Tetra­aqua­bis(5-fluoro­uracil-1-acetato)manganese(II)

In the centrosymmetric title compound, [Mn(C₆H₄N₂O₄F)₂(H₂O)₄], each Mn^II ion is coordinated by two 5-fluoro­uracil-1-acetate anions via the carboxyl­ate O atoms and four water mol­ecules, forming a six-coordinate octa­hedral environment. N—H...O and O—H...O hydrogen-bonding inter­actions link adjacent mol­ecules into a three-dimensional network.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C)= 0.003 Å
• R factor = 0.039
• wR factor = 0.093
• Data-to-parameter ratio = 11.0

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S1. Comment

5-Fluorouracil (5-FU) is an antimetabolite with good antimicrobial and antitumor activity, but its administration is accompanied by significant toxic side effects and delivery problems (Ouchi et al., 1997; Nichifor & Schacht, 1994; Nichifor et al., 1997; Hulme et al., 2005). In order to improve the topical delivery of 5-FU and reduce the side effects, many derivatives of 5-FU have been synthesized, some of which have better biological activity. 5-Fluorouracil-1-acetic acid (5-FUAA) is a member of this family (Sloan et al., 1993; Li et al., 2000; Beall & Sloan, 2001; Beall & Sloan, 2002). As increasing attention has been paid to the anticancer activity of 5-FU and its derivatives (Akgerman & Guney, 2000), several transition metal complexes have been reported (Wang et al., 1993; Huang et al., 2000; Hu et al., 2005). The manganese derivative adduct, Mn(C₆H₄N₂O₄F)₂(H₂O)₄, (I), is reported here to build on these studies.

Mononuclear (I) consists of an Mn atom, four coordinated water molecules and two 5-fluorouracil-1-acetate anions, which bind through their carboxylate O atoms. The Mn atom lies on an inversion center and the geometry around the Mn ion is octahedral (Fig.1 and Table 1). A square plane is formed by atoms O5, O5ⁱ, O6 and O6ⁱ [symmetry code: (i) −x, −y, −z + 1], which is crystallographically imposed to be flat. The N—H···O and O—H···O hydrogen bonds link the mononuclear units to form a three-dimensional network (Fig. 2 and Table 2).

S2. Experimental

5-Fluorouracil-1-acetic acid (2 mmol, 0.75 g) and 1,3-di(4-pyridyl)propane (2 mmol, 0.40 g) were dissovled in a mixture of water (2 ml) and ethanol (8 ml). The solution was then added dropwise to a stirred aqueous solution (10 ml) of MnCl₂·2H₂O (1 mmol, 0.16 g). The resulting solution was filtered and allowed to evaporate slowly at room temperature. After four weeks, prismatic pink crystals of (I) appeared.

S3. Refinement

Water H atoms were located in difference density maps and refined with O—H and H···H distances restrained to 0.82 (2) Å and 1.39 (1) Å, respectively, with U_iso(H) = 1.2U_eq(parent atom). The other H atoms were positioned geometrically and allowed to ride on their parent atoms at distances of Csp²—H = 0.93 Å with U_iso(H) = 1.2U_eq(C), Csp³—H = 0.97 Å with U_iso(H) = 1.5U_eq(C), and N—H = 0.86 Å with U_iso(H) = 1.2U_eq(N).

Computing details

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2002); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. The coordination environment of the manganese(II) ion in (I), showing the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry code: (i) −x, −y, −z + 1.]
	Fig. 2. The three-dimensional network formed by hydrogen-bonding interactions, which are shown as dashed lines.

Tetraaquabis(5-fluorouracil-1-acetato)manganese(II)

Crystal data

[Mn(C6H4N2O4F)2(H2O)4]	F(000) = 510
Mr = 501.23	Dx = 1.763 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P2ybc	Cell parameters from 2209 reflections
a = 13.1820 (13) Å	θ = 2.9–25.2°
b = 5.1106 (5) Å	µ = 0.79 mm^−1
c = 14.2202 (14) Å	T = 298 K
β = 99.809 (2)°	Prism, pink
V = 943.98 (16) Å^3	0.32 × 0.16 × 0.13 mm
Z = 2

Data collection

Bruker APEX area-detector diffractometer	1687 independent reflections
Radiation source: fine-focus sealed tube	1619 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.019
ϕ and ω scans	θmax = 25.2°, θmin = 1.6°
Absorption correction: multi-scan (SADABS; Bruker, 2002)	h = −15→15
Tmin = 0.786, Tmax = 0.904	k = −6→5
4685 measured reflections	l = −17→12

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) = 0.093	H atoms treated by a mixture of independent and constrained refinement
S = 1.16	w = 1/[σ^2(Fo^2) + (0.0419P)^2 + 0.5989P] where P = (Fo^2 + 2Fc^2)/3
1687 reflections	(Δ/σ)max < 0.001
154 parameters	Δρmax = 0.19 e Å^−3
6 restraints	Δρmin = −0.26 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > σ(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	0.0000	0.0000	0.5000	0.02985 (18)
F1	0.53352 (12)	0.6796 (4)	0.83103 (14)	0.0620 (5)
O1	0.07545 (12)	0.2476 (3)	0.61413 (12)	0.0371 (4)
O2	0.22799 (13)	0.0597 (4)	0.66409 (13)	0.0411 (5)
O3	0.22356 (13)	0.0596 (4)	0.88419 (13)	0.0380 (4)
O4	0.56390 (12)	0.2580 (4)	0.95277 (13)	0.0408 (5)
O5	−0.02257 (13)	−0.2963 (3)	0.60239 (14)	0.0373 (4)
O6	−0.15636 (14)	0.1442 (4)	0.50959 (14)	0.0459 (5)
N1	0.28011 (14)	0.4091 (4)	0.80833 (13)	0.0273 (4)
N2	0.39240 (14)	0.1666 (4)	0.91748 (13)	0.0296 (5)
H2	0.4017	0.0384	0.9572	0.036*
C1	0.16163 (17)	0.2270 (4)	0.66883 (17)	0.0286 (5)
C2	0.18008 (17)	0.4377 (5)	0.74602 (17)	0.0297 (5)
H2A	0.1765	0.6085	0.7159	0.036*
H2B	0.1260	0.4285	0.7844	0.036*
C3	0.29390 (17)	0.2043 (4)	0.87080 (16)	0.0272 (5)
C4	0.47840 (18)	0.3104 (5)	0.90815 (16)	0.0295 (5)
C5	0.45491 (19)	0.5243 (5)	0.84221 (18)	0.0331 (6)
C6	0.36076 (18)	0.5661 (5)	0.79462 (16)	0.0297 (5)
H6	0.3492	0.7038	0.7514	0.036*
H6A	−0.1832 (18)	0.262 (4)	0.5366 (15)	0.036*
H6B	−0.1888 (19)	0.097 (5)	0.4588 (13)	0.036*
H5A	0.0123 (15)	−0.434 (4)	0.6055 (19)	0.036*
H5B	−0.0839 (12)	−0.323 (5)	0.6023 (19)	0.036*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Mn1	0.0271 (3)	0.0249 (3)	0.0344 (3)	0.0020 (2)	−0.0039 (2)	−0.0040 (2)
F1	0.0373 (9)	0.0633 (12)	0.0805 (13)	−0.0184 (8)	−0.0036 (8)	0.0368 (10)
O1	0.0327 (9)	0.0298 (10)	0.0424 (10)	0.0060 (7)	−0.0123 (8)	−0.0071 (8)
O2	0.0354 (10)	0.0390 (10)	0.0444 (11)	0.0107 (8)	−0.0062 (8)	−0.0089 (8)
O3	0.0274 (9)	0.0352 (10)	0.0494 (11)	−0.0040 (8)	0.0011 (8)	0.0122 (8)
O4	0.0261 (9)	0.0418 (11)	0.0500 (11)	−0.0015 (8)	−0.0061 (8)	0.0138 (9)
O5	0.0290 (9)	0.0309 (9)	0.0511 (11)	0.0061 (8)	0.0042 (8)	0.0037 (8)
O6	0.0359 (10)	0.0487 (12)	0.0490 (12)	0.0123 (9)	−0.0048 (8)	−0.0215 (10)
N1	0.0278 (10)	0.0245 (10)	0.0265 (10)	0.0004 (8)	−0.0042 (8)	0.0004 (8)
N2	0.0282 (10)	0.0266 (11)	0.0314 (11)	−0.0020 (8)	−0.0023 (8)	0.0092 (8)
C1	0.0290 (12)	0.0241 (12)	0.0309 (12)	0.0005 (10)	−0.0004 (10)	0.0034 (9)
C2	0.0268 (12)	0.0267 (12)	0.0320 (13)	0.0034 (9)	−0.0048 (10)	0.0005 (10)
C3	0.0291 (12)	0.0245 (12)	0.0260 (12)	0.0017 (10)	−0.0007 (9)	0.0014 (9)
C4	0.0302 (12)	0.0287 (13)	0.0276 (12)	−0.0020 (10)	−0.0005 (10)	0.0002 (10)
C5	0.0316 (13)	0.0312 (13)	0.0357 (13)	−0.0070 (10)	0.0033 (10)	0.0067 (10)
C6	0.0362 (13)	0.0241 (12)	0.0266 (12)	−0.0012 (10)	−0.0008 (10)	0.0033 (9)

Geometric parameters (Å, º)

Mn1—O5	2.1563 (18)	O6—H6B	0.810 (15)
Mn1—O5^i	2.1563 (18)	N1—C3	1.365 (3)
Mn1—O1^i	2.1620 (16)	N1—C6	1.372 (3)
Mn1—O1	2.1620 (16)	N1—C2	1.465 (3)
Mn1—O6	2.2148 (18)	N2—C3	1.368 (3)
Mn1—O6^i	2.2148 (18)	N2—C4	1.376 (3)
F1—C5	1.336 (3)	N2—H2	0.8600
O1—C1	1.267 (3)	C1—C2	1.527 (3)
O2—C1	1.233 (3)	C2—H2A	0.9700
O3—C3	1.226 (3)	C2—H2B	0.9700
O4—C4	1.225 (3)	C4—C5	1.439 (3)
O5—H5A	0.836 (16)	C5—C6	1.326 (3)
O5—H5B	0.820 (15)	C6—H6	0.9300
O6—H6A	0.826 (15)
O5—Mn1—O5^i	180.0	C3—N2—C4	127.4 (2)
O5—Mn1—O1^i	89.83 (7)	C3—N2—H2	116.3
O5^i—Mn1—O1^i	90.17 (7)	C4—N2—H2	116.3
O5—Mn1—O1	90.17 (7)	O2—C1—O1	126.4 (2)
O5^i—Mn1—O1	89.83 (7)	O2—C1—C2	120.0 (2)
O1^i—Mn1—O1	180.0	O1—C1—C2	113.5 (2)
O5—Mn1—O6	87.43 (7)	N1—C2—C1	112.40 (19)
O5^i—Mn1—O6	92.57 (7)	N1—C2—H2A	109.1
O1^i—Mn1—O6	85.81 (7)	C1—C2—H2A	109.1
O1—Mn1—O6	94.19 (7)	N1—C2—H2B	109.1
O5—Mn1—O6^i	92.57 (7)	C1—C2—H2B	109.1
O5^i—Mn1—O6^i	87.43 (7)	H2A—C2—H2B	107.9
O1^i—Mn1—O6^i	94.19 (7)	O3—C3—N1	122.9 (2)
O1—Mn1—O6^i	85.81 (7)	O3—C3—N2	121.3 (2)
O6—Mn1—O6^i	180.00 (10)	N1—C3—N2	115.7 (2)
C1—O1—Mn1	131.45 (15)	O4—C4—N2	122.3 (2)
Mn1—O5—H5A	119.2 (18)	O4—C4—C5	125.5 (2)
Mn1—O5—H5B	111.3 (18)	N2—C4—C5	112.3 (2)
H5A—O5—H5B	113 (2)	C6—C5—F1	121.4 (2)
Mn1—O6—H6A	138.4 (17)	C6—C5—C4	122.3 (2)
Mn1—O6—H6B	101.6 (17)	F1—C5—C4	116.3 (2)
H6A—O6—H6B	115 (2)	C5—C6—N1	120.9 (2)
C3—N1—C6	121.36 (19)	C5—C6—H6	119.5
C3—N1—C2	118.45 (19)	N1—C6—H6	119.5
C6—N1—C2	119.67 (19)

Symmetry code: (i) −x, −y, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2···O4^ii	0.86	1.99	2.843 (3)	175
O6—H6A···O3^iii	0.83 (2)	2.02 (2)	2.834 (3)	170 (2)
O6—H6B···O2^i	0.81 (2)	1.91 (2)	2.699 (3)	163 (2)
O5—H5A···O1^iv	0.84 (2)	1.82 (2)	2.656 (2)	174 (2)
O5—H5B···O3^v	0.82 (2)	1.98 (2)	2.788 (2)	170 (2)

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