TETRAPHENYLBORATE COORDINATION CHEMISTRY - SYNTHESIS, SOLID-STATE AND SOLUTION CHARACTERIZATION, AND PROPERTIES OF ([(C2H4)2RH(ETA(6)-PH)]2BPH2)O3SCF3 AND ([(C2H4)2RH(ETA(6)-PH)]3BPH)(O3SCF3)2 - THE 1ST EXAMPLES OF A TETRAPHENYLBORATE ANION ACTING AS A 12-E OR 18-E DONOR TO METAL CENTERS

{[(C2H4)2Rh(eta6-Ph)]2BPh2}O3SCF3(3) and {[(C2H4)2Rh(eta6-Ph)] 3BPh}(O3SCF3)2(4) have been synthesized by reaction Of (C2H4)2Rh(eta6-PhBPh3) with in situ generated Rh(C2H4)2(O3SCF3) (1 or 2 mol, respectively). 3 and 4 are the first examples of a tetraphenylborate anion bridging two and three metal centers, respectively. {[(C2H4)2Rh(eta6-Ph)]2BPh2}O3SCF3 has been characterized in the solid state by X-ray diffraction (crystals of {[(C2H4)2Rh(eta6-Ph)]2BPh2}O3-SCF3.(CH3)2CO are monoclinic, space group P2(1)/n; a = 13.050(1) angstrom, b = 14.805(2) angstrom, c = 19.736-(4) angstrom, beta = 70.71(l)-degrees, Z = 4, V = 3599 angstrom3) and in solution by means of H-1 and C-13 NMR spectroscopy. Complex 3 shows, in solution, at room temperature, a complicated fluxional behavior involving the rotation of the coordinated ethylene molecules around the metal-olefin bond axis, the rotation of the (C2H4)2Rh fragments around the respective Rh-arene bond vector, and the interconversion of its enantiomeric forms upon rotation of the BPh4- phenyl rings around the B-C bonds. The energy barrier at 301 K relative to the rotation of the olefin molecules has been measured as being DELTAG double dagger (301 K) = 57.7 kJ mol-1. Complex 4 has been characterized in solution by H-1 NMR spectroscopy. In solution of poorly coordinating solvents it has been shown to be partially dissociated into 3 and Rh(C2H4)2(O3SCF3). The dissociation is temperature dependent. The first example of a tetraphenylborate anion transfer between two metal centers is also described.