Poly[aqua­bis­­(μ-formato-κ²O:O′)(μ-pyrazine-κ²N:N′)nickel(II)]

In the title compound, [Ni(CHO₂)₂(C₄H₄N₂)(H₂O)], the nickel(II) cations are coordinated by three O-bonded-formato anions, two N-bonded-pyrazine ligands and one water mol­ecule in an octa­hedral coordination mode. The nickel(II) cations are connected by μ-1,3-bridging formato anions and N,N′-bridging pyrazine ligands into a three dimensional coordination network. The asymmetric unit consists of one nickel(II) cation, one water mol­ecule and two crystallograph­ically independent formato anions in general positions as well as two crystallographically independent pyrazine ligands, which are located on centers of inversion.

Related literature

For background of this work, see: Boeckmann & Näther (2010), Wriedt et al. (2009); Boeckmann et al. (2010). For a related structure, see: Manson et al. (2003). For a description of the Cambridge Structural Database, see: Allen (2002).

Experimental

Crystal data

• [Ni(CHO₂)₂(C₄H₄N₂)(H₂O)]

• M_r = 246.85

• Monoclinic, P 2₁ /c

• a = 7.8169 (4) Å

• b = 7.0077 (3) Å

• c = 15.6586 (7) Å

• β = 98.971 (4)°

• V = 847.26 (7) ų

• Z = 4

• Mo Kα radiation

• μ = 2.29 mm⁻¹

• T = 293 K

• 0.19 × 0.15 × 0.12 mm

Data collection

• Stoe IPDS-2 diffractometer

• Absorption correction: numerical (X-SHAPE and X-RED32; Stoe, 2008) T_min = 0.658, T_max = 0.770

• 15596 measured reflections

• 2291 independent reflections

• 2091 reflections with I > 2σ(I)

• R_int = 0.036

Refinement

• R[F² > 2σ(F²)] = 0.025

• wR(F²) = 0.059

• S = 1.10

• 2291 reflections

• 128 parameters

• H-atom parameters constrained

• Δρ_max = 0.47 e Å⁻³

• Δρ_min = −0.30 e Å⁻³

Data collection: X-AREA (Stoe, 2008); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008); software used to prepare material for publication: XP in SHELXTL and DIAMOND (Brandenburg, 2011).

Supporting information

S1. Comment

In our recent work on the synthesis, structures and properties of new coordination polymers based on paramagnetic transition metal, small-sized anions and N-donor ligands, we have shown that new ligand-deficient coordination polymers based on transition metal thiocyanates and selenocyanates can be prepared by thermal decomposition reactions (Wriedt, Jess & Näther, 2009 and Boeckmann & Näther, 2010). Later we have shown that also metal formates can be prepared by this route (Boeckmann, Wriedt & Näther, 2010). Within this project we tried to prepare new ligand-rich precursor compounds based on nickel(II) formate and pyrazine which resulted in the formation of the title compound that were identified by single crystal X-ray diffraction.

In the crystal structure of the title compound, each nickel(II) cation is coordinated by three bridging formato anions, two bridging pyrazine ligands and one water molecule (Fig. 1). The NiO₄N₂ octahedron is slightly distorted with Ni—OCHO distances between 2.0378 (11) Å and 2.0643 (12) Å and one Ni—OH₂ distance of 2.0420 (11) Å as well as two long Ni—N distances of 2.1066 (13) Å and 2.1171 (12) Å. The angles around the metal atoms range from 84.14 (5)° to 95.94 (5)° and from 173.18 (5)° to 179.19 (5)°. The nickel(II) cations are connected via µ-1,3 bridging formato anions into two dimensional Ni(O₂CHO)₂ layers that are further linked by the pyrazine ligands into a 3D coordination network (Fig. 2). The Ni—Ni distances between next neighboured Ni atoms ranges from 6.9770 (4) Å to 7.0689 (4) Å.

It must be noted that according to a search in the CCDC database (ConQuest Ver.1.12.) (Allen, 2002) compounds based on nickel(II) formate and pyrazine are unknown but with copper(II) formate one strcuture is reported (Manson et al., 2003).

Related literature

For background of this work, see: Boeckmann & Näther (2010), Wriedt et al. (2009); Boeckmann et al. (2010). For a related structure, see Manson et al. (2003). For a description of the Cambridge Structural Database, see: Allen (2002).

S2. Experimental

Nickel formate dihydrate [Ni(CHO₂)₂.H₂O] and pyrazine were obtained from Alfa Aesar. All chemicals were used without further purification. 0.25 mmol (46 mg) Ni(CHO₂)₂.H₂O and 0.5 mmol (40 mg) pyrazine were reacted in 2 ml water. Light blue block-shaped single crystals of the title compound were obtained after a few days at room temperature.

S3. Refinement

The C-H H atoms were positioned with idealized geometry and were refined isotropic with U_iso(H) = 1.2U_eq(C) and C—H distances of 0.93 Å using a riding model. The O-H H atoms were located in difference map, their bond lengths were set to 0.82 Å and afterwards they were refined isotropic with U_iso(H) = 1.5U_eq(O) using a riding model.

Computing details

Data collection: X-AREA (Stoe, 2008); cell refinement: X-AREA (Stoe, 2008); data reduction: X-AREA (Stoe, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008); software used to prepare material for publication: XP in SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 2011).

Figures

	Fig. 1. : Crystal structure of the title compound with labelling and displacement ellipsoids drawn at the 50 % probability level. Symmetry codes: i = -x+1, y+1/2 i = -x+1,y+1/2,-z+3/2; ii = -x+1,-y,-z+1; iii = -x,-y+1,-z+1.
	Fig. 2. : Crystal structure of the title compound with view along the crystallographic a-axis.

Poly[aquabis(µ-formato-κ²O:O')(µ- pyrazine-κ²N:N')nickel(II)]

Crystal data

[Ni(CHO2)2(C4H4N2)(H2O)]	F(000) = 504
Mr = 246.85	Dx = 1.935 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 15596 reflections
a = 7.8169 (4) Å	θ = 2.6–29.3°
b = 7.0077 (3) Å	µ = 2.29 mm^−1
c = 15.6586 (7) Å	T = 293 K
β = 98.971 (4)°	Block, light blue
V = 847.26 (7) Å^3	0.19 × 0.15 × 0.12 mm
Z = 4

Data collection

Stoe IPDS-2 diffractometer	2291 independent reflections
Radiation source: fine-focus sealed tube	2091 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.036
ω scan	θmax = 29.3°, θmin = 2.6°
Absorption correction: numerical (X-SHAPE and X-RED32; Stoe, 2008)	h = −10→10
Tmin = 0.658, Tmax = 0.770	k = −9→9
15596 measured reflections	l = −21→21

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.025	H-atom parameters constrained
wR(F^2) = 0.059	w = 1/[σ^2(Fo^2) + (0.025P)^2 + 0.4622P] where P = (Fo^2 + 2Fc^2)/3
S = 1.10	(Δ/σ)max = 0.001
2291 reflections	Δρmax = 0.47 e Å^−3
128 parameters	Δρmin = −0.30 e Å^−3
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0158 (13)

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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	0.30005 (2)	0.25657 (3)	0.649349 (11)	0.01731 (8)
N1	0.41659 (17)	0.10169 (18)	0.55756 (8)	0.0205 (2)
C1	0.3337 (2)	0.0453 (2)	0.48084 (10)	0.0250 (3)
H1	0.2169	0.0747	0.4654	0.030*
C2	0.5831 (2)	0.0558 (2)	0.57642 (10)	0.0257 (3)
H2	0.6452	0.0925	0.6294	0.031*
N11	0.12229 (17)	0.39364 (18)	0.55394 (8)	0.0209 (2)
C11	−0.0463 (2)	0.3831 (2)	0.55924 (11)	0.0241 (3)
H11	−0.0827	0.3027	0.6001	0.029*
C12	0.1684 (2)	0.5112 (2)	0.49450 (10)	0.0234 (3)
H12	0.2847	0.5224	0.4891	0.028*
O21	0.11734 (15)	0.04433 (16)	0.65066 (8)	0.0275 (3)
O22	0.0548 (2)	−0.25397 (17)	0.67969 (12)	0.0434 (4)
C21	0.1545 (2)	−0.1280 (2)	0.66185 (12)	0.0279 (3)
H21	0.2693	−0.1604	0.6602	0.042*
O31	0.46637 (15)	0.11818 (18)	0.74213 (8)	0.0282 (3)
O32	0.51992 (15)	−0.03704 (17)	0.86756 (7)	0.0260 (2)
C31	0.4364 (2)	0.0746 (2)	0.81445 (11)	0.0258 (3)
H31	0.3479	0.1347	0.8375	0.039*
O41	0.18980 (15)	0.40396 (16)	0.73925 (7)	0.0241 (2)
H1O	0.1126	0.3547	0.7617	0.036*
H2O	0.1500	0.5093	0.7246	0.036*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni1	0.01857 (11)	0.01683 (11)	0.01653 (11)	0.00177 (7)	0.00272 (7)	0.00092 (7)
N1	0.0220 (6)	0.0203 (6)	0.0198 (6)	0.0012 (5)	0.0049 (5)	−0.0023 (5)
C1	0.0200 (7)	0.0306 (8)	0.0238 (7)	0.0045 (6)	0.0020 (6)	−0.0043 (6)
C2	0.0230 (7)	0.0321 (8)	0.0212 (7)	0.0019 (6)	0.0007 (6)	−0.0070 (6)
N11	0.0214 (6)	0.0199 (6)	0.0206 (6)	0.0019 (5)	0.0007 (5)	0.0018 (5)
C11	0.0233 (7)	0.0245 (7)	0.0243 (7)	0.0000 (6)	0.0030 (6)	0.0059 (6)
C12	0.0194 (7)	0.0258 (7)	0.0248 (7)	0.0013 (6)	0.0029 (6)	0.0035 (6)
O21	0.0261 (6)	0.0184 (5)	0.0390 (7)	−0.0001 (4)	0.0077 (5)	0.0045 (5)
O22	0.0477 (8)	0.0184 (6)	0.0720 (11)	0.0009 (5)	0.0340 (8)	0.0041 (6)
C21	0.0283 (8)	0.0206 (7)	0.0372 (9)	0.0027 (6)	0.0128 (7)	0.0011 (6)
O31	0.0273 (6)	0.0356 (6)	0.0218 (5)	0.0097 (5)	0.0043 (5)	0.0080 (5)
O32	0.0296 (6)	0.0276 (6)	0.0208 (5)	0.0089 (5)	0.0039 (4)	0.0040 (4)
C31	0.0286 (8)	0.0266 (8)	0.0227 (7)	0.0087 (6)	0.0054 (6)	0.0020 (6)
O41	0.0264 (6)	0.0208 (5)	0.0271 (6)	0.0015 (4)	0.0101 (4)	−0.0002 (4)

Geometric parameters (Å, º)

Ni1—O31	2.0378 (11)	C11—C12^iii	1.385 (2)
Ni1—O41	2.0420 (11)	C11—H11	0.9300
Ni1—O32^i	2.0636 (11)	C12—C11^iii	1.385 (2)
Ni1—O21	2.0643 (12)	C12—H12	0.9300
Ni1—N11	2.1066 (13)	O21—C21	1.2479 (19)
Ni1—N1	2.1171 (12)	O22—C21	1.238 (2)
N1—C2	1.328 (2)	C21—H21	0.9300
N1—C1	1.333 (2)	O31—C31	1.230 (2)
C1—C2^ii	1.382 (2)	O32—C31	1.2492 (19)
C1—H1	0.9300	O32—Ni1^iv	2.0636 (11)
C2—C1^ii	1.382 (2)	C31—H31	0.9299
C2—H2	0.9300	O41—H1O	0.8200
N11—C12	1.334 (2)	O41—H2O	0.8200
N11—C11	1.335 (2)
O31—Ni1—O41	92.30 (5)	C1^ii—C2—H2	119.2
O31—Ni1—O32^i	93.04 (5)	C12—N11—C11	117.00 (13)
O41—Ni1—O32^i	95.94 (5)	C12—N11—Ni1	123.80 (11)
O31—Ni1—O21	90.89 (5)	C11—N11—Ni1	118.62 (10)
O41—Ni1—O21	89.46 (5)	N11—C11—C12^iii	121.75 (14)
O32^i—Ni1—O21	173.18 (5)	N11—C11—H11	119.1
O31—Ni1—N11	178.28 (5)	C12^iii—C11—H11	119.1
O41—Ni1—N11	87.46 (5)	N11—C12—C11^iii	121.25 (14)
O32^i—Ni1—N11	88.68 (5)	N11—C12—H12	119.4
O21—Ni1—N11	87.40 (5)	C11^iii—C12—H12	119.4
O31—Ni1—N1	86.89 (5)	C21—O21—Ni1	123.54 (11)
O41—Ni1—N1	179.19 (5)	O22—C21—O21	125.53 (16)
O32^i—Ni1—N1	84.14 (5)	O22—C21—H21	118.4
O21—Ni1—N1	90.52 (5)	O21—C21—H21	115.9
N11—Ni1—N1	93.35 (5)	C31—O31—Ni1	125.64 (11)
C2—N1—C1	116.76 (13)	C31—O32—Ni1^iv	130.50 (10)
C2—N1—Ni1	118.93 (11)	O31—C31—O32	127.86 (15)
C1—N1—Ni1	124.31 (10)	O31—C31—H31	120.4
N1—C1—C2^ii	121.65 (14)	O32—C31—H31	111.6
N1—C1—H1	119.2	Ni1—O41—H1O	120.0
C2^ii—C1—H1	119.2	Ni1—O41—H2O	116.4
N1—C2—C1^ii	121.59 (15)	H1O—O41—H2O	103.1
N1—C2—H2	119.2

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