A two-dimensional manganese(II) coordination polymer: poly­[[di­aqua­manganese(II)]-μ-4,4-bi­pyridine-κ²N:N′-μ-(p-phenyl­ene­dioxy­diacetato)-κ²O:O′]

In the title two-dimensional coordination polymer, [Mn(1,4-BDOA)(4,4-bipy)(H₂O)₂]_n [1,4-BDOA²⁻ is the p-phenyl­ene­dioxy­di­acetate dianion (C₁₀H₈O₆) and 4,4-bipy is 4,4-bi­pyridine (C₁₀H₈N₂)], each Mn^II atom displays octahedral coordination by two O atoms of the 1,4-BDOA²⁻ groups, two N atoms of the 4,4-bipy ligands and two solvent water mol­ecules. The Mn^II atom, 4,4-bipy ligand and 1,4-BDOA²⁻ group occupy different inversion centres. Adjacent Mn^II atoms are bridged by 1,4-BDOA²⁻ groups and 4,4-bipy ligands, forming a two-dimensional network with Mn...Mn separations of 11.592 (2) and 11.699 (2) Å. Hydro­gen bonds from a water O—H group link the layers in the third dimension.

S1. Comment

The construction of coordination polymers and networks by the self-assembly of organic ligands and transition metal ions is a rapidly growing area of research (Xia et al., 2004). Considerable interest is fuelled by their impact on basic structural chemistry and also by their possible applications in a number of fields. The general strategy for designing a coordination polymer relies on the use of multidentate N– or O-donor ligands that have the capacity to bridge metal centres (Li et al., 2003). Among such N-donor ligands, the rigid 4,4-bipyridine (4,4-bipy) molecule and its related species are often chosen to construct coordination polymers, and usually act as a linear bridge between metal centres (Sun et al., 2004). It is found that the introduction of an O-donor ligand, such as polycarboxylate, into the N-donor system can alter the structural and functional properties of coordination polymers. Although the structures of a few corresponding polymers have been reported (Lightfoot & Snedden, 1999; Lu et al., 1999; Zheng et al., 1999), the architecture of coordination polymers formed from mixed multiligands is still a challenge to chemists, because prediction of the compositions or structures of the products is difficult.

The versatile polycarboxylates, such as benzene-1,4-dioxyacetic acid (1,4-BDOAH₂), have been widely used in the construction of high-dimensional porous materials, on the basis of their high symmetry and the varied carboxylate coordination modes. However, the coordination chemistry and structural properties of the flexible 1,4-BDOAH₂ molecule itself have received little attention to date. Recently, we have reported some Co^II and Cu^II one-dimensional coordination polymers using this ligand, in which the 1,4-BDOA²⁻ dianion acts as a bi- or tridentate bridging ligand with N-heterocyclic coligands (Gao et al., 2004a,b). In this paper, we report the structure of the title novel two-dimensional manganese(II) coordination polymer, [Mn(1,4-BDOA)(4,4-bipy)(H₂O)₂]_n, (I), obtained by the hydrothermal reaction of MnCl₂·6H₂O, 4,4-bipy and 1,4-BDOAH₂. \sch

As illustrated in Fig. 1, complex (I) consists of an Mn^II cation, one 1,4-BDOA²⁻ dianion, one 4,4-bipy ligand and two coordinated water molecules, whereby the Mn^II atom, 4,4-bipy ligand and 1,4-BDOA²⁻ group occupy three different inversion centres. The local coordination environment around the Mn^II atom can be described as approximately octahedral, involving two N atoms of the 4,4-bipy ligands, two monodentate carboxyl O atoms of the 1,4-BDOA²⁻ groups and two solvent water molecules [Mn1—O1W 2.212 (2) Å]. The Mn—O1(carboxylate) bond length [2.163 (2) Å] is somewhat shorter than Mn—N1 bond distance [2.292 (2) Å]

It is worth noting that the C1—O1 bond [1.266 (4) Å] is slightly longer than C1—O2 [1.245 (4) Å], consistent with the monodentate coordination mode of carboxyl groups. The 1,4-BDOA²⁻ ligands are not planar: the C3—O3—C2—C1 torsion angle is 68.3 (4)°. The dihedral angle between the benzene ring and the 4,4-bipy ligand is 53.8 (3)°.

Both 4,4-bipy and 1,4-BDOA²⁻ act as bidentate bridging ligands to link Mn metal centres, leading to the formation of a two-dimensional coordination polymer (Fig. 2). Each 1,4-BDOA²⁻ ligand behaves as a bis-monodentate ligand, bridging two adjacent Mn^II atoms through its carboxyl O atoms to produce a zigzag chain parallel to the c axis, with an intrachain Mn···Mn separation of 11.592 (2) Å. This is somewhat longer than in Mn-terephthalate complexes. To the best of our knowledge, few six-coordinate Mn^II polymers based on the terephthalate ligand (tp) have been structurally characterized to date (Yang et al., 2003; Hong & Do, 1997; Tan et al., 1997; Cano et al., 1997). In these complexes, the intrachain Mn···Mn separations vary from 9.655 Å in [Mn(5-methylpyrazole)₂(tp)]_n (Hong & Do, 1997) to the longest distance of 11.457 Å in [Mn₂(phen)₄(H₂O)₂(tp)][ClO₄] (Cano et al., 1997).

Neighbouring chains in (I) are further connected by the N atoms of the bis-monodentate bridging 4,4-bipy ligand, generating a two-dimensional layer architecture parallel to the crystallographic bc plane, with an Mn···Mn separation of 11.699 (2) Å. The shortest interlayer Mn···Mn separation in (I) is 10.672 (2) Å.

The coordinated water molecules form hydrogen bonds with carboxyl O atoms. Of the two independent hydrogen bonds (Table 2), one is inter- Something missing? and the other interlayer. The latter extends the two-dimensional layers into the third dimension.

S2. Experimental

Benzene-1,4-dioxyacetic acid was prepared following the method described for the synthesis of benzene-1,2-dioxyacetic acid by Mirci (1990). MnCl₂·6H₂O (4.68 g, 20 mmol), 4,4-bipy (3.12 g, 20 mmol) and 1,4-BDOAH₂ (4.52 g, 20 mmol) were dissolved in a 4:1 ethanol-water solution, and the pH was adjusted to 7 with 0.1M NaOH. The mixture was sealed in a 25 ml Teflon-lined stainless steel bomb and held at 423 K for 5 d. The bomb was allowed to cool naturally to room temperature. Pale-yellow crystals of (I) separated from the filtered solution after several days. Analysis, calculated for C₂₀H₂₀N₂O₈Mn: C 50.97, H 4.28, N 5.94%; found: C 51.06, H 4.34, N 5.88%.

S3. Refinement

C-bonded H atoms were placed in calculated positions, with C—H = 0.93 or 0.97 Å and U_iso(H) = 1.2U_eq(C), and were refined in the riding-model approximation. Water H atoms were located in a difference map and refined, with O—H and H···H distance restraints of 0.85 (1) and 1.39 (1) Å, respectively, and with U_iso(H) = 1.5U_eq(O).

Computing details

Data collection: RAPID-AUTO (Rigaku, 1998); cell refinement: RAPID-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: ORTEPII (Johnson, 1976); molecular graphics: SHELXL97 (Sheldrick, 1997).

Figures

	Fig. 1. A view of (I) with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radii. Hydrogen bonds are shown as dashed lines.
	Fig. 2. The two-dimensional layer structure of (I), viewed along the a axis. Please check added text.

poly[[diaquamanganese(II)]-µ-4,4-bipyridine-κ²N:N'-µ- (p-phenylenedioxydiacetato)-κ²O:O']

Crystal data

[Mn(C10H8O6)(C10H8N2)(H2O)2]	Z = 1
Mr = 471.32	F(000) = 243
Triclinic, P1	Dx = 1.617 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71074 Å
a = 5.783 (2) Å	Cell parameters from 3999 reflections
b = 8.229 (2) Å	θ = 3.7–27.5°
c = 10.827 (3) Å	µ = 0.74 mm^−1
α = 105.65 (3)°	T = 293 K
β = 97.48 (3)°	Prism, pale yellow
γ = 97.689 (9)°	0.29 × 0.23 × 0.17 mm
V = 484.2 (3) Å^3

Data collection

Rigaku R-AXIS RAPID diffractometer	2181 independent reflections
Radiation source: fine-focus sealed tube	1527 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.057
Detector resolution: 10 pixels mm^-1	θmax = 27.5°, θmin = 3.6°
ω scans	h = −7→7
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	k = −10→10
Tmin = 0.815, Tmax = 0.885	l = −14→14
4561 measured reflections

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)] = 0.058	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.107	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ^2(Fo^2) + (0.046P)^2 + 0.0764P] where P = (Fo^2 + 2Fc^2)/3
2181 reflections	(Δ/σ)max < 0.001
148 parameters	Δρmax = 0.43 e Å^−3
3 restraints	Δρmin = −0.28 e Å^−3

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

	x	y	z	Uiso*/Ueq
Mn1	0.5000	0.5000	0.0000	0.0213 (2)
N1	0.5089 (5)	0.7027 (3)	0.1940 (2)	0.0254 (6)
O1	0.7084 (4)	0.3614 (2)	0.1021 (2)	0.0283 (5)
O2	0.4240 (4)	0.1530 (3)	0.1092 (3)	0.0472 (7)
O3	1.0265 (4)	0.2625 (3)	0.2682 (2)	0.0350 (6)
O1W	0.1667 (4)	0.3516 (3)	0.0211 (2)	0.0351 (6)
C1	0.6340 (6)	0.2265 (4)	0.1306 (3)	0.0264 (7)
C2	0.8191 (6)	0.1452 (4)	0.1937 (3)	0.0348 (8)
C3	1.0006 (6)	0.3792 (4)	0.3818 (3)	0.0270 (7)
C4	0.8021 (6)	0.3753 (4)	0.4409 (3)	0.0339 (8)
C5	0.8025 (6)	0.4955 (4)	0.5587 (3)	0.0325 (8)
C6	0.6763 (6)	0.7262 (4)	0.2977 (3)	0.0292 (7)
C7	0.6803 (6)	0.8403 (4)	0.4176 (3)	0.0292 (7)
C8	0.5027 (5)	0.9382 (3)	0.4358 (3)	0.0209 (6)
C9	0.3299 (6)	0.9159 (4)	0.3283 (3)	0.0349 (8)
C10	0.3381 (6)	0.7979 (4)	0.2105 (3)	0.0355 (8)
H1W1	0.059 (5)	0.387 (4)	0.062 (3)	0.053*
H1W2	0.226 (6)	0.279 (4)	0.053 (3)	0.053*
H2A	0.7472	0.0876	0.2502	0.042*
H2B	0.8662	0.0587	0.1260	0.042*
H4	0.6684	0.2920	0.4014	0.041*
H5	0.6690	0.4917	0.5980	0.039*
H6	0.7970	0.6620	0.2883	0.035*
H7	0.8017	0.8517	0.4864	0.035*
H9	0.2087	0.9798	0.3349	0.042*
H10	0.2196	0.7844	0.1398	0.043*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Mn1	0.0231 (4)	0.0225 (4)	0.0176 (4)	0.0062 (3)	0.0042 (3)	0.0034 (3)
N1	0.0298 (15)	0.0254 (13)	0.0191 (13)	0.0052 (10)	0.0053 (11)	0.0027 (10)
O1	0.0305 (13)	0.0286 (11)	0.0285 (12)	0.0079 (9)	0.0059 (10)	0.0112 (10)
O2	0.0323 (15)	0.0454 (14)	0.0708 (19)	0.0075 (11)	0.0106 (13)	0.0273 (13)
O3	0.0307 (14)	0.0444 (14)	0.0303 (13)	0.0113 (10)	0.0042 (10)	0.0098 (10)
O1W	0.0258 (13)	0.0443 (14)	0.0406 (14)	0.0086 (10)	0.0104 (11)	0.0181 (11)
C1	0.0291 (18)	0.0295 (16)	0.0224 (16)	0.0101 (13)	0.0076 (13)	0.0069 (13)
C2	0.039 (2)	0.0305 (17)	0.038 (2)	0.0112 (14)	0.0046 (16)	0.0133 (15)
C3	0.0263 (17)	0.0350 (17)	0.0255 (17)	0.0105 (13)	0.0039 (14)	0.0164 (14)
C4	0.0270 (18)	0.0413 (19)	0.0352 (19)	0.0034 (14)	0.0044 (15)	0.0159 (15)
C5	0.0219 (18)	0.0457 (19)	0.0374 (19)	0.0098 (14)	0.0126 (15)	0.0195 (15)
C6	0.0331 (19)	0.0282 (16)	0.0258 (17)	0.0141 (13)	0.0052 (14)	0.0028 (13)
C7	0.0355 (19)	0.0275 (16)	0.0219 (16)	0.0108 (13)	−0.0026 (14)	0.0039 (13)
C8	0.0247 (16)	0.0199 (14)	0.0183 (15)	0.0027 (12)	0.0047 (13)	0.0056 (11)
C9	0.0322 (19)	0.0458 (19)	0.0216 (17)	0.0176 (15)	0.0015 (14)	−0.0022 (14)
C10	0.033 (2)	0.048 (2)	0.0191 (16)	0.0141 (15)	−0.0029 (14)	−0.0014 (14)

Geometric parameters (Å, º)

Mn1—N1	2.292 (2)	C2—H2B	0.9700
Mn1—O1	2.163 (2)	C3—C4	1.386 (5)
Mn1—O1W	2.212 (2)	C3—C5^ii	1.383 (4)
O1—C1	1.266 (4)	C4—C5	1.387 (4)
O2—C1	1.245 (4)	C4—H4	0.9300
Mn1—N1^i	2.292 (2)	C5—C3^ii	1.383 (4)
Mn1—O1^i	2.163 (2)	C5—H5	0.9300
Mn1—O1W^i	2.212 (2)	C6—C7	1.377 (4)
N1—C6	1.336 (4)	C6—H6	0.9300
N1—C10	1.341 (4)	C7—C8	1.390 (4)
O3—C2	1.428 (4)	C7—H7	0.9300
O3—C3	1.380 (4)	C8—C8^iii	1.492 (5)
O1W—H1W1	0.85 (3)	C8—C9	1.385 (4)
O1W—H1W2	0.85 (3)	C9—C10	1.389 (4)
C1—C2	1.519 (4)	C9—H9	0.9300
C2—H2A	0.9700	C10—H10	0.9300
N1^i—Mn1—N1	180.0	O1W^i—Mn1—N1	88.84 (9)
O1—Mn1—N1	89.63 (8)	C1—O1—Mn1	126.8 (2)
O1—Mn1—N1^i	90.37 (8)	C1—C2—H2A	108.6
O1^i—Mn1—O1	180.0	C1—C2—H2B	108.6
O1—Mn1—O1W^i	88.82 (9)	C3—O3—C2	117.1 (3)
O1—Mn1—O1W	91.18 (9)	C3—C4—C5	120.1 (3)
O1W—Mn1—N1^i	88.84 (9)	C3—C4—H4	119.9
O1W—Mn1—N1	91.16 (9)	C3^ii—C5—C4	120.6 (3)
O1W—Mn1—O1W^i	180.0	C3^ii—C5—H5	119.7
O1—C1—C2	116.8 (3)	C4—C5—H5	119.7
O2—C1—C2	117.2 (3)	C5^ii—C3—C4	119.2 (3)
Mn1—O1W—H1W1	129 (2)	C5—C4—H4	119.9
Mn1—O1W—H1W2	98 (2)	C6—N1—Mn1	122.1 (2)
N1—C6—C7	123.7 (3)	C6—N1—C10	116.7 (2)
N1—C6—H6	118.2	C6—C7—C8	119.9 (3)
N1—C10—C9	123.1 (3)	C6—C7—H7	120.0
N1—C10—H10	118.5	C7—C6—H6	118.2
O1^i—Mn1—N1^i	89.63 (8)	C7—C8—C8^iii	122.0 (3)
O1^i—Mn1—N1	90.37 (8)	C8—C7—H7	120.0
O1^i—Mn1—O1W	88.82 (9)	C8—C9—C10	119.9 (3)
O1^i—Mn1—O1W^i	91.18 (9)	C8—C9—H9	120.0
O2—C1—O1	125.9 (3)	C9—C8—C7	116.7 (3)
O3—C2—C1	114.7 (2)	C9—C8—C8^iii	121.3 (3)
O3—C2—H2A	108.6	C9—C10—H10	118.5
O3—C2—H2B	108.6	C10—N1—Mn1	121.2 (2)
O3—C3—C4	125.7 (3)	C10—C9—H9	120.0
O3—C3—C5^ii	115.0 (3)	H1W1—O1W—H1W2	110 (2)
O1W^i—Mn1—N1^i	91.16 (9)	H2A—C2—H2B	107.6
Mn1—N1—C6—C7	−176.4 (2)	O1W—Mn1—N1—C10	−63.2 (3)
Mn1—N1—C10—C9	176.6 (3)	O1W^i—Mn1—N1—C10	116.8 (3)
Mn1—O1—C1—O2	−3.1 (5)	O1W—Mn1—O1—C1	12.0 (2)
Mn1—O1—C1—C2	175.38 (18)	O1W^i—Mn1—O1—C1	−168.0 (2)
N1^i—Mn1—O1—C1	−76.9 (2)	C2—O3—C3—C4	11.1 (4)
N1—Mn1—O1—C1	103.1 (2)	C2—O3—C3—C5^ii	−171.6 (3)
N1—C6—C7—C8	0.3 (5)	C3—O3—C2—C1	68.3 (4)
O1^i—Mn1—N1—C6	−157.7 (2)	C3—C4—C5—C3^ii	0.4 (5)
O1—Mn1—N1—C6	22.3 (2)	C5^ii—C3—C4—C5	−0.4 (5)
O1^i—Mn1—N1—C10	25.6 (3)	C6—N1—C10—C9	−0.2 (5)
O1—Mn1—N1—C10	−154.4 (3)	C6—C7—C8—C9	−1.0 (5)
O1—C1—C2—O3	28.5 (4)	C6—C7—C8—C8^iii	179.2 (3)
O2—C1—C2—O3	−152.9 (3)	C7—C8—C9—C10	1.1 (5)
O3—C3—C4—C5	176.8 (3)	C8^iii—C8—C9—C10	−179.1 (3)
O1W—Mn1—N1—C6	113.4 (2)	C8—C9—C10—N1	−0.5 (6)
O1W^i—Mn1—N1—C6	−66.6 (2)	C10—N1—C6—C7	0.3 (5)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1W1···O1^iv	0.85 (3)	2.12 (2)	2.903 (3)	152 (3)
O1W—H1W2···O2	0.85 (3)	1.80 (3)	2.630 (3)	164 (3)

Symmetry code: (iv) x−1, y, z.