Synthese und Eigenschaften von Rhenium-Komplexen mit N2-, N2H2-, N2H4- und NH3-Liganden / Synthesis and Properties of Rhenium Complexes with N2, N2H2, N2H4 and NH3 Ligands

Abstract

UV irradiation of C5H5Re(CO)3 in tetrahydrofuran (THF) yields the THF complex C5H5Re(CO)2THF and traces of [(C5H5)2Re2(CO)5]. C5H5Re(CO)2THF is stable at room temperature, its reaction with N2/100 bar yields C5H5Re(CO)2N2, which also forms in the reaction with N2O whereby the THF complex is partially oxidized and decomposed. The reaction with an excess of N2H4 yields C5H5Re(CO)2N2H4, the oxidation of which leads to C5H5Re(CO)2N2 and the by-product trans-N2H2[C5H5Re(CO)2]2, in which the under ambient conditions unstable HN=NH molecule could be stabilized in a rhenium complex for the first time. In contrast to the analogous manganese complex C5H5Re(CO)2N2H4 disproportionates easily to C5H5Re(CO)2N2 and C5H5Re(CO)2NH3 at room temperature; the NH3 complex can be synthesized directly only by irradiating C5H5Re(CO)3 in hexane in the presence of NH3. The complexes are characterized spectroscopically and by elemental analyses; the different electronic influence of the nitrogen ligands on the C5H5Re(CO)2 system is discussed.