Pseudosymmetric fac-diaquatrichlorido[(dimethylphosphoryl)methanaminium-κO]manganese(II)

In the title compound, [Mn(C3H11NOP)Cl3(H2O)2], the MnII metal center has a distorted octahedral geometry, coordinated by the three chloride ligands showing a facial arrangement. Two water molecules and the O-coordinated dpmaH cation [dpmaH = (dimethylphosphoryl)methanaminium] complete the coordination sphere. Each complex molecule is connected to its neighbours by O—H⋯Cl and N—H⋯Cl hydrogen bonds. Two of the chloride ligands and the two water ligands form a hydrogen-bonded polymeric sheet in the ab plane. Furthermore, these planes are connected to adjacent planes by hydrogen bonds from the aminium function of cationic dpmaH ligand. A pseudo-mirror plane perpendicular to the b axis in the chiral space group P21 is observed together with inversion twinning [ratio = 0.864 (5):0.136 (5)].

In the title compound, [Mn(C 3 H 11 NOP)Cl 3 (H 2 O) 2 ], the Mn II metal center has a distorted octahedral geometry, coordinated by the three chloride ligands showing a facial arrangement. Two water molecules and the O-coordinated dpmaH cation [dpmaH = (dimethylphosphoryl)methanaminium] complete the coordination sphere. Each complex molecule is connected to its neighbours by O-HÁ Á ÁCl and N-HÁ Á ÁCl hydrogen bonds. Two of the chloride ligands and the two water ligands form a hydrogen-bonded polymeric sheet in the ab plane. Furthermore, these planes are connected to adjacent planes by hydrogen bonds from the aminium function of cationic dpmaH ligand. A pseudo-mirror plane perpendicular to the b axis in the chiral space group P2 1 is observed together with inversion twinning [ratio = 0.864 (5):0.136 (5)].
Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2011); software used to prepare material for publication: publCIF (Westrip, 2010 Manganese complexes are of general interest as these metal centers play important roles in biological systems such as metalloproteins (Wieghardt, 1989). More than one hundred manganese complexes built by aqua, chlorido and any organic donor ligands at the same time are structurally characterized and deposited in the Cambridge Structural Database. If we limit the search on compounds with at least one aqua, one chloride and a ligand with a O-coordinated phosphoryl group the number is reduced to only two examples (Głowiak & Sawka-Dobrowolska, 1977;Kubíček et al., 2003) which are comparable with the title complex. Furthermore, alkyldiphosphinates are known to be efficient tectons (for the term tecton, see: Brunet et al., 1997) to construct hydrogen bonded frameworks (Glidewell et al., 2000). Especially it has also been shown that amino phosphinic anions are able to form hydrogen bonded one-dimensional, two-dimensional and three-dimensional supramolecular architectures (Chen et al., 2010). For the neutral dmpa there are some examples that show its ability to coordinate transition metals (Borisov et al. 1994;Kochel, 2009) and also a salt containing the protonated dpmaH cation has been structurally characterized (Reiss & Jörgens, 2012). The structure determination on facdiaquatrichlorido((dimethylphosphoryl)methanaminium)manganese(II) is part of our continuing interest in the hydrogen bonding of methylphosphinic acids and its derivatives (Reiss & Engel, 2008) and the field of application as a tectons for the construction of new hydrogen bonded networks (e.g. Meyer et al., 2010).
The title structure crystallizes in the monoclinic, chiral space group P2 1 . The asymmetric unit consists of one formula unit of the fac-diaquatrichlorido((dimethylphosphoryl)methanaminium)manganese(II) complex. The three chlorido ligands show a facial arrangement with Mn-Cl distances between 2.5137 (3) and 2.5717 (3) Å which is in excellent agreement with other Mn(II) complexes (Głowiak & Sawka-Dobrowolska, 1977;Kubíček et al., 2003;Karthikeyan et al., 2011). The Cl-Mn-Cl angles of 92.163 (8)° to 93.346 (8)° are in the typical range of hexacoordinate aqua-chlorido manganese(II) complexes (e.g. Feist et al. 1997). The distorted octahedral coordination at the Mn(II) metal center is completed by two water molecules and a O-coordinated dpmaH cation. All Mn-O bond length as well as the geometrical parameters of the dpmaH cation are in the expected ranges. Each manganese complex is connected to adjacent complexes by O-H···Cl and N-H···Cl hydrogen bonds. Two of the chlorido ligands and the two water ligands form a hydrogen bonded two-dimensional polymer in the ab plane (Fig. 1). Adjacent layers are connected to each other by the cationic dpmaH ligand which is located between them. In detail the dpmaH ligand coordinates the manganese of one layer by its oxygen atom and forms a hydrogen bond to the next layer by its aminium group. The hydrogen bonding scheme of the formal two-dimensional polymer in the ab plane is characterized by three different types of annealed rings ( Fig. 2; A, B and C-ring). All rings are classified to belong to the R 2 2 (8) graph-set descriptor (Etter et al., 1990, Bernstein et al., 1995, but they are different in detail. Ring A and B show a pseudo-inversion symmetry (for a more general introduction into pseudo-symmetry, see: Ruck, 2000) whereas ring C seems to have a mirror symmetry. The pseudo-supplementary materials sup-2 Acta Cryst. (2013). E69, m250-m251 symmetry features of the hydrogen bonding motifs are related to a pseudo-mirror plane present perpendicular to the b axis. According to the checkcif algorithm more than 90% of the atom positions of the title structure fulfill this additional symmetry element. Figure 1 visualizes this pseudosymmetry situation and it is abundantly clear that the aminium group significantly breaks this additional symmetry element. Especially in pseudosymmetric cases where no additional (superstructure) reflections are present a close look on the plausibility of structural model (Reiss, 2002a;Reiss, 2002b;Reiss & Konietzny, 2002;) and on the difference density maps are needed (Jones et al., 1988). In the latter stages of the refinement the presence of inversion twinning (ratio: 0.864 (5) / 0.136 (5)) was detected. The general hydrogen bonding scheme within the ab plane can be abstracted by a so-called constructor graph ( Fig. 3; Grell et al., 2002). Especially in the constructor graph of the title structure the pseudosymmetry can be clearly seen. The infrared and Raman spectra of the title compound are shown in Fig. 4. Both spectra show bands similar to those reported for dpmaHCl (Reiss & Jörgens, 2012). A further assignment, especially for the far-infrared region of the Raman spectrum, is difficult as several lines are observed which may belong to modes of the dpma ligand or may result from stretch modes of Mn-O and Mn-Cl bonds.

Experimental
For the synthesis of the title compound (I) equimolar amounts of dpma and manganese(II)chloride tetrahydrate were dissolved in concentrated HCl. Slow evaporation of this solution at room temperature yielded crystals suitable for a crystallographic structure determination.

Refinement
Methyl H-atoms were identified in difference syntheses, idealized and refined using rigid groups allowed to rotate about the P-C bond (AFIX 137 option of the SHELXL97 program). The coordinates of all other H-atoms were refined freely with individual U iso values.

Figure 4
Showing the Raman-and the infrared spectra of the title compound.

fac-diaquatrichlorido[(dimethylphosphoryl)methanaminium-κO]manganese(II)
Crystal data 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 > σ(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq