[Mn(bpb)(DMAP)(NO)], an {Mn–NO}6 nitrosyl with Z′ = 8

The structure of the title compound octakis{[4-(dimethylamino)pyridine](nitrosyl)[N,N′-(o-phenylene)bis(pyridine-2-carboxamidato)]manganese(II)} ethanol heptasolvate 3.5-hydrate, [Mn(C18H12N4O2)(C7H10N2)(NO)]8·7C2H5OH·3.5H2O, or 8[Mn(bpb)(DMAP)(NO)]·7EtOH·3.5H2O, is an unusual example of a structure with Z′ = 8. The tetradentate bpb ligand, together with the nitrosyl and dimethylaminopyridine ligands, gives rise to a distorted octahedral coordination environment for the Mn(II) ion. The average Mn—N(N=O) bond length is 1.631 (13) Å. The eight molecules in the asymmetric unit differ mainly in the rotation of the DMAP pyridine plane with respect to a reference plane of the Mn and three N atoms, one of which is the N atom of the NO group. The dihedral angles between the normals to these planes range from a minimum of 28.0 (2)° to a maximum of 64.2 (2)°. There are also some differences in O—H⋯O hydrogen bonding interactions. For example, of the sixteen C=O acceptors, there are seven different interactions with EtOH donors and two interactions with H2O donors. The crystal studied was found to be a two-component twin, with a 179.9° rotation about the real axis [−0.535, 0.004, 1.000]. Due to the presence of a superlattice and, consequently, the large number of weak reflections, the refinement utilized rigid solvate groups and isotropic displacement parameters for all except the Mn atoms. H atoms were not located for hydrate molecules.

The structure of the title compound octakis{ [4-(dimethylamino)pyridine](nitrosyl)[N,N 0 -(o-phenylene)bis(pyridine-2-carboxamidato)]manganese(II)} ethanol heptasolvate 3.5-hydrate, [Mn(C 18 H 12 N 4 O 2 )(C 7 H 10 N 2 )(NO)] 8 Á7C 2 H 5 OHÁ-3.5H 2 O, or 8[Mn(bpb)(DMAP)(NO)]Á7EtOHÁ3.5H 2 O, is an unusual example of a structure with Z 0 = 8. The tetradentate bpb ligand, together with the nitrosyl and dimethylaminopyridine ligands, gives rise to a distorted octahedral coordination environment for the Mn(II) ion. The average Mn-N (N=O) bond length is 1.631 (13) Å . The eight molecules in the asymmetric unit differ mainly in the rotation of the DMAP pyridine plane with respect to a reference plane of the Mn and three N atoms, one of which is the N atom of the NO group. The dihedral angles between the normals to these planes range from a minimum of 28.0 (2) to a maximum of 64.2 (2) . There are also some differences in O-HÁ Á ÁO hydrogen bonding interactions. For example, of the sixteen C O acceptors, there are seven different interactions with EtOH donors and two interactions with H 2 O donors. The crystal studied was found to be a two-component twin, with a 179.9 rotation about the real axis [À0.535, 0.004, 1.000]. Due to the presence of a superlattice and, consequently, the large number of weak reflections, the refinement utilized rigid solvate groups and isotropic displacement parameters for all except the Mn atoms. H atoms were not located for hydrate molecules.
MMO thanks the University of California, Davis, for the purchase of the X-ray diffractometer. PKM acknowledges financial support from the NSF (grant CHE-0957251).
Hydrogen bonding interactions between the ethanol molecules and C═O groups of the bpb ligands are listed in Table 1.
Additional hydrogen bonding that involves hydrate molecules is clearly present but not listed due to the difficulty in locating H atoms attached to the water molecules.

Refinement
The crystal was found to be a two-component twin, with a 179.9° rotation about the real axis [-0.535, 0.004, 1.000]. Integration was carried out with two components, and the absorption correction was applied with TWINABS (Sheldrick, 2005).
For the HKLF 5 file, both components and composites were retained. The refined twin parameters were 0.32 (3) for the components and 0.12 (2) for and 0.08 (3) for racemic scale factors. In the final cycles of refinement, nextra was set to 75667 in order to better estimate the su's. Due to the large number of weak reflections in the dataset, it was not possible to refine all the atoms with anisotropic displacement parameters. Only the eight Mn atoms were assigned anisotropic displacement parameters. The seven molecules of ethanol were modeled using idealized geometry and treated as rigid groups in the final cycles of refinement. Three of the water molecules appeared to be at full occupancy, and a fourth was assigned the ad hoc value of 0.5 occupancy. The water hydrogen atoms could not be located with certainty and were not included in the model. Hydrogen atoms of the manganese complexes were added by geometry and refined as riding atoms with distances of H-C(sp 2 ) = 0.95 and H-C(methyl) = 0.98 Å and with U iso (H) set to 1.2 (1.5 for methyl) U eq (C). Crystal data [Mn(C 18 (7) 0.4072 (11) 0.5015 (7) 0.026 (6) (7) 0.0997 (13) 0.4722 (7) 0.041 (7)* C63 0.2935 (7) 0.0159 (12) 0.5007 (7) 0.027 (6)* C64 0.3509 (7) 0.0354 (11) 0.5234 (6) 0.020 (5) (17) 179. Symmetry codes: (i) x, y−1, z; (ii) x, −y, z+1/2; (iii) x, y+1, z; (iv) x, −y+1, z+1/2.