TriorganophosphinegoId(1) complexes of the anions derived from pyridine-2-thione (2-pySH) and 1 H-pyrimidine-2-thione (2-pymSH), [Au(PR,)(SR')] ( R = Et, Ph or C,H,,), have been prepared and characterized by spectroscopic (IR, l H and 13C NMR and fast atom bombardment MS) methods and for the PPh, compounds by X-ray crystallographic techniques. The mononuclear compounds feature linear gold atom geometries defined by P and S atoms with important parameters for [Au(PPh3)(2-pyS)]: Au-P 2.258(1), Au-S 2.297(2) A and P-Au-S 177.9(1)O and for [Au(PPh3)(2-pymS)]: Au-P 2.253(2), Au-S 2.310(3) A and P-Au-S 174.7(1)". The [Au(PPh3)(2-pyS)] complex 2 crystallizes in the monoclinic space group P2Jc with unit-cell dimensions a = 12.235(1), b = 10.009(2), c = 17.292(2) A, p = 104.08(1)" and Z = 4; [Au(PPh3)(2-pymS)] 5 crystallizes in the triclinic space group P i with a = 11.006(2), b = 11.356(4), c = 8.873(1) A, a = 109.85(2), p = 95.72(1), y = 93.55(2)O and Z = 2.The structures were refined to final R = 0.025 for 2527 reflections with / 2 2.50(/) and R = 0.057 for 341 6 reflections with / 2 2.50(/) for 2 and 5, respectively.

Rcprinlr arailable dncaly from the publishcr ph0tocop)ing permit!cd by IiDensc only 8 I992 Gordon and Brcach Scitncc Publishers S.A. Compounds of the type R,PAu(SC,H,CO,H), R = El, Ph or c-hexyl have been prepared and characterized by IR, 'H and I3C NhlR and FAB h1S spectroscopic techniques. The Au atom has been shown to be linearly coordinated by the R,P ligand and the S atom of the thiolate; there is no interaction bctwecn the carboxylic acid lunction and the Au atom. These results \yere verified by a crystal structure analysis of the R=c-hexyl derivative which showed the Au atom to exist in a linear geometry with Au-S 2.313(1), Au-P 2.271(1)A and S-Au-P 176.8(1)". The c-hexyl,PAu(SC,H,CO,H) compound crystallizes in the triclinicspacegroup Pi, with unit cell dirnensionsa= 11.018(2), b = 13.752(1),~=9.858(1)A, z= 107.72(1), p=97.99(1), y = 111.46(1)" and Z=2. The structure has been refined to final R=0.036 and R,=0.036 for 4849 reflections with f22.50(1).

A series of phosphinegold(I) thionucleobase analogues, [R3PAu(SRx)] (R = Et, Ph or chexyl; HSR1 = 2-mercaptobenzoic acid, HSR2 = 2-thiouracil, HSR3 = 6-mercaptopurine and HSR4 = 6-thioguanine) have been examined for their in vitro cytotoxicity in L1210 murine leukemia cells in culture. The range of ID50 values (continuous 48 h exposure) for the complexes is 0.041 - 0.131 μM. The complexes with SR3 and SR4 are generally the most active; however, there is no clear trend associated with the phosphine ligands.

A number of phosphinegold(I) thiolates where, generally, the thiolate is derived from a thionucleobase, have been screened for anti-arthritic activity in Dark Agouti rats, a gold sensitive model for arthritis. Potency and toxicity data showed that, generally, the Ph3P derivatives and species based on thiopurines were the most effective and that with other complexes enhanced activity was accompanied by greater toxicity.

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