Poly[[diaqua­manganese(II)]-bis­(μ-4-fluoro­benzoato-κ²O:O′)]

In the crystal structure of the title complex, [Mn(C₇H₄FO₂)₂(H₂O)₂]_n, the Mn^II atom is located on an inversion centre. It is coordinated by two water mol­ecules in the apical directions and four 4-fluoro­benzoate (PFB) anions, bridging the symmetry related Mn atoms in the basal plane to form an infinite two-dimensional polymeric structure parallel to (100). The four O atoms of the PFB anions around the Mn^II atom form a slightly distorted square-planar arrangement, while the slightly distorted octa­hedral coordination is completed by the two O atoms of the water mol­ecules. The dihedral angle between the carboxyl­ate group and the adjacent benzene ring is 27.29 (16)°. The O—H...O hydrogen bonds further connect the manganese-carboxyl­ate units. π–π contacts between the benzene rings [centroid-centroid distance = 3.6894 (15) Å] further stabilize the crystal structure.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.039
• wR factor = 0.111
• Data-to-parameter ratio = 15.4

checkCIF/PLATON results

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Alert level B
PLAT934_ALERT_3_B Number of (Iobs-Icalc)/SigmaW .gt. 10 Outliers .          1

Alert level C
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       2.77
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          1
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600          4
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600          8

Alert level G
PLAT004_ALERT_5_G Info: Polymeric Structure Found with Dimension .          1

   0 ALERT level A = Most likely a serious problem - resolve or explain
   1 ALERT level B = A potentially serious problem, consider carefully
   4 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   1 ALERT level G = General information/check it is not something unexpected

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
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S1. Comment

As a part of our ongoing investigations of transition metal complexes of nicotinamide (NA), one form of niacin (Krishnamachari, 1974), and/or the nicotinic acid derivative N,N-diethylnicotinamide (DENA), an important respiratory stimulant (Bigoli et al., 1972), the title compound was synthesized and its crystal structure is reported herein.

In the title two-dimensional polymeric structure the Mn^II atom is located on a centre of invesion, and surrounded by four 4-fluorobenzoate (PFB) anions and two water molecules (Fig. 1). The PFB anions bridge the symmetry related Mn atoms. The four O atoms [O1, O2, O1'' and O2'', symmetry code: ('') -x, -y, -z] in the equatorial plane around the Mn atom form a slightly distorted square-planar arrangement, while the slightly distorted octahedral coordination is completed by the symmetry related O atoms of the coordinated water molecules (O3 and O3'') in the axial positions (Fig. 1).

The near equalities of the C1—O1 [1.257 (3) Å] and C1—O2 [1.268 (3) Å] bonds in the carboxylate group indicate a delocalized bonding arrangement, rather than localized single and double bonds, and may be compared with the corresponding distances: 1.263 (2), 1.279 (2), 1.263 (2) and 1.278 (2) Å in {[Mn(C₁₁H₁₄NO₂)₂(H₂O)₃].2(H₂O)}_n, (II) (Hökelek et al., 2009), 1.256 (6) and 1.245 (6) Å in [Mn(DENA)₂(C₇H₄ClO₂)₂(H₂O)₂], (III) (Hökelek et al., 2008) and 1.265 (6) and 1.275 (6) Å in [Mn(C₉H₁₀NO₂)₂(H₂O)₄].2(H₂O), (IV) (Hökelek & Necefoğlu, 2007).

The Mn—O bond lengths are in the range of 2.1489 (17) - 2.1988 (19) Å, and are close to standard values (Allen et al., 1987) with an average Mn-O bond length of 2.1735 (18) Å. The Mn atom is displaced out of the least-square plane of the carboxylate group (O1/C1/O2) by -1.5976 (1) Å. The dihedral angle between the planar carboxylate group and the adjacent benzene ring A (C2—C7) is 27.29 (16)°.

In the crystal structure, (Fig. 2), intermolecular O—H···O hydrogen bonds (Table 1) link the manganese-carboxylate units, and may be effective in the stabilization of the structure. The π···π contacts between the benzene rings, Cg1—Cg1ⁱ [symmetry code: (i) x, 1/2 - y, z - 1/2, where Cg1 is the centroid of the ring A (C2—C7)] may further stabilize the structure, with a centroid-centroid distance of 3.6894 (15) Å.

Related literature

For literature on niacin, see: Krishnamachari (1974). For infomation on the nicotinic acid derivative N,N-diethylnicotinamide, see: Bigoli et al. (1972). For related structures, see: Hökelek et al. (2008, 2009); Hökelek & Necefoğlu (2007). For bond-length data, see: Allen et al. (1987).

S2. Experimental

The title compound was prepared by the reaction of MnSO₄.H₂O (0.85 g, 5 mmol) in H₂O (100 ml) and isonicotinamide (1.22 g, 10 mmol) in H₂O (50 ml) with sodium 4-fluorobenzoate (1.62 g, 10 mmol) in H₂O (50 ml) at room temperature. The mixture was filtered and set aside to crystallize at ambient temperature for two weeks, giving blue single crystals.

S3. Refinement

Atoms H31 and H32 (for H₂O) were located in a difference Fourier map and were freely refined. The C-bound H-atoms were positioned geometrically with C—H = 0.95 Å for aromatic H-atoms, and constrained to ride on their parent atoms, with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX publication routines (Farrugia, 1999) and PLATON (Spek, 2009).

Figures

	Fig. 1. The molecular structure of the title molecule with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level [symmetry codes: (') -x, y + 1/2, 1/2 - z, ('') -x, -y, -z, (''') x, 1/2 - y, 1/2 + z]. Hydrogen atoms, except those of the water molecules, have been omitted for clarity.
	Fig. 2. A view along the a-axis of the crystal packing of the title compound [c-axis horizontal; b-axis vertical]. Hydrogen atoms, except those of the water molecules (violet balls), have been omitted for clarity.

Poly[[diaquamanganese(II)]-bis(µ-4-fluorobenzoato-κ²O:O')]

Crystal data

[Mn(C7H4FO2)2(H2O)2]	F(000) = 374
Mr = 369.18	Dx = 1.752 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 9752 reflections
a = 14.5065 (6) Å	θ = 2.8–28.5°
b = 6.6107 (3) Å	µ = 1.00 mm^−1
c = 7.3708 (3) Å	T = 100 K
β = 98.179 (2)°	Block, blue
V = 699.66 (5) Å^3	0.34 × 0.27 × 0.24 mm
Z = 2

Data collection

Bruker Kappa APEXII CCD area-detector diffractometer	1758 independent reflections
Radiation source: fine-focus sealed tube	1720 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.029
ϕ and ω scans	θmax = 28.5°, θmin = 2.8°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −19→19
Tmin = 0.728, Tmax = 0.786	k = −8→7
11656 measured reflections	l = −9→9

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.111	H atoms treated by a mixture of independent and constrained refinement
S = 1.28	w = 1/[σ^2(Fo^2) + (0.031P)^2 + 1.8232P] where P = (Fo^2 + 2Fc^2)/3
1758 reflections	(Δ/σ)max < 0.001
114 parameters	Δρmax = 1.24 e Å^−3
0 restraints	Δρmin = −0.45 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.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > 2sigma(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	Uiso*/Ueq
Mn1	0.5000	1.0000	0.5000	0.00934 (15)
O1	0.39762 (12)	1.0833 (3)	0.2723 (2)	0.0133 (4)
O2	0.58287 (12)	0.9092 (3)	0.2904 (2)	0.0133 (4)
O3	0.57162 (13)	1.2939 (3)	0.5150 (3)	0.0146 (4)
H31	0.575 (3)	1.370 (6)	0.604 (6)	0.027 (10)*
H32	0.566 (3)	1.361 (6)	0.425 (6)	0.031 (10)*
F1	0.99509 (11)	0.7768 (3)	0.6699 (2)	0.0279 (4)
C1	0.63126 (16)	0.7488 (4)	0.2983 (3)	0.0099 (4)
C2	0.72835 (17)	0.7562 (4)	0.3993 (3)	0.0123 (5)
C3	0.76860 (18)	0.9415 (4)	0.4534 (4)	0.0169 (5)
H3	0.7340	1.0629	0.4285	0.020*
C4	0.85953 (19)	0.9492 (4)	0.5439 (4)	0.0207 (5)
H4	0.8885	1.0748	0.5792	0.025*
C5	0.90623 (17)	0.7696 (5)	0.5807 (4)	0.0184 (5)
C6	0.86858 (19)	0.5840 (4)	0.5321 (4)	0.0200 (5)
H6	0.9030	0.4633	0.5614	0.024*
C7	0.77816 (18)	0.5780 (4)	0.4383 (4)	0.0168 (5)
H7	0.7505	0.4517	0.4008	0.020*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Mn1	0.0082 (2)	0.0104 (3)	0.0089 (2)	0.00104 (17)	−0.00066 (17)	−0.00106 (17)
O1	0.0120 (8)	0.0117 (8)	0.0150 (8)	0.0013 (6)	−0.0025 (6)	0.0011 (6)
O2	0.0145 (8)	0.0125 (8)	0.0131 (8)	0.0030 (7)	0.0025 (6)	0.0003 (6)
O3	0.0200 (9)	0.0128 (8)	0.0106 (8)	−0.0009 (7)	0.0010 (7)	0.0003 (7)
F1	0.0112 (7)	0.0423 (11)	0.0272 (9)	−0.0031 (7)	−0.0071 (6)	−0.0018 (8)
C1	0.0092 (10)	0.0115 (10)	0.0091 (10)	−0.0004 (8)	0.0024 (8)	0.0008 (8)
C2	0.0117 (10)	0.0154 (11)	0.0097 (10)	−0.0011 (8)	0.0010 (8)	−0.0007 (8)
C3	0.0163 (12)	0.0152 (12)	0.0185 (12)	−0.0015 (9)	−0.0002 (9)	−0.0012 (9)
C4	0.0176 (12)	0.0210 (13)	0.0226 (13)	−0.0073 (10)	−0.0003 (10)	−0.0053 (10)
C5	0.0083 (10)	0.0314 (15)	0.0147 (11)	−0.0023 (10)	−0.0014 (9)	−0.0008 (10)
C6	0.0153 (12)	0.0219 (13)	0.0216 (13)	0.0046 (10)	−0.0016 (10)	0.0013 (10)
C7	0.0154 (11)	0.0153 (12)	0.0184 (12)	0.0002 (9)	−0.0016 (9)	−0.0010 (9)

Geometric parameters (Å, º)

Mn1—O1	2.1489 (17)	C1—C2	1.498 (3)
Mn1—O1^i	2.1489 (17)	C2—C3	1.391 (3)
Mn1—O2	2.1728 (17)	C2—C7	1.390 (3)
Mn1—O2^i	2.1728 (17)	C3—H3	0.9500
Mn1—O3	2.1988 (19)	C4—C3	1.392 (4)
Mn1—O3^i	2.1988 (19)	C4—H4	0.9500
O1—C1^ii	1.257 (3)	C5—C4	1.375 (4)
O2—C1	1.268 (3)	C6—C5	1.370 (4)
O3—H31	0.82 (4)	C6—H6	0.9500
O3—H32	0.79 (4)	C7—C6	1.394 (4)
F1—C5	1.362 (3)	C7—H7	0.9500
C1—O1^iii	1.257 (3)
O1—Mn1—O1^i	180.0	O1^iii—C1—C2	117.9 (2)
O1—Mn1—O2	84.62 (7)	O2—C1—C2	118.1 (2)
O1^i—Mn1—O2	95.38 (7)	C3—C2—C1	119.9 (2)
O1—Mn1—O2^i	95.38 (7)	C7—C2—C1	120.0 (2)
O1^i—Mn1—O2^i	84.62 (7)	C7—C2—C3	120.2 (2)
O1—Mn1—O3	94.69 (7)	C2—C3—C4	120.0 (2)
O1^i—Mn1—O3	85.31 (7)	C2—C3—H3	120.0
O1—Mn1—O3^i	85.31 (7)	C4—C3—H3	120.0
O1^i—Mn1—O3^i	94.69 (7)	C3—C4—H4	121.0
O2—Mn1—O2^i	180.0	C5—C4—C3	118.0 (2)
O2—Mn1—O3	88.55 (7)	C5—C4—H4	121.0
O2^i—Mn1—O3	91.45 (7)	F1—C5—C4	118.1 (2)
O2—Mn1—O3^i	91.45 (7)	F1—C5—C6	118.2 (2)
O2^i—Mn1—O3^i	88.55 (7)	C6—C5—C4	123.7 (2)
O3—Mn1—O3^i	180.00 (10)	C5—C6—C7	117.9 (2)
C1^ii—O1—Mn1	134.33 (16)	C5—C6—H6	121.1
C1—O2—Mn1	123.85 (15)	C7—C6—H6	121.1
Mn1—O3—H31	124 (3)	C2—C7—C6	120.2 (2)
Mn1—O3—H32	118 (3)	C2—C7—H7	119.9
H31—O3—H32	108 (4)	C6—C7—H7	119.9
O1^iii—C1—O2	124.0 (2)
O2—Mn1—O1—C1^ii	−106.1 (2)	O2—C1—C2—C7	169.1 (2)
O2^i—Mn1—O1—C1^ii	73.9 (2)	C1—C2—C3—C4	−178.6 (2)
O3—Mn1—O1—C1^ii	−18.0 (2)	C7—C2—C3—C4	1.1 (4)
O3^i—Mn1—O1—C1^ii	162.0 (2)	C1—C2—C7—C6	179.9 (2)
O1^i—Mn1—O2—C1	41.54 (19)	C3—C2—C7—C6	0.2 (4)
O3—Mn1—O2—C1	126.69 (19)	C5—C4—C3—C2	−1.4 (4)
O3^i—Mn1—O2—C1	−53.31 (19)	F1—C5—C4—C3	−179.8 (2)
Mn1—O2—C1—O1^iii	93.1 (3)	C6—C5—C4—C3	0.5 (4)
Mn1—O2—C1—C2	−86.2 (2)	C7—C6—C5—F1	−179.0 (2)
O1^iii—C1—C2—C3	169.5 (2)	C7—C6—C5—C4	0.7 (4)
O1^iii—C1—C2—C7	−10.3 (3)	C2—C7—C6—C5	−1.1 (4)
O2—C1—C2—C3	−11.2 (3)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H32···O2^ii	0.79 (4)	2.51 (4)	3.039 (3)	125 (4)
O3—H32···O1^ii	0.79 (4)	2.18 (4)	2.935 (3)	158 (4)

Symmetry code: (ii) −x+1, y+1/2, −z+1/2.