trans-Bis(methanol-κO)bis(quinoline-2-carboxylato-κ2 N,O)manganese(II)

The title compound, [Mn(C10H6NO2)2(CH4O)2], was obtained unintentionally as the product of an attempt to synthesize a polynuclear carboxylate bridged manganese(III/IV) complex, using methanol to reduce the permanganate ion. The molecule is centrosymmetric; the pairs of equivalent ligands coordinate trans to each other in a distorted octahedral geometry. Intramolecular C—H⋯O bonds lying in the equatorial plane stabilize the molecule. In the crystal, molecules are linked by O—H⋯O and C—H⋯O hydrogen bonds, creating a three-dimensional supramolecular structure. π–π and C—H⋯π interactions are also observed. The dihedral angle and centroid-to-centroid distance between the pyridine ring (A) and the benzene ring (B i) of a symmetrically related molecule [symmetry code: (i) −1 − x, −y, −z] are 1.27 (11)° and 3.974 (2) Å, respectively. For the C—H⋯π interactions, the relevant distances and angles are: C⋯Cg[A ii] = 3.643 (2) Å, H⋯Cg[A ii] = 2.750 (2) Å and C—H⋯Cg[A ii] = 155 (1)° [symmetry code: (ii) x, −1 + y, z].

The title compound, [Mn(C 10 H 6 NO 2 ) 2 (CH 4 O) 2 ], was obtained unintentionally as the product of an attempt to synthesize a polynuclear carboxylate bridged manganese(III/IV) complex, using methanol to reduce the permanganate ion. The molecule is centrosymmetric; the pairs of equivalent ligands coordinate trans to each other in a distorted octahedral geometry. Intramolecular C-HÁ Á ÁO bonds lying in the equatorial plane stabilize the molecule. In the crystal, molecules are linked by O-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds, creating a threedimensional supramolecular structure.and C-HÁ Á Á interactions are also observed. The dihedral angle and centroid-to-centroid distance between the pyridine ring (A) and the benzene ring (B i ) of a symmetrically related molecule [symmetry code: (i) À1 À x, Ày, Àz] are 1.27 (11) and 3.974 (2) Å , respectively. For the C-HÁ Á Á interactions, the relevant distances and angles are: CÁ Á ÁCg[A ii ] = 3.643 (2)

S1. Comment
The quinoline-2-carboxylate (quin-2-c) ion is known as an effective chelator. A few Mn(II) complexes with the quin-2-c ion and different coligands have been reported previously (Okabe et al., 1997, Goher et al., 1993, Haendler, 1996, Dobrzyńska et al., 2004, 2005. The title complex, (I), is centrosymmetric (Fig. 1). The quin-2-c ion coordinates in a typical O,N chelate mode. The pairs of the equivalent ligands lie trans to each other in a distorted octahedral geometry.
The bite angle of the chelating ligand is 74.93 (7)° and falls in the range observed for other manganese(II) complexes with the quin-2-c ion (73.1° -78.5°; see references quoted above). The intramolecular C-H···O bonds lying in the equatorial plane stabilize the molecule (Table 1).
In the crystal molecules are linked by O-H···O and C-H···O hydrogen bonds creating a three-dimensional supramolecular structure (see Table 1

S2. Experimental
Compound (I) was obtained unintentionally as the product of an attempt to synthesize the polynuclear, carboxylate bridged manganese(III/IV) complex mixing a methanol solution of quinoline-2-carboxylic acid and potassium permanganate at room temperature.

S3. Refinement
The hydroxyl H-atom was located in a difference Fourier map and refined isotropically with the O-H distance restrained  The molecular structure of compound (I), with atom labels and 50% probability displacement ellipsoids for non-H atoms.

trans-Bis(methanol-κO)bis(quinoline-2-carboxylato-κ 2 N,O)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.