Vibrational characterization of a diiron bridging hydride complex – a model for hydrogen catalysis

Abstract

Fe–H–Fe bridging iron hydrides in model systems and metalloenzymes: benefits and challenges in revealing their vibrational signatures using NRVS spectroscopy and DFT calculations.

Nuclear Resonance Vibrational Spectroscopy: A Modern Tool to Pinpoint Site-Specific Cooperative Processes

“…People need 36-48 h to move in and set up the HRM and other instruments at the beginning of each beamtime [8]. Nevertheless, researchers are rewarded with amazing NRVS results [7,8,45,47,[65][66][67][68][69].…”

“…A rough recommendation is that NMA should be utilized for smaller/high-symmetry systems where the size of the parameter space can be reasonable and group theory insights are useful. However, in recent years, DFT calculations have been popular as a straightforward approach to interpret vibrational spectra including NRVS [ 7 , 14 , 30 , 32 , 36 , 38 , 44 , 66 , 68 ].…”

High-Frequency Fe–H and Fe–H2 Modes in a trans-Fe(η2-H2)(H) Complex: A Speed Record for Nuclear Resonance Vibrational Spectroscopy

“…Nuclear resonance vibrational spectroscopy (NRVS) 13−16 has become a popular technique for elucidating the elementselective normal modes of appropriate Mossbauer isotopes. 13−18 In previous work, we have shown that 57 Fe-NRVS can be utilized to observe Fe−H bending and Fe−H−Fe(Ni) wagging modes in various model compounds 19 as well as intermediate species of [NiFe] 20 and [FeFe] hydrogenases. 21−23 However, to date, the only reported Fe−H stretching modes were the bands around 1230/1430 cm −1 for a doubly bridging Fe(μ-H) 2 Fe complex 24 and at 1468/1532 cm −1 for a singly bridging Ni(μ-H)Fe complex.…”

“…Nuclear resonance vibrational spectroscopy (NRVS) − has become a popular technique for elucidating the element-selective normal modes of appropriate Mössbauer isotopes. − In previous work, we have shown that 57 Fe-NRVS can be utilized to observe Fe–H bending and Fe–H–Fe­(Ni) wagging modes in various model compounds as well as intermediate species of [NiFe] and [FeFe] hydrogenases. − However, to date, the only reported Fe–H stretching modes were the bands around 1230/1430 cm –1 for a doubly bridging Fe­(μ-H) 2 Fe complex and at 1468/1532 cm –1 for a singly bridging Ni­(μ-H)Fe complex . To better gauge the feasibility for observing even higher frequency stretching modes expected for an iron-terminal hydride and dihydrogen, we have applied NRVS to examine a well-studied trans -[ 57 Fe­(η 2 -H 2 )­(H)­(dppe) 2 ]­[BPh 4 ] [dppe = 1,2-bis­(diphenylphosphino)­ethane] complex, , hereafter called 1 H H2 .…”

Integrated bio-metal science: New frontiers of bio-metal science opened with cutting-edge techniques

“…NRVS is a unique technique using high intensity X-ray, produced by synchrotron radiation, to investigate the atomic vibration in molecules. Vibration modes of a specific atom, selectively excited via the nuclear level, give quite different and complementary information from that taken by Raman or infrared (IR) spectroscopy in the examination of the active center of metalloenzyme (Figure 4) [8][9][10][11][12]. X-rays from the synchrotron radiation can be also utilized for light source of new imaging systems that visualize biometal distribution and chemical status in tissues or even in cells.…”