Product distributions in the addition of the hydride ion to cyclopentadienyliron complexes of substituted benzenes

Sutherland, R. G.; Zhang, C.H.; Chowdhury, Ratan; Piórko, Adam; Lee, C.C.

doi:10.1016/s0022-328x(00)99813-9

Cited by 21 publications

(8 citation statements)

References 11 publications

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“…Once this information was obtained, I3C chemical shifts were then assigned using CH COSY. It has been established that a phenoxy substituent attached to the arene CpFef complex directs the addition of the nucleophile to meta > ortho > para, whereas a methyl substituent directs ortho > meta >para (29)(30)(31)(32)37). In this study, it was very clear that the phenoxy substituent has a stronger influence on the site of addition than has the methyl substituent due to its greater strength as an electron-donating group.…”

Section: Resultsmentioning

confidence: 78%

“…Sutherland et al examined the hydride addition reactions of various substituted. [(C6H,X)FeCpIf systems (37). This study demonstrated that strongly electrondonating substitutents direct hydride addition to the meta and para positions of the substituent, while the strongly electronwithdrawing substituent directs to the ortho position.…”

Section: Introductionmentioning

confidence: 67%

“…Due to the complexity of the NMR spectra of these adducts, the mono-iron systems were used as models for this investigation. While hydride addition to CpFef complexes of monosubstituted arenes has been carefully examined (37), hydride addition to disubstituted arene complexes has not been reported. Reactions of (q6-isomeric phenoxytoluene-r(s-cyclopentadienyliron) cations with an excess of sodium borohydride gave rise to a mixture of adducts, as illustrated in Scheme 1.…”

Section: Resultsmentioning

confidence: 99%

“…However, cyanide addition did not display the same sensitivity to steric factors; addition in this case occurred in the ortho position only. It was proposed that steric, electronic, and free valency effects all play a role in nucleophilic addition reactions (32,37).…”

Section: Introductionmentioning

confidence: 99%

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Nucleophilic addition to di- and poly-iron arene complex cations

Abd‐El‐Aziz¹,

Armstrong²,

Bernardin³

et al. 1996

Can. J. Chem.

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Abstract:Hydride and cyanide addition to a series of di-and polycyclopentadienyliron arene complex cations with etheric bridges is described. Reaction of the di-iron complexes with sodium borohydride resulted in the formation of a number of adducts. p-Methyl-and o,o-dimethylphenoxybenzene cyclopentadienyliron complexes were used as models in this study to allow for the characterization of the analagous di-iron complexes. The use of HH COSY and CH COSY NMR techniques enabled us to identify the isomeric nature of these adducts. The hydride addition results indicated that the etheric substituent had the predominant effect over the methyl group, leading to a higher addition ratio to the meta-, followed by the ortho-, then the para-positions. It was also clear that in the di-iron system, the hydride addition to each complexed arene ring took place independently. The addition of the cyanide anion to di-and poly-iron arene systems was more selective than that of the hydride anion. Reaction of sodium cyanide with p-methyl-or o-methyl-substituted arene complexes led to the formation of one adduct, with the cyanide being added to the meta position to the etheric bridges. However, cyanide addition to the di-iron complex, with a methyl substituent attached at the meta position of each complexed arene, led to the formation of a mixture of adducts. Cyanide addition to the poly-iron system withp-substituted arenes proved to be very selective, allowing for the formation of one adduct.Oxidative demetallation with 2,3-dichloro-5,6-dicyano-1.4-benzoquinone (DDQ) produced the uncomplexed polyaromatic ethers with cyano groups in a very good yield. des Cthers polyaromatiques non complexCs portant des groupes cyano.

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Section: Resultsmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 67%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nucleophilic addition to di- and poly-iron arene complex cations

Abd‐El‐Aziz¹,

Armstrong²,

Bernardin³

et al. 1996

Can. J. Chem.

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“…Similarly, reduction of 1′ provides the neutral compound [(η 5 -cyclopentadienyl)Fe(η 5 -methylcyclohexadienyl)] ( 2′ ). 30 In contrast to 1 and 1′ , complexes 2 and 2′ are highly soluble in aliphatic media and can even be dissolved in alkyd resin without additional solvent. Upon mixing a heptane solution of 2 or 2′ with Setal-270, a fast color change from red to yellow takes place, suggesting aerobic oxidation of the neutral complex to the cationic complex at room temperature.…”

Section: Results and Discussionmentioning

confidence: 99%

Photoactive Fe Catalyst for Light-Triggered Alkyd Paint Curing

Bootsma

Browne

Flapper

et al. 2022

JACS Au

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Herein, we show that the photoactive complexes [(Cp)Fe(arene)] + (Cp = cyclopentadienyl; arene = C 6 H 6 , C 6 H 5 Me) act as latent catalysts that allow for photochemical control over the onset of alkyd paint curing, without the need for antiskinning agents such as the volatile 2-butanone oxime normally used to prevent curing during paint storage. The highly soluble neutral complexes [(Cp)Fe(Ch)] and [(Cp)Fe(Ch′)] (Ch = cyclohexadienyl, Ch′ = methylcyclohexadienyl) readily convert to the photoactive complexes [(Cp)Fe(arene)] + upon oxidation in alkyd, allowing the latter to be dosed in a wide range of concentrations. Infrared and Raman studies show similar spectral changes of the alkyd paint matrix as have been observed in alkyd curing mediated by well-known, industrially applied cobalt- and manganese-based catalyst Co(neodecanoate) 2 and [(Me 3 TACN) 2 Mn 2 (μ-OOCR) 3 ](OOCR). The [(Cp)Fe(Ch)]/[(Cp)Fe(arene)] + system performs equally well as these cobalt- and manganese-based catalysts in terms of drying time and outperform the manganese catalyst by showing a hardness development (increase) similar to that of the cobalt-based catalyst. Based on electron paramagnetic resonance and light–activity studies, we propose that photolysis of [(Cp)Fe(arene)] + generates short-lived active Fe II species, explaining the desired latency. The [(Cp)Fe(Ch)]/[(Cp)Fe(arene)] + alkyd curing systems presented herein are unique examples of intrinsically latent paint curing catalysts that (1) are based on an abundant and harmless transition metal (Fe), (2) do not require any antiskinning agents, and (3) show favorable performance in terms of drying times and hardness development.

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Benzene(cyclopentadienyl)iron Hexafluorophosphate

Pike

2001

Encyclopedia of Reagents for Organic Synthesis

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Product distributions in the addition of the hydride ion to cyclopentadienyliron complexes of substituted benzenes

Cited by 21 publications

References 11 publications

Nucleophilic addition to di- and poly-iron arene complex cations

Nucleophilic addition to di- and poly-iron arene complex cations

Photoactive Fe Catalyst for Light-Triggered Alkyd Paint Curing

Benzene(cyclopentadienyl)iron Hexafluorophosphate

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