Synthesis and molecular structures of palladium and platinum complexes of PTFA: Models of Grignard cross-coupling catalysts

A number of palladium(0) and palladium(II) as well as platinum(0) and platinum(II) complexes of (eta(5)-cyclopentadienyl)-(eta(5)-4-endo-N, N-dimethylamino-3-diphenylphosphino-4,5,6,7-tetrahydro-1H-indenyl)iron (PTFA) of the type (PTFA)M(0)(alkene) and (PTFA)M(II)(R)X, (M = Pd, Pt; alkene = dibenzylideneacetone, maleic anhydride, fumaronitrile and tetracyanoethylene; R = CH3, Ph and PhCH(2); X = Cl, Br and I) have been synthesized as models of Grignard cross-coupling catalysts. All complexes were prepared either by proper ligand exchange or via oxidative addition reactions. A comparison of the X-ray structures of five complexes ((PTFA)Pd(fumaronitrile), 4, (PTFA)PdCl2, 8, (PTFA)Pd(Ph)I, 10, (PTFA)Pt(tetracyanoethylene), 6, and (PTFA)Pt(CH3)Cl, 13) showed that, in contrast to complexes of 2-(1-N,N-dimethylaminoethyl)-1-diphenylphosphino-ferrocene (PPFA), the overall molecular structures of PTFA complexes are comparable; they neither strongly depend on the oxidation state of the metal nor on the type of additional ligands coordinated to the metal, Compound 4, C32H32FeN3PPd . CH2Cl2, crystallizes in the monoclinic space group P2(1)/c (no. 14), with a = 19.237(2), b = 9.0737(10), c = 17.917(3) Angstrom, beta = 96.458(11)degrees, V = 3107.6(7) Angstrom(3), Z = 4. The structure refinement converged to R1 = 0.0579 for 3832 F-0 > 4 sigma(F-0) and wR2 = 0.1276 for all 6520 unique data, S = 0.94. Compound 6, C34H30FeN5PPt . C4H10O, crystallizes in the triclinic space group P (1) over bar (no, 2), with a = 11.845(3), b = 12.120(4), c = 12.979(3) Angstrom, alpha = 81.68(2)degrees, beta = 82.06(2)degrees, gamma = 68.11(3)degrees, V = 1703.6(8) Angstrom(3), Z = 2. The structure refinement converged to R1 = 0.0402 for 6459 F-0 > 4 sigma(F-0) and wR2 = 0.1076 for all 7235 unique data, S = 1.04. Compound 13, C29H33ClFeNPPt, crystallizes in the monoclinic space group P2(1)/c (no. 14), with a = 16.122(2), b = 10.1608(11), c = 21.716(3) Angstrom, beta = 132.202(11)degrees, V = 2635.2(5) Angstrom(3), Z = 4. The structure refinement converged to R1 = 0.0322 for 3846 F-0 > 4 sigma(F-0) and wR2 = 0.0734 for all 4612 unique data, S = 1.03.