Roberta Cargnelutti

Metal complexes with bis(2-pyridyl)diselenoethers: structural chemistry and catalysis

Bis(2-pyridyl)diselenoethers with the general formula (2-PySe)2(CH2)n [n = 1, 3 and 4] react with CuI, AgNO3, CuCl2·2H2O and CoCl2·6H2O resulting in the formation of products with molecular or multidimensional structures depending on the stoichiometry of the reactants and the conditions applied. The versatility of this class of selenium-containing ligands is demonstrated with the synthesis and structural characterization of six new complexes of the composition [CuCl2{(2-PySe)2CH2}]n (1), [Cu4I4{(2-PySe)2CH2}2] (2), [CuCl2{(2-PySe)2(CH2)3}2] (3), [CoCl2{(2-PySe)2(CH2)3}]n (4), [Ag{(2-PySe)2–(CH2)}3]n(NO3)n (5) and [CuCl2{(2-PySe)2(CH2)4}]n (6), respectively. The Cu(I) complex (2) was tested as catalyst in cross-coupling reactions.

Tellurium-promoted stereoselective hydrodebromination of 1,1-dibromoalkenes: synthesis of (E)-bromoalkenes

We describe herein an efficient and simple method for the stereoselective hydrodebromination of 1,1-dibromoalkenes by using a catalytic amount of the nucleophilic species of tellurium, generated in situ by the reaction of elemental tellurium with NaBH4. By this methodology, (E)-bromoalkenes were obtained in moderate to excellent yields under mild reaction conditions, without the use of transition metals or base. Furthermore, a high stereoselectivity for the (E)-isomer was observed when 1,1-dibromoarylalkenes were used, thus indicating a promising alternative for future applications in organic synthesis.

Synthesis and structural chemistry of CoII, CuII, CuI and PdII complexes containing a flexible monoselenoether ligand

Monoselenoether ligand [PySeCH2Py] (L) reacts with CoCl2, CuCl2, CuI and Pd(OAc)2 resulting in the formation of molecular or polymeric complexes. The synthesis and structural elucidation of the complexes [CoCl2(L)] (1), [Cu2Cl4(L)2] (2a), [CuCl2(L)] (2b), [Cu2Cl2(PySe)2] (2c), [Cu(2-PyCOO)2] (2d), [Cu2I2(L)2] (3), [Cu2I2(L)]n (4) and [Pd2(CH3COO)2(PySeCHPy)2]·7H2O (5) demonstrate the versatility of this class of pyridylselenium ligands. For all compounds, the ligand offers N and/or Se atoms as donors and, in the case of 5, the ligand also builds C–Pd bonds to generate a cyclometallated palladium(II) complex.