Crystal structure of aqua-trans-bis-(dimethyl sulfoxide-κO)(pyridine-2,6-di-carboxyl-ato-κ3O2,N,O6)nickel(II).

In the title complex, [Ni(C7H3NO4)(C2H6OS)2(H2O)], the NiII cation is situated on a twofold rotation axis and exhibits a distorted octa-hedral NO5 coordination environment defined by a tridentate pyridine-2,6-di-carb-oxy-lic acid dianion (dpa2-), two dimethyl sulfoxide (DMSO) mol-ecules, and a water mol-ecule. In the crystal, the complex mol-ecules are linked by O-H⋯O and C-H⋯O hydrogen bonds into a three-dimensional network whereby DMSO mol-ecules from neighboring complexes overlap to form layers parallel to (001), alternating with layers of NiII-dpa2- moieties. The title complex is isotypic with its cobalt(II) analogue.

Chemical context

Crystal engineering plays an important role in the research of mol­ecule-based functional materials by providing an effective approach towards the rational design and preparation of compounds with special structural features (Robin & Fromm, 2006 ▸; Cook et al., 2013 ▸; Wang et al., 2013 ▸). The crystallization of coordination polymers involves both the formation of a local coordination geometry and the propagation and packing of extended polymeric structures in the three-dimensional space. The competition among various types of inter­molecular inter­actions plays a critical role in this process and is strongly influenced by synthetic conditions such as the choice of solvent, temperature, and the mol­ecular features of the starting materials (Li & Du, 2011 ▸; Du et al., 2013 ▸). Although much has been learned about how the synthetic conditions affect inter­molecular inter­actions and the final crystal structures, the targeted synthesis of a coordination polymer with a particular crystal structure is still a challenge. We recently reported an NiII-containing one-dimensional coordination polymer based on the tridentate 2,6-pyridine di­carb­oxy­lic acid dianion (dpa2−) and bridging pyrazine mol­ecules that was prepared by using DMSO as the solvent (Liu et al., 2016 ▸). The one-dimensional polymeric structure exhibits π–π inter­actions that were not previously observed when water was used as the solvent under the same preparation conditions. In order to explore the bridging effect of substituted pyrazine, we have repeated this preparation using 2-chloro­pyrazine to replace pyrazine under the same synthetic conditions. We report herein the synthesis and crystal structure of the resulting title compound for which incorporation of 2-chloro­pyrazine was not observed.

Structural commentary

The title complex crystallizes in the monoclinic space group C2/c with half of the mol­ecule in the asymmetric unit, the other half being generated by twofold rotation symmetry. The tridentate 2,6-pyridine di­carb­oxy­lic acid dianion coordinates to the NiII cation in a meridional fashion via the pyridine nitro­gen atom and two carboxyl­ate oxygen atoms (Fig. 1 ▸). The reactant 2-chloro­pyrazine is not found in the structure of the title complex. Instead, the NiII cation is further coordinated by two trans-positioned DMSO mol­ecules and a water mol­ecule through their oxygen atoms. Water mol­ecules may have been produced as a result of the reaction between 2,6-pyridine di­carb­oxy­lic acid and nickel carbonate. The two Ni1—O1dpa bonds have the same length 2.1130 (7) Å] and the two Ni1—O4DMSO bonds have the same length [2.0934 (7) Å]. The Ni1—N1 bond length is 1.9613 (12) Å and the Ni1—O3water bond length is 2.0040 (11) Å, both being significantly shorter than the other four bonds, resulting in a distorted octa­hedral NO5 coordination environment of the NiII cation. These bond lengths are very similar to those observed in the pyrazine-bridged one-dimensional structure reported previously (Liu et al., 2016 ▸).

Figure 1

The mol­ecular structure of the title compound, with displacement ellipsoids drawn at the 50% probability level. Unlabeled atoms are related by the symmetry transformation −x, y,  − z.

Supra­molecular features

In the crystal, the mononuclear complexes are linked via an extensive network of C—H⋯O and O—H⋯O hydrogen bonds where the hydrogen-bond donors are the C—H groups of DMSO mol­ecules and the O—H groups of the coordinating water mol­ecules and the hydrogen-bond acceptors are the non-coordinating O2 atoms of the 2,6-pyridine di­carb­oxy­lic acid dianion and the O4 atoms of the DMSO mol­ecules (Table 1 ▸, Fig. 2 ▸). In the crystal packing, layers of the NiII–dpa2− complexes alternating with layers of DMSO mol­ecules are formed parallel to (001) (Fig. 2 ▸).

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3⋯O2i	0.790 (17)	1.867 (17)	2.6555 (10)	176.3 (18)
C5—H5B⋯O2i	0.98	2.58	3.3650 (14)	137
C6—H6A⋯O2ii	0.98	2.62	3.3504 (13)	132
C6—H6B⋯O4iii	0.98	2.38	3.3302 (14)	162

Symmetry codes: (i) ; (ii) ; (iii) .

Figure 2

The crystal packing of the title compound, showing hydrogen bonds as dashed lines.

Database survey

A search of the Cambridge Structural Database (Groom et al., 2016 ▸) returned eight structures that are related to the title complex. These structures incorporate some or all of the ligands in the title complex and include mononuclear and binuclear complexes, as well as coordination polymers. One of the structures is mer-aqua-bis­(di­methyl­sulfoxide-O)(pyridine-2,6-di­carboxyl­ato-N,O,O′)cobalt(II) (Felloni et al., 2010 ▸) that crystallizes isotypically with the title complex. Therefore bond lengths and bond angles surrounding the CoII are very similar to those in the title complex. Another mononuclear complex is aqua­chlorido­(dimethyl sulfoxide-O)(pyridine-2,6-di­carboxyl­ato-N,O,O′)iron(III) (Rafizadeh et al., 2006 ▸). In the crystal, this complex also forms alternating layers parallel to (001) due to the inter­digitation of DMSO mol­ecules. Other complexes in the search results involve either coordinating or non-coordinating DMSO mol­ecules and one or more 2,6-pyridine di­carboxyl­ate dianions coordinating to a metal ion.

Synthesis and crystallization

Anhydrous NiCO3 (0.33 mmol, 39.56 mg), 2,6-pyridine di­carb­oxy­lic acid (0.33 mmol, 55.71 mg), and 2-chloro­pyrazine (0.50 mmol, 57.26 mg) were mixed in 10 ml dimethyl sulfoxide under stirring for 30 minutes. The resulting mixture was placed in a stainless steel autoclave. The autoclave was then sealed and heated to 373 K for 24 h and cooled to room temperature at a rate of 0.1 K per minute. The resulting green crystals were collected by filtration (yield 30.0%). Selected IR bands (KBr, cm−1): 3134.9 (O—H), 1613.1 (C=O), 1365.8 (C—O), 999.6 (S=O).

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2 ▸. The title complex is located on a twofold rotation axis, thus half of it occupies the asymmetric unit. The coordinating water mol­ecule lies on the symmetry axis which requires one hydrogen atom to be located while the other is related by symmetry. This hydrogen atom was obtained from a difference-Fourier map and was refined freely. The other hydrogen atoms were positioned geometrically (C—H = 0.93/1.00 Å) and allowed to ride with U iso(H)= 1.2/1.5U eq(C). Methyl hydrogen atoms were allowed to rotate but not to tip.

Table 2

Experimental details

Crystal data
Chemical formula	[Ni(C7H3NO4)(C2H6OS)2(H2O)]
M r	398.08
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	100
a, b, c (Å)	9.8767 (5), 11.4597 (5), 14.3166 (7)
β (°)	104.4577 (7)
V (Å3)	1569.09 (13)
Z	4
Radiation type	Mo Kα
μ (mm−1)	1.53
Crystal size (mm)	0.46 × 0.17 × 0.11
Data collection
Diffractometer	Bruker APEXII DUO CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2014 ▸)
T min, T max	0.678, 0.910
No. of measured, independent and observed [I > 2σ(I)] reflections	18746, 1936, 1907
R int	0.011
(sin θ/λ)max (Å−1)	0.666
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S	0.016, 0.043, 1.06
No. of reflections	1936
No. of parameters	108
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)	0.46, −0.24

Computer programs: APEX2 and SAINT (Bruker, 2014 ▸), SHELXT (Sheldrick, 2015a ▸), SHELXL2014 (Sheldrick, 2015b ▸), XP in SHELXTL-Plus (Sheldrick, 2008 ▸) and publCIF (Westrip, 2010 ▸).

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989017006090/wm5380sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989017006090/wm5380Isup2.hkl

CCDC reference: 1545417

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

[Ni(C7H3NO4)(C2H6OS)2(H2O)]	F(000) = 824
Mr = 398.08	Dx = 1.685 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 9.8767 (5) Å	Cell parameters from 9953 reflections
b = 11.4597 (5) Å	θ = 2.0–28.0°
c = 14.3166 (7) Å	µ = 1.53 mm−1
β = 104.4577 (7)°	T = 100 K
V = 1569.09 (13) Å3	Block, green
Z = 4	0.46 × 0.17 × 0.11 mm

Bruker APEXII DUO CCD diffractometer	1907 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.011
phi and ω scans	θmax = 28.3°, θmin = 2.8°
Absorption correction: multi-scan (SADABS; Bruker, 2014)	h = −13→13
Tmin = 0.678, Tmax = 0.910	k = −15→15
18746 measured reflections	l = −19→19
1936 independent reflections

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.016	Hydrogen site location: mixed
wR(F2) = 0.043	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ2(Fo2) + (0.0225P)2 + 1.5829P] where P = (Fo2 + 2Fc2)/3
1936 reflections	(Δ/σ)max = 0.001
108 parameters	Δρmax = 0.46 e Å−3
0 restraints	Δρmin = −0.24 e Å−3

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. All H atoms were positioned geometrically ( C—H = 0.93/1.00 Å) and allowed to ride with Uiso(H)= 1.2/1.5Ueq(C). Methyl ones were allowed to rotate around the corresponding C—C. The Ni complex is located on a 2-fold rotational axis of symmetry thus half of it occupies the asymmetric unit. The coordinated water molecule lies on the symmetry axis which requires one proton to be located while the other is related by the symmetry. The water proton was obtained from a Difference Fourier map and refined freely.

	x	y	z	Uiso*/Ueq
Ni1	0.0000	0.32387 (2)	0.2500	0.00867 (6)
S1	0.08818 (3)	0.40008 (2)	0.46249 (2)	0.01346 (7)
O1	0.16898 (7)	0.28806 (6)	0.18844 (5)	0.01235 (14)
O2	0.29613 (8)	0.13796 (7)	0.15626 (6)	0.01647 (15)
O3	0.0000	0.49874 (10)	0.2500	0.0186 (2)
H3	0.0626 (17)	0.5376 (15)	0.2789 (12)	0.033 (4)*
O4	0.13764 (8)	0.32772 (6)	0.38736 (5)	0.01257 (14)
N1	0.0000	0.15272 (10)	0.2500	0.0095 (2)
C1	0.0000	−0.08533 (12)	0.2500	0.0151 (3)
H1A	0.0000	−0.1682	0.2500	0.018*
C2	0.10055 (10)	−0.02463 (9)	0.21553 (7)	0.01328 (18)
H2A	0.1691	−0.0650	0.1919	0.016*
C3	0.09697 (10)	0.09684 (8)	0.21703 (7)	0.01026 (17)
C4	0.19693 (10)	0.18040 (9)	0.18444 (7)	0.01114 (18)
C5	0.24415 (12)	0.46192 (10)	0.53687 (8)	0.0204 (2)
H5A	0.2213	0.5058	0.5897	0.031*
H5B	0.2865	0.5145	0.4982	0.031*
H5C	0.3102	0.3994	0.5636	0.031*
C6	0.04879 (12)	0.29765 (11)	0.54609 (8)	0.0213 (2)
H6A	0.0278	0.3397	0.6004	0.032*
H6B	0.1294	0.2463	0.5699	0.032*
H6C	−0.0324	0.2508	0.5138	0.032*

	U11	U22	U33	U12	U13	U23
Ni1	0.00926 (9)	0.00735 (9)	0.00927 (9)	0.000	0.00206 (6)	0.000
S1	0.01554 (12)	0.01458 (12)	0.00942 (12)	0.00621 (9)	0.00155 (9)	−0.00145 (8)
O1	0.0122 (3)	0.0109 (3)	0.0147 (3)	−0.0010 (3)	0.0048 (3)	−0.0004 (3)
O2	0.0138 (3)	0.0181 (4)	0.0196 (4)	0.0040 (3)	0.0081 (3)	0.0023 (3)
O3	0.0178 (5)	0.0085 (5)	0.0237 (6)	0.000	−0.0057 (4)	0.000
O4	0.0131 (3)	0.0143 (3)	0.0099 (3)	0.0037 (3)	0.0021 (3)	−0.0030 (2)
N1	0.0102 (5)	0.0094 (5)	0.0083 (5)	0.000	0.0011 (4)	0.000
C1	0.0189 (7)	0.0091 (6)	0.0170 (7)	0.000	0.0038 (5)	0.000
C2	0.0143 (4)	0.0116 (4)	0.0136 (4)	0.0025 (4)	0.0028 (3)	−0.0008 (3)
C3	0.0103 (4)	0.0114 (4)	0.0085 (4)	0.0005 (3)	0.0012 (3)	0.0001 (3)
C4	0.0099 (4)	0.0140 (5)	0.0088 (4)	−0.0002 (3)	0.0009 (3)	0.0006 (3)
C5	0.0233 (5)	0.0204 (5)	0.0137 (5)	0.0012 (4)	−0.0022 (4)	−0.0044 (4)
C6	0.0227 (5)	0.0259 (6)	0.0180 (5)	0.0069 (4)	0.0105 (4)	0.0038 (4)

Ni1—N1	1.9613 (12)	N1—C3i	1.3327 (11)
Ni1—O3	2.0040 (11)	C1—C2i	1.3994 (12)
Ni1—O4	2.0934 (7)	C1—C2	1.3995 (12)
Ni1—O4i	2.0934 (7)	C1—H1A	0.9500
Ni1—O1i	2.1130 (7)	C2—C3	1.3927 (14)
Ni1—O1	2.1130 (7)	C2—H2A	0.9500
S1—O4	1.5316 (7)	C3—C4	1.5296 (13)
S1—C5	1.7860 (11)	C5—H5A	0.9800
S1—C6	1.7872 (12)	C5—H5B	0.9800
O1—C4	1.2686 (12)	C5—H5C	0.9800
O2—C4	1.2476 (12)	C6—H6A	0.9800
O3—H3	0.790 (17)	C6—H6B	0.9800
N1—C3	1.3326 (11)	C6—H6C	0.9800
N1—Ni1—O3	180.0	C2i—C1—C2	120.38 (13)
N1—Ni1—O4	91.21 (2)	C2i—C1—H1A	119.8
O3—Ni1—O4	88.79 (2)	C2—C1—H1A	119.8
N1—Ni1—O4i	91.21 (2)	C3—C2—C1	117.93 (10)
O3—Ni1—O4i	88.79 (2)	C3—C2—H2A	121.0
O4—Ni1—O4i	177.58 (4)	C1—C2—H2A	121.0
N1—Ni1—O1i	78.80 (2)	N1—C3—C2	120.60 (9)
O3—Ni1—O1i	101.20 (2)	N1—C3—C4	112.51 (9)
O4—Ni1—O1i	90.43 (3)	C2—C3—C4	126.88 (9)
O4i—Ni1—O1i	90.04 (3)	O2—C4—O1	126.23 (9)
N1—Ni1—O1	78.80 (2)	O2—C4—C3	118.26 (9)
O3—Ni1—O1	101.20 (2)	O1—C4—C3	115.51 (9)
O4—Ni1—O1	90.04 (3)	S1—C5—H5A	109.5
O4i—Ni1—O1	90.43 (3)	S1—C5—H5B	109.5
O1i—Ni1—O1	157.60 (4)	H5A—C5—H5B	109.5
O4—S1—C5	104.76 (5)	S1—C5—H5C	109.5
O4—S1—C6	106.00 (5)	H5A—C5—H5C	109.5
C5—S1—C6	99.26 (6)	H5B—C5—H5C	109.5
C4—O1—Ni1	114.28 (6)	S1—C6—H6A	109.5
Ni1—O3—H3	124.3 (13)	S1—C6—H6B	109.5
S1—O4—Ni1	115.15 (4)	H6A—C6—H6B	109.5
C3—N1—C3i	122.56 (12)	S1—C6—H6C	109.5
C3—N1—Ni1	118.72 (6)	H6A—C6—H6C	109.5
C3i—N1—Ni1	118.72 (6)	H6B—C6—H6C	109.5

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···O2ii	0.790 (17)	1.867 (17)	2.6555 (10)	176.3 (18)
C5—H5B···O2ii	0.98	2.58	3.3650 (14)	137
C6—H6A···O2iii	0.98	2.62	3.3504 (13)	132
C6—H6B···O4iv	0.98	2.38	3.3302 (14)	162