Crystal structures of [Mn(bdc)(Hspar)2(H2O)0.25]·2H2O containing MnO6+1 capped trigonal prisms and [Cu(Hspar)2](bdc)·2H2O containing CuO4 squares (Hspar = sparfloxacin and bdc = benzene-1,4-dicarboxylate)

The Mn2+ ion in [Mn(bdc)(Hspar)2(H2O)0.25]·2H2O (Hspar = sparfloxacin and bdc = benzene-1,4-dicarboxylate) is coordinated by two O,O′-bidentate Hspar neutral molecules (which exist as zwitterions) and an O,O′-bidentate bdc dianion to generate a distorted MnO6 trigonal prism. In [Cu(Hspar)2](bdc)·2H2O,the Cu2+ ion lies on a crystallographic inversion centre and a CuO4 square-planar geometry arises from its coordination by two O,O′-bidentate Hspar molecules. The bdc dianion acts as a counter-ion to the cationic complex and does not bond to the metal ion.

As well as hydrated Hspar, which occurs in the crystal in its zwitterionic form, i.e. proton transfer from the -CO 2 H carboxylic acid group to the remote secondary amine moiety of the piperazine ring (Sivalakshmidevi et al., 2000), the crystal structures of its anionic (spar À ) complexes with nickel (Skyrianou et al., 2009), copper (Efthimiadou et al., 2006) and zinc (Tarushi et al., 2011) have been reported. Hydrated ISSN 2056-9890 molecular salts of the H 2 spar + cation (i.e. containing both -CO 2 H and NH 2 + groups) with BF 4 À (Shingnapurkar et al., 2007) and SO 4 2À counter-ions (Li et al., 2011) are known. As part of our own studies in this area, we have recently described the structure of [Cd(spar) 2 ]ÁH 2 O , a onedimensional coordination polymer in which chains of CdO 6 octahedra bridged by the spar À species are found.
As a continuation of these studies, we now describe the syntheses and crystal structures of the title mixed-ligand complexes [Mn(bdc) ).

Structural commentary 2.1. Compound (I)
Compound (I) is a hydrated neutral mononuclear complex: the asymmetric unit contains an Mn 2+ cation, two neutral, zwitterionic Hspar molecules, a bdc dianion and three water molecules, one of which, O13, was modelled with a site occupancy factor of 1 4 (Fig. 1). The manganese ion in (I) is coordinated by two bidentate Hspar molecules, with the quinoline O atom and its syncarboxylate O atom (O3 and O2, respectively, in the C1containing molecule and O6 and O5, respectively, in the C20molecule) serving as the donor atoms, which generates a sixmembered chelate ring in each case, with O-Mn-O bite angles of 81.86 (8) and 82.05 (8) , respectively. The metal coordination sphere also features an O,O-bidentate bdc dianion and a very long [2.580 (12) Å ] Mn-O bond to the partly occupied O13 water molecule. Together, these lead to a distorted MnO 6+1 trigonal-prismatic polyhedron (Table 1) with the Mn-Ow bond capping through the square face defined by the two Hspar ligands (Fig. 2). The mean Mn-O separation of 2.137 Å for the Hspar bonds is significantly shorter than the mean of the Mn-O (bdc) bonds of 2.297 Å and the bond-valence sum (BVS) (Brown & Altermatt, 1985) for the metal ion for the six shorter bonds is 1.89 (expected value = 2.00). If the seventh bond to O13 is added, the manganese BVS increases to 1.99.

Figure 1
The molecular structure of (I), showing 50% displacement ellipsoids. H atoms bound to C atoms have been omitted for clarity and hydrogen bonds and the long Mn1Á Á ÁO13 contact are shown as double-dashed lines.
between the near-planar segments of the chelate rings is 29.74 (13) . Both Hspar molecules are orientated in the same sense with respect to the metal ion, with the NH 2 groups mutually syn.
The most important geometrical features of the first Hspar molecule (containing C1) are as follows: the C1-O1 and C1-O2 bond lengths of 1.251 (4) and 1.256 (4) Å , respectively, are typical for a delocalized carboxylate group and the dihedral angle between C1/O1/O2 and the adjacent N2-containing ring (r.m.s. deviation = 0.045 Å ) is 8.6 (8) . The dihedral angle between the cyclopropane ring and the N2 ring is 67.5 (3) . The N2 bond-angle sum of 359.8 is consistent with a bonding model of sp 2 hybridization for this atom. The dihedral angle between the N2 ring and the C5 ring (r.m.s. deviation = 0.028 Å ), which are fused at the C4-C9 bond, is 7.9 (2) , indicating a substantial puckering to the quinolone system.
The piperazinium ring adopts a typical chair conformation with the exocyclic N-C q (q = quinolone) bond in an equatorial orientation. The dihedral angle between the four C atoms that form the 'seat' of the chair and the C5 ring is 60.3 (2) . There was some suggestion that atoms C14 and C17 of this ring are positionally disordered, but refinements that attempted to model this effect were inconclusive.

Compound (II)
Compound (II) can be regarded as a hydrated molecular salt: the asymmetric unit contains a Cu 2+ cation lying on a crystallographic inversion centre, a neutral, zwitterionic, Hspar molecule, half a bdc dianion and a water molecule of crystallization (Fig. 3).
The copper ion in (II) is   Detail of (I) showing the capped trigonal prismatic coordination of the metal ion.

Figure 3
The molecular structure of (II) showing 50% probability displacement ellipsoids. Only one orientation of the disordered cyclopropyl ring is shown. Hydrogen bonds are shown as double-dashed lines. [Symmetry codes: (i) 1 À x, Ày, 1 À z; (ii) Àx, Ày, Àz.] with a bite angle of 93.24 (8) , which generates a sixmembered chelate ring. The result is a CuO 4 square-planar coordination polyhedron (Table 3) with a mean Cu-O separation of 1.898 Å . There are no atoms in possible axial sites within 3.5 Å of the metal ion. The -O2-C1-C2-C3-O3-Cu1-chelate ring is a shallow envelope, with the metal atom displaced by 0.124 (3) Å from the mean plane of the almost planar ligand atoms (r.m.s. deviation = 0.023 Å ).
In the Hspar molecule, the C1-O1 and C1-O2 bond lengths are distinctly different at 1.226 (4) Å and 1.283 (4) Å , respectively, unlike the situation in (I), where they are almost the same length. The dihedral angle between the C1/O1/O2 grouping in (II) and its attached ring is 6.2 (5) and the dihedral angle between the fused rings of the quinolone system is 3.2 (2) . The cyclopropane ring in (II) is disordered over two orientations in a 0.670 (8): 0.330 (8) ratio. The piperazine ring adopts a chair conformation as usual, and N4 (the secondary amine group) is protonated. The dihedral angle between the four carbon atoms forming the 'seat' of the chair and the F-bearing aromatic ring is 63.77 (10) .
In the bdc dianion, the C23/O4/O5 carboxylate group is rotated by 2.7 (6) with respect to the aromatic ring plane. The C23-O4 and C23-O5 bond lengths of 1.244 (4) and 1.253 (4) Å , respectively, are consistent with the approximately equal delocalization of the negative charge over both C-O bonds.

Supramolecular features
In the crystal of (I), a number of N-HÁ Á ÁO, O-HÁ Á ÁO and weak C-HÁ Á ÁO hydrogen bonds (Table 2) link the components into a three-dimensional network. A short C-HÁ Á Á interaction is also observed.

Database survey
So far as a search of the Cambridge Structural Database (Groom & Allen, 2014) reveals, (I) is the first crystal structure of a complex containing Mn 2+ ions and Hspar molecules. The O,O-chelating mode of the Hspar molecules is normal for other divalent transition metals (Skyrianou et al., 2009;Efthimiadou et al., 2006;Tarushi et al., 2011), as is that of the O,Obidentate bdc dianion for Mn 2+ (e.g. Ma et al., 2003), but the resulting trigonal-prismatic coordination geometry for the manganese ion in (I) is very unusual, although not unknown. An analogous structure is seen for [Mn(acac) 2 (bipy)] (acac = acetylacetonate, bipy = 2,2 0 -bipyridine; van Gorkum et al., 2005), where an almost regular MnN 2 O 4 trigonal prism occurs (i.e. there is no capping): as these authors note, the high-spin d 5 electronic configuration of Mn 2+ is the 'least unexpected' to show a trigonal-prismatic geometry because it has no crystalfield stabilization energy, which normally favours octahedral over trigonal-prismatic geometry (Karpishin et al., 1993). Based on DFT calculations, it was concluded that the trigonalprismatic and octahedral geometries for [Mn(acac) 2 (bipy)] have almost the same energy and the trigonal-prismatic geometry is adopted in the crystal because of favourable packing interactions (van Gorkum et al., 2005). The ligands in (I) are far bulkier and more flexible than acac or bipy and it is difficult to speculate on whether packing effects are equally important in establishing the capped trigonal-prismatic metalion coordination geometry in (I).
Cg9 is the centroid of the C39-C44 ring.
Cu ( purkar et al., 2007), the Cu 2+ ions are chelated by two spar À anions in the basal plane, with a long apical Cu-N bond [2.463 (4) Å ] arising from the -NH 2 group of an adjacent spar À anion generating a centrosymmetric, bimetallic assembly. It is thus notable that sparfloxacin can bind to Cu 2+ ions in its anionic, neutral and cationic forms and we are continuing our explorations of these systems.

Synthesis and crystallization
To prepare (I), a mixture of Mn(CH 3 CO 2 ) 2 Á4H 2 O (0.25 mmol), sparfloxacin (0.5 mmol), 1,4-benzenedicarboxylic acid (0.25 mmol), sodium hydroxide (1 mmol) and water (15 ml) was stirred for 30 minutes in air. The mixture was placed in a sealed 25 ml Teflon-lined hydrothermal reactor and heated to 423 K for 72 h under autogenous pressure. Upon cooling, colourless prisms of (I) were recovered from the reaction by vacuum filtration and rinsing with water.
Both (I) and (II) appear to be indefinitely stable when stored in dry air.

Refinement
Crystal data, data collection and structure refinement details for (I) and (II) are summarized in Table 5. In (I), the O13 water molecule is close to an inversion-generated clone and cannot be more than 50% occupied. Its site occupancy was refined and converged to close to 0.25: in the final cycles of refinement, it was fixed at 1 4 . In (II), the pendant cyclopropane group is disordered over two orientations in a 0.670 (8)  For both compounds, data collection: SMART (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and publCIF (Westrip, 2010).

(I) 0.25-Aqua(benzene-1,4-dicarboxylato-κ 2 O,O′)bis(sparfloxacin-κ 2 O,O′)manganese(II) dihydrate
Crystal data  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.  Hydrogen-bond geometry (Å, º) Cg9 is the centroid of the C39-C44 ring. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.56 e Å −3 Δρ min = −0.57 e Å −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. Symmetry codes: (i) −x+1, −y, −z+1; (iii) −x+1, y+1/2, −z+1/2; (iv) x, y+1, z; (v) −x, y+3/2, −z+1/2; (vi) x, −y+1/2, z−1/2; (vii) x, −y+1/2, z+1/2.