catena-Poly[[dipyridine­nickel(II)]-trans-di-μ-chlorido] from powder data

The asymetric unit of the title compound, [NiCl₂(C₅H₅N)₂]_n, contains two Ni^II ions located on different twofold rotational axes, two chloride anions and two pyridine rings in general positions. Each Ni^II ion is coordinated by two pyridine rings, which form dihedral angles of 33.0 (2) and 11.0 (2)° for the two centers, and four chloride anions in a distorted octa­hedral geometry. The chloride anions bridge Ni^II ions related by translation along the short b axes into two crystallographically independent polymeric chains.

Key indicators

• Powder X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.000
• wR factor = 0.000
• Data-to-parameter ratio = 0.0

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT073_ALERT_1_A H-atoms ref, but _hydrogen_treatment reported as     constr

Alert level C
REFI023_ALERT_1_C  _refine_diff_density_max is missing
            Maximum value of final difference map (e A-3).
            The following tests will not be performed
            DIFMN_01,DIFMX_01,DIFMX_02
REFI024_ALERT_1_C  _refine_diff_density_min is missing
            Minimum value of final difference map (e A-3).
            The following tests will not be performed
            DIFMN_01,DIFMN_02,DIFMN_03

Alert level G
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......         61
PLAT164_ALERT_4_G Nr. of Refined C-H H-Atoms in Heavy-Atom Struct.         10
PLAT808_ALERT_5_G No Parsable SHELXL style Weighting Scheme Found           !

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

   3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 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
   1 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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S1. Comment

The title compound (I) was prepared by thermal decomposition of [NiCl₂(C₅H₅N)₄]. The product, [NiCl₂(C₅H₅N)₂], is isotypic with trans-[CoCl₂(C₅H₅N)₂] (Dunitz, 1957). The space group of the title compound was determined to P2/c with a = 19.24 Å, b= 3.63 Å, c = 17.35 Å, β = 116.82 ° and Z = 4. The four nickel atoms are located on two special positions (the twofold axes; Wyckoff positions 2e and 2f). Each nickel atom is coordinated by four chlorine atoms in the equatorial plane and two nitrogen atoms of the pyridine rings in axial positions. This leads to two different distorted coordination octahedra which are connected by edge sharing via bridging Cl atoms to build up two different one-dimensional chains. The distance between neighboured nickel atoms in each chain is equal to the lattice parameter b= 3.63 Å. An orthorhombic unit cell, found by DICVOL (Boultif & Louër, 1991), is related to the pseudo-orthorhombic cell for the isostructural compound trans-[CoCl₂(C₅H₅N)₂], which was discussed by Dunitz (1957). Similar as for the last compound, we found that the structure solution and refinement in orthorhombic symmetry does not lead to satisfying results.

Related literature

For the preparation of related compounds, see: Liptay et al. (1986). For related polymeric chains of octahedrally coordinated transition metal ions, see: Hu et al. (2003) and McConnell et al. (1978). For the isostructural compound [CoCl₂(C₅H₅N)₂] with a detailed discussion of the pseudo-orthorhombic symmetry, see: Dunitz (1957). For details of the indexing algorithm, see: Boultif & Louër (1991). For details of Rietveld refinement, see: Young (1993).

S2. Experimental

[NiCl₂(C₅H₅N)₄] was heated to 400 K for 17 h (capillary, diameter: 0.5 mm).

S3. Refinement

Indexing with DICVOL (Boultif & Louër, 1991) led to two possible unit cells, a monoclinic and an orthorhombic one. The Pawley fit calculates nearly identical profile χ² values for both cells. The structure solution was carried out using simulated annealing with DASH (David et al., 2004) and a modified molecular structure model based on [CoCl₂(C₅H₅N)₂] (Dunitz, 1957). The structure solution was tried in both crystal systems: monoclinic in P2/c with a = 19.24 Å, b = 3.63 Å, c = 17.35 Å, β = 116.82 ° and Z = 4 and several orthorhombic space groups with C-centered cells with a = 17.35 Å, b = 34.34 Å, c = 3.63 Å and Z = 8. As for [CoCl₂(C₅H₅N)₂] (Dunitz, 1957) the structure solution was succesful only for the monoclinic cell. The Rietveld refinement was carried out using TOPAS (Coelho, 2007) with Chebychev polynomial background correction and the pyridine rings restrained to be flat. Thermal parameters of non-hydrogen atoms were combined refined, except Ni. Thermal parameters of hydrogen atoms were constrained to those of the non-hydrogen atoms. The smooth difference curve (Fig. 2) shows that the structure is correct.

Computing details

Data collection: WINXPOW (Stoe & Cie, 2004); cell refinement: DASH (David et al., 2004); data reduction: WINXPOW (Stoe & Cie, 2004; program(s) used to solve structure: DASH (David et al., 2004); program(s) used to refine structure: TOPAS (Coelho, 2007); molecular graphics: Mercury (Macrae et al., 2006); software used to prepare material for publication: PLATON (Spek, 2009).

Figures

	Fig. 1. A portion of the crystal structure of (I) showing the atomic numbering of independent atoms and 50% probability displacement spheres.
	Fig. 2. Experimental (black) and calculated (red) powder profiles of (I) with difference plot (blue).

catena-Poly[[dipyridinenickel(II)]-trans-di-µ-chlorido]

Crystal data

[NiCl2(C5H5N)2]	F(000) = 584.0
Mr = 287.79	Dx = 1.770 Mg m^−3
Monoclinic, P2/c	Cu Kα1 radiation, λ = 1.54056 Å
Hall symbol: -P 2yc	µ = 6.85 mm^−1
a = 19.2483 (4) Å	T = 298 K
b = 3.62535 (4) Å	Particle morphology: no specific habit
c = 17.3504 (2) Å	light green
β = 116.883 (2)°	cylinder, 12 × 0.5 mm
V = 1079.91 (3) Å^3	Specimen preparation: Prepared at 400 K
Z = 4

Data collection

Stoe Stadi-P diffractometer	Data collection mode: transmission
Radiation source: X-ray tube	Scan method: step
Primary focussing, Ge 111 monochromator	2θmin = 2°, 2θmax = 110°, 2θstep = 0.01°
Specimen mounting: Specimen was sealed in a 0.5 mm diameter borosilicate glass capillary

Refinement

Least-squares matrix: full with fixed elements per cycle	126 parameters
Rp = 0.024	61 restraints
Rwp = 0.032	3 constraints
Rexp = 0.028	H-atom parameters constrained
RBragg = 0.009	Weighting scheme based on measured s.u.'s w = 1/σ(Yobs)^2
10599 data points	(Δ/σ)max = 0.001
Excluded region(s): none	Background function: Chebychev polynomial
Profile function: modified Thompson–Cox–Hastings pseudo-Voigt (Young, 1993)	Preferred orientation correction: none

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

	x	y	z	Uiso*/Ueq
N1	0.08340 (13)	0.5786 (4)	0.19907 (14)	0.01963 (5)*
Ni1	0	0.5639 (4)	0.25	0.02118 (10)*
C11	0.15787 (11)	0.4942 (5)	0.25223 (11)	0.01963 (5)*
C15	0.06141 (11)	0.6731 (5)	0.11471 (12)	0.01963 (5)*
Cl1	−0.07443 (14)	1.0643 (6)	0.14865 (16)	0.01963 (5)*
H11	0.1719 (7)	0.428 (3)	0.3113 (6)	0.02356 (6)*
C12	0.21450 (11)	0.5012 (4)	0.22198 (12)	0.01963 (5)*
C14	0.11707 (11)	0.6807 (5)	0.08359 (12)	0.01963 (5)*
H15	0.0088 (6)	0.737 (4)	0.0767 (7)	0.02356 (6)*
H12	0.2662 (6)	0.443 (3)	0.2583 (7)	0.02356 (6)*
C13	0.19366 (11)	0.5934 (5)	0.13910 (12)	0.01963 (5)*
H14	0.1030 (5)	0.740 (4)	0.0275 (7)	0.02356 (6)*
H13	0.2309 (6)	0.599 (4)	0.1200 (7)	0.02356 (6)*
N2	0.58174 (12)	0.1488 (4)	0.37857 (14)	0.01963 (5)*
Ni2	0.5	0.1713 (5)	0.25	0.01780 (10)*
C21	0.55807 (11)	0.1700 (5)	0.44079 (12)	0.01963 (5)*
C25	0.65861 (11)	0.1073 (5)	0.39945 (12)	0.01963 (5)*
Cl2	0.42724 (14)	0.6650 (5)	0.27908 (17)	0.01963 (5)*
H21	0.5032 (6)	0.202 (4)	0.4254 (6)	0.02356 (6)*
C22	0.61220 (10)	0.1492 (5)	0.52776 (12)	0.01963 (5)*
C24	0.71442 (11)	0.0859 (5)	0.48673 (12)	0.01963 (5)*
H25	0.6734 (6)	0.098 (4)	0.3546 (7)	0.02356 (6)*
H22	0.5945 (6)	0.162 (4)	0.5697 (7)	0.02356 (6)*
C23	0.68985 (11)	0.1072 (5)	0.55017 (12)	0.01963 (5)*
H24	0.7656 (6)	0.057 (4)	0.5017 (7)	0.02356 (6)*
H23	0.7259 (6)	0.097 (4)	0.6068 (7)	0.02356 (6)*

Geometric parameters (Å, º)

Ni1—Cl1	2.481 (2)	C12—C13	1.349 (3)
Ni2—Cl2	2.461 (3)	C14—C13	1.385 (2)
N1—Ni1	2.155 (3)	C14—H14	0.91 (1)
N1—C11	1.343 (2)	C13—H13	0.92 (1)
N1—C15	1.371 (3)	C21—H21	0.97 (1)
N2—Ni2	2.070 (2)	C21—C22	1.395 (2)
N2—C21	1.350 (4)	C25—C24	1.408 (2)
N2—C25	1.363 (3)	C25—H25	0.94 (1)
C11—H11	0.96 (1)	C22—H22	0.93 (1)
C11—C12	1.408 (3)	C22—C23	1.372 (3)
C15—C14	1.401 (4)	C24—C23	1.383 (4)
C15—H15	0.954 (9)	C24—H24	0.90 (1)
C12—H12	0.93 (1)	C23—H23	0.912 (9)
Ni1—N1—C15	121.1 (2)	C11—C12—H12	121.0 (7)
Ni1—Cl1—Ni1	93.8 (1)	C11—C12—C13	119.7 (2)
Ni1—N1—C11	118.3 (2)	C11—N1—C15	120.6 (2)
Ni2—N2—C21	119.5 (2)	C12—C13—C14	120.3 (2)
Ni2—N2—C25	119.7 (2)	C12—C13—H13	119.2 (7)
Ni2—Cl2—Ni2	94.0 (1)	C13—C14—H14	120.4 (7)
N1—Ni1—Cl1	89.4 (1)	C14—C15—H15	119.1 (7)
N1—Ni1—N1	177.1 (1)	C14—C13—H13	120.3 (7)
N1—C11—C12	120.4 (2)	C15—C14—C13	119.0 (2)
N1—C15—C14	119.7 (2)	C15—C14—H14	120.5 (7)
N1—C15—H15	121.2 (7)	C21—N2—C25	120.8 (2)
N1—C11—H11	119.0 (7)	C21—C22—H22	118.9 (8)
N2—C21—H21	120.3 (7)	C21—C22—C23	119.84 (19)
N2—C21—C22	120.3 (2)	C22—C23—C24	120.1 (2)
N2—C25—C24	120.0 (2)	C22—C23—H23	120.7 (8)
N2—C25—H25	118.8 (8)	C23—C24—H24	120.6 (8)
N2—Ni2—Cl2	91.9 (1)	C23—C24—H24	120.6 (8)
N2—Ni2—N2	175.5 (1)	C24—C25—H25	120.5 (8)
Cl1—Ni1—Cl1	86.1 (1)	C24—C23—H23	119.2 (8)
Cl1—Ni1—Cl1	179.9 (1)	C25—C24—C23	118.9 (2)
Cl1—Ni1—Cl1	93.8 (1)	C25—C24—H24	120.8 (8)
Cl1—Ni1—Cl1	86.2 (1)	H11—C11—C12	119.7 (7)
Cl2—Ni2—Cl2	86.7 (1)	H12—C12—C13	119.3 (7)
Cl2—Ni2—Cl2	179.3 (1)	H22—C22—C23	121.3 (8)
Cl2—Ni2—Cl2	94.0 (1)	H21—C21—C22	119.1 (7)
Cl2—Ni2—Cl2	85.3 (1)