Triphenylphosphite and ionic liquids: positive effects in the Heck cross-coupling reaction

Cárdenas, Juan C.; Fadini, Luca; Sierra, César A.

doi:10.1016/j.tetlet.2010.10.104

Cited by 17 publications

(7 citation statements)

References 16 publications

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“…This high selectivity can be attributed to the steric hindrance and electronic properties of the phosphite ligand, which results in an enhanced orientation control of the substrates during the C–C coupling step and also in an improvement of the catalytic cycle kinetics. Moreover, the phosphite ligand confers to the Pd in the catalyst high stability, preventing the aggregation and precipitation of Pd(0) black . Spectroscopic characterization confirms the trans–trans configuration of this compound (see the Supporting Information).…”

Section: Resultsmentioning

confidence: 73%

Nature of Color Diversity in Phenylenevinylene-Based Polymorphs

Cárdenas

Aguirre-Díaz

Galindo

et al. 2019

Crystal Growth & Design

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In this work we present a joint experimental and theoretical study of the light emitting properties of (E,E)-2,5-dimethoxy-1,4-bis[2-(4-carboxylatestyryl)]benzene, a phenylenevinylene (PV, from now on) derivative in the solid state. Careful crystal growth under different conditions of this PV luminophore yields three different crystals with dissimilar color emissions with maxima ranging between 504 and 565 nm. Single crystal structure elucidations indicate that they correspond to a DMF solvate, denoted 2·DMF (yellow) and two conformational polymorphs named 2α (yellow) and 2β (orange). Analysis of the close contacts and the framework topologies help us to rationalize the different colors observed, not only on the basis of different intramolecular conformations but also of the different intermolecular interactions observed. Particularly, the presence of different C–H···π and π···π interactions in 2α and in 2β polymorphs, respectively, give rise to different supramolecular frameworks with hex and bcu topologies. Theoretical studies reinforce the hypothesis that cooperative π···π interactions in the crystal lattice are responsible for the red-shifted color observed in the polymorph 2β. In fact, in contrast to what is observed with the polymorph 2α, as we incorporate more monomers in the calculations of the optical properties of polymorph 2β, the estimated energy for the vertical excitation from the ground state to the first excited state moves to lower values.

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Section: Resultsmentioning

confidence: 73%

Nature of Color Diversity in Phenylenevinylene-Based Polymorphs

Cárdenas

Aguirre-Díaz

Galindo

et al. 2019

Crystal Growth & Design

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“…Unfortunately, though the reaction conditions are usually simple and there are no specific structural limitations for the precursors, most of the literature reported for the synthesis of PPVs with this methodology produced polymers with very low molecular weights [23,24]. However, many advances in the development of catalytic systems have been employed to improve the degree of polymerization under this protocol [25][26][27][28]. Notably, the most important feature of this reaction is that it allows obtaining configurationally pure trans PPVs.…”

Section: The Mizoroki-heck Reactionmentioning

confidence: 99%

“…As an example of the development of the oligomer approach, in order to solve the problem of low molecular weights obtained in the polymerization of PPVs through the Heck reaction reported by many research groups around the world [22], recent investigations showed that the use of a catalytic system composed of triphenylphosphite and Pd(dba) 2 in the presence of ionic liquids, significantly increases the reaction yields during the synthesis of oPVs and shows the catalyst reusability throughout several cycles [25]. Thus, these reaction conditions were applied to synthesize several oPVs [26][27][28] and according to the results obtained regarding the reaction yields as well as the optoelectronic properties, a segmented PPV with a degree of polymerization close to 20 (twice superior the size obtained previously with conventional Heck conditions) was obtained [27].…”

Section: The Oligomer Approachmentioning

confidence: 99%

Phenylenevinylene Systems: The Oligomer Approach

Cárdenas¹,

Ochoa‐Puentes²,

Sierra³

2016

Conducting Polymers

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Among conducting polymers, poly-p-phenylenevinylenes (PPVs) have attained a special place in polymer electronics. The optoelectronic properties initially exposed by PPVs in organic light-emitting diodes (OLEDs) turned these organic electronic conjugated systems from the solo academic interest into a technologically very promising area. The easiness of the tuning of their optoelectronic properties through synthetic modifications make PPVs an outstanding and suitable compound for technological applications and fundamental science development. Unfortunately, the synthesis and structural optoelectronic characterization of novel PPVs is a long and difficult task that sometimes yields unclear results. However, phenylenevinylene oligomers (oPV) can be synthesized and characterized in a very straightforward manner, and their performance in novel applications can be directly related to their structural analogue polymer, methodology designated as the oligomer approach. Herein, we describe the oligomer approach using the Mizoroki-Heck reaction as a synthetic route for oPVs and PPVs, and the importance of an extensive characterization for novel applications, such as photocatalysis and matrix-assisted laser desorption/ionization (MALDI) matrices, where these electronic conjugated systems have very promising applications.

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“…The present work introduces an alternative route to OPVs based on the Heck reaction. Heck coupling is shown to be a suitable approach for creating all-trans OPV-linkers [16] with improved yields and lower reagent costs relative to conventional methods.…”

Section: Introductionmentioning

confidence: 99%