms were positioned geometrically and refined as riding atoms, with C—H = 0.93 Å and with U_iso(H) = 1.2U_eq(C). The water H atoms were disordered over three positions for each water molecule and were refined as riding, with O—H = 0.82 Å and U_iso(H) = 1.5U_eq(O), using a split model with SOF = 0.6667 for each H atom.

Computing details

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA (Stoe & Cie, 2002); data reduction: X-AREA (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. The structure of the title compound with displacement ellipsoids drawn at the 30% probability level. Disordering of the H atoms is shown with full and open bonds. [Symmetry code: (i) -x+1, -y+1, -z+1.]
	Fig. 2. Packing arrangement of the title compound with view along the a axis.

Tetraaquabis(pyridine-κN)nickel(II) dinitrate

Crystal data

[Ni(C5H5N)2(H2O)4](NO3)2	F(000) = 428
Mr = 412.99	Dx = 1.523 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 12828 reflections
a = 7.3245 (4) Å	θ = 2.6–29.2°
b = 11.3179 (6) Å	µ = 1.13 mm^−1
c = 10.9347 (5) Å	T = 293 K
β = 96.436 (4)°	Block, light green
V = 900.75 (8) Å^3	0.28 × 0.16 × 0.07 mm
Z = 2

Data collection

Stoe IPDS-2 diffractometer	2427 independent reflections
Radiation source: fine-focus sealed tube	2087 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.040
ω scans	θmax = 29.2°, θmin = 2.6°
Absorption correction: numerical (X-SHAPE and X-RED32; Stoe & Cie, 2002)	h = −10→9
Tmin = 0.801, Tmax = 0.927	k = −15→15
12828 measured reflections	l = −15→14

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)] = 0.049	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.129	H-atom parameters constrained
S = 1.15	w = 1/[σ^2(Fo^2) + (0.0554P)^2 + 0.6589P] where P = (Fo^2 + 2Fc^2)/3
2427 reflections	(Δ/σ)max < 0.001
115 parameters	Δρmax = 0.32 e Å^−3
0 restraints	Δρmin = −0.47 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Ni1	0.5000	0.5000	0.5000	0.03618 (15)
N1	0.6201 (3)	0.32862 (19)	0.4879 (2)	0.0421 (5)
C1	0.5276 (4)	0.2407 (3)	0.4281 (3)	0.0526 (7)
H1	0.4095	0.2555	0.3908	0.063*
C2	0.5994 (6)	0.1285 (3)	0.4191 (4)	0.0678 (9)
H2	0.5305	0.0693	0.3770	0.081*
C3	0.7731 (6)	0.1062 (3)	0.4729 (4)	0.0735 (10)
H3	0.8250	0.0317	0.4676	0.088*
C4	0.8695 (4)	0.1951 (3)	0.5348 (4)	0.0629 (8)
H4	0.9881	0.1819	0.5722	0.076*
C5	0.7896 (4)	0.3040 (3)	0.5412 (3)	0.0486 (6)
H5	0.8560	0.3636	0.5844	0.058*
N2	1.0498 (3)	0.6620 (2)	0.7423 (2)	0.0501 (5)
O1	1.0070 (3)	0.5655 (2)	0.6942 (2)	0.0635 (6)
O2	1.1995 (4)	0.6760 (3)	0.8009 (3)	0.0956 (10)
O3	0.9347 (5)	0.7424 (3)	0.7281 (3)	0.0905 (9)
O4	0.7425 (3)	0.5820 (2)	0.4544 (2)	0.0624 (6)
H1O4	0.7224	0.6435	0.4154	0.094*	0.667
H2O4	0.8088	0.5431	0.4141	0.094*	0.667
H3O4	0.8104	0.5993	0.5166	0.094*	0.667
O5	0.5815 (4)	0.5041 (2)	0.6930 (2)	0.0670 (6)
H1O5	0.5830	0.4380	0.7239	0.101*	0.667
H2O5	0.6849	0.5295	0.7147	0.101*	0.667
H3O5	0.5148	0.5457	0.7304	0.101*	0.667

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni1	0.0330 (2)	0.0335 (2)	0.0415 (2)	−0.00085 (16)	0.00174 (15)	−0.00095 (18)
N1	0.0411 (10)	0.0356 (10)	0.0498 (11)	0.0028 (8)	0.0065 (9)	−0.0007 (9)
C1	0.0526 (15)	0.0430 (14)	0.0613 (17)	−0.0008 (12)	0.0017 (13)	−0.0071 (12)
C2	0.083 (2)	0.0423 (16)	0.079 (2)	−0.0013 (15)	0.0110 (18)	−0.0126 (15)
C3	0.080 (2)	0.0451 (17)	0.099 (3)	0.0188 (16)	0.025 (2)	0.0026 (18)
C4	0.0477 (16)	0.0579 (18)	0.085 (2)	0.0131 (14)	0.0137 (15)	0.0159 (17)
C5	0.0403 (13)	0.0465 (14)	0.0595 (16)	0.0008 (11)	0.0069 (11)	0.0062 (12)
N2	0.0541 (13)	0.0526 (14)	0.0443 (11)	−0.0080 (11)	0.0088 (10)	−0.0055 (10)
O1	0.0690 (14)	0.0510 (13)	0.0687 (14)	−0.0078 (10)	−0.0002 (11)	−0.0095 (11)
O2	0.0725 (18)	0.123 (3)	0.0858 (19)	−0.0316 (17)	−0.0137 (15)	−0.0169 (18)
O3	0.104 (2)	0.0689 (17)	0.102 (2)	0.0254 (16)	0.0278 (18)	−0.0123 (15)
O4	0.0518 (12)	0.0568 (13)	0.0788 (15)	−0.0035 (10)	0.0088 (10)	0.0059 (11)
O5	0.0763 (16)	0.0655 (15)	0.0575 (13)	−0.0031 (11)	0.0000 (11)	−0.0016 (11)

Geometric parameters (Å, º)

Ni1—O4	2.113 (2)	C4—H4	0.9300
Ni1—O5	2.128 (2)	C5—H5	0.9300
Ni1—N1	2.140 (2)	N2—O2	1.216 (4)
N1—C1	1.333 (4)	N2—O1	1.238 (3)
N1—C5	1.340 (3)	N2—O3	1.238 (4)
C1—C2	1.381 (4)	O4—H1O4	0.8200
C1—H1	0.9300	O4—H2O4	0.8200
C2—C3	1.365 (5)	O4—H3O4	0.8200
C2—H2	0.9300	O5—H1O5	0.8200
C3—C4	1.364 (5)	O5—H2O5	0.8200
C3—H3	0.9300	O5—H3O5	0.8200
C4—C5	1.369 (4)
O4—Ni1—O4^i	180.00 (11)	C4—C3—C2	118.9 (3)
O4—Ni1—O5^i	85.71 (10)	C4—C3—H3	120.6
O4^i—Ni1—O5^i	94.29 (10)	C2—C3—H3	120.6
O4—Ni1—O5	94.29 (10)	C3—C4—C5	119.3 (3)
O4^i—Ni1—O5	85.71 (10)	C3—C4—H4	120.4
O5^i—Ni1—O5	180.000 (1)	C5—C4—H4	120.4
O4—Ni1—N1	91.23 (9)	N1—C5—C4	123.1 (3)
O4^i—Ni1—N1	88.77 (9)	N1—C5—H5	118.5
O5^i—Ni1—N1	89.46 (9)	C4—C5—H5	118.5
O5—Ni1—N1	90.54 (9)	O2—N2—O1	120.5 (3)
O4—Ni1—N1^i	88.77 (9)	O2—N2—O3	122.1 (3)
O4^i—Ni1—N1^i	91.23 (9)	O1—N2—O3	117.3 (3)
O5^i—Ni1—N1^i	90.54 (9)	Ni1—O4—H1O4	112.9
O5—Ni1—N1^i	89.46 (9)	Ni1—O4—H2O4	117.0
N1—Ni1—N1^i	180.000 (1)	H1O4—O4—H2O4	105.0
C1—N1—C5	116.9 (2)	Ni1—O4—H3O4	110.9
C1—N1—Ni1	121.15 (19)	H1O4—O4—H3O4	106.6
C5—N1—Ni1	121.94 (19)	H2O4—O4—H3O4	103.5
N1—C1—C2	123.0 (3)	Ni1—O5—H1O5	112.2
N1—C1—H1	118.5	Ni1—O5—H2O5	116.2
C2—C1—H1	118.5	H1O5—O5—H2O5	103.3
C3—C2—C1	118.9 (3)	Ni1—O5—H3O5	113.0
C3—C2—H2	120.6	H1O5—O5—H3O5	107.4
C1—C2—H2	120.6	H2O5—O5—H3O5	103.7

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
O4—H1O4···O2^ii	0.82	2.39	3.209 (4)	174
O4—H2O4···O1^iii	0.82	2.26	3.077 (4)	179
O4—H3O4···O1	0.82	2.32	3.087 (3)	157
O5—H1O5···O3^iv	0.82	2.28	3.091 (4)	169
O5—H2O5···O1	0.82	2.43	3.191 (4)	155
C2—H2···O1^v	0.93	2.50	3.310 (4)	145
C4—H4···O2^vi	0.93	2.54	3.461 (4)	170

Symmetry codes: (ii) x−1/2, −y+3/2, z−1/2; (iii) −x+2, −y+1, −z+1; (iv) −x+3/2, y−1/2, −z+3/2; (v) x−1/2, −y+1/2, z−1/2; (vi) −x+5/2, y−1/2, −z+3/2.