A chiral “Siamese-Twin” calix[4]pyrrole tetramer

Galán, Albano; Aragay, Gemma; Ballester, Pedro J.

doi:10.1039/c6sc01843b

Cited by 16 publications

(7 citation statements)

References 36 publications

(25 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A few years ago, we reported the synthesis of the α,α,α,α isomer of tetra-p-iodopheny tetra-methyl calix [4]pyrrole in an overall yield of 16% [15]. Owing to the versatile and easy synthetic transformation of this molecular scaffold into a variety of super-aryl extended calix [4]pyrrole derivatives [16,17], we sought to optimize its preparation in a multigram scale.…”

Section: Synthesismentioning

confidence: 99%

See 1 more Smart Citation

Synthesis, X-ray Characterization and Density Functional Theory (DFT) Studies of Two Polymorphs of the α,α,α,α, Isomer of Tetra-p-Iodophenyl Tetramethyl Calix[4]pyrrole: On the Importance of Halogen Bonds

et al. 2020

Self Cite

View full text Add to dashboard Cite

This manuscript reports the improved synthesis of the α,α,α,α isomer of tetra-p-iodophenyl tetra-methyl calix[4]pyrrole and the X-ray characterization of two solvate polymorphs. In the solid state, the calix[4]pyrrole receptor adopts the cone conformation, including one acetonitrile molecule in its aromatic cavity by establishing four convergent hydrogen bonds between its nitrogen atom and the four pyrrole NHs of the former. The inclusion complexes pack into rods, displaying a unidirectional orientation. In turn, the rods form flat 2D-layers by alternating the orientation of their p-iodo substituents. The 2D layers stack on top of another, resulting in a head-to-head and tail-to-tail orientation of the complexes or their exclusive arrangement in a head-to-tail geometry. The dissimilar stacking of the layers yields two solvate polymorphs that are simultaneously present in the structures of the single crystals. The ratio of the two polymorph phases is regulated by the amount of acetonitrile added to the chloroform solutions from which the crystals grow. Halogen bonding interactions are highly relevant in the crystal lattices of the two polymorphs. We analyzed and characterized these interactions by means of density functional theory (DFT) calculations and several computational tools. Remarkably, single crystals of a solvate containing two acetonitrile molecules per calix[4]pyrrole were obtained from pure acetonitrile solution.

show abstract

Section: Synthesismentioning

confidence: 99%

“…The tetra-α isomer of the tetra-p-iodophenyl calix [4]pyrrole was synthesized using a modified procedure from the on reported in literature [15]. The new synthetic procedure is described in detail in the synthesis section of this paper and in the Supplementary Information, which also contains the spectral data of the compound.…”

Section: Materials and Techniquesmentioning

confidence: 99%

Synthesis, X-ray Characterization and Density Functional Theory (DFT) Studies of Two Polymorphs of the α,α,α,α, Isomer of Tetra-p-Iodophenyl Tetramethyl Calix[4]pyrrole: On the Importance of Halogen Bonds

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…5,[28][29][30] However, few examples of multi (more than two) calixpyrrole systems have been described to date, especially if we exclude examples in which calixpyrrole units were grafted onto either polymers or surfaces. Notable examples of multicalixpyrrole structures (three or more calix units) have been reported by Ballester 31 , Aoyan 32 and Kohnke. 33 As part of our work on the host-guest chemistry of bis-and tris-calix [4]pyrrole 27,33 receptors, we identified the anti-and syn-meso-1,3-(4-hydroxyphenyl)calix [4]pyrroles (anti-5 and syn-5 in Scheme 1) first reported by Lee 34 as useful precursors for the assembly of multi-component structures.…”

Section: Introductionmentioning

confidence: 95%

Rings of rings: calixpyrrole cyclotrimers

Saidi¹,

Kohnke²,

Ponassi³

et al. 2021

Arkivoc

View full text Add to dashboard Cite

Calixpyroles are a class of heteromacrocycles that have been a topic of considerable interest over the last two decades due to their rich host-guest chemistry as receptors for anions. A number of structures comprising more than one calixpyrrole unit have been reported as multitopic and multivalent receptors. Here we report the first syntheses of cyclotrimeric structures containing calixpyrrole rings (hence rings of rings) that can be obtained by the cyclo-oligomerization of either cis-or trans-1, 3-meso-4-hydoxyphenyl-calix[4]pyrrole with 1,5dichloro-2,4-dinitrobenzene via aromatic nucleophilic substitution reactions. The novel structures appear intriguing candidates for prospective molecular recognition studies.

show abstract

“…Moreover, the macrocyclization reaction might suffer, in some cases, from low reproducibility. 30,31 Over the last 15 years, our research group focused on the design and synthesis of AE-C[4]P receptors for the selective and efficient binding of anions, ion-pairs, and neutral polar molecules. In this Account, we discuss the binding properties of "two-wall" and "four-wall" AE-C [4]Ps and their derivatives, such as AE-C[4]P cavitands and super aryl-extended C [4]Ps (SAE-C[4]Ps).…”

Section: Introductionmentioning

confidence: 99%

Aryl-Extended and Super Aryl-Extended Calix[4]pyrroles: Design, Synthesis, and Applications

2023

Self Cite

View full text Add to dashboard Cite

Conspectus Proteins exhibit high-binding affinity and selectivity, as well as remarkable catalytic performance. Their binding pockets are hydrophobic but also contain polar and charged groups to contribute to the binding of polar organic molecules in aqueous solution. In the past decades, the synthesis of biomimetic receptors featuring sizable aromatic cavities equipped with converging polar groups has received considerable attention. “Temple” cages, naphthotubes, and aryl-extended calix[4]pyrroles are privileged examples of synthetic scaffolds displaying functionalized hydrophobic cavities capable of binding polar substrates. In particular, calix[4]pyrroles are macrocycles containing four pyrrole rings connected through their pyrrolic 2- and 5-positions by tetra-substituted sp3 carbon atoms (meso-substituents). In 1996, Sessler introduced the meso-octamethyl calix[4]pyrrole as an outstanding receptor for anion binding. Independently, Sessler and Floriani also showed that the introduction of aryl substituents in the meso-positions produced aryl-extended calix[4]pyrroles as a mixture of configurational isomers. In addition, aryl-extended calix[4]pyrroles bearing two and four meso-aryl substituents (walls) were reported. The cone conformation of “two-wall” αα-aryl-extended calix[4]pyrroles features an aromatic cleft with a polar binding site defined by four converging pyrrole NHs. On the other hand, “four-wall” αααα-calix[4]pyrrole isomers possess a deep polar aromatic cavity closed at one end by the converging pyrrole NHs. Because of their functionalized interior, aryl-extended calix[4]pyrroles are capable of binding anions, ion-pairs, and electron-rich neutral molecules in organic solvents. However, in water, they are restricted to the inclusion of neutral polar guests. Since the early 2000s, our research group has been involved in the design and synthesis of “two-wall” and “four-wall” aryl-extended calix[4]pyrroles and their derivatives, such as aryl-extended calix[4]pyrrole cavitands and super aryl-extended calix[4]pyrroles. In this Account, we mainly summarize our own results on the binding of charged and neutral polar guests with these macrocyclic receptors in organic solvents and in water. We also describe the applications of calix[4]pyrrole derivatives in the sensing of creatinine, the facilitated transmembrane transport of anions and amino acids, and the monofunctionalization of bis-isonitriles. Moreover, we explain the use of calix[4]pyrrole receptors as model systems for the quantification of anion−π interactions and the hydrophobic effect. Finally, we discuss the self-assembly of dimeric capsules and unimolecular metallo-cages based on calix[4]pyrrole scaffolds. We comment on their binding properties, as well as on those of bis-calix[4]pyrroles having a fully covalent structure. In molecular recognition, aryl-extended calix[4]pyrroles and their derivatives are considered valuable receptors owing to their ability to interact with a wide variety of electron-rich, neutral, and charged guests. Calix[4]pyrro...

show abstract

A chiral “Siamese-Twin” calix[4]pyrrole tetramer

Abstract: We describe our results in the attempted template syntheses of oligomacrocycle calix[4]pyrrole dimer 4, using Hay coupling reaction conditions, tetraalkynyl calix[4]pyrrole 5 as starting material and two bipyridyl N-oxides of different length as templates.

Cited by 16 publications

References 36 publications

Synthesis, X-ray Characterization and Density Functional Theory (DFT) Studies of Two Polymorphs of the α,α,α,α, Isomer of Tetra-p-Iodophenyl Tetramethyl Calix[4]pyrrole: On the Importance of Halogen Bonds

Synthesis, X-ray Characterization and Density Functional Theory (DFT) Studies of Two Polymorphs of the α,α,α,α, Isomer of Tetra-p-Iodophenyl Tetramethyl Calix[4]pyrrole: On the Importance of Halogen Bonds

Rings of rings: calixpyrrole cyclotrimers

Aryl-Extended and Super Aryl-Extended Calix[4]pyrroles: Design, Synthesis, and Applications

Contact Info

Product

Resources

About