Sulfato-bridged ECE-pincer palladium(II) complexes: structures in the solid-state and in solution, and catalytic properties.

ECE-pincer sulfato palladium complexes (pincer = [C(6)H(3)(CH(2)E)(2)-2,6](-); E = SPh (), SMe (), S(t)Bu (), NMe(2) ()) were synthesized and characterized. In the solid-state (X-ray determinations) and exist as neutral ECE-pincer palladium sulfato complexes with a mu(2)-O,O' bridging sulfato ligand. IR and Raman spectroscopic studies revealed that in the solid-state the complexes can be present as either solely neutral or as a mixture of neutral and ionic species, depending on the preparation and morphology of the solids. In water, ionic complexes with non-coordinating sulfate ions prevail. Preliminary studies of the catalytic activity of in the Suzuki-Miyaura C-C cross-coupling reaction of 3-iodobenzoic acid and sodium tetraphenylborate in water reveal that the C-C cross-coupling product is efficiently formed in good yields at room temperature.

Neutral pyridyl-functionalized C,N-ortho-chelated aminoaryl platinum(II) corner building blocks for application in coordination reactions.

Two homoleptic pyridyl-functionalized C,N-ortho-chelating aminoaryl platinum(II) complexes, cis-[Pt(eta(2)-C,N)] (3a,b), were prepared via an unconventional method involving the initial synthesis of a bromide-functionalized C,N-chelating aminoaryl platinum(II) precursor complex 8, to which subsequently pyridyl groups were attached via a Suzuki-Miyaura C-C coupling reaction. The electron-donating properties of the pyridyl nitrogen atoms of the resulting complexes (3a,b) were used in complexation reactions with monocationic NCN-pincer (NCN = [C6H3(CH2NMe2)(2-)2,6]-) platinum(II) (11a) and palladium(II) (12a) nitrate complexes [M(NCN)(NO3)], thereby obtaining four trimetallic coordination complexes 16-19. The difference in the pyridine-metal coordination behavior between platinum and palladium was studied by varying the ratios of the reagents and by variable-temperature NMR experiments. IR and Raman analyses of 11a and 12a were performed to determine the coordination behavior of the nitrate counteranion, and it was found that both NO3- and H2O coordinate to the metal centers. The crystal structure determinations of free pyridyl complex 3a, [Pt(NCN)(NO3)] (11a), and [Pt(NCN)(NO3)].(H2O) (11b), as well as the crystal structure of trisplatinum coordination complex 16, are reported.

Novel heteroleptic cis-(C--N)2Pd(II) chelates for the preparation of enantiopure planar chiral cyclopalladated 2-[tricarbonyl(eta6-phenyl)chromium]pyridine.

In the presence of large amounts of [Me4N]Cl, the reaction of ortho-chloromercurated 2-[(eta6-phenyl)tricarbonylchromium]pyridine with mu-chloro cyclopalladated aromatic compounds yields a series of new heteroleptic heterodinuclear cis-(C--N)2Pd(II) complexes, which are valuable precursors of planar chiral cyclopalladated (eta6-arene)Cr(CO)3 complexes.