COMPLEXES OF 2,3-BIS(DIPHENYLPHOSPHINO)PROPENE WITH PT-II, PD-II AND RU-II - SYNTHESIS, CHARACTERIZATION AND REARRANGEMENTS TO COMPLEXES OFCIS-1,2-BIS(DIPHENYLPHOSPHINO)PROPENE

Treatment of [PdCl2(PhCN)(2)] with 1 equivalent of 2,3-bis(diphenylpho sphino)propene (2,3-dpppn) in CH2Cl2 gave [PdCl2(2,3-dpppn)] 1 togethe r with some [PdCl2(1,2-dpppn)] 2 [1,2-dpppn = cis-1,2-bis(diphenylphos phino)propene]. Treatment of 1 with an excess of benzylamine did not l ead to addition to the double bond, but resulted in complete isomerisa tion to 2, as monitored by P-31-{H-1} and H-1 NMR spectroscopy. Metath esis of 2 with Nal in acetone gave [PdI2(1,2-dpppn)] 3. Platinum(II) c omplexes [PtCl2(2,3-dpppn)] 4 and [PtCl2(1,2-dpppn)] 5 were prepared a nd characterised analogously. Treatment of 2 or 5 with an excess of Me Li gave [PdMe2(1,2-dpppn)] 6 and [PtMe2(1,2-dpppn)] 7 respectively, an d treatment of 5 with hydrazine hydrate and an excess of HC=CPh in eth anol gave [Pt(CICPh)(2)(1,2-dpppn)] 8. Treatment of [PdCl2(PhCN)(2)] w ith 2 equivalents of AgBF4 and 2 equivalents of 2,3-dpppn gave a mixtu re of at least four isomeric complexes, probably cis- and trans-[Pd(2, 3-dpppn)(2)][BF4](2) and cis- and trans-[Pd(1,2-dpppn)(2)][BF4](2). On treatment with benzylamine, this mixture was converted into a ca. 1 : 1 mixture of two isomers, which NMR spectroscopic evidence suggested were cis-and trans-[Pd(1,2-dpppn)(2)][BF4](2) 9. Similarly, treatment of [PtCl2(PhCN)(2)] with AgBF4-2,3-dpppn gave cis- and trans-[Pt(1,2-d pppn)(2)][BF4](2) 10. A crystal structure determination was performed on the trans isomer, isolated on recrystallisation of the mixture from MeCN-Et2O. Treatment of [RuCl2(PPh3)(3)] with 2 equivalents of 2,3-dp ppn gave a very insoluble complex, trans-[RuCl2(dpppn)(2)] 11. Treatme nt of [RuCl(eta(5)-C5H5)(PPh3)(2)] with 2,3-dpppn in refluxing benzene gave [RuCl(eta(5)-C5H5)(1,2-dpppn)] 12. The formulation of 12 was con firmed by a single-crystal structure determination.