(anti-Chloridothiosemicabazide-κS)bis(triphenylphosphane-κP)copper(I) 0.48-hydrate

In the mononuclear title complex, [CuCl(CH5N3S)(C18H15P)2]·0.48H2O, the CuI ion is in a slightly distorted tetrahedral coordination geometry formed by two P atoms from two triphenylphosphane ligands, one S atom from a thiosemicarbazide ligand and one chloride anion. An intramolecular N—H⋯N hydrogen bond [graph-set motif S(5)] stabilizes the thiosemicarbazide ligand in its anti conformation, and an intramolecular N—H⋯Cl hydrogen bond between the hydrazine N—H group and the chloride anion influences the arrangement and orientation of the ligands around the metal center. A weak intramolecular C—H⋯Cl hydrogen bond is also present. In the crystal, complex molecules are connected through N—H⋯Cl hydrogen bonds originating from the amide –NH2 group, and through O—H⋯S and O—H⋯Cl hydrogen bonds involving the solvent water molecule. Both the direct N—H⋯Cl hydrogen bonds as well as the bridging hydrogen bonds mediated by the water molecule connect the complex molecules into zigzag chains that propagate along [010]. The solvent water molecule is partially occupied, with a refined occupancy of 0.479 (7).


Related literature
For the coordination of thiosemicarbazide and thiosemicarbazones with metal complexes, see: Andreetti et al.
Data collection: SMART (Bruker, 1998) Thiosemicarbazones, the condensation products of thiosemicarbazide and aldehydes, are compounds of considerable interest due to their remarkable number and variety of biological properties and the potential medical and pharmaceutical applications that result (Pelosi, 2010;Yu et al., 2009). Biological applications are not limited to the thiosemicarbazones, but their metal complexes have been described to also have similar effects, and are often even more active than the uncoordinated thiosemicarbazones. Metal complexes of thiosemicarbazones have been described to be active antimicrobial agents (Alagarsamy et al., 2011), are highly effective anticancer agents (Yu et al., 2009), they exhibit cytotoxicity and do interact with ribonucleotide reductase (Kowol et al., 2007), to name just a few of the properties they have been investigated for. The parent compound of all thiosemicarbazones, thiosemicarbazide, does also exhibit a rich metal coordination chemistry. Having no substituent at the hydrazide NH 2 group, thiosemicarbazide is able to coordinate to metal ions in an N,S-chelating mode, and this is realised in most of its complexes. Of 79 complexes of thiosemicarbazide reported in the Cambridge Structural Database (2013 release, Allen, 2002), 61 featured N,S-chelation of the ligand, 5 displayed N,S-chelation and additional coordination via the sulfur atom, and 13 displayed mono-or bidentate coordination via the sulfur only. Coordination via only nitrogen was not observed at all. The coordination mode towards the metal dicates the conformation of the thiosemicarbazide ligand. In N,S-chelating complexes, the ligand necessarily features a syn-conformation of the sulfur atom versus the hydrazide NH 2 group. In the complexes with only sulfur coordination both syn and anti conformation can be imagined. However, all reported examples feature the anticonformation which is also observed in the parent compound. In salts of with protonated thiosemicarbazide cations, on the other hand, the anti conformation is again the only one realised (Andreetti et al., 1970).
The reasons for the often increased biological activity of metal complexes, when compared to those of only the ligands by themselves, is manifold and depend highly on the individual case and type of biological activity under investigation.
Common to many mechanisms is the need for the active compounds to pass through the cell membrane, a barrier difficult to pentrate for polar compounds such as thiosemicarbazone. Coordination to metal complexes, especially when paired with other more lipophilic ligands, reduces the polarity of the thiosemicarbazide compound. In an effort to investigate the influence of metal coordination and use of various phenyl phosphane ligands on the antibacterial properties of copper(I) and silver(I) complexes of thiosemicarbazide we reacted thiosemicarbazide with the triphenylphosphine adduct of copper(I) chloride The use of monodenate triphenylphosphane lead to the formation or the mononuclear complex have prepared the title compound of this study, (anti-thiosemicabazide-κS)chloridobis(triphenylphosphane-κP)copper(I), which crystallized from acetonitrile in the form of its hemihydrate (with a refined occupancy of 0.479 (7)). As is typical for soft metal ions such as Cu(I), thiosemicarbazide coordination is via the soft sulfur donor only, as had been observed for the other two Cu(I) supplementary materials complexes of thiosemicarbazide (Jia et al., 2008a,b). Copper(II), on the other hand shows N,S-chelation with thiosemicarbazide (Villa et al., 1972a,b;Qirong et al., 1987;Chattopadhyay et al.,1991). In the title compound, the metal center is coordinated to one S donor of the thiosemicarbazide ligand, two P atoms of two triphenylphosphane ligands one chlorine atom. In agreement with expectation for a Cu(I) center with soft donor atoms, It displays a distorted tetrahedral coordination of the Cu I center. (Fig. 1). The Cu-S bond distance of 2.3841 (7) Å is slightly longer than in the other two Cu(I) thiosemicarbazides (2.2401 (10) to 2.3192 (13) Å, Jia et al., 2008a,b), but very similar to several other similar complexes such as the thiosemicarnzone complex [CuI(C 4 H 9 N 3 S)(C 18 H 15 P) 2 ] with a Cu-S bond length of 2.3866 (7) Å (Wattanakanjana et al., 2012). As in all other complexes with S-only coordination of thiosemicarbazides the ligand is in the anti-conformation, which is stablized by an intramolecular N-H···N hydrogen bond between N1-H1A and N3 (graph set designator as S(5) (Bernstein et al., 1995)). Another intramolecular hydrogen bond, between the hydrazine N2 -H2 group and the chloride anion, orients the hyrdrazide N-H group towards the chlorine atom and, through this, influences the arrangement and orientation of the ligands around the Cu I center. Neighboring complexes are connected with each other through N1-H1B···Cl1 hydrogen bonds originating from the amide NH 2 group, and through O1-H1D···S1 and O1-H1C···Cl1 hydrogen bonds involving the solvate water molecule. Both the direct N2-H2···Cl1 hydrogen bonds as well as the bridging H-bonds mediated by the water molecule are linking molecules with each other leading to formation of a one-dimentional zigzag chain parallel to the b axis (see Table and

Experimental
Triphenylphosphane (0.53 g, 2 mmol) was dissolved in 30 cm 3 of acetonitrile at 335 K. CuCl (0.10 g, 1 mmol) was added and the mixture was stirred for 1.5 h. Thiosemicarbazide (0.09 g, 1 mmol) was added and the reaction mixture was heated to reflux of the solvent for 5.5 h. The resulting clear solution was filtered and left to evaporate at room temperature. The crystalline solid, which precipitated upon standing for three days, was filtered off and dried under reduced pressure (0.

Refinement
The two hydrazide NH 2 H atoms were located in a difference Fourier map and refined isotropically, with N-H distances restrained to 0.86 (2) Å, with U iso (H) = 1.2U eq (N). The remaining H atoms bonded to N or C atoms were positioned geometrically and refined using a riding model, with C-H = 0.93, N-H = 0.86 Å with U iso (H) = 1.2U eq (C/N). A solvate water molecule is partailly occupied, the occupancy of the water molecule refined to 0.479 (7). The H atoms attached to the water molecules were located in a difference Fourier map and refined isotropically, with O-H distances restrained to 0.82 (2) Å, with U iso (H) = 1.2U eq (N).  The molecular struture with displacement ellipsoids drawn at the 50% probability level.