NUCLEOPHILIC-ATTACK ON OR DISPLACEMENT OF COORDINATED 1,5-CYCLOOCTADIENE - STRUCTURES OF [PT(SIGMA-ETA-2-C8H12(PPH3))(DPPE)][CLO4]2 AND [PT(DPPE)(H2O)2][SO3CF3]2

The complex [Pt(cod)(dppe)][ClO4]2 reacts with acetonitrile to give [Pt(dppe)(CH3CN)2]2+, from which the solvent molecules may be displaced by tertiary phosphines. In contrast, in CH2Cl2 solution phosphine attack at the coordinated diene takes place and the crystal structure of [Pt{sigma:eta-2-C8H12(PPh3)}(dppe)][ClO4]2 (1) has been determined. The compound crystallizes in the triclinic space group P1BAR with a = 13.749 (5) angstrom, b = 14.126 (4) angstrom, c = 14.356 (3) angstrom, alpha = 118.48 (2)-degrees, beta = 94.47 (2)-degrees, gamma = 96.78 (2)-degrees, V = 2404.7 (12) angstrom 3, and Z = 2. Least-squares refinement converged at R = 0.0616 and R(w) = 0.0686 based on 6348 reflections with F > 4.0-sigma(F). In [Pt(cod)(dppe)][SO3CF3]2 the diene is slowly displaced by triflate, and [M(SO3CF3)2(dppe)] (M = Pd, Pt) and [Pt(SO3CF3)2(dppm)] have been prepared by reaction of the dichloro complex with AgSO3CF3. When isolated the dppe complexes contain two water molecules and the crystal structure of the platinum derivative shows that it exists as [Pt(dppe)(H2O)2][SO3CF3]2 (2) in the solid state. The latter crystallizes in the monoclinic space group P2(1)/n with a = 10.663 (3) angstrom, b = 24.255 (9) angstrom, c = 13.720 (2) angstrom, beta = 104.36 (2)-degrees, V = 3437.6 (17) angstrom 3, and Z = 4. Least-squares refinement converged at R = 0.0529 and R(w) = 0.0454 based on 3291 reflections with F > 4.0-sigma(F).