Poly[hexa-μ-acetato-bis(dimethyl sulfoxide)trimanganese(II)]

In the title complex, [Mn3(CH3CO2)6(C2H6SO)2]n, the MnII ions exhibit similar MnO6 octahedral coordination geometries but with different coordination environments. One type of MnII ion is surrounded by five acetate groups and a terminal dimethyl sulfoxide group, while the other lies on a twofold axis and is coordinated by six O atoms from three symmetry-related acetate ions. The acetate anions exhibit three independent bridging modes, which flexibly bridge the MnII ions along the c-axis direction, forming an infinite chain structure; the chains are further interconnected through weak C—H⋯O and C—H⋯S hydrogen-bonding interactions.

In the title complex, [Mn 3 (CH 3 CO 2 ) 6 (C 2 H 6 SO) 2 ] n , the Mn II ions exhibit similar MnO 6 octahedral coordination geometries but with different coordination environments. One type of Mn II ion is surrounded by five acetate groups and a terminal dimethyl sulfoxide group, while the other lies on a twofold axis and is coordinated by six O atoms from three symmetryrelated acetate ions. The acetate anions exhibit three independent bridging modes, which flexibly bridge the Mn II ions along the c-axis direction, forming an infinite chain structure; the chains are further interconnected through weak C-HÁ Á ÁO and C-HÁ Á ÁS hydrogen-bonding interactions.

Related literature
For metal complexes of DMSO, see: Calligaris et al. (2004). For the structure of a related complex, see: Wang et al. (2000).

Comment
The coordination chemistry of dimethyl sulfoxid (DMSO) has been widely studied. Herein, we report the preparation and crystal strcuture of a new manganese(II) complex with dimethyl sulfoxide (DMSO). In the title complex, the two independent Mn II ions (Mn1 and Mn2) exhibit a similar O6-octahedral coordination geometry with different coordination environments (Fig. 1). The Mn1 ion is surrounded by five acetates and one η 1 -bonding DMSO, while the Mn2 lies on a two-fold axis and is coordinated by six oxygen atoms of three symmetry related acetate ions. The acetate anions exhibit three independent bridging modes, syn, syn η 1 :η 1 :µ 2 -mode (C2-symmetric O3-containing acetate and O5-, O6-containing acetate), the syn, syn, ant η 1 :η 2 :µ 3 -mode (O1-, O2-containing acetate) and the syn, ant, syn, ant η 2 :η 2 :µ 3 -mode (C2-symmetric O7-containing acetate). The Mn1 and Mn2 ions are flexibly bridged by these anions and assemble into an infinite chain along the c direction (Fig. 2). The parallel arrays interconnect through C-H···O and C-H···S type H-bonding interactions (Table 1).
In the termianl dimethyl sulfoxide, the S1═O4 of 1.501 (2)Å bond is slightly longer than that of the neat DMSO, which can be ascribed to the reduced bond order as that found in the protonated and η 1 -coordinated alkyl sulfoxides (Calligaris et al., 2004). The Mn1-O4 bond length of 2.153 (2)Å is comparable to 2.158 (2)Å found in catena-(tetrakis(µ 2 -thiocyanato- et al., 2000), in which the dimethyl sulfoxide shows a similar terminal η 1 -coordinated bonding to the Mn II .

Experimental
Mn(CH 3 CO 2 ) 2 .4H 2 O (25 mg, 0.1 mmol) was dissolved in 3 ml deionized water with stirring at room temperature. After half an hour, 1 ml dimethyl sulfoxide was added to the solution. The mixed solution was stirred for another half hour, and then filtered. The clear solution obtained was left to stand in the air to let the solvent to evaporate. The colorless crystals were deposited after one week (12.60 mg, yield 56%).

Refinement
An absolute structure was determined using the Flack (1983) method. The hydrogen atoms were placed in idealized positions and allowed to ride on the parent carbon atoms, with C-H = 0.96 Å and U iso (H) = 1.5U eq (C). Fig. 1. A view of the title complex with the atom-numbering scheme; hydrogen atoms are omitted for clarity. Displacement ellipsoids are drawn at 30% probability level. Symmetry codes: i x, y, z-1; ii -x+2,y,-z; iii -x + 2, y, -z +1.  supplementary materials sup-3

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger. An absolute structure was established with the Flack parameter of 0.034 (17). O4-S1-C8 103.40 (16) H7B-C7-H7C 109.5 O4-S1-C7 105.3 (2) S1-C8-H8A 109.5 C8-S1-C7 98.3 (2) S1-C8-H8B 109.5