127540-60-7Relevant academic research and scientific papers
Synthesis and Properties of New Dimeric η2-Diyne Complexes of Cobalt Linked through an Azobenzene Ligand
Moreno, Consuelo,Arnanz, Avelina,Medina, Rosa-María,Macazaga, María-José,Pascual, Mario,García-Frutos, Eva M.,Martínez-Gimeno, Esther,Marcos, María-Luisa
, p. 2971 - 2984 (2015)
The reaction between 4,4′-diiodoazobenzene (0) with excess trimethylsilylacetylene or dec-1-yne in the presence of catalytic amounts of PdCl2(PPh3)2 and CuI, Sonogashira coupling conditions, gave rise to the formation of 4,4′-bis(trimethylsilylethynyl)azobenzene (1) and 4,4′-bis(dec-1-ynyl)azobenzene (2), in good yield, in addition to icosa-9,11-diyne (3) as byproduct in the last case. The analogous reactions from 0 and the alkynyl-cobalt complexes Co2(CO)4(μ-L-L)(μ2-η2-SiMe3C2)](C≡CH) (L-L = dppm, dmpm) afforded 12-14. Complexes 4-7 and 15 have been obtained by direct reaction between Co2(CO)8 and the organic ligands 1-3. In order to increase the stabilization of Co-Co bonds, diphenylphosphinomethane-substituted alkyne-carbonyl complexes 8-11 were prepared by substitution reaction of carbonyl ligands in the presence of Me3NO at the Co2(CO)6 units from 4-7. All products were characterized by analytical and spectroscopic data (IR, 1H, 13C, and 31P NMR, and MS). Crystals of 9 suitable for single-crystal X-ray diffraction were grown, and the molecular structure of this compound is discussed. In this paper we report a comparative electrochemical study of these complexes by means of cyclic and square-wave voltammetry techniques, the trans-cis photoisomerization study of azobenzene compounds, and the thermotropic liquid-crystalline behavior. (Chemical Equation Presented).
