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The title polymer, [Mn(C2O4)(H2O)2]n, was synthesized by the reaction of manganese(II) nitrate tetra­hydrate with a proton-transfer compound, (pipzH2)(ox) (where oxH2 is oxalic acid and pipz is piperazine), in aqueous solution. The structure features a six-coordinate Mn2+ ion located on a twofold rotation axis, with a distorted octa­hedral geometry [Mn—O = 2.1728 (8)–2.1914 (9) Å]. The bond angles show that the two coordinated water mol­ecules are arranged trans. One-dimensional linear chains are formed through bis-bidentate oxalate ligands bridging the MnII ions. These structural units are held together by O—H...O hydrogen bonds. A neutron diffraction study of [Mn(μ-ox)(D2O)2]n, using powdered samples, has been published recently in the same space group [Sledzinska, Murasik & Fischer (1987). J. Phys. Solid State Phys. 20, 2247–2259]. However, it should be noted that an ortho­rhom­bic polymorph for the title polymer is also known [Huizing, van Hal, Kwestroo, Langereis & van Loosdregt (1977). Mater. Res. Bull. 12, 605–611; Lethbridge, Congreve, Esslemont, Slawin & Lightfoot (2003). J. Solid State Chem. 172, 212–218]. The present single-crystal X-ray study deals with the monoclinic polymorph. This phase is isostructural with the CoII analogue.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807040470/bh2112sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536807040470/bh2112Isup2.hkl
Contains datablock I

CCDC reference: 660144

Key indicators

  • Single-crystal X-ray study
  • T = 296 K
  • Mean [sigma](C-C) = 0.002 Å
  • R factor = 0.016
  • wR factor = 0.046
  • Data-to-parameter ratio = 14.1

checkCIF/PLATON results

No syntax errors found



Alert level B PLAT369_ALERT_2_B Long C(sp2)-C(sp2) Bond C1 - C1_d ... 1.57 Ang.
Alert level C PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) . 1.11 Ratio
Alert level G PLAT794_ALERT_5_G Check Predicted Bond Valency for Mn1 (2) 2.08
0 ALERT level A = In general: serious problem 1 ALERT level B = Potentially serious problem 1 ALERT level C = Check and explain 1 ALERT level G = General alerts; check 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 0 ALERT type 3 Indicator that the structure quality may be low 1 ALERT type 4 Improvement, methodology, query or suggestion 1 ALERT type 5 Informative message, check

Comment top

Oxalato-bridged coordination compounds have played a key role in the theoretical and experimental development of areas such as molecular magnetism (Verdaguer, 2001) and crystal engineering (Marinescu et al., 2002). It has been established that two crystal hydrates are formed in this system MnC2O4.2H2O and MnC2O4.3H2O. Both crystal hydrates differ in color and structure. The white α-MnC2O4.2H2O is monoclinic, space group C2/c (Deyrieux et al., 1973), while the pink-colored MnC2O4.3H2O is orthorhombic, space group Pcca (Huizing et al., 1977, Fu et al., 2005; Wu et al., 2005). However, the paper published by Deyrieux et al. does not include atomic coordinates. A neutron diffraction study for MnC2O4.two-dimensional2O, using powdered samples, has been published recently (Sledzinska et al., 1987). It is noticeable that an orthorhombic polymorphs for the title polymer is also known (Huizing et al., 1977; Lethbridge et al.., 2003;). In this way, our X-ray study deals with the monoclinic polymorph. It is expected that the difference in the crystal lattice of the compounds and the different way of bonding of water molecules would affect some properties, such as a thermal stability, oxidation, and magnetic behavior. The wide variety of coordination modes of the oxalate anion with different metals allows the use of metal-oxalato units as excellent building blocks to construct a great diversity of homo- and heterometallic structural frameworks ranging from discrete polymeric entities (Chiozzone et al., 2003) to one-, two- and three-dimensional networks (Castillo et al. 2001).

Figure 1 shows that the O3 and O3d atoms of the two coordinated water molecules occupy the axial positions, while O1, O1d, O2a and O2c atoms of bridging oxalate ligands form the equatorial plane. The O3—Mn—O3d angle is almost linear, 179.05 (4)°. Therefore, coordination sphere around the MnII center, placed on a twofold symmetry axis, is almost octahedral. The torsion angles show that the oxalate ligand is planar. Also, the result shows that one-dimensional linear chains are formed in the crystal structure through bridging bis-bidentate oxalate ligands. The bond angles show that the two coordinated water molecules are arranged trans. A remarkable feature in the crystal structure of (I) is the presence of strong O—H···O hydrogen bonds, connecting one-dimensional chains in the crystal structure (Fig. 2). The title complex is isomorphous to the corresponding CoII-based polymer (Bacsa et al., 2005).

Related literature top

A preliminary report on the monoclinic polymorph of the title polymer was published by Deyrieux et al. (1973). For a neutron study of [Mn(µ-ox)(D2O)2]n, see Sledzinska et al. (1987). The reported structure is isostructural with that based on CoII (Bacsa et al., 2005). For further details of the related chemistry, see: Chiozzone et al. (2003); Aghabozorg et al. (2006); Verdaguer (2001); Marinescu et al. (2002); Castillo et al. (2001); Fu et al. (2005); Wu et al. (2005). [From the Section Editors: Please revise the scheme. The C?C bond should be single and the C—O bonds should be single/double or delocalized.]

Experimental top

A solution of Mn(NO3)2.4H2O (125 mg, 0.5 mmol) in water (20 ml) was added to an aqueous solution of (pipzH2)(ox) (253 mg, 1.0 mmol) in water (20 ml) in a 2:1 molar ratio (oxH2 is oxalic acid and pipz is piperazine; see Aghabozorg et al., 2006). Colorless crystals of (I) were obtained after a few days at room temperature.

Refinement top

H atoms for the water molecule O3 were found in a difference map but their positions regularized with O—H bond lengths constrained to 0.95 Å. H atoms were constrained to ride on O3 and were refined with an isotropic displacement parameter fixed to Uiso(H) = 1.2 Ueq(O3).

Structure description top

Oxalato-bridged coordination compounds have played a key role in the theoretical and experimental development of areas such as molecular magnetism (Verdaguer, 2001) and crystal engineering (Marinescu et al., 2002). It has been established that two crystal hydrates are formed in this system MnC2O4.2H2O and MnC2O4.3H2O. Both crystal hydrates differ in color and structure. The white α-MnC2O4.2H2O is monoclinic, space group C2/c (Deyrieux et al., 1973), while the pink-colored MnC2O4.3H2O is orthorhombic, space group Pcca (Huizing et al., 1977, Fu et al., 2005; Wu et al., 2005). However, the paper published by Deyrieux et al. does not include atomic coordinates. A neutron diffraction study for MnC2O4.two-dimensional2O, using powdered samples, has been published recently (Sledzinska et al., 1987). It is noticeable that an orthorhombic polymorphs for the title polymer is also known (Huizing et al., 1977; Lethbridge et al.., 2003;). In this way, our X-ray study deals with the monoclinic polymorph. It is expected that the difference in the crystal lattice of the compounds and the different way of bonding of water molecules would affect some properties, such as a thermal stability, oxidation, and magnetic behavior. The wide variety of coordination modes of the oxalate anion with different metals allows the use of metal-oxalato units as excellent building blocks to construct a great diversity of homo- and heterometallic structural frameworks ranging from discrete polymeric entities (Chiozzone et al., 2003) to one-, two- and three-dimensional networks (Castillo et al. 2001).

Figure 1 shows that the O3 and O3d atoms of the two coordinated water molecules occupy the axial positions, while O1, O1d, O2a and O2c atoms of bridging oxalate ligands form the equatorial plane. The O3—Mn—O3d angle is almost linear, 179.05 (4)°. Therefore, coordination sphere around the MnII center, placed on a twofold symmetry axis, is almost octahedral. The torsion angles show that the oxalate ligand is planar. Also, the result shows that one-dimensional linear chains are formed in the crystal structure through bridging bis-bidentate oxalate ligands. The bond angles show that the two coordinated water molecules are arranged trans. A remarkable feature in the crystal structure of (I) is the presence of strong O—H···O hydrogen bonds, connecting one-dimensional chains in the crystal structure (Fig. 2). The title complex is isomorphous to the corresponding CoII-based polymer (Bacsa et al., 2005).

A preliminary report on the monoclinic polymorph of the title polymer was published by Deyrieux et al. (1973). For a neutron study of [Mn(µ-ox)(D2O)2]n, see Sledzinska et al. (1987). The reported structure is isostructural with that based on CoII (Bacsa et al., 2005). For further details of the related chemistry, see: Chiozzone et al. (2003); Aghabozorg et al. (2006); Verdaguer (2001); Marinescu et al. (2002); Castillo et al. (2001); Fu et al. (2005); Wu et al. (2005). [From the Section Editors: Please revise the scheme. The C?C bond should be single and the C—O bonds should be single/double or delocalized.]

Computing details top

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); 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, 2005); software used to prepare material for publication: SHELXTL.

Figures top
[Figure 1] Fig. 1. Molecular structure of compound (I), displacement ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. Crystal packing of the title compound (I), hydrogen bonds are shown as dashed lines.
catena-poly[[diaquamanganese(II)]-µ-oxalato-κ4O1,O2:O1',O2'] top
Crystal data top
[Mn(C2O4)(H2O)2]F(000) = 356
Mr = 178.99Dx = 2.288 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 3637 reflections
a = 11.7648 (14) Åθ = 3.4–27.5°
b = 5.6550 (6) ŵ = 2.49 mm1
c = 9.6367 (11) ÅT = 296 K
β = 125.843 (6)°Block, colourless
V = 519.71 (10) Å30.21 × 0.21 × 0.11 mm
Z = 4
Data collection top
Bruker SMART CCD area-detector
diffractometer
607 independent reflections
Radiation source: fine-focus sealed tube604 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.025
Detector resolution: 100 pixels mm-1θmax = 27.7°, θmin = 4.2°
ω scansh = 1515
Absorption correction: multi-scan
(SADABS; Bruker, 1998)
k = 76
Tmin = 0.616, Tmax = 0.763l = 1212
4187 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.016H-atom parameters constrained
wR(F2) = 0.046 w = 1/[σ2(Fo2) + (0.0267P)2 + 0.4357P]
where P = (Fo2 + 2Fc2)/3
S = 1.10(Δ/σ)max < 0.001
607 reflectionsΔρmax = 0.46 e Å3
43 parametersΔρmin = 0.40 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0173 (15)
Crystal data top
[Mn(C2O4)(H2O)2]V = 519.71 (10) Å3
Mr = 178.99Z = 4
Monoclinic, C2/cMo Kα radiation
a = 11.7648 (14) ŵ = 2.49 mm1
b = 5.6550 (6) ÅT = 296 K
c = 9.6367 (11) Å0.21 × 0.21 × 0.11 mm
β = 125.843 (6)°
Data collection top
Bruker SMART CCD area-detector
diffractometer
607 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 1998)
604 reflections with I > 2σ(I)
Tmin = 0.616, Tmax = 0.763Rint = 0.025
4187 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0160 restraints
wR(F2) = 0.046H-atom parameters constrained
S = 1.10Δρmax = 0.46 e Å3
607 reflectionsΔρmin = 0.40 e Å3
43 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Mn10.50000.56903 (4)0.75000.00841 (13)
C10.55073 (12)1.07019 (17)0.85025 (14)0.0084 (2)
O10.58713 (8)0.87221 (15)0.92326 (10)0.01030 (19)
O20.58807 (8)1.26771 (14)0.92238 (10)0.00973 (19)
O30.31804 (9)0.56581 (13)0.75879 (11)0.0116 (2)
H3A0.23460.61370.65320.014*
H3B0.33040.65690.84950.014*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Mn10.01051 (17)0.00518 (17)0.00806 (17)0.0000.00461 (13)0.000
C10.0080 (5)0.0101 (6)0.0070 (6)0.0001 (3)0.0044 (5)0.0001 (3)
O10.0124 (4)0.0067 (4)0.0085 (4)0.0003 (3)0.0043 (3)0.0007 (3)
O20.0124 (4)0.0065 (4)0.0080 (4)0.0005 (3)0.0047 (3)0.0006 (3)
O30.0121 (4)0.0121 (4)0.0086 (4)0.0005 (3)0.0049 (4)0.0009 (3)
Geometric parameters (Å, º) top
Mn1—O2i2.1728 (8)C1—O21.2515 (13)
Mn1—O2ii2.1728 (8)C1—O11.2566 (13)
Mn1—O12.1849 (9)C1—C1iii1.567 (2)
Mn1—O1iii2.1849 (9)O2—Mn1iv2.1728 (8)
Mn1—O32.1914 (9)O3—H3A0.9501
Mn1—O3iii2.1914 (9)O3—H3B0.9500
O2i—Mn1—O2ii76.70 (4)O1—Mn1—O3iii90.24 (3)
O2i—Mn1—O1179.57 (3)O1iii—Mn1—O3iii90.50 (3)
O2ii—Mn1—O1103.35 (3)O3—Mn1—O3iii179.05 (4)
O2i—Mn1—O1iii103.35 (3)O2—C1—O1126.19 (11)
O2ii—Mn1—O1iii179.57 (3)O2—C1—C1iii116.80 (6)
O1—Mn1—O1iii76.61 (4)O1—C1—C1iii117.00 (6)
O2i—Mn1—O389.07 (3)C1—O1—Mn1114.69 (7)
O2ii—Mn1—O390.19 (3)C1—O2—Mn1iv114.84 (7)
O1—Mn1—O390.50 (3)Mn1—O3—H3A112.1
O1iii—Mn1—O390.24 (3)Mn1—O3—H3B113.9
O2i—Mn1—O3iii90.19 (3)H3A—O3—H3B109.6
O2ii—Mn1—O3iii89.07 (3)
O2—C1—O1—Mn1179.34 (9)O3—Mn1—O1—C190.31 (8)
C1iii—C1—O1—Mn10.46 (15)O3iii—Mn1—O1—C190.28 (8)
O2ii—Mn1—O1—C1179.38 (7)O1—C1—O2—Mn1iv179.48 (9)
O1iii—Mn1—O1—C10.18 (6)C1iii—C1—O2—Mn1iv0.72 (15)
Symmetry codes: (i) x+1, y1, z+3/2; (ii) x, y1, z; (iii) x+1, y, z+3/2; (iv) x, y+1, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H3A···O1v0.951.852.7696 (12)162
O3—H3B···O2vi0.951.862.7517 (12)155
Symmetry codes: (v) x1/2, y+3/2, z1/2; (vi) x+1, y+2, z+2.

Experimental details

Crystal data
Chemical formula[Mn(C2O4)(H2O)2]
Mr178.99
Crystal system, space groupMonoclinic, C2/c
Temperature (K)296
a, b, c (Å)11.7648 (14), 5.6550 (6), 9.6367 (11)
β (°) 125.843 (6)
V3)519.71 (10)
Z4
Radiation typeMo Kα
µ (mm1)2.49
Crystal size (mm)0.21 × 0.21 × 0.11
Data collection
DiffractometerBruker SMART CCD area-detector
Absorption correctionMulti-scan
(SADABS; Bruker, 1998)
Tmin, Tmax0.616, 0.763
No. of measured, independent and
observed [I > 2σ(I)] reflections
4187, 607, 604
Rint0.025
(sin θ/λ)max1)0.653
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.016, 0.046, 1.10
No. of reflections607
No. of parameters43
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.46, 0.40

Computer programs: SMART (Bruker, 1998), SAINT (Bruker, 1998), SAINT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 2005), SHELXTL.

Selected geometric parameters (Å, º) top
Mn1—O2i2.1728 (8)Mn1—O32.1914 (9)
Mn1—O12.1849 (9)
O2ii—Mn1—O2i76.70 (4)O2ii—Mn1—O3iii90.19 (3)
O2ii—Mn1—O1179.57 (3)O2i—Mn1—O3iii89.07 (3)
O2i—Mn1—O1103.35 (3)O1—Mn1—O3iii90.24 (3)
O2ii—Mn1—O1iii103.35 (3)O1iii—Mn1—O3iii90.50 (3)
O2i—Mn1—O1iii179.57 (3)O3—Mn1—O3iii179.05 (4)
O1—Mn1—O1iii76.61 (4)C1—O1—Mn1114.69 (7)
O2ii—Mn1—O389.07 (3)C1—O2—Mn1iv114.84 (7)
O2i—Mn1—O390.19 (3)Mn1—O3—H3A112.1
O1—Mn1—O390.50 (3)Mn1—O3—H3B113.9
O1iii—Mn1—O390.24 (3)H3A—O3—H3B109.6
Symmetry codes: (i) x, y1, z; (ii) x+1, y1, z+3/2; (iii) x+1, y, z+3/2; (iv) x, y+1, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H3A···O1v0.951.852.7696 (12)162.0
O3—H3B···O2vi0.951.862.7517 (12)155.0
Symmetry codes: (v) x1/2, y+3/2, z1/2; (vi) x+1, y+2, z+2.
 

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