Pyridine-2-thione derivatives of silver(I) and mercury(II): crystal structures of dimeric [bis(diphenylphosphino)methane][(1-oxopyridine-2-thionato)silver(I), [2-(benzylsulfanyl)pyridine 1-oxide]dichloromercury(II) and phenyl(pyridine-2-thionato)mercury(II)

Silver(I) complexes, [Ag(O,S-C5H4NOS)(L)] [L = Ph2PCH2PPh2 (dppm) 1, Ph2P(C H2)(4)PPh2 (dppb) 2, PPh3 3 or P(C6H4M e-m)(3) 4] were obtained from silver (I) acetate and neutral 1-hydroxypyridine-2-thione(C5H5NOS) in water-ethano l medium followed by addition of tertiary phosphines. Direct reaction of me rcury(II) halides with 2-benzylsulfanyl)pyridine 1-oxide[C5H4NO(SCH2C6H5)] in ethanol formed [HgX2{C5H4NO(SCH2C6H5}] [X = Cl 5 or Br 6]. Similarly, or ganomercury(II) derivatives, Hg(R)L [R = m-O2NC6H4, L = C5H4NS- 7 or C5H4NO S- 8; R = p-ClC6H4, L = C5H4NS- 9 or C5H4NOS- 10; R = C6H5, L = C5H5NS- 11 or C5H4NOS- 12] were prepared from Hg(R)(O2CCH3) and neutral pyridine-2-thi ones(C5H5NS or C5H5NOS). All these have been characterised using analytical data, IR, far-IR, NMR (H-1,C-13 or P-31) spectroscopy and for 1, 5 and II X-ray crystallography. Complex 1 exists as a dimer with dppm bridging the t wo Ag atoms leading to the formation of an eight membered metallacyclic rin g with C5H4NOS- moieties chelating to each Ag atom via O,S-donor atoms. The geometry about each Ag is highly distorted tetrahedral with bond angles va rying from 72.85(7) to 137.92(4)degrees Compounds 5 and 11 acquire formally dimeric structures via weaker interactions. For example, in 5, Hg binds st rongly to one O, two Cl and weakly to one Cl and one S atom of a second lig and molecule. The geometry about each Hg is formally highly distorted trigo nal bipyramidal with Cl(1)-Hg-Cl(2) and O(1)-Hg-S(1*) bond angles of 172.84 (5) and 151.70(9)degrees respectively. Finally in 11 HE is bonded strongly to one C and one S atom, relatively weakly to N{Hg-N 2.795(10), 2.879(9) An gstrom} and very weakly to a second S atom of a second ligand molecule {Hg- S 3.312(3), 3.365(3) Angstrom}. If secondary interactions are ignored the g eometry about Hg is formally distorted T-shaped.