Post-synthetic modification of a macrocyclic receptor via regioselective imidazolium ring-opening

Jia, Shang; Rambo, Brett M.; Hao, Xiang; Xiang, Junfeng; Gong, Hongmei; Sessler, Jonathan L.

doi:10.1039/c5sc04860e

Cited by 14 publications

(6 citation statements)

References 107 publications

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“…Previous work with 1 4+ revealed that treatment with hydroxide anion could lead to irreversible imidazolium ring opening and destruction of the macrocycle. 42 Decomposition of [TxSB-CO 2 H] 4+ was seen when it was treated with tetrabutylammonium hydroxide (TBAOH) in DMSO-d 6 or with TEA in D 2 O base (see SI, Figures S17 and S18). The fully deprotonated form, TxSB-CO 2…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Supramolecular Properties of a Monocarboxylic Acid-Functionalized “Texas-Sized” Molecular Box

Chi

Hirao

et al. 2018

J. Am. Chem. Soc.

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A new carboxylic acid-functionalized "Texas-sized" molecular box TxSB-COH has been prepared by combining two separate building blocks via an iodide-catalyzed macrocyclization reaction. A single-crystal X-ray diffraction analysis revealed a paired "clip-like" dimer in the solid state. Concentration-dependent behavior is seen for samples of TxSB-COH as prepared, as inferred from H NMR spectroscopic studies carried out in DMSO- d. However, in the presence of excess acid (1% by weight of deuterated trifluoracetic acid; TFA- d), little evidence of aggregation is seen in DMSO- d except at the highest accessible concentrations. In contrast, the conjugate base form, TxSB-CO, produced in situ via the addition of excess triethylamine to DMSO- d solutions of TxSB-COH acts as a self-complementary monomer that undergoes self-assembly to stabilize a formal oligomer ([TxSB-CO] ) with a degree of polymerization of approximately 5-6 at a concentration of 70 mM. Evidence in support of the proposed oligomerization of TxSB-CO in solution and in the solid state came from one- and two-dimensional H NMR spectroscopy, X-ray crystallography, dynamic light scattering (DLS), and scanning electron microscopy (SEM). A series of solution-based analyses carried out in DMSO and DMSO- d provide support for the notion that the self-assembled constructs produced from TxSB-CO are responsive to environmental stimuli, including exposure to the acetate anion (as its tetrabutylammonium, TBA, salt), and changes in overall concentration, temperature, and protonation state. The resulting transformations are thought to reflect the reversible nature of the underlying noncovalent interactions. They also permit the stepwise interconversion between TxSB-COH and [TxSB-CO] via the sequential addition of triethylamine and TFA- d. The present work thus serves to illustrate how appropriately functionalized molecular box-type macrocycles may be used to develop versatile stimuli-responsive materials. It also highlights how aggregated forms seen in the solid state are not necessarily retained under competitive solution-phase conditions.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Supramolecular Properties of a Monocarboxylic Acid-Functionalized “Texas-Sized” Molecular Box

Chi

Hirao

et al. 2018

J. Am. Chem. Soc.

Self Cite

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“…116,153 The type of novel receptors exhibit binding affinity toward the anion due to the presence of hydrogen bonds and electrostatic interactions. 154,155 Following most host−guest systems, imidazolium macrocyclic receptors are notably fascinating for the construction of supramolecular adhesive hydrogels. Sessler et al developed another multifluorescent supramolecular polymeric hydrogel containing tetracationic receptor-anion recognition motifs and gel-specific fluorophores.…”

Section: Macrocyclic Host-molecule-functionalized Adhesive Hydrogelsmentioning

confidence: 99%

“…In addition to the above-mentioned synthetic macrocycles, macrocyclic anions are ubiquitous, and they have attracted considerable attention in the fields of recognition, extraction, catalysis, transport, and so on. Among all macrocyclic anions, imidazolium macrocyclic receptors have been extensively studied since at least 1999. , The type of novel receptors exhibit binding affinity toward the anion due to the presence of hydrogen bonds and electrostatic interactions. , Following most host–guest systems, imidazolium macrocyclic receptors are notably fascinating for the construction of supramolecular adhesive hydrogels. Sessler et al developed another multifluorescent supramolecular polymeric hydrogel containing tetracationic receptor-anion recognition motifs and gel-specific fluorophores .…”

Section: Adhesive Hydrogels Based On Supramolecular Strategiesmentioning

confidence: 99%

Supramolecular Adhesive Hydrogels for Tissue Engineering Applications

et al. 2022

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Tissue engineering is a promising and revolutionary strategy to treat patients who suffer the loss or failure of an organ or tissue, with the aim to restore the dysfunctional tissues and enhance life expectancy. Supramolecular adhesive hydrogels are emerging as appealing materials for tissue engineering applications owing to their favorable attributes such as tailorable structure, inherent flexibility, excellent biocompatibility, near-physiological environment, dynamic mechanical strength, and particularly attractive self-adhesiveness. In this review, the key design principles and various supramolecular strategies to construct adhesive hydrogels are comprehensively summarized. Thereafter, the recent research progress regarding their tissue engineering applications, including primarily dermal tissue repair, muscle tissue repair, bone tissue repair, neural tissue repair, vascular tissue repair, oral tissue repair, corneal tissue repair, cardiac tissue repair, fetal membrane repair, hepatic tissue repair, and gastric tissue repair, is systematically highlighted. Finally, the scientific challenges and the remaining opportunities are underlined to show a full picture of the supramolecular adhesive hydrogels. This review is expected to offer comparative views and critical insights to inspire more advanced studies on supramolecular adhesive hydrogels and pave the way for different fields even beyond tissue engineering applications.

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“…Macrocycle synthesis relies on one of the approaches depicted in Figure 1. The statistical approach proceeds under kinetic control and yields mixtures of linear and cyclic oligomers; [15] template‐assisted syntheses operate under thermodynamic control, favoring one particular ring; [16] and post‐synthetic modifications serve to alter preassembled rings [17, 18] . Although these approaches are used disjointedly, we envisioned that by applying all three in tandem, a single precursor—the tether—could be transformed into multiple rings.…”

Section: Figurementioning

confidence: 99%

Cycling a Tether into Multiple Rings: Pt‐Bridged Macrocycles for Differentiated Guest Recognition, Pseudorotaxane Transformations, and Guest Capture and Release

et al. 2022

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Macrocycle engineering is a key topic in supramolecular chemistry. When synthesizing a ring, one can obtain either complex mixtures of macrocycles of different sizes or a single ring if a template is utilized. Here, we unite these approaches along with postsynthetic modifications to transform a single tether into multiple rings-up to five per tether. The macrocycles contain two bridged phenylpyridine ligands that are connected through a Pt atom, which defines the rings' shape, size, and host activity. All rings undergo redox reactions (between Pt II and Pt IV ) that allow for large conformational changes. Their reactivity, together with their host performance, is a convenient way to control the capture and release of guests, to mediate ring transformations, and to control pseudorotaxane-to-pseudorotaxane conversions. This novel approach could serve to assemble other libraries of small ring molecules, create cyclic polymers bridged by responsive-at-metal nodes, and produce processable mechanically interlocked molecules. Since Pedersen's seminal work on crown ethers, [1,2] the synthesis of macrocycles has been central to supramolecular chemistry. [3] The library of known ring molecules is vast, encompassing diverse compositions, geometries and sizes. [4][5][6][7][8][9] Macrocycles are being investigated for applications [10] such as sensing, [11] molecular delivery, [12] molecular machinery, [13] and more. [14] Macrocycle synthesis relies on one of the approaches depicted in Figure 1. The statistical approach proceeds under kinetic control and yields mixtures of linear and cyclic oligomers; [15] template-assisted syntheses operate under thermodynamic control, favoring one particular ring; [16] and post-synthetic modifications serve to alter preassembled rings. [17,18] Although these approaches are used disjointedly, we envisioned that by applying all three in tandem, a single precursor-the tether-could be transformed into multiple rings. Forming and isolating many macrocycles from one tether is not only economical but can also lead to rings with distinct cavity sizes, and hence differentiated host activity.Labile and inert metal-organic compounds have been crucial in recent developments of supramolecular chemistry. [19][20][21] Phenylpyridine (phpy) derivatives are important in the synthesis of cyclometalated complexes (e.g., with

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Post-synthetic modification of a macrocyclic receptor via regioselective imidazolium ring-opening

Abstract: Shown in graphic form is the use of mild basic conditions to effect the post-synthetic, ring-opening based modification of a tetraimidazolium macrocycle known as the “Texas box”. This ring opening modulates the intrinsic binding characteristics of the system.

Cited by 14 publications

References 107 publications

Supramolecular Properties of a Monocarboxylic Acid-Functionalized “Texas-Sized” Molecular Box

Supramolecular Properties of a Monocarboxylic Acid-Functionalized “Texas-Sized” Molecular Box

Supramolecular Adhesive Hydrogels for Tissue Engineering Applications

Cycling a Tether into Multiple Rings: Pt‐Bridged Macrocycles for Differentiated Guest Recognition, Pseudorotaxane Transformations, and Guest Capture and Release

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