E-beam Mediated Ligand Dissociation of Alkyne-Dicobaltcarbonyl Complexes as Potential Photochemical Alkyne Precursor

摘要

Arrayed alkyne group on a solid surface have been of interest for the attachment of diverse agents useful in electronic device coating, fluorescence nanopatterning, and surface reforming. For example, Huisgen reaction of alkynes with organic azides on a surface has been reported to connecting DNA, enzyme and fluorophores on the solid surface. The selective immobilization of alkynes on a surface could be progressed by covalent bonding with the arrayed alkyhalide or vinyl halide via Sonogashira reaction or by selective thermal degradation of Alkene-SO2(diarylthiiren-l,l-dioxide). In practice, however, these methods have limitations for the application into surface modification because of relatively vigorous reaction conditions or synthetic difficulty in the precursor supply and requiring of metal catalyst might be interfering with solid surface such as gold and silicone. As an alternate method for selective alkyne generation on the surface, photochemical transformations of furoxane have been reported. Photochemical conversion of furoxane to alkyne on the surface does not require either solvent or catalyst. In a continuation effort to provide efficient alkyne precursors, we synthesized alkyne-cobalt-CO complexes (1-5) and analyzed electron beam (e-beam) mediated ligand dissociation in gas phase using MS spectrometer. The complex includes alkynes containing aldehyde and chlorine ligands since those groups could play a role of immobilizing anchor onto gold or silica surface. The ligands, CO and phosphine of cobalt complexes underwent dissociations by e-beam irradiation in gas phase to lead conversion of complexes to alkynes.