Stepwise substitution of terminal and bridging phosphines in [Pd2(μ-PBut,2)(μ-PBut,2H)(PBut,2H)2]BF4 and the reactivity of [Pd2(μ-PBut,2)(PPh3)3]BF4

The dipalladium(I) cationic complex [Pd-2(mu-PBu2t)(mu-(PBu2H)-H-t)((PBu2H)-H-t)(2)]BF4 1, with a central [Pd-2(mu-PBu2t)](+) core binding two different types of (PBu2H)-H-t molecules, was treated with tertiary phosphines (PR3, R = Me, Et, Ph or C6H4OMe-2). The terminally bonded (PBu2H)-H-t molecules were substituted under mild conditions yielding the new derivatives [Pd-2(mu-PBu2t)(mu-(PBu2H)-H-t)(PR3)(2)]BF4, which still bear a bridging secondary phosphine. The latter can be substituted under more forcing conditions which allow the isolation of the persubstituted [Pd-2(mu-PBu2t)(PR3)(n)]BF4. The reactions of one of these derivatives, [Pd-2(mu-PBu2t)(PPh3)(3)]BF4, with CO, MeCN or isoprene giving, respectively, [Pd-2(mu-PBu2t)(PPh3)(3)L]BF4 (L = CO or MeCN) or [Pd-2(mu-PBu2t)(mu-eta(2);eta(2)-CH2=CHCMe=CH2)(PPh3)(2)]BF4 are also described.