Reactivity of the di-μ-hydroxo-complexes [{Pd(NN)}2(μ-OH)2][ClO4]2 (NN=bis(pyrazol-1-yl)alkanes) towards protic electrophiles. Hydration of coordinated nitriles at a palladium(II) site

Selective NaOH-catalysed hydration of aromatic nitriles to amides

The selective synthesis of aromatic and heteroaromatic amides through base-catalysed hydration of nitriles was achieved using inexpensive and commercially available NaOH as the only catalyst.

Reactivity of polynuclear palladium carboxylate complexes towards acetonitrile: synthesis and X-ray study of Pd2(C6H4-o-C(=NH)CH3)2(CH3CO2)2 and Pd5(CH3C(=N)OC(=N)CH3)(NO)(NO2)x(RCO2)7-x

Reactions of the polynuclear palladium carboxylate complexes (binary palladium carboxylates and palladium nitrosyl carboxylates) with acetonitrile in some common organic solvents are described. It was found that reaction of palladium acetate Pd(3)(μ-CH(3)CO(2))(6) with acetonitrile and benzene leads to the formation of a binuclear complex Pd(2)(C(6)H(4)-o-C(=NH)CH(3))(2)(CH(3)CO(2))(2) containing molecules of orthometallated 1-phenylethanimine formed as a result of C-C-coupling of acetonitrile and benzene. Nitrosyl carboxylate complexes Pd(4)(NO)(2)(RCO(2))(6) promote more complicated transformations of acetonitrile that leads to the formation of coordinated acetimidic anhydride, which was found in Pd(5)(CH(3)C(=N)OC(=N)CH(3))(NO)(NO(2))(x)(RCO(2))(7-x) clusters. Structures of all the complexes contained products of acetonitrile transformations and a new palladium nitrosyl carboxylate Pd(4)(NO)(2)(cyclo-C(6)H(11)CO(2))(6) was studied with XRD. Analysis of the structures allowed finding a "building block" of palladium nitrosyl carboxylate clusters, that is a 4-nuclear metal chain -Pd(μ-RCO(2))(2)Pd(μ-NO)(μ-RCO(2))Pd(μ-RCO(2))(2)Pd-.

Iron-promoted nucleophilic additions to diimine-type ligands: a synthetic and structural study

We report here three examples of the reactivity of protic nucleophiles with diimine-type ligands in the presence of Fe(II) salts. In the first case, the iron-promoted alcoholysis reaction of one nitrile group of the ligand 2,3-dicyano-5,6-bis(2-pyridyl)-pyrazine (L1) permitted the isolation of an stable E-imido-ester, [Fe(L1')(2)](CF(3)SO(3))(2) (1), which has been characterized by spectroscopic studies (IR, ES-MS, Mössbauer), elemental analysis, and crystallographically. Compound 1 consists of mononuclear octahedrally coordinated Fe(II) complexes where the Fe(II) ion is in its low-spin state. The iron-mediated nucleophilic attack of water to the asymmetric ligand 2,3-bis(2-pyridyl)pyrido[3,4-b]pyrazine (L2) has also been studied. In this context, the crystal structures of two hydration-oxidation Fe(III) products, [Fe(L2')(2)](ClO(4))(3).3CH(3)CN (2) and trans-[FeL2"Cl(2)] (3), are described. Compounds 2 and 3 are both mononuclear Fe(III) complexes where the metals occupy octahedral positions. In principle, L2 is expected to coordinate to metal ions through its bipyridine-type units to form a five-membered ring; however, this is not the case in compounds 2 and 3. In 2, the ligand coordinates through its pyridines and through the hydroxyl group attached to the pyrazine imino carbon after hydration, that is, in an N,O,N tridentate manner. In compound 3, the ligand has suffered further transformations leading to a very stable diamido complex. In this case, the metal ion achieves its octahedral geometry by means of two pyridines, two amido N atoms, and two axial chlorine atoms. Magnetic susceptibility measurements confirmed the spin state of these two Fe(III) species: compounds 2 and 3 are low-spin and high-spin, respectively.