Syntheses and Structural Studies of Triorganophosphinegold(I) Mercaptobenzoate Complexes

Abstract

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).

Characterisation and In Vitro Cytotoxicity ofTriorganophosphinegold(I) 2‐Mercaptobenzoate Complexes

“…The three R3PAu(2mba), R Et, Ph and Cy, complexes display IR characteristics consistent with an earlier report [8]. Full asignment of 1H and 13C chemical shifts, obtained in both CDCI3 and Tables 2 and 3.…”

“…The gold atom exists in an almost linear geometry defined by a sulfur atom derived from the 2mba anion and the phosphorus atom; S--Au--P is 173.1(1) . The Au--S and Au--P distances of 2.298(3) ,& and 2.269 (3) A, respectively are comparable to the equivalent distances of 2.313(1) and 2.271(1) A, respectively found in the R Cy analogue [8]. As can be noted from Figure the carboxyl residue is orientated so as to place the carbonyl O(1) atom in close proximity to the gold atom.…”

“…A total of 4151 data (3942 unique) were collected and of these, 2792 that satisfied the I_> 3.0c(/) criterion were used in the subsequent analysis. (7) 0.0677 (7) 0.488(1) 0 (2) 0.0701 (8) 0.0898 (7) 0.697 (1) (5) , I 107.72 (5) , y 102.51 (6) , V 1112(1") A3, Z 2, Dcalc 1.828 g cm"3, F(000) 592, 68.19 cm-1.…”

“…There are no Au...Au contacts less than 6.0 A in the I,ttice. Interestingly, in the R Cy structure [8], an alternative conformation of the 2mba ligand is found such that the carboxyl residue is directed away from the gold centre and is best described as adopting an exo conformation as opposed to a endo conformation as for the R Ph structure; see (3) Au---P(1) 2.269(3) S(2)--C (2) 1.77(1) P(1)---C(11) 1.83(1) P(1)--C (21) 1.80(1) P(1)--C(31) 1.83 (1) S (2)--Au--P(1). Au--P(1 )--C(11 Au--P(1 )---C(31) C(11)--P(1)--C(31) 173.1 (1) Au---S(2)--C(2) 110.5(3) 114.8 (3) Au---P(1 )--C(21) 112.0(3) 113.7 (3) C(11)--P(1 )---C(21) 107.0(5) 103.0 (5) C(21 )--P(1)--C(31) 105.5 (5) The effect on the gold atom geometry of the intramolecular Au...O(1) interaction in the R Ph structure is minimal with the major influence being a greater distortion from linearity, i.e.…”

“…complexes containing the P--Au---S arrangement as found in auranofin, the in vitro cytotoxicity of three R3PAu(2mba) complexes is reported where R Et, Ph and Cy, and 2mba is the anion derived from 2-mercaptobenzoic acid. The preparation of these complexes has been reported in the patent [6,7] and chemical literature [8], and the crystal structure determination of the R Cy complex is also known [8].…”