Vibrational spectrum of the spin crossover complex [Fe(phen)(2)(NCS)(2)] studied by IR and Raman spectroscopy, nuclear inelastic scattering and DFT calculations.
Phys Chem Chem Phys
; 8(40): 4685-93, 2006 Oct 28.
Article
em En
| MEDLINE
| ID: mdl-17047767
ABSTRACT
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 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 FeN(6) octahedron.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fenantrolinas
/
Compostos Ferrosos
/
Quelantes de Ferro
Tipo de estudo:
Qualitative_research
Idioma:
En
Ano de publicação:
2006
Tipo de documento:
Article