Cholesterylaminecobalto(III)-11-tungstoborate and other organoheteropoly-tungstate preparations: organic ligand substrate and heteropoly anion syntheses.

Abstract

Salts of the following heteropolytungstate anions (HPA), [(H20)CoO5SiO4WIIO30]6-, [(H20)CoO5SiO4W11O30]5-, [(H20)CoO5BO4W11O30]7-, and [(H20)CoO5BO4WIIO30]6-, have been prepared and analyzed by optical microscope, FTIR spectra, UV-visible spectra, and the characteristic reaction with Zn. Organic ligand substrates, cholesterylamine and 2-octylamine, have been synthesized by the Mitsunobu reaction. These organic ligand substrates were characterized by proton NMR, FTIR, thin layer chromatography (TLC), and some physical-chemical properties. Organoheteropolytungstates, [(C27H47N)CoO5BO4WIIO30]6-and [(C9H7N)CoO5BO4WIIO30]6-, have been prepared and isolated by using a phase transfer catalysis (PTC) technique through ligand substitution. The UV-visible spectra were used to monitor the formation of organoheteropoly-tungstates. A phase transfer catalysis cycle has been suggested as the mechanism in the ligand substitution of HPA via PTe. Some organic amine derivatives, pyridine, isoquinoline, quinoline, 8-methylquinoline, and 2-octylamine, have been used to investigate the steric and electronic effects. A geometric steric hindrance cavity has been suggested in the ligand substitution of HPA based on the structure-reactivity relationships.