Reaction of [Fe2(CO)8(μ-CF2)] with AsMe3and Other Lewis Bases:  Syntheses, Crystal Structures of [Fe(CO)6(AsMe3)2(μ-CF2)] and [Fe(CO)5(AsMe3)3(μ-CF2)], and Theoretical Considerations

DelaVarga, Meritxell; Petz, Wolfgang; Neumüller, Bernhard; Costa, Ramon

doi:10.1021/ic0604011

Cited by 8 publications

(3 citation statements)

References 59 publications

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“… a Experimental ground states obtained from references − . b All compounds were optimized in water using the PCM, while [Fe(Me–Lt) 2 ] 2+ was optimized in vacuum. …”

Section: Resultsmentioning

confidence: 99%

Low-Spin versus High-Spin Ground State in Pseudo-Octahedral Iron Complexes

2012

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Pseudo-octahedral complexes of iron find applications as switches in molecular electronic devices, materials for data storage, and, more recently, as candidates for dye-sensitizers in dye-sensitized solar cells. Iron, as a first row transition metal, provides a weak ligand-field splitting in an octahedral environment. This results in the presence of low-lying (5)T excited states that, depending on the identity of iron ligands, can become the ground state of the complex. The small energy difference between the low-spin, (1)A, and high-spin, (5)T, states presents a challenge for accurate prediction of their ground state using density functional theory. In this work, we investigate the applicability of the B3LYP functional to the ground state determination of first row transition metal complexes, focusing mainly on Fe(II) polypyridine complexes with ligands of varying ligand field strength. It has been shown previously that B3LYP artificially favors the (5)T state as the ground state of Fe(II) complexes, and the error in the energy differences between the (1)A and (5)T states is systematic for a set of structurally related complexes. We demonstrate that structurally related complexes can be defined as pseudo-octahedral complexes that undergo similar distortion in the metal-ligand coordination environment between the high-spin and low-spin states. The systematic behavior of complexes with similar distortion can be exploited, and the ground state of an arbitrary Fe(II) complex can be determined by comparing the calculated energy differences between the singlet and quintet electronic states of a complex to the energy differences of structurally related complexes with a known, experimentally determined ground state.

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“… a Experimental ground states obtained from references − . b All compounds were optimized in water using the PCM, while [Fe(Me–Lt) 2 ] 2+ was optimized in vacuum. …”

Section: Resultsmentioning

confidence: 99%

Low-Spin versus High-Spin Ground State in Pseudo-Octahedral Iron Complexes

2012

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“…Bond angles and bond lengths are comparable to those found in previously characterized compounds like [Fe(phen) 3 ]Cl 2 for example. 25 The FeSe 4 core of the anion is slightly more distorted (Se(1)-Fe(1)-Se(3) 98.76(4)-Se(3)-Fe(1)-Se(4) 118.25(4) • ) than the one observed in (NEt 4 ) 2 [Fe(SePh) 4 ] (103.6-114.9 • ) 26 while the Fe-Se bond lengths are similar.…”

Section: Synthesis and Structurementioning

confidence: 99%

Homoleptic 1-D iron selenolate complexes—synthesis, structure, magnetic and thermal behaviour of 1∞[Fe(SeR)2] (R = Ph, Mes)

Eichhöfer

Buth

Dolci³

et al. 2011

Dalton Trans.

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The first examples of polymeric homoleptic iron chalcogenolato complexes (1)(∞)[Fe(SePh)(2)] and (1)(∞)[Fe(SeMes)(2)] (Ph = phenyl = C(6)H(5), Mes = mesityl = C(6)H(2)-2,4,6-(CH(3))(3)) have been both prepared by reaction of [Fe(N(SiMe(3))(2))(2)] with two equivalents of HSeR (R = Ph, Mes) while (1)(∞)[Fe(SePh)(2)] was found to be also easily accessible through reactions of either FeCl(2), Fe(OOCCH(3))(2) or FeCl(3) with PhSeSiMe(3) in THF. In the crystal, the two compounds form one-dimensional chains with bridging selenolate ligands comprising distinctly different Fe-Se-Fe bridging angles, namely 71.15-72.57° in (1)(∞)[Fe(SePh)(2)] and 91.80° in (1)(∞)[Fe(SeMes)(2)]. Magnetic measurements supported by DFT calculations reveal that this geometrical change has a pronounced influence on the antiferromagnetic exchange interactions of the unpaired electrons along the chains in the two different compounds with a calculated magnetic exchange coupling constant of J = -137 cm(-1) in (1)(∞)[Fe(SePh)(2)] and J = -20 cm(-1) in (1)(∞)[Fe(SeMes)(2)]. In addition we were able to show that the ring molecule [Fe(SePh)(2)](12) which is a structural isomer of (1)(∞)[Fe(SePh)(2)] behaves magnetically similar to the latter one. Investigations by powder XRD reveal that the ring molecule is only a metastable intermediate which converts in THF completely to form (1)(∞)[Fe(SePh)(2)]. Thermal gravimetric analysis of (1)(∞)[Fe(SePh)(2)] under vacuum conditions shows that the compound is thermally labile and already starts to decompose above 30 °C in a two step process under cleavage of SePh(2) to finally form at 250 °C tetragonal PbO-type FeSe. The reaction of (1)(∞)[Fe(SePh)(2)] with the Lewis base 1,10-phenanthroline yielded, depending on the conditions, the octahedral monomeric complexes [Fe(SePh)(2)(1,10-phen)(2)] and [Fe(1,10-phen)(3)][Fe(SePh)(4)].

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“…For example, it is generally agreed that 2,2′-bipyridine (bpy) and 1,10-phenantroline (phen) act as π-acceptors that lower the energy of the metal’s t 2 g orbitals, thus increasing the ligand-field splitting. Indeed, their tris-homoleptic complexes, such as [Fe(phen) 3 ]Cl 2 , are found almost exclusively in the LS state. In contrast, the tris-homoleptic Fe(II) complexes of 2,2′-biimidazole (bim), such as [Fe(bim) 3 ](SO 4 ), are always found in the HS state, due to the weaker π-accepting ability of the five-member rings in the bim ligand.…”

Section: Introductionmentioning

confidence: 99%

A Simple Approach for Predicting the Spin State of Homoleptic Fe(II) Tris-diimine Complexes

et al. 2017

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We propose a simple method for predicting the spin state of homoleptic complexes of the Fe(II) d ion with chelating diimine ligands. The approach is based on the analysis of a single metric parameter within a free (noncoordinated) ligand: the interatomic separation between the N-donor metal-binding sites. An extensive analysis of existing complexes allows the determination of critical N···N distances that dictate the regions of stability for the high-spin and low-spin complexes, as well as the intermediate range in which the magnetic bistability (spin crossover) can be observed. The prediction has been tested on several complexes that demonstrate the validity of our method.

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Reaction of [Fe₂(CO)₈(μ-CF₂)] with AsMe₃and Other Lewis Bases: Syntheses, Crystal Structures of [Fe(CO)₆(AsMe₃)₂(μ-CF₂)] and [Fe(CO)₅(AsMe₃)₃(μ-CF₂)], and Theoretical Considerations

Cited by 8 publications

References 59 publications

Low-Spin versus High-Spin Ground State in Pseudo-Octahedral Iron Complexes

Low-Spin versus High-Spin Ground State in Pseudo-Octahedral Iron Complexes

Homoleptic 1-D iron selenolate complexes—synthesis, structure, magnetic and thermal behaviour of 1∞[Fe(SeR)2] (R = Ph, Mes)

A Simple Approach for Predicting the Spin State of Homoleptic Fe(II) Tris-diimine Complexes

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