TY - JOUR
T1 - Vibrational spectrum of the spin crossover complex [Fe(phen) 2(NCS)2] studied by IR and Raman spectroscopy, nuclear inelastic scattering and DFT calculations
AU - Ronayne, Kate L.
AU - Paulsen, Hauke
AU - Höfer, Andreas
AU - Dennis, Andrew C.
AU - Wolny, Juliusz A.
AU - Chumakov, Aleksandr I.
AU - Schünemann, Volker
AU - Winkler, Heiner
AU - Spiering, Hartmut
AU - Bousseksou, Azzedine
AU - Gütlich, Philipp
AU - Trautwein, Alfred X.
AU - McGarvey, John J.
PY - 2006/11/9
Y1 - 2006/11/9
N2 - 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, ΔS vib, which is - together with the electronic entropy difference ΔSel - the driving force for the spin-transition, has been determined from the measured and from the calculated frequencies. The calculated difference (ΔSvib = 57-70 J mol-1 K-1, depending on the method) is in qualitative agreement with experimental values (20-36 J mol-1 K-1). Only the low energy vibrational modes (20% of the 147 modes of the free molecule) contribute to the entropy difference and about three quarters of the vibrational entropy difference are due to the 15 modes of the central FeN6 octahedron.
AB - 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, ΔS vib, which is - together with the electronic entropy difference ΔSel - the driving force for the spin-transition, has been determined from the measured and from the calculated frequencies. The calculated difference (ΔSvib = 57-70 J mol-1 K-1, depending on the method) is in qualitative agreement with experimental values (20-36 J mol-1 K-1). Only the low energy vibrational modes (20% of the 147 modes of the free molecule) contribute to the entropy difference and about three quarters of the vibrational entropy difference are due to the 15 modes of the central FeN6 octahedron.
UR - http://www.scopus.com/inward/record.url?scp=33750590435&partnerID=8YFLogxK
U2 - 10.1039/b610634j
DO - 10.1039/b610634j
M3 - Journal articles
C2 - 17047767
AN - SCOPUS:33750590435
SN - 1463-9076
VL - 8
SP - 4685
EP - 4693
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
IS - 40
ER -
