Crystal structure of di-aqua-bis-(2-chloro-pyridine-κN)bis-(thio-cyanato-κN)nickel(II).

The asymmetric unit of the title compound, [Ni(NCS)2(C5H4ClN)2(H2O)2], consists of one nickel(II) cation that is located on a center of inversion and one thio-cyanate anion, one water mol-ecule and one 2-chloro-pyridine ligand all occupying general positions. The NiII cation is octa-hedrally coordinated by two terminal N-bound thio-cyanato ligands, two aqua ligands and two N-bound 2-chloro-pyridine ligands into discrete complexes. Individual complexes are linked by inter-molecular O-H⋯S and O-H⋯Cl hydrogen-bonding inter-actions into a layered network extending parallel to the bc plane. Weak inter-actions of types C-H⋯S and C-H⋯Cl consolidate the crystal packing.

Chemical context

The synthesis of materials with inter­esting cooperative magnetic properties is still a major field in coordination chemistry (Zhang et al., 2011 ▸). One feasible strategy for the preparation of such compounds is to link paramagnetic cations with small anionic ligands such as, for example, thio­cyanate anions to enable a magnetic exchange between the cations (Palion-Gazda et al., 2015 ▸; Massoud et al., 2013 ▸). In this regard, our group has reported on a number of coordination polymers with bridging thio­cyanato ligands. Dependent on the metal cation and the neutral co-ligand, they show different magnetic phenomena including a slow relaxation of the magnetization, which is indicative for single-chain magnetism (Werner et al., 2014 ▸, 2015a ▸,b ▸,c ▸). In the context of this research, discrete complexes are likewise of inter­est because such compounds can be transformed into the desired polymeric systems by thermal decomposition (Näther et al., 2013 ▸). In view of our systematic studies, we became inter­ested into compounds based on 2-chloro­pyridine as co-ligand, for which only two different polymorphs were found for representatives containing Zn or Co (Wöhlert et al., 2013 ▸). In a more recent study, investigations were also carried out for Ni that led to the title compound being characterized by single crystal X-ray diffraction. Unfortunately, no single-phase crystalline powder could be synthesized, which prevented further investigations of its physical properties.

Structural commentary

The asymmetric unit of the title compound, [Ni(NCS)2(C5H4NCl)2(H2O)2], consists of one NiII cation, one thio­cyanate anion, one water mol­ecule and one neutral 2-chloro­pyridine co-ligand. The cation is located on a center of inversion whereas all ligands are located on general positions. The NiII cation is coordinated by two terminal N-bound inorganic anionic ligands, two water mol­ecules and two 2-chloro­pyridine ligands that are coordinated via the pyridine N atom in an all-trans configuration (Fig. 1 ▸). As expected, and in agreement with values reported in literature (Đaković et al., 2008 ▸; Werner et al., 2015b ▸), the Ni—N bond lengths to the thio­cyanato ligands are significantly shorter[2.018 (3) Å] than to the pyridine N atom of the neutral 2-chloro­pyridine ligand [2.208 (3) Å].

Figure 1

View of a discrete complex with labelling and displacement ellipsoids drawn at the 50% probability level. [Symmetry code: (i) −x + , −y + , -z.+1.]

Supra­molecular features

In the crystal, discrete complexes are linked by pairs of inter­molecular O—H⋯S hydrogen bonds between one of the two water H atoms and the thio­cyanato S atoms of a neighboring complex into centrosymmetric dimers that are further connected into chains along the b axis (Fig. 2 ▸, Table 1 ▸). Neighbouring complexes are additionally linked in the same direction by pairs of C—H⋯Cl hydrogen bonds between the chloro substituent of one complex and one pyridine H atom of a neighbouring complex (Fig. 2 ▸, Table 1 ▸). These chains are further linked by O—H⋯S hydrogen bonding between the second water H atom of one complex and a thio­cyanato S atom of a neighbouring complex into layers parallel to the bc plane (Fig. 3 ▸, Table 1 ▸). Within these layers, weak C—H⋯Cl hydrogen bonding is present (Table 1 ▸). Weak intra­molecular O—H⋯Cl inter­actions are also observed (Figs. 2 ▸ and 3 ▸, Table 1 ▸).

Figure 2

View of the hydrogen-bonded chain that elongates along the b axis. Hydrogen bonds are shown as dashed lines.

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C11—H21⋯S1i	0.95	2.99	3.904 (4)	162
C13—H23⋯S1ii	0.95	2.99	3.796 (4)	143
C14—H24⋯Cl1iii	0.95	2.96	3.796 (4)	147
O1—H1O1⋯S1iv	0.82	2.39	3.175 (2)	160
O1—H2O1⋯S1v	0.82	2.53	3.239 (2)	145
O1—H2O1⋯Cl1vi	0.82	2.75	3.180 (3)	115

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) ; (vi) .

Figure 3

Crystal structure of the title compound showing the hydrogen-bonded layers with hydrogen bonds shown as dashed lines.

Database survey

To the best of our knowledge, there are only four coordination compounds containing thio­cyanato and 2-chloro­pyridine ligands deposited in the Cambridge Structure Database (Version 5.37, last update 2015; Groom et al., 2016 ▸). The structures consist of tetra­hedrally coordinated metal cations (Co and Zn) where each metal cation is surrounded by two 2-chloro­pyridine ligands as well as two thio­cyanate anions (Wöhlert et al., 2013 ▸). A general search for coordination compounds with 2-chloro­pyridine ligands resulted in 16 structures including the aforementioned ones. Two examples relate to a Pd compound, similar to the Co and Zn ones, however with the PdII cation in a square-planar conformation coordinated by two 2-chloro­pyridine ligands as well as two azide anions (Beck et al., 2001 ▸) as well as a Cu compound with a square-pyramidal coordinated metal cation surrounded by two 2-chloro­pyridine ligands, one water ligand and two chloride anions (Jin et al., 2005 ▸).

Synthesis and crystallization

Ba(NCS)2·3H2O, Ni(SO4)·6H2O and 2-chloro­pyridine were purchased from Alfa Aesar. Ni(NCS)2 was synthesized by stirring 17.5 g Ba(NCS)2·3H2O (57 mmol) with 15.0 g Ni(SO4)·6H2O (57 mmol) in 500 ml water. The green residue was filtered off and the filtrate was dried using a rotary evaporator. The homogeneity was checked by X-ray powder diffraction and elemental analysis. Crystals of the title compound suitable for single crystal X-ray diffraction were obtained by the reaction of 26.2 mg Ni(NCS)2 (0.15 mmol) with 56.0 µl 2-chloro­pyridine (0.6 mmol) in ethanol (1.0 ml) after a few days.

Refinement

Crystal data, data collection, and structure refinement details are summarized in Table 2 ▸. The CH H atoms were positioned with idealized geometry and were refined in a riding model with U iso(H) = 1.2U eq(C). The OH H atoms were located in a difference map, and their bond lengths constrained to 0.82 Å, with U iso(H) = 1.5U eq(O).

Table 2

Experimental details

Crystal data
Chemical formula	[Ni(NCS)2(C5H4ClN)2(H2O)2]
M r	437.99
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	200
a, b, c (Å)	19.5045 (15), 7.5486 (5), 14.9387 (11)
β (°)	125.560 (7)
V (Å3)	1789.3 (3)
Z	4
Radiation type	Mo Kα
μ (mm−1)	1.63
Crystal size (mm)	0.14 × 0.09 × 0.06
Data collection
Diffractometer	STOE IPDS1
Absorption correction	Numerical (X-RED32 and X-SHAPE; Stoe, 2008 ▸)
T min, T max	0.796, 0.881
No. of measured, independent and observed [I > 2σ(I)] reflections	7195, 1568, 1321
R int	0.086
(sin θ/λ)max (Å−1)	0.596
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S	0.049, 0.123, 1.03
No. of reflections	1568
No. of parameters	107
H-atom treatment	H-atom parameters constrained
Δρmax, Δρmin (e Å−3)	0.87, −0.87

Computer programs: X-AREA (Stoe, 2008 ▸), SHELXS97 (Sheldrick, 2008 ▸), SHELXL2014/7 (Sheldrick, 2015 ▸), XP in SHELXTL (Sheldrick, 2008 ▸), DIAMOND (Brandenburg, 1999 ▸) and publCIF (Westrip, 2010 ▸).

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989016015218/wm5326sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989016015218/wm5326Isup2.hkl

CCDC reference: 1506903

Additional supporting information: crystallographic information; 3D view; checkCIF report

[Ni(NCS)2(C5H4ClN)2(H2O)2]	F(000) = 888
Mr = 437.99	Dx = 1.626 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 19.5045 (15) Å	Cell parameters from 7195 reflections
b = 7.5486 (5) Å	θ = 2.8–25.1°
c = 14.9387 (11) Å	µ = 1.63 mm−1
β = 125.560 (7)°	T = 200 K
V = 1789.3 (3) Å3	Block, blue
Z = 4	0.14 × 0.09 × 0.06 mm

STOE IPDS-1 diffractometer	1321 reflections with I > 2σ(I)
Phi scans	Rint = 0.086
Absorption correction: numerical (X-Red and X-Shape; Stoe, 2008)	θmax = 25.1°, θmin = 2.8°
Tmin = 0.796, Tmax = 0.881	h = −23→23
7195 measured reflections	k = −8→8
1568 independent reflections	l = −17→17

Refinement on F2	Hydrogen site location: mixed
Least-squares matrix: full	H-atom parameters constrained
R[F2 > 2σ(F2)] = 0.049	w = 1/[σ2(Fo2) + (0.0887P)2] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.123	(Δ/σ)max < 0.001
S = 1.03	Δρmax = 0.87 e Å−3
1568 reflections	Δρmin = −0.87 e Å−3
107 parameters	Extinction correction: SHELXL-2014/7 (Sheldrick 2015), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraints	Extinction coefficient: 0.0046 (11)

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.

	x	y	z	Uiso*/Ueq
Ni1	0.2500	0.7500	0.5000	0.0294 (3)
N1	0.2189 (2)	0.5551 (4)	0.3900 (2)	0.0374 (7)
C1	0.2063 (2)	0.4433 (4)	0.3291 (3)	0.0307 (7)
S1	0.18836 (7)	0.28294 (11)	0.24339 (8)	0.0404 (3)
N10	0.1155 (2)	0.7772 (4)	0.4334 (3)	0.0360 (7)
C10	0.0670 (2)	0.9202 (4)	0.4075 (3)	0.0367 (8)
C11	−0.0154 (3)	0.9163 (6)	0.3732 (3)	0.0500 (10)
H21	−0.0466	1.0227	0.3568	0.060*
C12	−0.0520 (3)	0.7528 (6)	0.3630 (4)	0.0586 (12)
H22	−0.1088	0.7447	0.3395	0.070*
C13	−0.0039 (3)	0.6027 (6)	0.3879 (4)	0.0520 (10)
H23	−0.0271	0.4888	0.3814	0.062*
C14	0.0780 (3)	0.6201 (5)	0.4222 (3)	0.0425 (8)
H24	0.1104	0.5153	0.4391	0.051*
Cl1	0.11007 (7)	1.12552 (11)	0.41519 (9)	0.0523 (4)
O1	0.26098 (19)	0.5775 (3)	0.6135 (2)	0.0506 (8)
H1O1	0.2506	0.5933	0.6588	0.076*
H2O1	0.2750	0.4730	0.6262	0.076*

	U11	U22	U33	U12	U13	U23
Ni1	0.0383 (4)	0.0205 (4)	0.0375 (4)	0.0053 (2)	0.0267 (3)	0.0031 (2)
N1	0.0443 (18)	0.0298 (14)	0.0434 (17)	0.0060 (11)	0.0285 (15)	−0.0008 (12)
C1	0.0350 (18)	0.0247 (15)	0.0417 (19)	0.0052 (12)	0.0276 (17)	0.0077 (13)
S1	0.0613 (7)	0.0251 (4)	0.0505 (6)	−0.0030 (3)	0.0415 (5)	−0.0032 (3)
N10	0.0388 (17)	0.0317 (14)	0.0423 (17)	0.0040 (11)	0.0264 (15)	0.0018 (11)
C10	0.036 (2)	0.0375 (17)	0.0383 (19)	0.0087 (14)	0.0225 (17)	0.0037 (14)
C11	0.036 (2)	0.064 (2)	0.043 (2)	0.0151 (18)	0.019 (2)	0.0064 (18)
C12	0.034 (2)	0.087 (4)	0.050 (3)	−0.0007 (19)	0.022 (2)	−0.004 (2)
C13	0.042 (2)	0.057 (2)	0.054 (3)	−0.0120 (19)	0.026 (2)	−0.0078 (19)
C14	0.042 (2)	0.0371 (18)	0.051 (2)	−0.0066 (14)	0.029 (2)	−0.0054 (15)
Cl1	0.0574 (7)	0.0308 (5)	0.0770 (8)	0.0163 (4)	0.0438 (6)	0.0128 (4)
O1	0.079 (2)	0.0367 (13)	0.0661 (18)	0.0270 (13)	0.0597 (18)	0.0243 (12)

Ni1—N1i	2.018 (3)	C10—Cl1	1.734 (4)
Ni1—N1	2.018 (3)	C11—C12	1.389 (6)
Ni1—O1	2.048 (2)	C11—H21	0.9500
Ni1—O1i	2.048 (2)	C12—C13	1.377 (6)
Ni1—N10	2.208 (3)	C12—H22	0.9500
Ni1—N10i	2.208 (3)	C13—C14	1.372 (6)
N1—C1	1.158 (4)	C13—H23	0.9500
C1—S1	1.645 (3)	C14—H24	0.9500
N10—C10	1.336 (4)	O1—H1O1	0.8198
N10—C14	1.352 (4)	O1—H2O1	0.8201
C10—C11	1.375 (6)
N1i—Ni1—N1	180.0	C14—N10—Ni1	112.9 (2)
N1i—Ni1—O1	87.27 (12)	N10—C10—C11	124.6 (4)
N1—Ni1—O1	92.73 (12)	N10—C10—Cl1	117.9 (3)
N1i—Ni1—O1i	92.73 (12)	C11—C10—Cl1	117.4 (3)
N1—Ni1—O1i	87.27 (12)	C10—C11—C12	118.3 (4)
O1—Ni1—O1i	180.0	C10—C11—H21	120.8
N1i—Ni1—N10	90.88 (11)	C12—C11—H21	120.8
N1—Ni1—N10	89.12 (11)	C13—C12—C11	118.4 (4)
O1—Ni1—N10	87.55 (11)	C13—C12—H22	120.8
O1i—Ni1—N10	92.45 (11)	C11—C12—H22	120.8
N1i—Ni1—N10i	89.11 (11)	C14—C13—C12	119.0 (4)
N1—Ni1—N10i	90.88 (11)	C14—C13—H23	120.5
O1—Ni1—N10i	92.45 (11)	C12—C13—H23	120.5
O1i—Ni1—N10i	87.55 (11)	N10—C14—C13	124.0 (4)
N10—Ni1—N10i	180.0	N10—C14—H24	118.0
C1—N1—Ni1	175.7 (3)	C13—C14—H24	118.0
N1—C1—S1	179.4 (3)	Ni1—O1—H1O1	129.3
C10—N10—C14	115.6 (3)	Ni1—O1—H2O1	131.5
C10—N10—Ni1	131.4 (2)	H1O1—O1—H2O1	99.1

D—H···A	D—H	H···A	D···A	D—H···A
C11—H21···S1ii	0.95	2.99	3.904 (4)	162
C13—H23···S1iii	0.95	2.99	3.796 (4)	143
C14—H24···Cl1iv	0.95	2.96	3.796 (4)	147
O1—H1O1···S1v	0.82	2.39	3.175 (2)	160
O1—H2O1···S1vi	0.82	2.53	3.239 (2)	145
O1—H2O1···Cl1i	0.82	2.75	3.180 (3)	115