High-field Mössbauer spectroscopy on dinuclear iron(II) spin crossover complexes

Bauer, Thomas; Graf, Michèle; Kelm, Harald; Krüger, Hans‐Jörg; Schünemann, Volker

doi:10.1007/s10751-013-0914-6

Cited by 3 publications

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“…The 5 T 2g ground state of the investigated Fe(II) complexes in their HS configuration is split by a low-symmetry ligand field and spin–orbit coupling. Low-temperature high magnetic field 57 Fe Mössbauer spectroscopy and saturation magnetization measurements provide information about these interactions. ,,− We decided to apply these methods to [Fe(H 2 B(pz) 2 ) 2 (Me 2 -phen)] ( 6 ), as this complex is locked in the HS state (see above), which allows investigation of the 5 T 2g state and its magnetic properties at low temperatures without the need of populating a metastable HS state by light irradiation.…”

Section: Resultsmentioning

confidence: 99%

Electronic Structure, Vibrational Spectra, and Spin-Crossover Properties of Vacuum-Evaporable Iron(II) Bis(dihydrobis(pyrazolyl)borate) Complexes with Diimine Coligands. Origin of Giant Raman Features

et al. 2019

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The vibrational properties of spin-crossover complexes [Fe(H2B(pz)2)2(L)] (pz = pyrazole) containing L = 2,2′-bipyridine (bipy) and 1,10-phenanthroline (phen) ligands are investigated by temperature-dependent infrared and Raman spectroscopy. For comparison, the analogous cobalt(II) complexes [Co(H2B(pz)2)2(L)] (L = bipy and phen) and iron(II) compounds with L = 4,4′-dimethyl-2,2′-bipyridine and 4,7-dimethyl-1,10-phenanthroline coligands are studied. Highly intense, structured bands (giant Raman features, GRFs) are observed in the resonance Raman spectra of all Fe(II) complexes between 400 and 500 cm–1 at low temperatures in the HS state which, for the SCO complexes, is excited by the Raman laser. On the basis of magnetic field Mössbauer and saturation magnetization data electronic Raman effects are excluded to account for these features. Furthermore, detailed vibrational analysis also allows excluding a vibrational resonance Raman effect involving one of the modes of the individual complexes as a possible origin of the GRFs. Consequently, these features are attributed to coherent two-phonon excitation of metal–ligand stretching vibrations in molecular dimers coupled by π–π stacking interactions.

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Section: Resultsmentioning

confidence: 99%

Electronic Structure, Vibrational Spectra, and Spin-Crossover Properties of Vacuum-Evaporable Iron(II) Bis(dihydrobis(pyrazolyl)borate) Complexes with Diimine Coligands. Origin of Giant Raman Features

et al. 2019

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Determination of electronic ground state properties of a dinuclear iron(II) spin crossover complex

et al. 2016

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The dinuclear complex Me 2 )) 2 (BiBzIm)](ClO 4 ) 2 · 2EtCN (1) has been investigated by Mössbauer spectroscopy carried out in the temperature range from 5 to 150 K with externally applied magnetic fields of up to B = 5 T. By means of a consistent simulation of all experimental data sets within the Spin Hamiltonian formalism, the zerofield splitting D and the rhombicity parameter E/D of the ferrous high-spin (HS) site in this complex was determined to be D = −15.0 ± 1.0 cm −1 and E/D = 0.33 respectively. The sign of the quadrupole splitting of the HS site is positive which indicates that this iron site of the dinuclear complex 1 has an electronic ground state with the d xy orbital being twofold occupied.

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A luminescent Pt₂Fe spin crossover complex

et al. 2017

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A heterotrinuclear [PtFe] spin crossover (SCO) complex was developed and synthesized employing a ditopic bridging bpp-alkynyl ligand L and alkynyl coordinated Pt terpy units: [Fe(L-Pt)](BF) (1). We identified two different types of crystals of 1 which differ in their molecular packing and the number of co-crystallized solvent molecules: 1H (1·3.5CHCl in P1[combining macron]) and 1L (1·10CHCl in C2/c); while 1L shows a reversible SCO with a transition temperature of 268 K, the analogous compound 1H does not show any SCO and remains blocked in the HS state. The temperature-dependent magnetic properties of 1H and 1L were complementarily studied by Mössbauer spectroscopy. It has been shown that 1L performs thermal spin crossover and that 1L can be excited to a LIESST state. The vibrational properties of 1 were investigated by experimental nuclear resonance vibrational spectroscopy. The experimentally determined partial density of vibrational states (pDOS) was compared to a DFT-based simulation of the pDOS. The vibrational modes of the different components were assigned and visualized. In addition, the photophysical properties of 1 and L-Pt were investigated in the solid state and in solution. The ultrafast transient absorption spectroscopy of 1 in solution was carried out to study the PL quenching channel via energy transfer from photoexcited Pt terpy units to the Fe-moiety.

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High-field Mössbauer spectroscopy on dinuclear iron(II) spin crossover complexes

Cited by 3 publications

References 6 publications

Electronic Structure, Vibrational Spectra, and Spin-Crossover Properties of Vacuum-Evaporable Iron(II) Bis(dihydrobis(pyrazolyl)borate) Complexes with Diimine Coligands. Origin of Giant Raman Features

Electronic Structure, Vibrational Spectra, and Spin-Crossover Properties of Vacuum-Evaporable Iron(II) Bis(dihydrobis(pyrazolyl)borate) Complexes with Diimine Coligands. Origin of Giant Raman Features

Determination of electronic ground state properties of a dinuclear iron(II) spin crossover complex

A luminescent Pt₂Fe spin crossover complex

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High-field Mössbauer spectroscopy on dinuclear iron(II) spin crossover complexes

Cited by 3 publications

References 6 publications

Electronic Structure, Vibrational Spectra, and Spin-Crossover Properties of Vacuum-Evaporable Iron(II) Bis(dihydrobis(pyrazolyl)borate) Complexes with Diimine Coligands. Origin of Giant Raman Features

Electronic Structure, Vibrational Spectra, and Spin-Crossover Properties of Vacuum-Evaporable Iron(II) Bis(dihydrobis(pyrazolyl)borate) Complexes with Diimine Coligands. Origin of Giant Raman Features

Determination of electronic ground state properties of a dinuclear iron(II) spin crossover complex

A luminescent Pt2Fe spin crossover complex

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A luminescent Pt₂Fe spin crossover complex