Di­chlorido­(pyridine-κN)[2,3,5,6-tetra­kis­(pyridin-2-yl)pyrazine-κ3N2,N1,N6]nickel(II)

Ha, K.

doi:10.1107/S2414314621000948

metal-organic compounds

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ISSN: 2414-3146

Volume 6| Part 2| February 2021| x210094

https://doi.org/10.1107/S2414314621000948

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Dichlorido(pyridine-κN)[2,3,5,6-tetrakis(pyridin-2-yl)pyrazine-κ³N²,N¹,N⁶]nickel(II)

Kwang Ha ^a ^*

^aChonnam National University, School of Chemical Engineering, Research Institute of Catalysis, Gwangju, Republic of Korea
^*Correspondence e-mail: hakwang@chonnam.ac.kr

Edited by M. Weil, Vienna University of Technology, Austria (Received 21 January 2021; accepted 26 January 2021; online 2 February 2021)

In the title complex, [NiCl₂(C₅H₅N)(C₂₄H₁₆N₆)], the Ni^II ion is six-coordinated in a distorted octahedral coordination environment defined by three N atoms of the tridentate 2,3,5,6-tetra-2-pyridylpyrazine ligand, one N atom of the pyridine ligand and two Cl⁻ anions, with the latter being mutually trans. The complex is disposed about a twofold rotation axis along the a axis. The complex molecules are connected in the crystal via C—H⋯Cl, C—H⋯N and π–π [closest inter-centroid separation = 3.7446 (14) Å between pyridyl rings].

Keywords: crystal structure; nickel(II) complex; pyridine; 2,3,5,6-tetra-2-pyridylpyrazine.

CCDC reference: 2058988

Structure description

With reference to the title compound, [NiCl₂(py)(tppz)] (py = pyridine, tppz = 2,3,5,6-tetra-2-pyridylpyrazine), the crystal structures of a related tetranuclear Ni^II complex, [Ni₄Cl₆(tppz)₂(CH₃OH)₄]Cl₂·CH₃OH (Winpenny et al., 2005 ), and of a dinuclear Mn^II complex, [Mn₂Cl₄(tppz)₂] (Ha, 2011 ), have been determined previously.

In the title complex, the central Ni^II cation is six-coordinated in a considerably distorted octahedral coordination environment defined by three N atoms of the tridentate tppz ligand, one N atom of the pyridine ligand and two Cl⁻ anions (Fig. 1). The complex is disposed about a twofold rotation axis along the a axis; thus the asymmetric unit contains one half of the complex. The main contribution to the distortion is the tight N—Ni—N chelating angle [<N1—Ni1—N3 = 77.97 (5)°], which results in a non-linear trans arrangement of the N3—Ni1—N3ⁱ bonds [<N3—Ni1—N3ⁱ = 155.95 (11)°; symmetry code: (i) x − y, −y, −z], whereas the Cl1—Ni1—Cl1ⁱ bonds are almost linear [<Cl1—Ni1—Cl1ⁱ = 175.77 (4)°]. The Ni—N[pyrazine(N1) or pyridyl(N3, N5)] bond lengths are roughly equivalent, with distances of 2.008 (3) – 2.1026 (19) Å. The pyrazine ring (N1—C1ⁱ) slightly deviates from planarity, with a maximum deviation of 0.057 (2) Å for the C2 atom from the least-squares plane of the ring. The dihedral angles between the nearly planar pyridyl rings and the least-squares plane of their carrier pyrazine ring are 14.90 (4)° for the coordinating pyridyl ring (N3—C7) and 54.42 (9)° for the non-coordinating pyridyl ring (N4—C12), respectively. The dihedral angle between the pyrazine ring and the pyridine ligand (N5—C13ⁱ) is 57.8 (1)°.

Figure 1
The molecular structure of the title compound showing the atom labelling and displacement ellipsoids drawn at the 50% probability level for all non-H atoms. [Symmetry code: (i) x − y, −y, −z.]

In the crystal, the complex displays numerous inter- and intramolecular π–π interactions between adjacent six-membered rings. The most significant interaction of this kind is that between Cg1 (the centroid of the ring N3/C3–C7) and Cg1ⁱⁱ [symmetry code: (ii) x, x − y, −z + $[{1\over 6}]$ ], with a centroid-to-centroid distance of 3.7446 (14) Å and a dihedral angle between the ring planes of 22.24 (12)°. In addition, the complex exhibits inter- and intramolecular C—H⋯N and C—H⋯Cl hydrogen bonds (Table 1) that consolidate the three-dimensional packing (Fig. 2).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C6—H6⋯Cl1ⁱ	0.94	2.78	3.513 (3)	136
C10—H10⋯N4ⁱⁱ	0.94	2.46	3.360 (3)	161
C12—H12⋯Cl1ⁱⁱⁱ	0.94	2.71	3.602 (3)	160
C13—H13⋯Cl1^iv	0.94	2.68	3.261 (3)	121
Symmetry codes: (i) $[x-y, x, z+{\script{1\over 6}}]$ ; (ii) $[y+1, -x+y+1, z-{\script{1\over 6}}]$ ; (iii) $[-y+1, x-y, z+{\script{1\over 3}}]$ ; (iv) .

Figure 2
The packing in the crystal of the title compound, viewed approximately along the a axis. Hydrogen-bonding interactions are drawn as dashed lines. Colour codes are as in Fig. 1

Synthesis and crystallization

To a solution of NiCl₂·6H₂O (0.3779 g, 1.590 mmol) in ethanol (20 ml) was added 2,3,5,6-tetra-2-pyridylpyrazine (0.6220 g, 1.601 mmol), followed by stirring for 24 h at rooom temperature. The formed precipitate was separated by filtration, washed with ethanol and acetone, and dried at 323 K, to give a brown powder (0.5045 g). Brown crystals suitable for X-ray analysis were obtained by slow evaporation from its pyridine/N,N-dimethylformamide (DMF) solution at 333 K.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The maximum and minimum remaining electron density peaks in the difference Fourier map are located 0.34 and 0.74 Å, respectively, from atoms C9 and Ni1.

Table 2
Experimental details

Crystal data
Chemical formula	[NiCl₂(C₅H₅N)(C₂₄H₁₆N₆)]
M_r	597.14
Crystal system, space group	Hexagonal, P6₁22
Temperature (K)	223
a, c (Å)	13.8244 (4), 23.8935 (8)
V (Å³)	3954.6 (3)
Z	6
Radiation type	Mo Kα
μ (mm⁻¹)	0.97
Crystal size (mm)	0.15 × 0.10 × 0.07

Data collection
Diffractometer	PHOTON 100 CMOS detector
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	0.700, 0.744
No. of measured, independent and observed [I > 2σ(I)] reflections	125055, 2614, 2412
R_int	0.106
(sin θ/λ)_max (Å⁻¹)	0.618

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.024, 0.054, 1.08
No. of reflections	2614
No. of parameters	179
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.22, −0.14
Absolute structure	Flack x determined using 894 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013 ).
Absolute structure parameter	−0.002 (5)
Computer programs: APEX2 and SAINT (Bruker, 2016 ), SHELXT (Sheldrick, 2015a ), SHELXL (Sheldrick, 2015b ) and ORTEP-3 for Windows (Farrugia, 2012 ).

Structural data

CCDC reference: 2058988

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314621000948/wm4144sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314621000948/wm4144Isup2.hkl

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2016); cell refinement: SAINT (Bruker, 2016); data reduction: SAINT (Bruker, 2016); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL (Sheldrick, 2015b); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: SHELXL (Sheldrick, 2015b).

Dichlorido(pyridine-κN)[2,3,5,6-tetrakis(pyridin-2-yl)pyrazine-κ³N²,N¹,N⁶]nickel(II) top

Crystal data top

[NiCl₂(C₅H₅N)(C₂₄H₁₆N₆)]	D_x = 1.504 Mg m⁻³
M_r = 597.14	Mo Kα radiation, λ = 0.71073 Å
Hexagonal, P6₁22	Cell parameters from 9199 reflections
a = 13.8244 (4) Å	θ = 2.4–26.0°
c = 23.8935 (8) Å	µ = 0.97 mm⁻¹
V = 3954.6 (3) Å³	T = 223 K
Z = 6	Block, brown
F(000) = 1836	0.15 × 0.10 × 0.07 mm

Data collection top

PHOTON 100 CMOS detector diffractometer	2412 reflections with I > 2σ(I)
Radiation source: sealed tube	R_int = 0.106
φ and ω scans	θ_max = 26.1°, θ_min = 2.4°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −17→17
T_min = 0.700, T_max = 0.744	k = −17→17
125055 measured reflections	l = −29→29
2614 independent reflections

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.024	H-atom parameters constrained
wR(F²) = 0.054	w = 1/[σ²(F_o²) + (0.0277P)² + 0.9047P] where P = (F_o² + 2F_c²)/3
S = 1.08	(Δ/σ)_max < 0.001
2614 reflections	Δρ_max = 0.22 e Å⁻³
179 parameters	Δρ_min = −0.14 e Å⁻³
0 restraints	Absolute structure: Flack x determined using 894 quotients [(I⁺)-(I^-)]/[(I⁺)+(I^-)] (Parsons et al., 2013).
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.002 (5)

Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Ni1	0.41510 (3)	0.0000	0.0000	0.01866 (12)
Cl1	0.44000 (6)	0.03687 (5)	−0.09968 (3)	0.03369 (17)
N1	0.56034 (18)	0.0000	0.0000	0.0181 (6)
N2	0.75658 (19)	0.0000	0.0000	0.0204 (6)
N3	0.53182 (16)	0.17007 (16)	0.01208 (8)	0.0196 (4)
N4	0.86393 (17)	0.24353 (17)	0.07265 (9)	0.0265 (5)
N5	0.2636 (2)	0.0000	0.0000	0.0303 (7)
C1	0.65538 (19)	0.09724 (18)	0.00453 (10)	0.0177 (5)
C2	0.75545 (19)	0.09505 (19)	0.00914 (9)	0.0194 (5)
C3	0.6391 (2)	0.19584 (19)	0.00471 (10)	0.0187 (5)
C4	0.7236 (2)	0.30472 (19)	−0.00359 (11)	0.0242 (5)
H4	0.7967	0.3205	−0.0114	0.029*
C5	0.6992 (2)	0.3896 (2)	−0.00019 (12)	0.0290 (6)
H5	0.7557	0.4642	−0.0056	0.035*
C6	0.5912 (2)	0.3645 (2)	0.01124 (10)	0.0279 (6)
H6	0.5734	0.4213	0.0157	0.033*
C7	0.5104 (2)	0.2537 (2)	0.01591 (10)	0.0236 (6)
H7	0.4362	0.2361	0.0221	0.028*
C8	0.8647 (2)	0.1935 (2)	0.02484 (10)	0.0199 (5)
C9	0.9581 (2)	0.2297 (2)	−0.00795 (12)	0.0299 (6)
H9	0.9555	0.1912	−0.0408	0.036*
C10	1.0561 (2)	0.3239 (2)	0.00830 (12)	0.0385 (7)
H10	1.1210	0.3514	−0.0137	0.046*
C11	1.0565 (2)	0.3761 (2)	0.05722 (11)	0.0323 (6)
H11	1.1217	0.4403	0.0694	0.039*
C12	0.9594 (2)	0.3327 (2)	0.08824 (11)	0.0309 (6)
H12	0.9608	0.3679	0.1221	0.037*
C13	0.1829 (2)	−0.0605 (2)	0.03686 (14)	0.0414 (7)
H13	0.1959	−0.1024	0.0638	0.050*
C14	0.0811 (3)	−0.0642 (3)	0.03700 (18)	0.0579 (10)
H14	0.0250	−0.1105	0.0624	0.070*
C15	0.0629 (3)	0.0000	0.0000	0.0639 (15)
H15	−0.0051	0.0000	0.0000	0.077*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ni1	0.01813 (17)	0.0145 (2)	0.0222 (2)	0.00723 (11)	0.00093 (9)	0.00185 (17)
Cl1	0.0480 (4)	0.0269 (3)	0.0215 (3)	0.0152 (3)	−0.0012 (3)	0.0025 (2)
N1	0.0175 (10)	0.0147 (13)	0.0210 (14)	0.0073 (7)	−0.0002 (6)	−0.0003 (12)
N2	0.0200 (11)	0.0174 (14)	0.0231 (15)	0.0087 (7)	−0.0006 (6)	−0.0012 (13)
N3	0.0212 (10)	0.0172 (10)	0.0196 (10)	0.0091 (9)	0.0005 (8)	0.0004 (8)
N4	0.0234 (11)	0.0264 (11)	0.0231 (11)	0.0074 (9)	0.0023 (9)	−0.0022 (9)
N5	0.0247 (12)	0.0244 (16)	0.0417 (19)	0.0122 (8)	0.0024 (8)	0.0048 (15)
C1	0.0189 (11)	0.0155 (11)	0.0171 (12)	0.0073 (9)	0.0013 (10)	−0.0007 (9)
C2	0.0195 (12)	0.0165 (12)	0.0194 (12)	0.0069 (10)	0.0017 (10)	0.0010 (10)
C3	0.0220 (12)	0.0163 (11)	0.0176 (11)	0.0095 (10)	−0.0010 (10)	−0.0016 (10)
C4	0.0192 (13)	0.0189 (12)	0.0329 (14)	0.0082 (10)	0.0026 (11)	0.0010 (11)
C5	0.0285 (14)	0.0168 (12)	0.0393 (16)	0.0094 (11)	0.0007 (13)	0.0016 (12)
C6	0.0345 (14)	0.0184 (12)	0.0351 (14)	0.0166 (12)	0.0002 (12)	−0.0012 (11)
C7	0.0257 (13)	0.0237 (13)	0.0254 (14)	0.0153 (11)	0.0025 (10)	0.0015 (10)
C8	0.0186 (12)	0.0160 (12)	0.0241 (13)	0.0080 (10)	−0.0010 (10)	−0.0004 (10)
C9	0.0228 (13)	0.0280 (14)	0.0321 (15)	0.0075 (11)	0.0047 (12)	−0.0085 (12)
C10	0.0206 (14)	0.0381 (16)	0.0406 (18)	0.0025 (12)	0.0078 (12)	−0.0054 (14)
C11	0.0227 (14)	0.0252 (15)	0.0332 (16)	0.0003 (12)	−0.0021 (12)	−0.0018 (12)
C12	0.0319 (14)	0.0260 (14)	0.0232 (13)	0.0057 (12)	−0.0020 (12)	−0.0053 (11)
C13	0.0311 (16)	0.0357 (17)	0.0571 (19)	0.0166 (15)	0.0107 (15)	0.0109 (15)
C14	0.0347 (18)	0.057 (2)	0.082 (3)	0.0222 (17)	0.0195 (18)	0.013 (2)
C15	0.0362 (19)	0.067 (4)	0.098 (5)	0.0336 (18)	0.0005 (18)	0.001 (4)

Geometric parameters (Å, º) top

Ni1—N1	2.008 (3)	C4—H4	0.9400
Ni1—N5	2.094 (3)	C5—C6	1.380 (4)
Ni1—N3ⁱ	2.1026 (19)	C5—H5	0.9400
Ni1—N3	2.1026 (19)	C6—C7	1.377 (4)
Ni1—Cl1ⁱ	2.4238 (6)	C6—H6	0.9400
Ni1—Cl1	2.4238 (6)	C7—H7	0.9400
N1—C1	1.334 (3)	C8—C9	1.373 (3)
N1—C1ⁱ	1.334 (3)	C9—C10	1.385 (4)
N2—C2ⁱ	1.340 (3)	C9—H9	0.9400
N2—C2	1.340 (3)	C10—C11	1.373 (4)
N3—C7	1.332 (3)	C10—H10	0.9400
N3—C3	1.353 (3)	C11—C12	1.380 (4)
N4—C12	1.332 (3)	C11—H11	0.9400
N4—C8	1.338 (3)	C12—H12	0.9400
N5—C13ⁱ	1.337 (3)	C13—C14	1.382 (4)
N5—C13	1.337 (3)	C13—H13	0.9400
C1—C2	1.403 (3)	C14—C15	1.362 (4)
C1—C3	1.488 (3)	C14—H14	0.9400
C2—C8	1.489 (3)	C15—C14ⁱ	1.362 (4)
C3—C4	1.382 (3)	C15—H15	0.9400
C4—C5	1.377 (4)

N1—Ni1—N5	180.0	C5—C4—H4	120.5
N1—Ni1—N3ⁱ	77.97 (5)	C3—C4—H4	120.5
N5—Ni1—N3ⁱ	102.03 (5)	C4—C5—C6	119.5 (2)
N1—Ni1—N3	77.97 (5)	C4—C5—H5	120.3
N5—Ni1—N3	102.03 (5)	C6—C5—H5	120.3
N3ⁱ—Ni1—N3	155.95 (11)	C7—C6—C5	118.0 (2)
N1—Ni1—Cl1ⁱ	87.89 (2)	C7—C6—H6	121.0
N5—Ni1—Cl1ⁱ	92.11 (2)	C5—C6—H6	121.0
N3ⁱ—Ni1—Cl1ⁱ	87.19 (5)	N3—C7—C6	123.4 (2)
N3—Ni1—Cl1ⁱ	91.94 (5)	N3—C7—H7	118.3
N1—Ni1—Cl1	87.89 (2)	C6—C7—H7	118.3
N5—Ni1—Cl1	92.11 (2)	N4—C8—C9	123.2 (2)
N3ⁱ—Ni1—Cl1	91.93 (5)	N4—C8—C2	114.9 (2)
N3—Ni1—Cl1	87.18 (5)	C9—C8—C2	121.9 (2)
Cl1ⁱ—Ni1—Cl1	175.77 (4)	C8—C9—C10	118.8 (2)
C1—N1—C1ⁱ	122.5 (3)	C8—C9—H9	120.6
C1—N1—Ni1	118.76 (13)	C10—C9—H9	120.6
C1ⁱ—N1—Ni1	118.76 (13)	C11—C10—C9	118.6 (2)
C2ⁱ—N2—C2	119.7 (3)	C11—C10—H10	120.7
C7—N3—C3	118.1 (2)	C9—C10—H10	120.7
C7—N3—Ni1	126.90 (16)	C10—C11—C12	118.7 (2)
C3—N3—Ni1	113.83 (15)	C10—C11—H11	120.6
C12—N4—C8	117.2 (2)	C12—C11—H11	120.6
C13ⁱ—N5—C13	117.1 (4)	N4—C12—C11	123.4 (3)
C13ⁱ—N5—Ni1	121.44 (18)	N4—C12—H12	118.3
C13—N5—Ni1	121.44 (18)	C11—C12—H12	118.3
N1—C1—C2	118.0 (2)	N5—C13—C14	122.7 (3)
N1—C1—C3	113.6 (2)	N5—C13—H13	118.7
C2—C1—C3	128.4 (2)	C14—C13—H13	118.7
N2—C2—C1	120.2 (2)	C15—C14—C13	119.4 (4)
N2—C2—C8	115.7 (2)	C15—C14—H14	120.3
C1—C2—C8	124.0 (2)	C13—C14—H14	120.3
N3—C3—C4	121.6 (2)	C14ⁱ—C15—C14	118.6 (5)
N3—C3—C1	114.0 (2)	C14ⁱ—C15—H15	120.7
C4—C3—C1	124.4 (2)	C14—C15—H15	120.7
C5—C4—C3	119.1 (2)

C1ⁱ—N1—C1—C2	−5.20 (15)	C4—C5—C6—C7	−3.4 (4)
Ni1—N1—C1—C2	174.80 (15)	C3—N3—C7—C6	1.8 (4)
C1ⁱ—N1—C1—C3	175.6 (2)	Ni1—N3—C7—C6	−164.88 (19)
Ni1—N1—C1—C3	−4.4 (2)	C5—C6—C7—N3	2.6 (4)
C2ⁱ—N2—C2—C1	−5.36 (16)	C12—N4—C8—C9	0.2 (4)
C2ⁱ—N2—C2—C8	173.8 (2)	C12—N4—C8—C2	−179.4 (2)
N1—C1—C2—N2	10.7 (3)	N2—C2—C8—N4	−125.1 (2)
C3—C1—C2—N2	−170.2 (2)	C1—C2—C8—N4	54.0 (3)
N1—C1—C2—C8	−168.31 (19)	N2—C2—C8—C9	55.3 (3)
C3—C1—C2—C8	10.8 (4)	C1—C2—C8—C9	−125.6 (3)
C7—N3—C3—C4	−5.6 (4)	N4—C8—C9—C10	−1.4 (4)
Ni1—N3—C3—C4	162.80 (19)	C2—C8—C9—C10	178.1 (3)
C7—N3—C3—C1	176.4 (2)	C8—C9—C10—C11	1.3 (5)
Ni1—N3—C3—C1	−15.3 (3)	C9—C10—C11—C12	0.1 (5)
N1—C1—C3—N3	13.1 (3)	C8—N4—C12—C11	1.3 (4)
C2—C1—C3—N3	−166.0 (2)	C10—C11—C12—N4	−1.4 (5)
N1—C1—C3—C4	−164.9 (2)	C13ⁱ—N5—C13—C14	1.5 (3)
C2—C1—C3—C4	16.0 (4)	Ni1—N5—C13—C14	−178.5 (3)
N3—C3—C4—C5	4.8 (4)	N5—C13—C14—C15	−3.1 (5)
C1—C3—C4—C5	−177.3 (2)	C13—C14—C15—C14ⁱ	1.5 (3)
C3—C4—C5—C6	−0.2 (4)

Symmetry code: (i) x−y, −y, −z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6···Cl1ⁱⁱ	0.94	2.78	3.513 (3)	136
C10—H10···N4ⁱⁱⁱ	0.94	2.46	3.360 (3)	161
C12—H12···Cl1^iv	0.94	2.71	3.602 (3)	160
C13—H13···Cl1ⁱ	0.94	2.68	3.261 (3)	121

Symmetry codes: (i) x−y, −y, −z; (ii) x−y, x, z+1/6; (iii) y+1, −x+y+1, z−1/6; (iv) −y+1, x−y, z+1/3.

Acknowledgements

The author thanks the KBSI, Seoul Center, for the X-ray data collection.

Funding information

This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (grant No. 2018R1D1A1B07050550).

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