Far-infrared spectra of some Fe(1,10-phenanthroline) 2X2 complexes

Takemoto, James; Streusand, B. J.; Hutchinson, Bennett

doi:10.1016/0584-8539(74)80199-6

Cited by 33 publications

(14 citation statements)

References 22 publications

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“…1 for the case of SCO in iron(II) compounds, thermal spin state conversion from HS to LS states is connected with depletion of charge in the antibonding e g orbitals and simultaneous increase of charge in the lower lying slightly bonding t 2g orbitals on lowering of the temperature. This results in strengthening of the metal–donor-atom bonds and can be observed in the vibrational spectrum recorded in the far-infrared (FIR) region between ~250 and ~500 cm −1 , where the central metal–donor-atom stretching frequencies of transition metal compounds generally appear [61–63]. Detailed and often tedious band assignment is not necessary.…”

Section: Reviewmentioning

confidence: 99%

“…Examples are the N-coordinated ligands NCS − and NCSe − , for instance in the “classical” systems [Fe(phen) 2 (NCS) 2 ] and [Fe(phen) 2 (NCSe) 2 ] [61–63]. The C–N stretching bands of NCS − and NCSe − are seen as a strong doublet near 2060–2070 cm −1 in the HS state.…”

Section: Reviewmentioning

confidence: 99%

“…The C–N stretching bands of NCS − and NCSe − are seen as a strong doublet near 2060–2070 cm −1 in the HS state. Upon cooling of [Fe(phen) 2 (NCS) 2 ] to below the transition temperature (175 K), this doublet decreases in intensity, favoring the appearance of a new doublet at 2100–2110 cm −1 , which obviously stems from the LS state [61–63]. One has also found that certain vibrational modes of lattice constituents, such as non-coordinating anions or solvent molecules, interconnecting the spin state changing metal complexes via hydrogen bonds, van der Waals or other interactions, can “feel” spin state changes at the metal centers and can therefore be made use of to study ST phenomena.…”

Section: Reviewmentioning

confidence: 99%

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Spin state switching in iron coordination compounds

Gütlich¹,

Gaspar²,

Garcia³

2013

Beilstein J. Org. Chem.

648

608

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SummaryThe article deals with coordination compounds of iron(II) that may exhibit thermally induced spin transition, known as spin crossover, depending on the nature of the coordinating ligand sphere. Spin transition in such compounds also occurs under pressure and irradiation with light. The spin states involved have different magnetic and optical properties suitable for their detection and characterization. Spin crossover compounds, though known for more than eight decades, have become most attractive in recent years and are extensively studied by chemists and physicists. The switching properties make such materials potential candidates for practical applications in thermal and pressure sensors as well as optical devices.The article begins with a brief description of the principle of molecular spin state switching using simple concepts of ligand field theory. Conditions to be fulfilled in order to observe spin crossover will be explained and general remarks regarding the chemical nature that is important for the occurrence of spin crossover will be made. A subsequent section describes the molecular consequences of spin crossover and the variety of physical techniques usually applied for their characterization. The effects of light irradiation (LIESST) and application of pressure are subjects of two separate sections. The major part of this account concentrates on selected spin crossover compounds of iron(II), with particular emphasis on the chemical and physical influences on the spin crossover behavior. The vast variety of compounds exhibiting this fascinating switching phenomenon encompasses mono-, oligo- and polynuclear iron(II) complexes and cages, polymeric 1D, 2D and 3D systems, nanomaterials, and polyfunctional materials that combine spin crossover with another physical or chemical property.

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Section: Reviewmentioning

confidence: 99%

Section: Reviewmentioning

confidence: 99%

Section: Reviewmentioning

confidence: 99%

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Spin state switching in iron coordination compounds

Gütlich¹,

Gaspar²,

Garcia³

2013

Beilstein J. Org. Chem.

648

608

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“…IR bands in the region above ca 3100 cm À1 could be assigned to the (N-H) vibrations, while strong bands around 1570 cm À1 were characteristic for the C N double bond in the amidine ligands. In the far-infrared region, the M-Cl bands could be clearly assigned by comparison with literature values (Clark & Williams, 1965;Takemoto et al, 1974) and IR spectra of the respective anhydrous metal(II) chlorides, MCl 2 (M = Mn, Fe, Co; for details see the Synthesis and crystallization section). Fig.…”

Section: Chemical Contextmentioning

confidence: 97%

Synthesis and structural characterization of four dichloridobis(cyclopropylalkynylamidine)metal complexes

et al. 2018

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“…The first detailed study aimed at assigning metal-ligand vibrational modes in SCO compounds was carried out by Takamoto and Hutchinson [14][15][16][17] using metal isotope substitution on [Fe(phen) 2 (NCS) 2 ] and related compounds. They assigned a shift of Fe-N(phen) and Fe-N(NCS) stretching frequencies from 220 cm 1 (HS) to 375 cm 1 (LS) and from 252 cm 1 (HS) to 530 cm 1 (LS), respectively.…”

Section: Metal-ligand Vibrationsmentioning

confidence: 99%