Abstract
High-spin iron species with bridging hydrides have been detected in species trapped during nitrogenase catalysis, but there are few general methods of evaluating Fe-H bonds in high-spin multinuclear iron systems. An (57) Fe nuclear resonance vibrational spectroscopy (NRVS) study on an Fe(μ-H)(2) Fe model complex reveals Fe-H stretching vibrations for bridging hydrides at frequencies greater than 1200 cm(-1) . These isotope-sensitive vibrational bands are not evident in infrared (IR) spectra, showing the power of NRVS for identifying hydrides in this high-spin iron system. Complementary density functional theory (DFT) calculations elucidate the normal modes of the rhomboidal iron hydride core.