Synthese von [cis-(bipy)Pt(CCPh)2]AgFBF3 und dessen Reaktionsverhalten gegenüber Lewis-Basen; die Festkörperstruktur von cis-(bipy)Pt(CCPh)2 und [(bipy)Pt(CCPh)(PPh3)]BF4

The synthesis of the heterobimetallic platinum(II)–silver(I) complex {cis-[Pt](CCPh)2}AgFBF3 (3) in which the respective transition metals are bridged by σ- and π-bound phenylacetylides, succeeds by the reaction of cis-[Pt](CCPh)2 {[Pt]=(bipy′)Pt, bipy′=4,4′-dimethyl-2,2′-bipyridine} (1) with equimolar amounts of [AgBF4] (2). The reaction chemistry towards different Lewis-bases L (L=tetrahydrofuran, NR3, PPh3) is reported. Although 3 reacts with L to give coordination adducts of general type [{cis-[Pt](CCPh)2}AgL]BF4 in which the Lewis-base L is datively bound to the silver(I) ion, such a complex could only be isolated and characterised when L resembles PPh3 (4). All other Lewis-bases L are forming reversible adducts, which are only stable, when an excess of L is used. While [{cis-[Pt](CCPh)2}Ag(PPh3)]BF4 (5) is stable in the solid-state, it appeared that in solution it rearranges to produce the mononuclear, ionic platinum(II) complex {[Pt](CCPh) (PPh3)}BF4 (6) along with [AgCCPh] (8). The result of the X-ray structure analysis of 1 and 6 is reported. Complex 1 crystallises in the monoclinic space group C2/c with following cell parameters: a=19.3538(3), b=13.5356(3), c=8.9716(2) Å, β=108.540(1)°, V=2228.27(8) Å3, Z=4 and δ=1.734 g mol−1. Complex 6 crystallises in the monoclinic space group P21/n with a=9.0321(1), b=22.8014(4), c=15.6304(3) Å, β=100.2414(7)°, V=3167.71(9) Å3, Z=4 and δ=1.739 g mol−1. In both complexes a square-planar environment around the d8-configurated platinum(II) ion is typical. Each complex features a chelate-bound bipy′ group. To reach the coordination number four, two PhCC ligands (1) or one phenylacetylide and a PPh3 group (6) are σ- or datively bound to the platinum atom.