Poly­[manganese(II)-[mu]₂-benzidine-[kappa]²N:N'-[mu]₃-bi­phenyl-2,2'-di­carboxylato-[kappa]⁴O:O',O'':O''']

The title compound, [Mn(C₁₄H₈O₄)(C₁₂H₁₂N₂)]_n, with a novel three-dimensional framework, has been prepared by a hydro­thermal reaction at 433 K. Each Mn atom lies on a twofold axis in a slightly distorted octahedral geometry, coordinated by two N atoms from two benzidine ligands and four O atoms from three symmetry-related biphenyl-2,2'-dicarboxylate (bpdc) ligands. The benzidine ligands lie about inversion centres and the bpdc ligands about twofold axes. Each bpdc ligand is bonded to three Mn ions to form a continuous chain of metal ions. The bpdc ligands are accommodated in a series of distorted holes resembling hexagonal prisms.

S1. Comment

The design and syntheses of multidimensional coordination polymers are an attractive area of research because of their intriguing structural diversity and potential applications in functional materials (Moulton & Zaworotko, 2001). Coordination polymers are built by the rational selection of metal ions and the use of structurally interesting ligands with specific functionality to construct metal-organic frameworks. 2,2'-Diphenyldicarboxylic acid (H₂bpdc) is useful as a building block for the construction of coordination polymers, and a few coordination polymers using 2,2'-biphenyldicarboxylate (bpdc) as a bridging ligand have been reported (Speier et al., 2001; Rueff et al., 2002; Wang et al., 2002; Wang et al., 2003a; Kumagai et al., 2002; Wang et al., 2003b; Wang et al., 2003c; Thirumurugan et al., 2003). We report here a novel three-dimensional manganese polymer, [Mn(C₁₄H₈O₄)(C₁₂H₁₂N₂)]_n, (I), constructed from bpdc and benzidine.

The coordination environment of the Mn^II ion is shown in Fig.1, with the geometry listed in Table 1. Atom Mn1, which lies on a crystallographic twofold axis, is coordinated to three symmetrically related bpdc ligands via atoms O2ⁱ [symmetry code: (i) x, 1 − y, 1/2 + z] and O2ⁱⁱ [symmetry code: (ii) −x, 1 − y, −z] of two bpdc ligands related by the twofold axis, and atoms O1 and O1ⁱⁱⁱ [symmetry code: (iii) −x, y, 1/2 − z] of one bpdc ligand, which itself lies on the twofold axis through atom Mn1. The axial coordination sites of the resulting octahedral environment of atom Mn1 are occupied by N atoms of the benzidine moiety, which itself lies astride a centre of symmetry.

This configuration results in columns (or chains) of linked Mn^II ions coordinated to an approximately square array of O atoms, as shown in Fig. 2 and end on in Fig. 3. The benzidine ligands link adjacent columns but bind to different columns alternately along the chain, thus producing a three-dimensional network structure in which every Mn^II column is linked to four adjacent columns. The Mn^II–benzidine links can be thought of as forming a network of distorted hexagonal holes in which the phenyl rings of the bpdc ligands are contained along the b direction (Fig. 3).

The bpdc group acts as a quadridentate µ₃-bridging ligand to link three Mn atoms (Fig. 2). Each bpdc ligand is in a twisted mode, and the dihedral angle between the planes of the two phenyl rings in the bpdc ligand is 68.53 (7)°. The two phenyl rings are coplanar in the centrosymmetric benzidine ligands, but the two benzidine ligands that are linked to the same Mn atom are not in parallel planes. This mode of µ₃ binding is found for one of the bpdc ligands in seven, apparently isostructural, complexes of Nd, Dy and Y (Thirumurugan et al., 2003), and La, Pr, Eu and Tb (Wang et al., 2003b), but in these structures a second crystallographically distinct bpdc ligand binds in a different way. The continuous µ₃ mode of binding of bpdc ligands to produce the tertiary structure found in (I) (Fig. 2) is unique according to the Cambridge Structural Database (Version 5.25 of July 2004; Allen, 2002).

Only one of the H atoms attached to atoms N1 appears to take part in hydorgen bonding (Table 2).

S2. Experimental

All reagents were of AR grade and were used without further purification. A mixture of 2,2'-diphenic acid (0.242 g, 1 mmol), benzidine (0.184 g, 1 mmol) and MnCl₂ (0.170 g, 1 mmol) with H₂O (15 ml) was placed in a Teflon-lined stainless steel vessel, heated to 333 K and maintained at that temperature for 96 h, and then cooled slowly to room temperature. The resulting deep-orange crystals were collected by filtration and washed with water (yield 80%). Interestingly, although we changed the ratio of the mixture to 1:2:1 and 1:2:2, we got the same deep-orange crystals.

S3. Refinement

H atoms attached to C atoms were treated as riding, with C—H distances of 0.93 Å and N—H distances of 0.90 Å, and with U_iso(H) values of 1.2U_eq(C,N).

Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2000); program(s) used to refine structure: SHELXL97 (Sheldrick, 2000); molecular graphics: SHELXTL/PC (Sheldrick, 1999); software used to prepare material for publication: SHELXTL/PC.

Figures

	Fig. 1. The coordination environment of the Mn^II ions, with displacement ellipsoids shown at the 30% probability level. All H atoms have been omitted for clarity. The crystallographic twofold axis is vertical. [Symmetry codes: (i) x, 1 − y, 1/2 + z; (ii) −x, 1 − y, −z; (iii) −x, y, 1/2 − z.]
	Fig. 2. A segment of the Mn-containing columns viewed from the side, approximately down a. Atoms Mn1 and Mn1A are separated by c/2. A l l H atoms and the benzidine ligands, except for the coordinated N atoms (dotted), have been omitted for clarity.
	Fig. 3. A view of three-dimensional framework, along the c axis. The columns of coordinated Mn ions of Fig. 2 are seen end on, with the bpdc ligands extending in the b direction. All H atoms have been omitted for clarity.

Poly[manganese(II)-µ₃-µ₂-benzidine-k²N,N'-2,2'-biphenyldicarboxylato- κ⁴O:O',O'':O''']

Crystal data

[Mn(C14H8O4)(C12H12N2)]	F(000) = 988
Mr = 479.38	Dx = 1.407 Mg m^−3
Monoclinic, C2/c	Melting point: not measured K
Hall symbol: -C 2yc	Mo Kα radiation, λ = 0.71073 Å
a = 24.309 (10) Å	Cell parameters from 1010 reflections
b = 10.161 (4) Å	θ = 2.2–21.8°
c = 9.326 (4) Å	µ = 0.62 mm^−1
β = 100.677 (7)°	T = 293 K
V = 2263.7 (16) Å^3	Needle, dark orange
Z = 4	0.42 × 0.28 × 0.23 mm

Data collection

Bruker SMART 1K CCD area-detector diffractometer	2005 independent reflections
Radiation source: fine-focus sealed tube	1313 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.053
ϕ and ω scans	θmax = 25.0°, θmin = 1.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 2000)	h = −23→28
Tmin = 0.781, Tmax = 0.871	k = −12→11
5868 measured reflections	l = −11→10

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)] = 0.042	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.083	H-atom parameters constrained
S = 0.87	w = 1/[σ^2(Fo^2) + (0.0322P)^2] where P = (Fo^2 + 2Fc^2)/3
2005 reflections	(Δ/σ)max = 0.012
150 parameters	Δρmax = 0.39 e Å^−3
0 restraints	Δρmin = −0.22 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	1.02748 (6)	0.2500	0.0341 (2)
N1	0.08919 (9)	1.0167 (2)	0.1954 (2)	0.0403 (6)
H1A	0.0980	0.9307	0.1943	0.048*
H1B	0.0862	1.0456	0.1030	0.048*
O1	−0.02209 (7)	0.87500 (16)	0.08064 (18)	0.0340 (5)
O2	0.02422 (8)	0.82012 (17)	−0.0958 (2)	0.0438 (5)
C1	0.01373 (11)	0.8068 (3)	0.0298 (3)	0.0331 (7)
C2	0.04916 (12)	0.7112 (2)	0.1287 (3)	0.0329 (7)
C3	0.03001 (12)	0.6489 (2)	0.2438 (3)	0.0364 (7)
C4	0.06742 (15)	0.5777 (3)	0.3431 (3)	0.0576 (9)
H4	0.0548	0.5349	0.4191	0.069*
C5	0.12285 (16)	0.5684 (3)	0.3326 (4)	0.0711 (11)
H5	0.1476	0.5230	0.4034	0.085*
C6	0.14186 (14)	0.6264 (3)	0.2174 (4)	0.0611 (10)
H6	0.1792	0.6186	0.2085	0.073*
C7	0.10477 (12)	0.6961 (3)	0.1157 (3)	0.0437 (8)
H7	0.1173	0.7338	0.0367	0.052*
C8	0.13668 (11)	1.0814 (3)	0.2784 (3)	0.0374 (7)
C9	0.16671 (12)	1.0233 (3)	0.4007 (3)	0.0489 (8)
H9	0.1575	0.9387	0.4261	0.059*
C10	0.21072 (12)	1.0890 (3)	0.4872 (3)	0.0516 (8)
H10	0.2300	1.0480	0.5708	0.062*
C11	0.22682 (11)	1.2141 (3)	0.4525 (3)	0.0364 (7)
C12	0.19660 (12)	1.2679 (3)	0.3265 (3)	0.0454 (8)
H12	0.2069	1.3505	0.2976	0.054*
C13	0.15205 (12)	1.2056 (3)	0.2415 (3)	0.0466 (8)
H13	0.1322	1.2472	0.1590	0.056*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Mn1	0.0340 (4)	0.0410 (4)	0.0264 (4)	0.000	0.0033 (3)	0.000
N1	0.0341 (14)	0.0472 (14)	0.0381 (14)	−0.0052 (12)	0.0026 (11)	−0.0098 (12)
O1	0.0345 (12)	0.0374 (11)	0.0301 (11)	0.0019 (9)	0.0058 (9)	−0.0021 (9)
O2	0.0578 (14)	0.0482 (12)	0.0276 (11)	0.0107 (11)	0.0136 (10)	0.0060 (9)
C1	0.0337 (18)	0.0323 (16)	0.0317 (18)	−0.0064 (14)	0.0016 (14)	−0.0034 (13)
C2	0.0410 (18)	0.0303 (15)	0.0278 (16)	0.0030 (14)	0.0074 (13)	−0.0019 (13)
C3	0.0496 (19)	0.0300 (14)	0.0317 (16)	0.0050 (14)	0.0126 (15)	−0.0023 (13)
C4	0.073 (3)	0.054 (2)	0.052 (2)	0.0235 (19)	0.0274 (19)	0.0217 (17)
C5	0.078 (3)	0.080 (3)	0.059 (2)	0.045 (2)	0.022 (2)	0.029 (2)
C6	0.049 (2)	0.070 (2)	0.067 (3)	0.0235 (19)	0.0178 (19)	0.016 (2)
C7	0.050 (2)	0.0416 (18)	0.043 (2)	0.0068 (16)	0.0184 (16)	0.0029 (15)
C8	0.0277 (16)	0.0465 (17)	0.0384 (18)	−0.0006 (14)	0.0066 (14)	−0.0101 (15)
C9	0.0435 (19)	0.0403 (17)	0.057 (2)	−0.0090 (16)	−0.0049 (16)	0.0030 (16)
C10	0.042 (2)	0.0534 (19)	0.052 (2)	−0.0047 (17)	−0.0095 (16)	0.0092 (17)
C11	0.0286 (16)	0.0392 (17)	0.0411 (19)	−0.0043 (14)	0.0060 (14)	−0.0044 (14)
C12	0.0460 (19)	0.0409 (18)	0.046 (2)	−0.0104 (16)	−0.0010 (16)	0.0035 (15)
C13	0.048 (2)	0.0451 (18)	0.0418 (19)	−0.0025 (16)	−0.0045 (16)	0.0035 (15)

Geometric parameters (Å, º)

Mn1—O2^i	2.1214 (19)	C4—H4	0.9300
Mn1—O2^ii	2.1214 (19)	C5—C6	1.378 (4)
Mn1—O1	2.2066 (18)	C5—H5	0.9300
Mn1—O1^iii	2.2066 (18)	C6—C7	1.377 (4)
Mn1—N1^iii	2.320 (2)	C6—H6	0.9300
Mn1—N1	2.320 (2)	C7—H7	0.9300
N1—C8	1.426 (3)	C8—C9	1.369 (4)
N1—H1A	0.9000	C8—C13	1.378 (4)
N1—H1B	0.9000	C9—C10	1.386 (4)
O1—C1	1.271 (3)	C9—H9	0.9300
O2—C1	1.251 (3)	C10—C11	1.385 (4)
O2—Mn1^ii	2.1214 (19)	C10—H10	0.9300
C1—C2	1.498 (3)	C11—C12	1.378 (4)
C2—C7	1.388 (4)	C11—C11^iv	1.490 (5)
C2—C3	1.398 (3)	C12—C13	1.372 (4)
C3—C4	1.377 (4)	C12—H12	0.9300
C3—C3^iii	1.485 (5)	C13—H13	0.9300
C4—C5	1.372 (4)
O2^i—Mn1—O2^ii	86.23 (11)	C2—C3—C3^iii	122.1 (3)
O2^i—Mn1—O1	176.45 (7)	C5—C4—C3	121.5 (3)
O2^ii—Mn1—O1	91.55 (7)	C5—C4—H4	119.2
O2^i—Mn1—O1^iii	91.55 (7)	C3—C4—H4	119.2
O2^ii—Mn1—O1^iii	176.45 (7)	C4—C5—C6	120.1 (3)
O1—Mn1—O1^iii	90.81 (9)	C4—C5—H5	119.9
O2^i—Mn1—N1^iii	92.22 (8)	C6—C5—H5	119.9
O2^ii—Mn1—N1^iii	91.73 (7)	C7—C6—C5	119.0 (3)
O1—Mn1—N1^iii	90.61 (7)	C7—C6—H6	120.5
O1^iii—Mn1—N1^iii	85.58 (7)	C5—C6—H6	120.5
O2^i—Mn1—N1	91.73 (7)	C6—C7—C2	121.4 (3)
O2^ii—Mn1—N1	92.22 (8)	C6—C7—H7	119.3
O1—Mn1—N1	85.58 (7)	C2—C7—H7	119.3
O1^iii—Mn1—N1	90.61 (7)	C9—C8—C13	118.4 (3)
N1^iii—Mn1—N1	174.58 (11)	C9—C8—N1	120.5 (3)
C8—N1—Mn1	123.66 (16)	C13—C8—N1	121.1 (3)
C8—N1—H1A	106.4	C8—C9—C10	120.8 (3)
Mn1—N1—H1A	106.4	C8—C9—H9	119.6
C8—N1—H1B	106.4	C10—C9—H9	119.6
Mn1—N1—H1B	106.4	C11—C10—C9	121.8 (3)
H1A—N1—H1B	106.5	C11—C10—H10	119.1
C1—O1—Mn1	123.84 (16)	C9—C10—H10	119.1
C1—O2—Mn1^ii	129.37 (18)	C12—C11—C10	115.7 (3)
O2—C1—O1	124.3 (3)	C12—C11—C11^iv	122.5 (3)
O2—C1—C2	116.9 (2)	C10—C11—C11^iv	121.7 (3)
O1—C1—C2	118.6 (2)	C13—C12—C11	123.3 (3)
C7—C2—C3	119.0 (3)	C13—C12—H12	118.4
C7—C2—C1	118.5 (2)	C11—C12—H12	118.4
C3—C2—C1	122.1 (3)	C12—C13—C8	119.9 (3)
C4—C3—C2	118.8 (3)	C12—C13—H13	120.0
C4—C3—C3^iii	118.9 (3)	C8—C13—H13	120.0

Symmetry codes: (i) x, −y+2, z+1/2; (ii) −x, −y+2, −z; (iii) −x, y, −z+1/2; (iv) −x+1/2, −y+5/2, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O1^ii	0.90	2.24	2.990 (3)	140

Symmetry code: (ii) −x, −y+2, −z.