catena-Poly[4,4'-bipyridinium [[cis-di­chloro­manganese(II)]-di-[mu]-chloro]], a novel manganese(II) coordination polymer with 4,4'-bipyridinium

The title novel manganese(II) coordination polymer, {(C₁₀H₁₀N₂)[MnCl₄]}_n, consists of a one-dimensional infinite zigzag chain composed of polymeric [MnCl₄]^2- units in which each Mn²⁺ ion is located on a twofold rotation axis and is coordinated to two terminal Cl atoms and four bridging chloro ligands. Adjacent Mn²⁺ ions are linked by double Cl bridges arranged about a centre of inversion, thus forming anionic chains of distorted edge-sharing octa­hedra. Rows of approximately parallel 4,4'-bipyridinium cations run side-by-side with the MnCl₄ chains. A two-dimensional layer structure is constructed via hydrogen bonds and by additional [pi]-[pi] stacking inter­actions.

S1. Comment

Polymeric manganese chloride compounds with fascinating topological chemistry have received considerable interest (Law et al., 1998; Yachandra et al., 1996). In these studies, bipyridine and bipyridine-related ligands play a key role in constructing these topological structures. Since MnCl₃L compounds (L = bipy and phen) were isolated from the reaction of L with the purple ether extract of the black solid obtained from reduction of MnO₂ with dry HCl in CCl₄ by Goodwin & Sylva (1965), similar compounds have been reported (Lubben et al., 1995; Perlepes et al., 1991; Lumme & Lindell, 1988; Wang et al., 2005). To date, however, manganese chloride polymers with 4,4'-bipyridine molecules have not been reported. We present here for the first time the structure of a novel manganese chloride polymer with diprotonated 4,4'-bipyridine, [(H₂bipy)(MnCl₄)]_n, (I).

The molecular structure of (I) is shown in Fig. 1 and the two-dimensional layer structure is given in Fig. 2. The crystal structure of (I) contains polymeric [MnCl₄] units, which are linked to each other through double chloro-bridging ligands between adjacent Mn sites to construct a one-dimensional infinite chain, and a group of isolated 4,4'-bipyridinium cations with approximately parallel arrangement (Fig. 2). The Mn²⁺ ion is coordinated by six Cl atoms, with Mn—Cl distances ranging from 2.4935 (4) to 2.6579 (3) Å and Cl—Mn—Cl angles deviating from 90 or 180° by 4–11°, indicating a moderately distorted octahedral geometry. The MnCl octahedra are edge-shared to form a one-dimensional infinite chain extending along the a axis. Columns of diprotonated 4,4'-bipyridine molecules pack in alternating rows with the one-dimensional chains. In the diprotonated 4,4'-bipyridine, the dihedral angle between the bipy rings is 21.2°, which is comparable with the dihedral angle of 23.4° in the reported [(H₂NCH₂CONHCH₂COO)Cu(OH)(C₁₀H₈N₂)Cu(OH)₂ (H₂NCH₂CONHCH₂COO)]·9H₂O (Wang et al., 1994). There are Cl···N—H hydrogen-bonding interactions between the isolated 4,4'-bipyridinium cations and manganese chloride chains. In addition, the alternate stacking of the rings of the bipy molecules results in ring separations ranging from 3.5 to 4.4 Å, indicating weak π–π stacking interactions. As shown in Fig. 2, it is believed that these hydrogen-bonding and π–π interactions may play an important role in stabilizing the two-dimensional layer structure of (I).

S2. Experimental

All reagents and solvents were used as obtained without further purification. An aqueous solution (50 ml) containing Na₂MoO₄·2H₂O (14.5 g), whose pH was adjusted to 4.5 with concentrated HNO₃ solution, was added to an aqueous solution (4 ml) containing MnCl₂·4H₂O (1.98 g). The resulting mixture was stirred for 12 h and then filtered. Yellow crystals (0.2 g) were collected, redissolved in water (20 ml), and then added to an aqueous solution (20 ml) containing CrCl₃·6H₂O (0.3 g), CH₃CH₂OH (10 ml) and 4,4'-bipyridine (0.7 g). The resulting mixture was stirred for 2 h and filtered. Yellow crystals of (I) were collected after a few days. The formation of this compound appears to be a chance event and attempts to synthesize it in the absence of Na₂MoO₄·2H₂O and CrCl₃·6H₂O have so far been unsuccessful.

S3. Refinement

H atoms were placed in idealized positions and allowed to ride on their parent atoms with relative isotropic displacement parameters (U_iso) fixed at 1.2U_eq of the parent C and N atoms, with C—H distances of 0.93 Å and an N—H distance of 0.86 Å.

Computing details

Data collection: PROCESS-AUTO (Rigaku, 1998); cell refinement: PROCESS-AUTO (Rigaku, 2002); data reduction: CrystalStructure (Rigaku/MSC, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: WinGX (Farrugia, 1999); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. A view of the molecular structure of (I), showing the atom-numbering scheme. Symmetry equivalent Cl atoms have been included to show the complete coordination sphere of the Mn cation. [Symmetry codes: (A) −x − 1, −y, −z + 1; (B) −x − 3/2, y, −z + 1; (C) x − 1/2, −y, z.] Displacement ellipsoids are drawn at the 30% probability level.
	Fig. 2. The two-dimensional layer structure of (I). Hydrogen bonds are indicated by dashed lines.

catena-Poly[4,4'-bipyridinium [[dichloromanganese(II)]-di-µ-chloro]]

Crystal data

(C10H10N2)[MnCl4]	F(000) = 708
Mr = 177.47	Dx = 1.878 Mg m^−3
Monoclinic, I2/a	Mo Kα radiation, λ = 0.71073 Å
a = 6.9781 (6) Å	Cell parameters from 250 reflections
b = 12.7118 (13) Å	θ = 2.5–25°
c = 14.1568 (14) Å	µ = 1.88 mm^−1
β = 91.206 (2)°	T = 293 K
V = 1255.5 (2) Å^3	Block, yellow
Z = 8	0.26 × 0.19 × 0.17 mm

Data collection

Rigaku R-AXIS-IV diffractometer	1105 independent reflections
Radiation source: fine-focus sealed tube	1085 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.018
ω scans	θmax = 25.0°, θmin = 2.9°
Absorption correction: empirical (using intensity measurements) (ABSCOR; Higashi, 1995)	h = −8→8
Tmin = 0.643, Tmax = 0.745	k = −15→15
4519 measured reflections	l = −16→16

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.015	H-atom parameters constrained
wR(F^2) = 0.044	w = 1/[σ^2(Fo^2) + (0.027P)^2 + 0.6644P] where P = (Fo^2 + 2Fc^2)/3
S = 1.04	(Δ/σ)max = 0.001
1105 reflections	Δρmax = 0.25 e Å^−3
79 parameters	Δρmin = −0.18 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0071 (5)

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	−0.2500	0.580239 (19)	0.0000	0.02246 (12)
Cl1	−0.42432 (4)	0.43862 (2)	0.09931 (2)	0.02454 (12)
Cl2	−0.36929 (5)	0.71512 (2)	0.11234 (2)	0.03138 (12)
N1	−0.41127 (16)	0.08222 (9)	0.23090 (8)	0.0310 (3)
H1A	−0.4477	0.0838	0.2885	0.037*
C1	−0.41301 (19)	0.17143 (11)	0.18097 (9)	0.0323 (3)
H1B	−0.4570	0.2333	0.2080	0.039*
C2	−0.34973 (19)	0.17171 (10)	0.08953 (9)	0.0287 (3)
H2A	−0.3494	0.2339	0.0549	0.034*
C3	−0.28619 (17)	0.07842 (9)	0.04906 (9)	0.0214 (3)
C4	−0.29345 (17)	−0.01378 (10)	0.10270 (9)	0.0264 (3)
H4A	−0.2570	−0.0776	0.0765	0.032*
C5	−0.35474 (18)	−0.00973 (11)	0.19433 (9)	0.0315 (3)
H5A	−0.3570	−0.0705	0.2308	0.038*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Mn1	0.02549 (17)	0.02130 (17)	0.02074 (17)	0.000	0.00368 (11)	0.000
Cl1	0.02796 (18)	0.02295 (18)	0.02271 (18)	−0.00085 (11)	0.00080 (12)	0.00061 (11)
Cl2	0.0414 (2)	0.02460 (19)	0.02854 (19)	−0.00145 (13)	0.01037 (14)	−0.00408 (12)
N1	0.0268 (6)	0.0478 (8)	0.0185 (6)	−0.0021 (5)	0.0022 (4)	0.0000 (5)
C1	0.0338 (7)	0.0347 (7)	0.0287 (7)	0.0000 (6)	0.0043 (5)	−0.0070 (6)
C2	0.0348 (7)	0.0245 (7)	0.0269 (6)	0.0011 (5)	0.0048 (5)	−0.0006 (5)
C3	0.0192 (6)	0.0229 (6)	0.0220 (6)	−0.0011 (4)	−0.0009 (5)	0.0000 (4)
C4	0.0242 (6)	0.0256 (7)	0.0295 (6)	0.0015 (5)	0.0026 (5)	0.0040 (5)
C5	0.0262 (6)	0.0380 (8)	0.0303 (7)	0.0000 (5)	0.0009 (5)	0.0118 (6)

Geometric parameters (Å, º)

Mn1—Cl2	2.4935 (4)	C1—C2	1.3765 (19)
Mn1—Cl2^i	2.4935 (4)	C1—H1B	0.9300
Mn1—Cl1^i	2.6018 (4)	C2—C3	1.3935 (17)
Mn1—Cl1	2.6018 (4)	C2—H2A	0.9300
Mn1—Cl1^ii	2.6579 (3)	C3—C4	1.3981 (17)
Mn1—Cl1^iii	2.6579 (3)	C3—C3^i	1.488 (2)
Cl1—Mn1^ii	2.6579 (3)	C4—C5	1.3752 (19)
N1—C1	1.3363 (18)	C4—H4A	0.9300
N1—C5	1.3410 (18)	C5—H5A	0.9300
N1—H1A	0.8600
Cl2—Mn1—Cl2^i	93.119 (18)	C1—N1—H1A	118.8
Cl2—Mn1—Cl1^i	170.603 (10)	C5—N1—H1A	118.8
Cl2^i—Mn1—Cl1^i	87.992 (12)	N1—C1—C2	120.01 (12)
Cl2—Mn1—Cl1	87.992 (12)	N1—C1—H1B	120.0
Cl2^i—Mn1—Cl1	170.603 (10)	C2—C1—H1B	120.0
Cl1^i—Mn1—Cl1	92.435 (16)	C1—C2—C3	119.71 (12)
Cl2—Mn1—Cl1^ii	96.095 (12)	C1—C2—H2A	120.1
Cl2^i—Mn1—Cl1^ii	91.023 (12)	C3—C2—H2A	120.1
Cl1^i—Mn1—Cl1^ii	93.213 (11)	C2—C3—C4	118.33 (12)
Cl1—Mn1—Cl1^ii	79.581 (12)	C2—C3—C3^i	120.07 (8)
Cl2—Mn1—Cl1^iii	91.023 (12)	C4—C3—C3^i	121.60 (8)
Cl2^i—Mn1—Cl1^iii	96.095 (12)	C5—C4—C3	119.77 (12)
Cl1^i—Mn1—Cl1^iii	79.581 (12)	C5—C4—H4A	120.1
Cl1—Mn1—Cl1^iii	93.213 (11)	C3—C4—H4A	120.1
Cl1^ii—Mn1—Cl1^iii	169.651 (17)	N1—C5—C4	119.78 (12)
Mn1—Cl1—Mn1^ii	100.419 (12)	N1—C5—H5A	120.1
C1—N1—C5	122.34 (12)	C4—C5—H5A	120.1

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···Cl2^iv	0.86	2.54	3.2042 (12)	135
N1—H1A···Cl1^iv	0.86	2.60	3.2468 (12)	132

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