Extending the range of pentasubstituted cyclopentadienyl compounds: The synthesis of a series of tetramethyl(alkyl or aryl)cyclopentadienes (Cp ∗ R ), their iridium complexes and their catalytic activity for asymmetric transfer hydrogenation

Morris, David; McGeagh, Michael; Peña, David De; Merola, Joseph S.

doi:10.1016/j.poly.2014.06.053

Cited by 35 publications

(35 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Cp* offers several advantages over Cp, beginning with the fact that it can be stored conveniently since it does not undergo Diels Alder dimerization . In mechanistic terms, the electron density of Cp*, imparted by the inductive effect of the methyl groups, is – compared to unsubstituted Cp – increased and contributes in general to an enhanced crystallizability and protection of the metal against reduction . Furthermore, the steric expansion of Cp* exerts a protective effect on the metal center and limits the accessibility of other ligands and substrate from this side.…”

Section: Introductionmentioning

confidence: 99%

A Precious Catalyst: Rhodium‐Catalyzed Formic Acid Dehydrogenation in Water

Fink

Laurenczy

2019

Eur J Inorg Chem

View full text Add to dashboard Cite

show abstract

Section: Introductionmentioning

confidence: 99%

A Precious Catalyst: Rhodium‐Catalyzed Formic Acid Dehydrogenation in Water

Fink

Laurenczy

2019

Eur J Inorg Chem

View full text Add to dashboard Cite

show abstract

“…On the basis of our previous studies, in which Cp* iridium complexes exhibited excellent catalytic activity [36][37][38][39][40][41][42][43][44][45][46][47], we attempted to modify one methyl group in the Cp* ligand to hydrogen, ethyl, isopropyl, and t-butyl groups in order to improve the catalytic properties (Scheme 2). A series of cyclopentadienyl-ligated iridium dichloride dimers 1a-1e were synthesized by the reaction of iridium trichloride with parent cyclopentadiene derivatives [62][63][64]. The structure of novel complex 1e was successfully identified by X-ray crystallographic analysis.…”

Section: Resultsmentioning

confidence: 99%

Effect of a Substituent in Cyclopentadienyl Ligand on Iridium-Catalyzed Acceptorless Dehydrogenation of Alcohols and 2-Methyl-1,2,3,4-tetrahydroquinoline

Jeong¹,

Shimbayashi²,

Fujita³

2019

Catalysts

View full text Add to dashboard Cite

New iridium(III)-bipyridonate complexes having cyclopentadienyl ligands with a series of alkyl substituents were synthesized for the purpose of tuning the catalytic activity for acceptorless dehydrogenation reactions. A comparison of the catalytic activity was performed for the reaction of alcoholic substrates such as 1-phenylethanol, 2-octanol, and benzyl alcohol. The 1-t-butyl-2,3,4,5-tetramethylcyclopentadienyl iridium complex exhibited the best performance, which surpassed that of the 1,2,3,4,5-pentamethylcyclopentadienyl (Cp*) iridium catalyst in the dehydrogenation reaction of alcohols. The catalytic activity in the dehydrogenation of 2-methyl-1,2,3,4-tetrahydroquinoline was also examined. The highest efficiency was obtained in the reaction catalyzed by the same t-butyl-substituted cyclopentadienyl iridium complex.

show abstract

“…Roswell Park Memorial Institute (RPMI‐1640) medium, trypsin and phosphate‐buffered saline (PBS) were purchased from Sigma‐Aldrich and Fisher Scientific, while 5‐(diethoxyphosphoryl)‐5‐methyl‐1‐pyrroline‐ N ‐oxide (DEPMPO) was purchased from Enzo Life Sciences (Farmingdale, NY, USA). Complexes [Ir(μ‐Cl)(η 5 ‐Cp ph )Cl] 2 and [Ir(η 5 ‐Cp ph )(phen)Cl]PF 6 ( 1‐Cl ) 5a were prepared using the modification of the reported procedures. The synthesis of silver(I) 4‐phenylbutyrate (AgPB) is described elsewhere …”

Section: Methodsmentioning

confidence: 99%

Cell‐based studies of the first‐in‐class half‐sandwich Ir(III) complex containing histone deacetylase inhibitor 4‐phenylbutyrate

Štarha

Trávníček

Drahoš

et al. 2018

Applied Organom Chemis

View full text Add to dashboard Cite

We report on a cytotoxic half-sandwich iridium(III) complex [Ir(η 5 -Cp ph )(phen) (PB)]PF 6 (1-PB), containing a monodentate coordinated O-donor 4phenylbutyrato ligand (PB) belonging to the family of histone deacetylase inhibitors (HDACi); HCp ph = (2,3,4,5-tetramethylcyclopenta-2,4-dien-1-yl)benzene, phen = 1,10-phenanthroline. The solution behaviour studies indicated that complex 1-PB partially hydrolysed in the mixture of methanol and water (1:4, v/v), resulting in the release of the PB ligand. The extent of the PB ligand release increased in the presence of 2 molar equiv. of the reduced glutathione (GSH). Complex 1-PB exhibited comparable in vitro cytotoxicity against the cisplatin-sensitive (IC 50 = 15.8 μM) and -resistant (IC 50 = 13.0 μM) variants of the A2780 human ovarian carcinoma cells, while its potency against the MRC-5 human normal fibroblast cells was markedly lower (IC 50 = 124.1 μM). The cytotoxicity studies revealed an ability of complex 1-PB to overcome the acquired resistance against cisplatin, with the resistance factor (RF = 0.8) being markedly lower than for complex 1-Cl (RF = 1.8) and cisplatin (RF = 2.9). The A2780 cell-based flow cytometry experiments showed different cell cycle modification induced by complex 1-PB and cisplatin, induction of production of reactive oxygen species, and higher mitochondria membrane potential depleted cell populations after the treatment by complex 1-PB as compared with cisplatin. In the cell-free assay, complex 1-PB inhibited the HDAC activity to ca 66% as compared to ca 74% valid for NaPB. The [Ir(η 5 -Cp ph )(phen)(H 2 O)] 2+ species (1-OH 2 ), representing the hydrolysis product of both complexes 1-PB and 1-Cl, induced hydroxyl radical from the hydrogen peroxide, as proved by the EPR spin trapping studies with the 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline-N-oxide (DEPMPO) spin trap.

show abstract

Extending the range of pentasubstituted cyclopentadienyl compounds: The synthesis of a series of tetramethyl(alkyl or aryl)cyclopentadienes (Cp ∗ R ), their iridium complexes and their catalytic activity for asymmetric transfer hydrogenation

Cited by 35 publications

References 47 publications

A Precious Catalyst: Rhodium‐Catalyzed Formic Acid Dehydrogenation in Water

A Precious Catalyst: Rhodium‐Catalyzed Formic Acid Dehydrogenation in Water

Effect of a Substituent in Cyclopentadienyl Ligand on Iridium-Catalyzed Acceptorless Dehydrogenation of Alcohols and 2-Methyl-1,2,3,4-tetrahydroquinoline

Cell‐based studies of the first‐in‐class half‐sandwich Ir(III) complex containing histone deacetylase inhibitor 4‐phenylbutyrate

Contact Info

Product

Resources

About