Resumen de Synthesis of η2-Dihydrogen Complex, trans-{Fe(η2-H2)(H)[1,2-bis(diphenylphosphino)-ethane]2}[BF4]:: An Experiment for an Advanced Inorganic Chemistry Laboratory Involving Synthesis and NMR Properties of an η2-H2 Complex.
Maria T. Bautista, Lynikka D. Bynum, Cynthia K. Schauer
An experiment for an advanced inorganic chemistry laboratory involving synthesis and NMR properties of the molecular hydrogen complex [Fe(n2-H2)(H)(dppe)2](BF4) (1) (dppe = 1,2-bis(diphenylphosphino)ethane) is described. The precursor to the dihydorgen complex, Fe(H)2(dppe)2, is prepared by refluxing anhydrous FeCl2 with excess dppe and NaBH4 under an inert atmosphere. Protonation of the dihydride with HBF4 · O(C2H5)2 under an argon or hydrogen atmosphere generates 1 in 80% yield. Exchange of the hydride ligand with the hydrogen atoms of the dihydrogen ligand can be demonstrated in a variable temperature 1H NMR experiment for 1. Preparation of the deuterated analog of 1, [Fe(n2-HD)(H)(dppe)2](BF4) by reaction of Fe(H)2(dppe)2 with DBF4, allows measurement of the H-D coupling constant, a characteristic parameter of a molecular hydrogen compound.
