10.1016/S0277-5387(00)00474-5
This research focuses on the coordination chemistry of sulfamethizole, an antibacterial drug, with various metal ions. The study aims to synthesize and characterize copper, cobalt, nickel, and zinc complexes of sulfamethizole, and to determine their crystal structures for the first time. The researchers used sulfamethizole (Hsmtz) as the ligand and synthesized complexes with copper (II), cobalt (II), nickel (II), and zinc (II) ions using reagents such as CuSO4·5H2O, CoCl2·6H2O, NiCl2·6H2O, and ZnCl2·2H2O. The crystal structures were determined using X-ray diffraction, revealing different coordination geometries for the metal ions in these complexes.
10.1002/chem.201705463
The research aims to develop the first cobalt-catalyzed enantioselective Negishi cross-coupling reaction, focusing on the arylation of α-halo esters with arylzinc halides. This innovative method employs a cobalt-bisoxazoline catalyst to achieve high enantioselectivities and yields (up to 97% ee and 98% yield) in the synthesis of various α-arylalkanoic esters from racemic α-bromo esters and arylzincs. The study demonstrates the reaction's versatility with a wide range of functional groups, including ethers, halides, thioethers, silyls, amines, esters, acetals, amides, olefins, and heteroaromatics, and its scalability, as shown in the synthesis of (R)-xanthorrhizol. Radical clock experiments support a radical pathway in the mechanism. The research concludes that this cobalt-catalyzed cross-coupling reaction offers a powerful and environmentally benign alternative to noble metal catalysts for constructing enantioenriched α-arylalkanoic esters, with potential applications in medicinal chemistry.
10.1021/ja1012382
The research aims to synthesize and characterize a series of cobalt isocyanide complexes, [Co(CNR)4]n (n = 1+, 0, 1-), using m-terphenyl isocyanide (CNArMes2) as the ligand, to mimic the geometric and electronic structures of the reactive intermediates in industrial hydroformylation and carbonylation processes. The study successfully isolated the tetraisocyanometalate salt Na[Co(CNArMes2)4], the neutral complex Co(CNArMes2)4, and the diamagnetic salt [Co(CNArMes2)4]BArF4. The geometric and electronic structures of these complexes were elucidated through various techniques such as X-ray diffraction, FTIR, and EPR spectroscopy. The findings revealed that the Co complexes exhibit unique structural and spectroscopic features, with the neutral complex Co(CNArMes2)4 showing a temperature-dependent structural progression from C2V to D2d symmetry. The study concludes that the CNArMes2 ligand stabilizes these cobalt complexes in different oxidation states and geometries, providing valuable insights into the behavior of cobalt isocyanide complexes and their potential applications in catalysis.
Xn:Harmful;
