Nitrosyltris(pyridine-2-thiolato-κ2 N,S)molybdenum(II) dihydrate

In the title compound, [Mo(C5H4NS)3(NO)]·2H2O, the Mo atom is coordinated by a nitrosyl ligand and three monoanionic N,S-bidentate ligands in a distorted MoN4S3 pentagonal-bipyramidal molecular geometry. The pyridine N atom of one pyridine-2-thiolate (pyt) ligand is coordinated to the Mo atom in the trans position relative to the NO ligand [N(pyt)—Mo—N(NO) = 170.62 (19)°]. The compound has C s symmetry, with a mirror plane that includes one pyt ring and the NO group. The S—Mo—N(NO) and N(pyt)—Mo—N(NO) angles [97.24 (12) and 91.87 (8)°, respectively] are large relative to the ideal angles of 90°. In the crystal, the molecules pack in a zigzag arrangement. The cavities between the molecules are occupied by disordered water molecules of crystallization.

In the title compound, [Mo(C 5 H 4 NS) 3 (NO)]Á2H 2 O, the Mo atom is coordinated by a nitrosyl ligand and three monoanionic N,S-bidentate ligands in a distorted MoN 4 S 3 pentagonal-bipyramidal molecular geometry. The pyridine N atom of one pyridine-2-thiolate (pyt) ligand is coordinated to the Mo atom in the trans position relative to the NO ligand [N(pyt)-Mo-N(NO) = 170. 62 (19) ]. The compound has C s symmetry, with a mirror plane that includes one pyt ring and the NO group. The S-Mo-N(NO) and N(pyt)-Mo-N(NO) angles [97.24 (12) and 91.87 (8) , respectively] are large relative to the ideal angles of 90 . In the crystal, the molecules pack in a zigzag arrangement. The cavities between the molecules are occupied by disordered water molecules of crystallization.  Data collection: WinAFC (Rigaku/MSC, 2000); cell refinement: WinAFC; data reduction: CrystalStructure (Rigaku/MSC, 2007); 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, 1997); software used to prepare material for publication: CrystalStructure.

Comment
In recent years, pyridinethiolate-or pyrimidinethiolate-type ligands and their complexes have been investigated as antimetabolite and antiviral agents, as well as for their unique photochemical properties (Halpenny & Mascharak, 2009;Rose et al., 2007;Cini et al., 2003). For example, attempts to regulate NO in vivo have prompted studies of NO scavengers and NO-releasing drugs. Although some photoinduced NO-releasing reactions of mononitrosyl complexes have been reported, relatively little is known about the analogous reactions of dinitrosyl complexes in this respect (Maurya et al., 2006;Kunkely & Vogler, 2003;Ford et al., 1998). We previously reported on the preparation, characterization and interesting photo-dimerization reactions of some dinitrosyl-molybdenum complexes containing thiolate ligands, which were accompanied by NO cleavage (Yonemura et al., 2001(Yonemura et al., , 2006. This highlighted the need to further study the reactivities and properties of these dinitrosyl-molybdenum complexes. That communication described a novel reaction of dinitrosyl-molybdenum [Mo(bidentate-N,S) 2 (NO) 2 ]-type complexes with PPh 3 (Yonemura, et al., 2006). This reaction, which uses pyridine-2-thiolate (pyt) as a thiolate ligand, was shown to form [Mo(pyt) 3 (NO)], [{(ON)Mo(pyt) 2 } 2 (µ-OH) 2 ], and Ph 3 PO. In this paper, we report on the structure of [Mo(pyt) 3 (NO)] Dihydrate.
In the title compound the molybdenum atom is coordinated to a nitrosyl ligand and three monoanionic N,S-bidentate ligands, producing a distorted MoN 5 S 2 pentagonal bipyramidal molecular geometry ( Fig. 1 and Table 1). The geometrical parameters are available in the archived CIF. This complex is derived from the elimination of one NO ligand from [Mo(pyt) 2 (NO) 2 ] and the introduction of a third pyt ligand, giving rise to a Mo atom surrounded by three pyt ligands and one NO ligand. The complex adopts a seven-coordinate structure with a distorted pentagonal bipyramidal coordination geometry about the Mo atom. Both the N and S atoms of two pyt ligands and an S atom of the third pyt ligand occupy the equatorial positions of the complex. The remaining N-atom of the third pyt ligand occupies one of the axial sites. The NO ligand occupies the other axial site in its linear mode [Mo1-N3-O1 = 179.6 (4)°], indicating that the NO ligand is coordinated as NO + (Proust et al., 1994;Ardon & Cohen, 1993;Calderon et al., 1969). Therefore, the oxidation state of the molybdenum atom in the title compound is formally +II; that is, the molybdenum atom is oxidized from 0 to +II. (1.828 (2) and 1.837 (2) Å). However, the Mo1-NO distance is almost the same as that in complex [{(ON)Mo(pyt) 2 } 2 (µ-OH) 2 ], that is 1.756 (2) Å (Yonemura et al., 2001). The S1-Mo1-N3(NO) and N1-Mo1-N3(NO) angles (97.24 (12) and 91.87 (8) In the crystal the molecules pack in a zigzag arrangement (Fig. 2). The cavities between the molecules are occupied by disordered water molecules of crystallization.

Refinement
The water molecules of solvent of crystallization are disordered with occupancies of 0.5 each, and it was not possible to locate their H-atoms. The C-bound H-atom were included in calculated positions and treated as riding: C-H = 0.93 Å, with U iso (H) = 1.2U eq (C). Fig. 1. A view of the molecular structure of the title compound, showing the atom-labelling scheme and 50% probability displacement ellipsoids. Atoms related by the mirror symmetry are marked by *; symmetry operation: x, -y+1/2, z.

Special details
Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles Refinement. Refinement was performed using all reflections. The weighted R-factor (wR) and goodness of fit (S) are based on F 2 . Rfactor (gt) are based on F. The threshold expression of F 2 > 2.0 σ(F 2 ) is used only for calculating R-factor (gt).