SYNTHESIS AND REACTIVITY OF HYDROXO-BRIDGED BINUCLEAR PLATINUM COMPLEXES - CRYSTAL-STRUCTURE OF [NBU4]2[(PT(C6F5)2(MU-OH))2]

The reaction of [NBu4]2[{Pt(C6X5)2(mu-Cl)}2] with NBu4OH(aq) in acetone leads to the formation of the hydroxo-complexes [NBu4]2[{Pt(C6X5)2(mu-OH)}2] (X = F 1 or Cl 2). These react with weak protic acids such as acetylacetone (Hacac), benzoylacetone (Hbzac) and 8-hydroxyquinoline (Hquin) yielding the mononuclear complexes [NBu4][Pt(C6X5)2(L-L)] (X = F, L-L = acac 3, bzac 4, or quin 5; X = Cl, L-L = acac 6, bzac 7, or quin 8). Treatment of complexes 1 and 2 with PhCN in the presence of HBF4 gives the mononuclear compounds cis-[Pt(C6X5)2(PhCN)2] (X = F 9 or Cl 10). When the benzonitrile complexes are treated with aniline the corresponding cis-[Pt(C6X5) (NH2Ph)2] (X = F 11 or Cl 12) are formed. The benzamido derivatives [NBu4][Pt(C6X5)2(HNOCPh) (H2O)] (X = F 13 or Cl 14) are formed when complexes 9 and 10 are treated with NBu4OH(aq) in acetone, and thermal treatment of 13 yields [NBu4]2[{Pt(C6F5)2(mu-HNOCPh)}2] 15. Complexes 9 and 10 react with methanol in the presence of NBu4OH to give corresponding imido ester derivatives [Pt(C6X5)2{HN = C (OMe)Ph}2] (X = F 16 or Cl 17). Spectroscopic (IR, H-1 and F-19) data have been used for structural assignments, and an X-ray structure determination carried out for [NBu4]2[{Pt(C6F5)2(mu-OH)}2] has established the centrosymmetric binuclear nature of the anion [(C6F5)2Pt(mu-OH)2Pt(C6F5)2]2-. The structure has been solved and refined up to R = 0.049 and R' = 0.056 based on 2278 observed reflections. The Pt atoms are four-co-ordinated and show slight deviations from a square-planar arrangement.