Fluktuierendes Verhalten von kationischen cis1‐Bis(ether‐phosphan)1‐palladium(II)1‐Komplexen. – 31P‐DNMR‐spektroskopische Untersuchungen, Linienformanalyse und Bestimmung der thermodynamischen Austauschparameter

Abstract

Fluxional Behavior of Cationic cis Bis(ether‐phosphane)palladium(II) Complexes. – 31P‐DNMR Spectroscopic Investigations, Line‐Shape Analysis, and Determination of Rearrangement BarriersHerrn Professor Heinrich Nöth zum 65. Geburtstag gewidmet. Reaction of X2Pd(P∼O)2 (XCl: 1a – g, k – n, p; XBr: 1′; XI: k″, l″, o″) with stoichiometric amounts of AgClO4 results in the formation of the monochelate complexes cis‐[ClPd(P∼O)(P∩O)][ClO4] (2a – g, k – n, p, l′, l″) (P∼O: η11‐P‐coordinated; P∩O: η21‐O,P‐chelated). In the case of compounds 1o, 1k″, and 1o″, which are provided with less basic etherphosphanes, the halide‐bridged dimers [(μ1‐X)Pd(P∼O)2]2[ClO4]2 (3o, k″, o″) are obtained. Temperature‐dependent 31P{1H}1‐NMR spectra of the fluxional complexes 2a – g, k – n, p, l′, l″ lead to δG≢ values. By using a modified version of DNMR5, computer‐generated spectra of 2a, b, f, k, l, p, l′, l″ were obtained and fitted to the experimental spectra. Graphic application of the Eyring equation to the kinetic data afforded the thermodynamic parameters δH≢, δS≢, and δG≢. The δS≢ values are in agreement with an associative exchange mechanism for 2a, b, f, l, p, l′, l″ and with a dissociative exchange mechanism for 2k, 2k and 3o crystallize in the monoclinic and triclinic space group P21/c and P&1marc; with Z4 and Z2, respectively.