Synthesis and Crystal Structure of Diaqua(1,10-Phenanthroline-N,N′)(Thiosulfato-O,S)Manganese(II). Biological Properties.

The synthesis of diaqua(1,10-phenanthroline-N,N′)(thiosulfato-O,S)manganese(ll) [Mn(phen)(S2O3)(H2O)2] was investigated. Its structure was determined by single crystal X-ray diffraction from 2418 reflections (I > 3 σ(I)) to a final value of R = 0.047 and Rw = 0.054. Crystal data are as follows : space group P21; a = 10.356(3), b = 7.097(3), c = 20.316(2) Å, β = 94.29(2)°, V = 1489.1(8) , Å3, Z = 2. There are two independent title compounds in the asymetric unit. Each manganese atom has a distorted octahedral Mn(SO)N2O2 geometry with the S and O atoms (from two neighbouring thiosulfate ligands) mutually trans, two N atoms from the 1,10-phenanthroline ligand and two water oxygen. The thiosulfate group behaves as a bridging ligand, connecting, through sulfur and oxygen, Mn atoms related by the binary b translation, thus forming infinite chains running parallel to this axis. Infrared and electronic spectra are reported.


Introduction
The molecule 1,10-phenanthroline (phen) and its derivatives are well known to exhibit antifungal, antiviral and mycoplasmal activities [1]. Their cytotoxicity might be due to chelation of transition metals such as copper or iron in test media. Complexation with some divalent transition metals enhances these biological activities. Thus, antiviral activity was found for divalent transition metals with substituted phenanthrolines in the following order of activity Cd > Cu >> Zn >> Mn > Fe > Co > Ni > Ru [2]. Moreover, these complexes are used as DNA intercalating agents [3] and have been found useful for examining distinctive conformations along the DNA helix [4]. Recently, ternary complexes of Cu(ll) with 3,5-diisopropylsalicylate and substituted phenanthrolines have been synthetised among them, the most potent was bis(diisopropylsalicylato) (2,9-dimethylphenanthroline)copper(ll) which exhibits cytotoxicity comparable with cisplatin (PtCI(NH)), an anticancer drug. It was suggested that incorporation of a phen ligand in this former ternary Cu(ll) complex may favour DNA intercalation [5].
To our knowledge, very few manganese thiosulfate complexes have been studied by X-ray diffraction. An X-ray study of these complexes would not only give the coordination around the metal atom but should also define the situation of the thiosulfate group, which could in theory coordinate as a monodentate ligand, a bidentate ligand, or as a bridging ligand between different metal atoms. Synthesis and Crystal Structure of Diaqua (1,N) (Thiosulfato-O,S)Manganese(II).Biological Properties 2.
Results and discussion.

2.2.
Infrared and electronic spectra. The most important aspect of the IR spectrum of [Mn(phen)(SOa)(HO)] concerns the bands of the thiosulfate anion.
It is known that the uncoordinated thiosulfate anion shows IR bands which are assigned to the Vibrations vs(S03), v(S-S), (as(S03), Mas(S03) (s(S03) and 9r(S03) at 995,446,669,1123,541 and 335 cm respectively [18] Synthesis and Crystal Structure of Diaqua (1, Symmetrycode'i =x, y-1, z;ii =x, y+ z, iii =x-1, y+ 1, z ;iv=x-1, y, z As a bridging ligand, the thiosulfate group shows the following changes in the stretching mode a shift to lower energy of v(S-S) and v(SO) and a splitting of Vas(SO) into two components due to the interactions M-O and M-S.
In fact, the IR spectrum of [Mn(phen)(SO)(HO)] is consistent with this coordination mode, namely the occurrence of bands assigned to v(S-S) at 420, v(SOa) at 970 and Va,(SOa) splitted in two components at 1100 and 1150 cm (the component at 1100 cm is due to the Mn-O and the second, to the Mn-S interactions).
Further absorption bands at 630, 720, 850, 960, 1000, 1420, 1440, 1520 and 1535 cm are assigned to the vibrational modes of phenanthroline, which indicate coordination of nitrogen atoms to the metal atom, and there is a band at 520 cm (pwHO) consistent with the coordinated water molecules.
The appearance of a metal-oxygen band at ca. 380 cm further supports this view. Thus, it appears that the manganese atom is coordinated by the N atoms from 1,10phenanthroline ligand, one sulfur atom from one thiosulfate group, one oxygen atom from one neighbouring SOa group and water oxygen. The thiosulfate group acts as bridging ligand through oxygen and sulfur atoms.
The and sodium chloride (8.5 g/L) in distilled water. The suspensions were adjusted to 1-3.10 a colonyforming units per mL (CFU/ml).
The orange-coloured product was sparingly soluble in hot solution, and was filtered off and the yellowish-green filtrat allowed to evaporate at room temperature. The pale yellow crystals separated after a few days; they were filtered off and washed with water and ethanol. (Found C 37.95,H 3.30,N 7.97,S 17.25 X-ray structure determination Data were collected at 291 K on an ENRAF-NONIUS CAD4 diffractometer. The final unit cell parameters were obtained by least-squares refinement of 25 reflections. Crystal decay was monitored by measuring three intensity control reflections every two hours. Only statistical fluctuations were observed in the intensity monitors over the course of data collection. The structure was solved by direct methods (SIR92) [22] and refined by least-squares procedures on Fobs. H atoms (excepted those attached to water molecules) were introduced in calculatated in idealized positions (d (C-H) 0.96 ,&,) and their atomic coordinates were recalculated after each cycle. They were given isotropic thermal parameters 20% higher than those of the carbon to which they were attached. Coordinates of the H atoms attached to O atoms could not be located on difference Fourier maps. Least-squares refinements were performed by minimizing the function Y_,w(IFol-IFl) , where Fo and Fc are the observed and calculated structure factors. The weighting scheme used in the last refinement cycles was w w'   Table  3. Criteria for a satisfactory complete analysis were ratios of rms shift to standard deviation less than 0.1 and no significant features in final difference maps. Details of data collection and refinement are given in Table 4. Synthesis and Crystal Structure of Diaqua (1,N) (Th iosulf ato-O,S)Manganese(II).Biological Properties  Table 4. Anisotropic thermal parameters for non-hydrogen atoms and atomic coordinates for H atoms have been deposited at the Cambridge Crystallographic Data Center.