Reactions of (sigma-alkynyl)platinum complexes with [Pd(eta(3)-C3H5)Cl](2). Synthesis of bis(eta(2)-alkyne)(eta(3)-allyl)palladium(II) complexes. Crystal and molecular structure of [cis-(PPh(3))(2)Pt(mu-eta(1):eta(2)-C C(t)Bu)(2)Pd(eta(3)-C3H5)](ClO4)

The sigma-bis and tetraalkynyl anions [cis-Pt(C6F5)(2)(C=CR)(2)](2-) and [Pt(C=CR)(4)](2-) (R = Ph, (t)Bu, SiMe(3)) have been shown to be useful reagents for the formation of bis(mu-alkynyl) complexes via halide displacement reactions. They thus react with {[Pd(eta(3)-C3H5)Cl](2)} in a 2:1 molar ratio to form anionic heterobinuclear zwitterionic Q[cis-(C6F5)(2)Pt(mu-eta(1):eta(2)-C=CR)(2)Pd(eta(3)-C3H5)] (Q = PMePh(3), R = Ph; Q = NBu(4), R = (t)Bu, SiMe(3) 1a-c) and (NBu(4))[(RC=C)(2)Pt(mu-eta(1):eta(2)-C=CR)(2)Pd(eta(3)-C3H5)] (R = Ph, (t)Bu, SiMe(3) 2a-c) complexes. The corresponding trinuclear 1:2 neutral adducts {[Pt(C=CR)(4)][Pd(eta(3)-C3H5)](2)} (R = Ph, (t)Bu, SiMe(3) 3a-c) were formed by the addition of 1 equiv of the tetraalkynyl anions to {[Pd(eta(3)-C3H5)Cl](2)}. Binuclear derivative analogue [(PPh(3))(2)Pt(mu-eta(1):eta(2)-C=CR)Pd(eta(3)-C3H5)](ClO4) (R = Ph, (t)Bu 4a,b) were produced by the reaction of {[Pd(eta(3)-C3H5)Cl](2)} with neutral [cis-Pt(PPh(3))(2)(C=CR)(2)] (1:2 ratio) in the presence of NaClO4 (excess). The heterobimetallic anionic 1c (R = SiMe(3)) and cationic 4b (R = (t)Bu) complexes were characterized by X-ray diffraction. In both, the two bridging alkynyl ligands remained a bonded to the platinum center and eta(2) coordinated to the palladium one.