New di- and trinuclear complexes with pyrazolato bridges. Crystal structures of [{(C6F5)(2)Pd(mu-pz)(mu-Cl)}(2)Pd](2-) and [(C6F5)(2)Pd(mu-pz)(2)Pd(eta(3)-C4H7)] (pz = pyrazolate)

Trinuclear complexes containing pyrazolate bridging ligands of the type [NB u4](2)[{(C6F5)(2) M(mu-pz)(mu-X)}(2)M'] (M, M' = Pd or Pt; X = Cl, OH, or p z) (Hpz = pyrazole) have been prepared using [NBu4][M(C6F5)(2)(acac)] (acac = acetylacetonate) or [NBU4](2)[M-2(C6F5)(4)(mu-OH)(2)] and [M'Cl-2(Hpz)(2 )] or [M'(Hpz)(4)](2+) as starting materials. Asymmetric home-and heterobim etallic complexes of the types [NBu4][R2M(mu-pz)(2)Pd(eta(3)-allyl)] and [R 2M(mu-pz)(2),M'L-2] (allyl = C3H5 or C4H7; L-2 = 2 PEt3 or bipy; R = C6F5 O r C6Cl5; M, M' = Pd Or Pt) have been obtained starting from [NBu4][MR2(pzHp z)] and [Pd(eta(3)-allyl)(acac)] or [M'L2Cl2], respectively. The identity o f the new complexes has been established by NMR (H-1, F-19 and (31)p) spect roscopy. The crystal structure of [{(C6F5)(2)Pd(mu-pz)(mu-Cl)}(2)Pd](2-) ha s an inversion centre, with a bent appearance of the Pd-3(mu-pz)(2)(mu-Cl)( 2) moiety. The crystal structure of [(C6F5)(2)Pd(mu-pz)(2)Pd(eta(3)-C4H7)] has also been determined by single-crystal X-ray diffraction, where a boat conformation of the central "Pd2N4" six-membered rings is observed.