부산대학교 도서관

Na[cyclo‐(P5tBu4)] (1) reacts with [NiCl2(PEt3)2] and [PdCl2(PMe2Ph)2] with elimination of tBuCl and formation of the corresponding metal(0) cyclopentaphosphene complexes [Ni{cyclo‐(P5tBu3)}(PEt3)2] (2) and [Pd{cyclo‐(P5tBu3)}(PMe2Ph)2] (3). In contrast, complexes with the more labile triphenylphosphane ligand, such as [MCl2(PPh3)2] (M=Ni, Pd), react with 1with formation of [NiCl{cyclo‐(P5tBu4)}(PPh3)] (4) and [Pd{cyclo‐(P5tBu4)}2] (5), respectively, in which the cyclo‐(P5tBu4) ligand is intact. In the case of palladium, the cyclopentaphosphene complex [Pd{cyclo‐(P5tBu3)}(PPh3)2] (6) in trace amounts is also formed. However, [Ni{cyclo‐(P5tBu4)}2] (7) is easily obtained by reaction of two equivalents of 1and one equivalent of [NiCl2(bipy)] at room temperature. Complex 7rearranges on heating in n‐hexane or toluene to the previously unknown [Ni{cyclo‐(P5tBu4)PtBu}{cyclo‐(P4tBu3)}] (8), which presumably is formed via the intermediate [Ni{cyclo‐(P5tBu4)}{cyclo‐(P4tBu3)PtBu}], which, after an unexpected and unprecedented phosphanediide migration, gives 8, but always as an inseparable mixture with 7. In the reaction of 1with [PtCl2(PPh3)2], ring contraction and formation of [PtCl{cyclo‐(P4tBu3)PtBu}(PMe2Ph)] (9) is observed. Complexes 3–5and 7–9were characterised by 31P NMR spectroscopy, and X‐ray structures were obtained for 5–9.