catena-Poly[[[diaquabis[4-(diethylamino)benzoato-κO]manganese(II)]-μ-aqua] dihydrate]

In the crystal structure of the title complex, {[Mn(C11H14NO2)2(H2O)3]·2H2O}n, the two independent MnII atoms are located on a centre of symmetry and coordinated by two 4-(diethylamino)benzoate (DEAB) anions and two water molecules in the basal plane while another water molecule bridges the Mn atoms in the apical directions, forming polymeric chains. The dihedral angles between the carboxylate groups and the adjacent benzene rings are 11.33 (13) and 10.90 (9)° and the benzene rings are oriented at a dihedral angle of 67.88 (6)°. The uncoordinated water molecules link the carboxylate groups and coordinated water molecules via O—H⋯O hydrogen bonding. Weak C—H⋯π interactions are also found in the crystal structure.


dihydrate]
Tuncer Hökelek, Hakan Dal, Barış Tercan, Özgür Aybirdi and Hacali Necefoğlu S1. Comment Transition metal complexes with biochemical molecules show interesting physical and/or chemical properties, through which they may find applications in biological systems (Antolini et al., 1982). Some benzoic acid derivatives, such as 4aminobenzoic acid, have been extensively reported in coordination chemistry, as bifunctional organic ligands, due to the varieties of their coordination modes (Chen & Chen, 2002;Amiraslanov et al., 1979;Hauptmann et al., 2000).
Nicotinamide (NA) is one form of niacin. A deficiency of this vitamin leads to loss of copper from the body, known as pellagra disease. Victims of pellagra show unusually high serum and urinary copper levels (Krishnamachari, 1974). The nicotinic acid derivative N,N-Diethylnicotinamide (DENA) is an important respiratory stimulant (Bigoli et al., 1972).
The structure-function-coordination relationships of the arylcarboxylate ion in Mn II complexes of benzoic acid derivatives may also change depending on the nature and position of the substituted groups on the benzene ring, the nature of the additional ligand molecule or solvent, and the pH and temperature of synthesis (Shnulin et al., 1981;Antsyshkina et al., 1980;Adiwidjaja et al., 1978). When pyridine and its derivatives are used instead of water molecules, the structure is completely different (Catterick et al., 1974).
The structure determination of the title compound, (I), a polymeric manganese complex with four 4-diethylaminobenzoate (DEAB) ligands and five coordinated and two uncoordinated water molecules, was undertaken in order to determine the properties of the ligands and also to compare the results obtained with those reported previously.
In the polymeric title complex, (I), each Mn atom is located on a centre of symmetry, and surrounded by two DEAB and four water molecules. The DEAB ligands are monodentate and a water molecule bridges the two Mn atoms (Fig. 1). The four O atoms (O2, O2′, O5, O5′ and O4, O4′, O7, O7′ atoms) in the equatorial planes around each Mn atom form a slightly distorted square-planar arrangement, while the slightly distorted octahedral coordination is completed by the symmetry related O atoms of the bridging water molecule (O6, O6′ and O6′′) in the axial positions (Table 1 and  In (I), the average Mn-O bond length is 2.1880 (14) Å and the Mn atoms are displaced out of the least-squares planes of the carboxylate groups (O1/C1/O2) and (O3/C12/O4) by -0.857 (1) Å and 1.004 (1) Å, respectively. The dihedral angles between the planar carboxylate groups and the adjacent benzene rings A (C2-C7) and B (C13-C18) are 11.33 (13)° and 10.90 (9)°, respectively, while those between rings A and B are A/B = 67.88 (6)°. Intramolecular O-H···O hydrogen bonds (Table 2) link the uncoordinated water molecules to the carboxylate groups and coordinated water molecules ( Fig. 1).
In the crystal structure, strong intra-and intermolecular O-H···O hydrogen bonds (Table 2) link the molecules into a supramolecular structure, in which they may be effective in the stabilization of the structure. There also exist two weak C -H···π interactions ( Table 2).

S2. Experimental
The title compound was prepared by the reaction of MnSO 4 .H 2 O (0.85 g, 5 mmol) in H 2 O (50 ml) and NA (1.22 g, 10 mmol) in H 2 O (50 ml) with sodium p-dimethylaminobenzoate (2.16 g, 10 mmol) in H 2 O (100 ml). The mixture was filtered and set aside to crystallize at ambient temperature for one week, giving single crystals.

S3. Refinement
H atoms of water molecules were located in difference Fourier maps and refined isotropically, with restrains of O5-H51

catena-Poly[[[diaquabis[4-(diethylamino)benzoato-κO]manganese(II)]-µ-aqua] dihydrate]
Crystal data [Mn(C 11 H 14  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.