Crystal structure of tris[μ2-bis(diphenylphosphanyl)methane-κ2 P:P′]di-μ3-bromido-trisilver(I) bromide–N,N′-phenylthiourea (1/1)

The title complex, [Ag3Br2(C25H22P2)3]Br·C7H8N2S, comprises a trinuclear [Ag3Br2(C25H22P2)3]+ unit, a Br− anion and one N,N′-dimethylthiourea molecule (ptu). Three AgI ions are linked via two μ3-bridging Br atoms, leading to a distorted triangular bipyramid with an Ag⋯Ag separation range of 3.1046 (6)–3.3556 (6) Å. The triangular Ag3 arrangement is stabilized by six P atoms from three chelating bis(diphenylphosphanyl)methane (dppm) ligands. The AgI ion presents a distorted tetrahedral coordination geometry. In the crystal, the bromide anion is connected to the ptu molecule through N—H⋯Br hydrogen bonds [graph-set motif R 2 1(6)]. Each bromide/ptu aggregate links the complex ion via C—H⋯S and C—H⋯Br hydrogen bonds, leading to the formation of a three-dimensional network. Two phenyl rings from two dppm ligands were modelled as disordered over two sites.


S1. Comment
The studies of silver(I) complexes with diphosphane has been receiving more attention (Matsumoto et al., 2001;Nicola et al., 2005;Nicola et al., 2006) because of their potential applications such as show interesting luminescence properties (Song et al., 2010;Sun et al., 2011). The coordination chemistry of silver(I) complexes with phosphorus and sulfur donor ligands, on the other hand have been of increasing interest due to their potential applications such as antimicrobial activities (Isab et al., 2010). Herein, the title complex was prepared by reacting silver (I) bromide and dppm ligand, followed by the addition of ptu in acetonitrile solvent. An unexpexted complex [Ag 3 (C 25 H 22 P 2 ) 3 (µ 3 -Br) 2 ] + unit was formed in the uncoordinated of ptu.
The title complex comprises of a trinuclear [Ag 3 (C 25 H 22 P 2 ) 3 (µ 3 -Br) 2 ] + unit, Br anion and one N,N′-dimethylthiourea molecule (ptu). The bromide anion forms a triple bridge from the both side of the Ag-3 plane leading to distorted triangular bipyramid with an Ag···Ag separation of 3.1046 (6)-3.3556 (6) Å. A triangular Ag 3 arrangement stabilized by six P atoms from three chelating dppm ligands (Fig.1). The Ag I ion presents a distorted tetrahedral coordination geometry.

S2. Experimental
Bis(diphenylphosphanyl)methane, dppm, (0.1 g, 0.26 mmol) was dissolved in 30 ml of acetonitrile at 343 K and then silver(I) bromide, AgBr, (0.05 g, 0.27 mmol) was added. The mixture was stirred for 4 hr and then N,N′-phenylthiourea, ptu, (0.04 g, 0.26 mmol) was added and the new reaction mixture was heated under reflux for 6 hr during which the precipitate gradually disappeared. The resulting clear solution was filtered and left to evaporate at room temperature. The crystalline complex, which deposited upon standing for several days, was filtered off and dried in vacuo (Mp = 490-492 K). supporting information sup-2 . E71, m89-m90

S2.1. Refinement
H atoms bonded to C and N atoms were included in calculated positions and were refined with a riding model using distances of 0.95 Å (aryl H), and U iso (H) = 1.2U eq (C); 0.99 Å (CH 2 ) and U iso (H) = 1.5U eq (C); 0.88 Å (NH), and U iso (H) = 1.2U eq (N). Two phenyl rings from two dppm ligands are disordered. The ADPs of ipso carbon atoms were constrained to be identical for each disordered pair of phenyl rings. The geometry of the minor moiety of each pair of disordered phenyl rings was restrained to be similar to that of the major moiety (within a standard deviation of 0.02 Angstroms). Carbon atoms of one phenyl ring were restrained with effective standard deviation 0.01 to have the same Uij components. To ensure satisfactory refinement the atoms of each disorder component of the phenyl rings were restrained to lie within a common plane. The overall ratio of the two components of disorder, refined with the same free variable, is 0.516:0.484 (3).

Figure 1
The molecular structure with displacement ellipsoids drawn at the 50% probability level. The minor component of disorder is omitted for clarity. The dashed lines show N-H···Br hydrogen bonds between the ptu and the bromide anion.  Part of the crystal structure showing intermolecular C-H···S and C-H···Br hydrogen bonds as dashed lines, forming a three-dimensional network. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.002 Δρ max = 1.48 e Å −3 Δρ min = −0.67 e Å −3

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.