FLUXIONAL BEHAVIOR OF CATIONIC CIS-BIS(ETHER-PHOSPHANE)PALLADIUM(II) COMPLEXES - P-31-DNMR SPECTROSCOPIC INVESTIGATIONS, LINE-SHAPE ANALYSIS, AND DETERMINATION OF REARRANGEMENT BARRIERS

Reaction of X2Pd(P is similar to O)2 (X = Cl:1a-g, k-n, p; X = Br:1'; X = I:k'', 1'', o'') with stoichiometric amounts of AgClO4 results in the formation of the monochelate complexes cis-[ClPd(P is similar to O)(P and O)][ClO4] (2a-g, k-n, p, 1', 1'') (P is similar to O: eta1-P-coordinated; P and O: eta2-O,P-chelated). In the case of compounds 1 o, 1 k'', and 1 o'', which are provided with less basic etherphosphanes, the halide-bridged dimers [(mu-X)Pd(P is similar to O)2]2[ClO4]2 (3 o, k'', o'') are obtained. Temperature-dependent P-31{H-1}-NMR spectra of the fluxional complexes 2a-g, k-n, p, 1', 1'' lead to DELTAG(not-equal) values. By using a modified version of DNMR5, computer-generated spectra of 2a, b, f, k, 1, p, 1', 1'' were obtained and fitted to the experimental spectra. Graphic application of the Eyring equation to the kinetic data afforded the thermodynamic parameters DELTAH(not-equal) DELTAS(not-equal), and DELTAG(not-equal). The DELTAS(not-equal) values are in agreement with an associative exchange mechanism for 2a, b, f, 1, p, 1', 1'' and with a dissociative exchange mechanism for 2k. 2k and 3 o crystallize in the monoclinic and triclinic space group P2(1)/c and P1BAR with Z = 4 and Z = 2, respectively.