0000000000423950
AUTHOR
Aleksandr I. Chumakov
Vibrational spectrum of the spin crossover complex [Fe(phen)(2)(NCS)(2)] studied by IR and Raman spectroscopy, nuclear inelastic scattering and DFT calculations.
The vibrational modes of the low-spin and high-spin isomers of the spin crossover complex [Fe(phen)(2)(NCS)(2)] (phen = 1,10-phenanthroline) have been measured by IR and Raman spectroscopy and by nuclear inelastic scattering. The vibrational frequencies and normal modes and the IR and Raman intensities have been calculated by density functional methods. The vibrational entropy difference between the two isomers, DeltaS(vib), which is--together with the electronic entropy difference DeltaS(el)--the driving force for the spin-transition, has been determined from the measured and from the calculated frequencies. The calculated difference (DeltaS(vib) = 57-70 J mol(-1) K(-1), depending on the m…
Dynamics of Metal Centers Monitored by Nuclear Inelastic Scattering
Nuclear inelastic scattering of synchrotron radiation has been used now since 10 years as a tool for vibrational spectroscopy. This method has turned out especially useful in case of large molecules that contain a M\"ossbauer active metal center. Recent applications to iron-sulfur proteins, to iron(II) spin crossover complexes and to tin-DNA complexes are discussed. Special emphasis is given to the combination of nuclear inelastic scattering and density functional calculations.
Spin- and phase transition in the spin crossover complex [Fe(ptz)6](BF4)2 studied by nuclear inelastic scattering of synchrotron radiation and by DFT calculations
Abstract Nuclear inelastic scattering (NIS) spectra of [Fe(ptz) 6 ](BF 4 ) 2 (ptz = 1- n -propyl-tetrazole) have been measured for five phases differing in spin state and crystallographic structure. Different spectral patterns have been found for the low-spin and high-spin phases and are described in terms of normal coordinate analysis of the complex molecule. For both low-spin and high-spin phases the conversion from ordered to disordered phase results in splitting of the observed NIS bands. Packing becomes visible in the NIS spectra via coupling of the Fe–N stretching vibrations with those of the terminal n -propyl groups. The DFT-based normal coordinate analysis also reveals the characte…