Metallabis(phosphonate) als Chelatliganden. II. Synthese und Reaktivität ein- und zweikerniger Palladiumbis(phosphonat)-Komplexe mit OHO- und OBF2O-Brückenbindungen

Metallabisphosphonates as Chelating Ligands. II. Synthesis and Reactivity of Mono- and Binuclear Palladiumbisphosphonate Complexes Containing OHO and OBF₂O Bridges The complexes C₅H₅Pd[{P(OR)₂O}₂H] ( 1 : R = Me; 2 : R = Et) are formed either by reaction of C₅H₅Pd(2-MeC₃H₄) with dimethyl- and diethylphosphite or by reaction of [ClPd{P(OR)₂O}₂H]₂ ( 3 : R = Me; 4 : R = Et) with TlC₅H₅. With excess HP(O)(OMe)₂, the π-allyl complex (2-MeC₃H₄)Pd[{P(OMe)₂O}₂H] ( 5 ) is also formed (besides 1 ) from C₅H₅Pd(2-MeC₃H₄). The ¹H and ³¹P n.m.r. spectra indicate that in 1 – 5 the PdP₂O₂H chelate ring presumably contains a symmetrical OHO-hydrogen bond. The reaction of 3 with BF₃ etherate leads to the binuclear complex [ClPd{P(OMe)₂O}₂BF₂]₂ ( 6 ) which reacts with TlC₅H₅ to yield C₅H₅Pd[{P(OMe)₂O}₂BF₂] ( 7 ). From C₅H₅Pd[{P(OR)₂O}₂H] ( 1 , 2 ) and NH₃ the bisamminepalladium bisphosphonates(NH₃)₂Pd[P(OR)₂O]₂ ( 8 , 9 ) are formed which probably possess a trans-configuration. The reaction of 8 , 9 with CF₃COOH does not lead to a corresponding Pd[{P(OR)₂O}₂H] chelate complex but instead gives by elimination of NH₃ polymeric palladium bisphosphonates [Pd{P(OR)₂O}₂]_n ( 10 , 11 ). 1 reacts with thallium acetylacetonate to give C₅H₅Pd[P(OMe)₂O]₂Tl ( 12 ).