Synthesis, crystal structure and Hirshfeld surface analysis of tetra­aqua­bis­(isonicotinamide-κN ¹)cobalt(II) fumarate

In the complex cation, the Co^II atom, located on an inverse centre, is coordinated by two isonicotinamide and four water mol­ecules in a distorted O₄N₂ octa­hedral geometry. The fumarate anion is located on another inverse centre and is linked to neighbouring complex cations via O—H⋯O and O—H⋯N hydrogen bonds and weak C—H⋯O hydrogen bonds. In the crystal, the complex cations are further linked by O—H⋯O, N—H⋯O an weak C—H⋯O hydrogen bonds, forming a three-dimensional supra­molecular architectecture.

Abstract

The reaction of cobalt(II) with fumaric acid (H₂fum) and isonicotinamide in a basic solution produces the title salt, [Co(C₆H₆N₂O)₂(H₂O)₄](C₄H₂O₄). In the complex cation, the Co^II atom, located on an inversion centre, is coordinated by two isonicotinamide and four water mol­ecules in a distorted N₂O₄ octa­hedral geometry. The fumarate anion is located on another inversion centre and is linked to neighbouring complex cations via O—H⋯O and N—H⋯O hydrogen bonds and weak C—H⋯O hydrogen bonds. In the crystal, the complex cations are further linked by O—H⋯O, N—H⋯O and weak C—H⋯O hydrogen bonds, forming a three-dimensional supra­molecular architectecture. Hirshfeld surface analyses (d _norm surfaces and two-dimensional fingerprint plots) for the title compound are presented and discussed.

Chemical context  

Metal carboxyl­ates have attracted intense attention because of their inter­esting framework topologies (Rao et al., 2004 ▸). Among metal carboxyl­ates, fumarate dianions (fum) have good conformational freedom and they possess some desirable features such as being versatile ligands because of the four electron-donor oxygen atoms they carry, and their ability to link inorganic moieties (Zheng et al., 2003 ▸). Moreover, metal fumarates exhibit interesting structural varieties.

Di­carb­oxy­lic acids such as fumaric acid and amides have been particularly useful in creating many supra­molecular structures involving isonicotinamide and a variety of carb­oxy­lic acid mol­ecules (Vishweshwar et al., 2003 ▸; Aakeröy et al., 2002 ▸). Di­carb­oxy­lic acid ligands are utilized in the synthesis of a wide variety of metal carboxyl­ates. For this reason they have been investigated extensively, both experimentally and computationally. We describe herein the synthesis, structural features and Hirshfeld surface analysis of the title salt.

Structural commentary  

The mol­ecular structure of the title compound is illustrated in Fig. 1 ▸. The Co^II cation and midpoint of the C=C bond of the fumarate anion are each located on an inversion centre. In the complex cation, the Co^II atom is coordinated to two isonicotinamide ligands and four water mol­ecules in a distorted N₂O₄ octa­hedral geometry. The fumarate anion interacts with neighboring complex cations via O—H⋯O and N—H⋯O hydrogen bonds and weak C—H⋯O hydrogen bonds (Table 1 ▸).

Figure 1.

The mol­ecular structure of the title compound, showing the atom labelling. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry codes: (i) –x + 1, −y + 1, −z + 1; (vii) –x + 1, −y + 1, −z + 2.]

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2A⋯O5i	0.86	1.96	2.814 (2)	171
O2—H2B⋯O4ii	0.86	1.88	2.7165 (19)	165
O3—H3A⋯O1iii	0.86	1.95	2.792 (2)	168
O3—H3B⋯O4	0.86	1.82	2.6652 (19)	172
N2—H2C⋯O5iv	0.86	2.13	2.955 (2)	160
N2—H2D⋯O1v	0.86	2.47	3.288 (3)	159
C1—H1⋯O4vi	0.93	2.41	3.322 (2)	168
C2—H2⋯O1v	0.93	2.30	3.225 (3)	173

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

Supra­molecular features  

In the crystal, the fumarate anions and complex cations are linked by O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds; the complex cations also interact with each other through O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds, forming a three-dimensional supra­molecular architecture (Table 1 ▸, Fig. 2 ▸).

Figure 2.

Packing of the title compound in the unit cell. Dashed lines indicate hydrogen bonds.

Hirshfeld surface analysis  

Crystal Explorer 17.5 (Turner et al., 2017 ▸) was used to analyse the inter­actions in the crystal and fingerprint plots mapped over d _norm (Figs. 3 ▸ and 4 ▸) were generated. The contact distances to the closest atom inside (d_i) and outside (d_e) of the Hirshfeld surface are used to analyse the inter­molecular inter­actions via the mapping of d _norm. The mol­ecular Hirshfeld surfaces were obtained using a standard (high) surface resolution with the three-dimensional d _norm surfaces mapped over a fixed colour scale of −1.227 (red) to 1.279 (blue). Many studies on Hirshfeld surfaces can be found in the literature (see, for example, Şen et al., 2018 ▸; Yaman et al., 2018 ▸).

Figure 3.

The Hirshfeld surface of the title compound mapped with d _norm. The red spots indicate the regions of the donor–acceptor inter­actions.

Figure 4.

d _norm mapped on the Hirshfeld surfaces for the title structure.

In a d _norm surface, any inter­molecular inter­actions will appear as red spots. The red spots indicate the regions of donor–acceptor inter­actions. There are many red spots in the d _norm surface (Fig. 3 ▸), which are usually on the O-acceptor atoms involved in the inter­actions listed in Table 1 ▸. Strong hydrogen-bond inter­actions, such as O—H⋯O, are seen as a bright-red areas on the Hirshfeld surfaces (Şen et al., 2017 ▸).

The fingerprint plot for the title complex is presented in Fig. 5 ▸. The H⋯H inter­actions appear in the middle of the scattered points in the two-dimensional fingerprint plots with an overall contribution to the Hirshfeld surface of 35.5% (Fig. 6 ▸ b). The contribution from the O⋯H/H⋯O contacts, corresponding to C—H⋯O, N—H⋯O and O—H⋯O inter­actions, is represented by a pair of sharp spikes characteristic of a strong hydrogen-bond inter­action (35.9%) (Fig. 6 ▸ a). The C⋯C/C⋯C contacts have a sharp spike between the O⋯H and H⋯O spikes (5.7%) (Fig. 6 ▸ d). The contribution of the other inter­molecular contacts to the Hirshfeld surfaces is C⋯H/H⋯C (10.3%) (Fig. 6 ▸ c).

Figure 5.

A fingerprint plot of the title complex.

Figure 6.

(a) O⋯H/H⋯O, (b) H⋯H/H⋯H, (c) C⋯H/H⋯C and (d) C⋯C/C⋯C contacts in the title complex, showing the percentages of contacts contributing to the total Hirshfeld surface area.

Database survey  

A search of the Cambridge Structural Database for fumaric acid and isonicotinamide revealed the presence of seven structures: isonicotinohyrazide nicotinamide fumaric acid (Aitipamula et al., 2013 ▸), catena-poly[[aqua­bis­[N-(pyridin-3-yl)isonicotinamide-κN ¹)copper(II)]-(μ₂-fumarato-κO,O′)-(Qiblawi & LaDuca, 2012 ▸), bis­(isonicotinamide) fumaric acid (Aakeröy et al., 2002 ▸), catena-[bis­(μ₂-fumarato)bis­(μ₂-3-pyridyl­isonicotinamide)­dizinctrihydrate] (Uebler et al., 2013 ▸) and catena-[bis­(μ-but-2-enedioato)bis­(μ-pyridine-4-carbohydrazide)dizinc(II)] (Naskar et al., 2017 ▸). In these compounds, the C—H⋯O hydrogen bonds have H⋯O distances ranging from 2.56 to 3.59 Å and C⋯O distances ranging from 3.27 to 3.96 Å. The N—H⋯O hydrogen bonds have H⋯O distances ranging from 1.86 to 2.33 Å and N⋯O distances ranging from 2.82 to 3.15 Å.

Synthesis and crystallization  

An aqueous solution of fumaric acid (26 mmol, 3 g) in water was added to a solution of NaOH (52 mmol, 2.07 g) while stirring. A solution of CoCl₂·6H₂O (25 mmol, 6.19 g) in water was added. The reaction mixture was stirred for an hour at room temperature. The pink mixture was filtered and left to dry. The pink crystals (0.88 mmol, 0.20 g) were dissolved in water and added to an aqueous solution of isonicotinamide (1.75 mmol, 0.21 g). The resulting suspension was filtered and allowed to crystallize for five weeks at room temperature yielding orange block-shaped crystals suitable for X-ray diffraction analysis.

Refinement  

Crystal data, data collection and structure refinement details are summarized in Table 2 ▸. The N-bound and C-bound hydrogen atoms were positioned geometrically and treated as riding: N—H = 0.86 Å and C—H = 0.93 Å with U _iso(H) = 1.2U _eq(C,N). Water H atoms were found in a difference-Fourier map, restrained with O—H = 0.85 Å and refined with U _iso(H) = 1.5U _eq(O).

Table 2. Experimental details.

Crystal data
Chemical formula	[Co(C6H6N2O)2(H2O)4](C4H2O4)
M r	489.30
Crystal system, space group	Monoclinic, P21/c
Temperature (K)	296
a, b, c (Å)	9.6914 (10), 10.0106 (11), 11.3811 (12)
β (°)	113.416 (3)
V (Å3)	1013.22 (19)
Z	2
Radiation type	Mo Kα
μ (mm−1)	0.91
Crystal size (mm)	0.25 × 0.19 × 0.16
Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Analytical (X-RED32; Stoe & Cie, 2002 ▸)
T min, T max	0.394, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	19963, 1962, 1830
R int	0.032
(sin θ/λ)max (Å−1)	0.617
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S	0.032, 0.077, 1.14
No. of reflections	1962
No. of parameters	144
H-atom treatment	H-atom parameters constrained
Δρmax, Δρmin (e Å−3)	0.35, −0.35

Computer programs: APEX2 and SAINT (Bruker, 2007 ▸), SHELXT2014 (Sheldrick, 2015a ▸), SHELXL2016 (Sheldrick, 2015b ▸), ORTEP-3 for Windows and WinGX (Farrugia, 2012 ▸) and PLATON (Spek, 2009 ▸).

Supplementary Material

CCDC reference: 1561543

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

supplementary crystallographic information

Crystal data

[Co(C6H6N2O)2(H2O)4](C4H2O4)	F(000) = 506
Mr = 489.30	Dx = 1.604 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 9.6914 (10) Å	Cell parameters from 9553 reflections
b = 10.0106 (11) Å	θ = 3.1–28.3°
c = 11.3811 (12) Å	µ = 0.91 mm−1
β = 113.416 (3)°	T = 296 K
V = 1013.22 (19) Å3	Block, orange
Z = 2	0.25 × 0.19 × 0.16 mm

Data collection

Bruker APEXII CCD diffractometer	1830 reflections with I > 2σ(I)
φ and ω scans	Rint = 0.032
Absorption correction: analytical (X-RED32; Stoe & Cie, 2002)	θmax = 26.0°, θmin = 3.1°
Tmin = 0.394, Tmax = 0.746	h = −11→11
19963 measured reflections	k = −12→12
1962 independent reflections	l = −14→13

Refinement

Refinement on F2	0 restraints
Least-squares matrix: full	Hydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.032	H-atom parameters constrained
wR(F2) = 0.077	w = 1/[σ2(Fo2) + (0.0211P)2 + 1.1735P] where P = (Fo2 + 2Fc2)/3
S = 1.14	(Δ/σ)max < 0.001
1962 reflections	Δρmax = 0.35 e Å−3
144 parameters	Δρmin = −0.35 e Å−3

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.

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

	x	y	z	Uiso*/Ueq
Co1	0.500000	0.500000	0.500000	0.01658 (12)
O3	0.60307 (15)	0.65750 (13)	0.62150 (13)	0.0237 (3)
H3A	0.696404	0.660264	0.635017	0.035*
H3B	0.594575	0.646860	0.692916	0.035*
O2	0.39661 (15)	0.64187 (13)	0.35319 (13)	0.0240 (3)
H2A	0.368923	0.604165	0.279836	0.036*
H2B	0.458953	0.704445	0.358200	0.036*
O4	0.55105 (17)	0.63859 (14)	0.83392 (14)	0.0283 (3)
O1	−0.09235 (17)	0.70328 (16)	0.68073 (17)	0.0365 (4)
O5	0.72605 (18)	0.48025 (16)	0.88934 (16)	0.0356 (4)
N1	0.31337 (18)	0.52596 (16)	0.55744 (16)	0.0208 (3)
C7	0.6189 (2)	0.54056 (19)	0.90123 (18)	0.0221 (4)
C3	0.1007 (2)	0.5713 (2)	0.66124 (18)	0.0216 (4)
C8	0.5656 (2)	0.48648 (19)	0.99864 (19)	0.0239 (4)
H8	0.629871	0.429951	1.061428	0.029*
N2	−0.0347 (3)	0.5112 (2)	0.7922 (2)	0.0491 (6)
H2C	−0.102155	0.523521	0.822413	0.059*
H2D	0.020826	0.440936	0.812861	0.059*
C4	0.1453 (2)	0.6727 (2)	0.6015 (2)	0.0268 (4)
H4	0.103978	0.757665	0.594549	0.032*
C2	0.1627 (2)	0.4464 (2)	0.6655 (2)	0.0297 (5)
H2	0.134441	0.375248	0.703564	0.036*
C6	−0.0163 (2)	0.6003 (2)	0.7141 (2)	0.0279 (4)
C5	0.2516 (2)	0.64642 (19)	0.5523 (2)	0.0263 (4)
H5	0.281757	0.715892	0.513627	0.032*
C1	0.2671 (2)	0.4283 (2)	0.6126 (2)	0.0275 (4)
H1	0.307396	0.343382	0.615691	0.033*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Co1	0.01724 (19)	0.01624 (19)	0.0214 (2)	−0.00028 (12)	0.01310 (14)	0.00056 (13)
O3	0.0239 (7)	0.0251 (7)	0.0276 (7)	−0.0036 (6)	0.0162 (6)	−0.0033 (6)
O2	0.0259 (7)	0.0220 (7)	0.0258 (7)	−0.0015 (5)	0.0121 (6)	0.0031 (5)
O4	0.0421 (8)	0.0219 (7)	0.0319 (7)	0.0059 (6)	0.0264 (7)	0.0046 (6)
O1	0.0332 (8)	0.0303 (8)	0.0602 (11)	−0.0001 (7)	0.0334 (8)	−0.0075 (7)
O5	0.0354 (8)	0.0430 (9)	0.0409 (9)	0.0129 (7)	0.0284 (7)	0.0091 (7)
N1	0.0207 (8)	0.0199 (8)	0.0274 (8)	−0.0003 (6)	0.0154 (7)	−0.0003 (6)
C7	0.0262 (9)	0.0217 (9)	0.0234 (9)	−0.0018 (8)	0.0151 (8)	−0.0023 (8)
C3	0.0178 (9)	0.0268 (10)	0.0247 (9)	−0.0017 (7)	0.0134 (7)	−0.0023 (8)
C8	0.0282 (10)	0.0240 (10)	0.0243 (10)	0.0033 (8)	0.0155 (8)	0.0037 (7)
N2	0.0411 (12)	0.0675 (15)	0.0591 (14)	0.0163 (11)	0.0416 (11)	0.0225 (11)
C4	0.0285 (10)	0.0182 (9)	0.0425 (12)	0.0012 (8)	0.0234 (9)	−0.0016 (8)
C2	0.0303 (10)	0.0270 (10)	0.0428 (12)	0.0024 (9)	0.0261 (10)	0.0110 (9)
C6	0.0208 (9)	0.0359 (12)	0.0330 (11)	−0.0056 (9)	0.0170 (8)	−0.0089 (9)
C5	0.0300 (10)	0.0191 (9)	0.0397 (11)	−0.0005 (8)	0.0245 (9)	0.0032 (8)
C1	0.0274 (10)	0.0204 (10)	0.0432 (12)	0.0039 (8)	0.0229 (9)	0.0058 (8)

Geometric parameters (Å, º)

Co1—O3i	2.0731 (13)	C7—C8	1.498 (3)
Co1—O3	2.0731 (13)	C3—C2	1.380 (3)
Co1—O2i	2.1171 (13)	C3—C4	1.383 (3)
Co1—O2	2.1171 (13)	C3—C6	1.509 (3)
Co1—N1	2.1694 (16)	C8—C8ii	1.313 (4)
Co1—N1i	2.1694 (16)	C8—H8	0.9300
O3—H3A	0.8556	N2—C6	1.320 (3)
O3—H3B	0.8555	N2—H2C	0.8600
O2—H2A	0.8564	N2—H2D	0.8600
O2—H2B	0.8564	C4—C5	1.380 (3)
O4—C7	1.258 (2)	C4—H4	0.9300
O1—C6	1.236 (3)	C2—C1	1.379 (3)
O5—C7	1.254 (2)	C2—H2	0.9300
N1—C1	1.332 (3)	C5—H5	0.9300
N1—C5	1.337 (2)	C1—H1	0.9300
O3i—Co1—O3	180.0	O4—C7—C8	118.86 (17)
O3i—Co1—O2i	88.15 (6)	C2—C3—C4	117.75 (17)
O3—Co1—O2i	91.85 (6)	C2—C3—C6	123.14 (18)
O3i—Co1—O2	91.85 (6)	C4—C3—C6	119.07 (18)
O3—Co1—O2	88.15 (6)	C8ii—C8—C7	124.4 (2)
O2i—Co1—O2	180.0	C8ii—C8—H8	117.8
O3i—Co1—N1	93.08 (6)	C7—C8—H8	117.8
O3—Co1—N1	86.92 (6)	C6—N2—H2C	120.0
O2i—Co1—N1	91.85 (6)	C6—N2—H2D	120.0
O2—Co1—N1	88.15 (6)	H2C—N2—H2D	120.0
O3i—Co1—N1i	86.92 (6)	C5—C4—C3	119.29 (18)
O3—Co1—N1i	93.08 (6)	C5—C4—H4	120.4
O2i—Co1—N1i	88.14 (6)	C3—C4—H4	120.4
O2—Co1—N1i	91.85 (6)	C1—C2—C3	119.26 (18)
N1—Co1—N1i	180.0	C1—C2—H2	120.4
Co1—O3—H3A	109.8	C3—C2—H2	120.4
Co1—O3—H3B	109.6	O1—C6—N2	123.2 (2)
H3A—O3—H3B	109.1	O1—C6—C3	119.28 (19)
Co1—O2—H2A	109.9	N2—C6—C3	117.5 (2)
Co1—O2—H2B	109.8	N1—C5—C4	123.21 (18)
H2A—O2—H2B	109.1	N1—C5—H5	118.4
C1—N1—C5	117.00 (16)	C4—C5—H5	118.4
C1—N1—Co1	122.07 (13)	N1—C1—C2	123.47 (19)
C5—N1—Co1	120.48 (13)	N1—C1—H1	118.3
O5—C7—O4	124.37 (18)	C2—C1—H1	118.3
O5—C7—C8	116.71 (18)
O5—C7—C8—C8ii	−161.6 (3)	C2—C3—C6—N2	15.6 (3)
O4—C7—C8—C8ii	15.7 (4)	C4—C3—C6—N2	−166.7 (2)
C2—C3—C4—C5	−1.8 (3)	C1—N1—C5—C4	0.4 (3)
C6—C3—C4—C5	−179.59 (19)	Co1—N1—C5—C4	−172.01 (17)
C4—C3—C2—C1	1.1 (3)	C3—C4—C5—N1	1.1 (3)
C6—C3—C2—C1	178.8 (2)	C5—N1—C1—C2	−1.2 (3)
C2—C3—C6—O1	−162.7 (2)	Co1—N1—C1—C2	171.10 (17)
C4—C3—C6—O1	14.9 (3)	C3—C2—C1—N1	0.5 (4)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2A···O5i	0.86	1.96	2.814 (2)	171
O2—H2B···O4iii	0.86	1.88	2.7165 (19)	165
O3—H3A···O1iv	0.86	1.95	2.792 (2)	168
O3—H3B···O4	0.86	1.82	2.6652 (19)	172
N2—H2C···O5v	0.86	2.13	2.955 (2)	160
N2—H2D···O1vi	0.86	2.47	3.288 (3)	159
C1—H1···O4vii	0.93	2.41	3.322 (2)	168
C2—H2···O1vi	0.93	2.30	3.225 (3)	173

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

Funding Statement

This work was funded by Female Center for Scientific and Medical Colleges, King Saud University grant .