SYNTHESIS, STRUCTURAL CHARACTERIZATION, AND REACTIVITY TOWARD WEAK, PROTIC ELECTROPHILES OF [(C6F5)2PD(MU-OH)2PD(C6F5)2]2-

The bis(mu-hydroxo) complex Q2[(C6F5)2Pd(mu-OH)2Pd(C6F5)2] (1) (Q = NBu4) has been obtained by reaction of cis-Pd-(C6F5)2(PhCN)2 with 20% aqueous QOH in acetone. 1 reacts with weak, protic electrophiles H(LL) in the 1:2 molar ratio to give Q2[(C6F5)2Pd(mu-LL)2Pd(C6F5)2] [LL = pyrazolate (2), 3,5-dimethylpyrazolate (3), 3-methylpyrazolate (4), indazolate (5)]. The reaction between 1 and H(LL) (acetylacetone, benzoylacetone, 8-hydroxoquinoline) in acetone leads to the formation of the corresponding mononuclear complexes Q[(C6F5)2Pd(LL)] (6-8). Q2[(C6F5)2Pd(mu-OH)(mu-dmpz)Pd(C6F5)2] (9) has been produced by treatment of Q2[(C6F5)2Pd(mu-Cl)2Pd(C6F5)2] with QOH and Hdmpz (1:2:1 molar ratio) in methanol. IR and H-1 and F-19 NMR spectra have been used for structural assignments. An X-ray structural determination, carried out with (NBu4)2[(C6F5)2Pd(mu-OH)2Pd(C6F5)2], has established the centrosymmetric binuclear nature of the anion, and the geometry around each Pd atom is that of a distorted planar square with Pd-O = 2.077 (6) and 2.068 (6) angstrom and Pd-C distances of 1.997 (7) and 2.006 (6) angstrom.