Unusual reactivity of a sterically hindered diphosphazane ligand, EtN{P(OR)(2)}(2), (R = C(6)H(3)(Pr(I))(2)-2,6) towards (eta(3)-allyl)palladium precursors.

The reactivity of (eta(3)-allyl)palladium chloro dimers [(1-R-eta(3)-C(3)H(4))PdCl](2) (R = H or Me) towards a sterically hindered diphosphazane ligand [EtN{P(OR)(2)}(2)] (R = C(6)H(3)(Pr(i))(2)-2,6), has been investigated under different reaction conditions. When the reaction is carried out using NH(4)PF(6) as the halide scavenger, the cationic complex [(1-R-eta(3)-C(3)H(4))Pd{EtN(P(OR)(2))(2)}]PF(6) (R = H or Me) is formed as the sole product. In the absence of NH(4)PF(6), the initially formed cationic complex, [(eta(3)-C(3)H(5))Pd{EtN(P(OR)(2))(2)}]Cl, is transformed into a mixture of chloro bridged complexes over a period of 4 days.

Oxidative Addition of Tetrachloro-1,2-benzoquinone to lambda(3)-Cyclotriphosphazanes. An Unusual Ring Contraction-Rearrangement.

The lambda(3)-cyclotriphosphazanes, [EtNP(OR)](3) [R = 2,6-Me(2)C(6)H(3) (1), 4-BrC(6)H(4) (2), or CH(2)CF(3)(3)], on treatment with tetrachloro-1,2-benzoquinone (TCB) give the lambda(5)-cyclodiphosphazanes, [EtNP(O(2)C(6)Cl(4))(OR)][EtNP(O(2)C(6)Cl(4)){N(Et)P(OR)(2)}] (5-7) by an unusual ring contraction-rearrangement. The reaction of the mixed substituent lambda(3)-cyclotriphosphazane, [(EtN)(3)P(3)(OR)(2)(OR')] [R = 2,6-Me(2)C(6)H(3), R' = 4-BrC(6)H(4)] (4), with TCB gives the lambda(5)-cyclodiphosphazane, [EtNP(O(2)C(6)Cl(4))(OR')][EtNP(O(2)C(6)Cl(4)){N(Et)P(OR)(2)}] (8), in which 4-bromophenoxide resides on one of the ring phosphorus atoms. The lambda(3)-bicyclic tetraphosphapentazane, (EtN)(5)P(4)(OPh)(2), on treatment with TCB undergoes a double ring contraction-rearrangement to give the lambda(5)-cyclodiphosphazane, (EtN)[(EtN)(2)P(2)(O(2)C(6)Cl(4))(2)(OPh)](2) (9).