Dicarbonyldichloridobis(trimethylphosphane)iron(II)–carbonyldichloridotris(trimethylphosphane)iron(II)–tetrahydrofuran (1/1/2)

Rath, Nigam P.; Stouffer, Meghan; Janssen, Matthew K.; Bleeke, John R.

doi:10.1107/s1600536811009305

Cited by 2 publications

(1 citation statement)

References 5 publications

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“…As such, isomer A is the first metal complex that features TP as a PPP pincer-type ligand . This behavior is, however, in accord with the expected binding mode of three phosphine donors to an octahedral monocarbonyl iron(II) species . The two terminal phosphorus atoms P2 and P3 in isomer A (Figure ) are trans to each other with similar bond distances to the iron center (2.2547(9) Å for Fe1–P2 and 2.2422(9) Å for Fe1–P3), while the Fe1–P1 bond distance 2.1852(10) Å) is significantly shorter.…”

Section: Results and Discussionmentioning

confidence: 62%

Photo- and Thermal Isomerization of (TP)Fe(CO)Cl₂ [TP = Bis(2-diphenylphosphinophenyl)phenylphosphine]

Bruin

Reek

et al. 2015

Organometallics

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The title complex displayed structural flexibility via photo-and thermal-isomerization reactions between three isomers: (mer-TP)Fe(CO)Cl 2 (A), unsym-( fac-TP)Fe(CO)-Cl 2 (B), and sym-( fac-TP)Fe(CO)Cl 2 (C). Irradiation of A at RT with 525 nm light selectively produces B, while at 0°C isomer C is formed with the intermediacy of B. UV−vis spectroscopy combined with TD-DFT calculations revealed the nature of the photoisomerization process. Kinetics of the thermal isomerization of C to B and B to A have been studied with 31 P NMR spectroscopy in CD 2 Cl 2 , and activation parameters were determined. Isomers A and B have been isolated and crystallographically characterized. ■ INTRODUCTIONThe ability of molecules to change their shape upon external stimuli opens a variety of potential applications as molecular switches or machines. 1 In particular, the use of light as the switching factor has recently gained much interest in broad contexts spanning from biological applications to material science. 2 In coordination chemistry, much attention has been focused on steering the properties of the transition metal by switching the conformation of a photoactive substituent appended to the ligand. In this way properties such as spin state of the metal can be tuned. 3 The opposite situation in which the photoevent within the coordination sphere of the metal dictates the conformational change of the ligand is much less common. Examples are the reversible phototriggered change of denticity of polyamine ligands accompanied by (de)coordination of an auxiliary ligand 4 and mer-fac-isomerization of octahedral complexes with tridentate ligands. 5 In the latter case the denticity of the isomerized ligand does not change; that is, there is no net formation or breaking of bonds, which can be beneficial when rigidity of photoswitches is desired. It is noteworthy that so far all the examples of photochemical metaldictated conformational change of the ligand proceeded on noble metal centers. As such, the discovery of base-metal complexes that reveal such behavior would enable the development of a new class of low-cost photoswitches.In the context of our studies on photochemical proton reduction, 6,7 we discovered that the iron complex (TP)Fe-(CO)Cl 2 (TP = bis[2-(diphenylphosphino)phenyl]-phenylphosphine) undergoes light-induced isomerization from the mer-to fac-coordination mode of the tridentate TP ligand, followed by a slow thermal reisomerization. Here, we report the synthesis and structural characterization of the title complex, photoisomerization, and kinetic studies of the thermal-isomerization reactions. ■ RESULTS AND DISCUSSIONSynthesis and Characterization of (TP)Fe(CO)Cl 2 Complexes. (mer-TP)Fe(CO)Cl 2 (A) was synthesized in 92% yield by treating FeCl 2 ·4H 2 O with a stoichiometric amount of TP in a mixture of CH 2 Cl 2 and MeOH under an atmosphere of carbon monoxide in the dark. Spectroscopic analysis of A revealed the presence of a single carbonyl ligand, as evidenced by the IR absorption band at 1972 cm −1 , and a C s sym...

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Section: Results and Discussionmentioning

confidence: 62%

Photo- and Thermal Isomerization of (TP)Fe(CO)Cl₂ [TP = Bis(2-diphenylphosphinophenyl)phenylphosphine]

Bruin

Reek

et al. 2015

Organometallics

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Iron Complexes of 4,5-Bis(diorganophosphinomethyl)acridine Ligands

Roca Jungfer,

Rominger,

Oeser

et al. 2024

Inorg. Chem.

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The search for an iron analog of the established ruthenium-based catalysts containing methylene-extended 4,5bis(diorganophosphinomethyl)acridine ligands, [FeHCl(CO)-(L R )], resulted in the discovery of a bidentate coordination mode of these usually tridentate pincer ligands toward iron. The acridines nitrogen atom does not coordinate to iron, leading to the formation of iron diphos-type complexes with unusually large cis bite angles of up to 124°as well as trans bite angles around 155°. The iron-containing complexeshave been isolated in crystalline form and characterized by spectroscopic methods and mass spectrometry. Their structures were verified unambiguously through X-ray diffraction. The stability of the iron(II) complexes decreased in the order Cy > Ph > i Pr and Cl > Br > I, although all iron(II) complexes were found to be relatively stable enough for short-term handling in air in the solid state. Notably, no iron(0) complex of the phenyl derivative could be isolated. The iron(0) complex [Fe(CO) 3 (κ 2 -L Cy )] was found to be significantly more stable toward hydrolysis and oxygen compared to [Fe(CO) 3 (κ 2 -L iPr )] and can be stored in air for months without significant decomposition in the solid state, while [Fe(CO) 3 (κ 2 -L iPr )] decomposes in air within seconds. The decomposition products [FeI 2 (κ 2 -O 2 L Cy )], [{Fe(CO) 3 (κ 2 -HL R )} 2 ] (R = i Pr, Cy) and [FeCl 2 (CO) 2 (κ 1 -L Cy )(κ 1 -OL Cy )] were identified and characterized crystallographically. The iron(0) complex [Fe(CO) 3 (κ 2 -L Cy )] is oxidized by [Fe(Cp) 2 ](BPh 4 ) to give the paramagnetic, low-spin iron(I) cation [Fe(CO) 3 (κ 2 -L Cy )] + . The electron paramagnetic resonance spectrum of the highly sensitive cation as well as density functional theory calculations suggest a partial delocalization of the unpaired electron over the three carbonyl ligands and the acridines aromatic ring system. The catalytic activity and photophysical properties of the complexes have been preliminarily investigated.

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Dicarbonyldichloridobis(trimethylphosphane)iron(II)–carbonyldichloridotris(trimethylphosphane)iron(II)–tetrahydrofuran (1/1/2)

Cited by 2 publications

References 5 publications

Photo- and Thermal Isomerization of (TP)Fe(CO)Cl₂ [TP = Bis(2-diphenylphosphinophenyl)phenylphosphine]

Photo- and Thermal Isomerization of (TP)Fe(CO)Cl₂ [TP = Bis(2-diphenylphosphinophenyl)phenylphosphine]

Iron Complexes of 4,5-Bis(diorganophosphinomethyl)acridine Ligands

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Dicarbonyldichloridobis(trimethylphosphane)iron(II)–carbonyldichloridotris(trimethylphosphane)iron(II)–tetrahydrofuran (1/1/2)

Cited by 2 publications

References 5 publications

Photo- and Thermal Isomerization of (TP)Fe(CO)Cl2 [TP = Bis(2-diphenylphosphinophenyl)phenylphosphine]

Photo- and Thermal Isomerization of (TP)Fe(CO)Cl2 [TP = Bis(2-diphenylphosphinophenyl)phenylphosphine]

Iron Complexes of 4,5-Bis(diorganophosphinomethyl)acridine Ligands

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Photo- and Thermal Isomerization of (TP)Fe(CO)Cl₂ [TP = Bis(2-diphenylphosphinophenyl)phenylphosphine]

Photo- and Thermal Isomerization of (TP)Fe(CO)Cl₂ [TP = Bis(2-diphenylphosphinophenyl)phenylphosphine]