Recent advances in dioxolene chemistry

Griffith, William P.

doi:10.1007/bf00139966

Cited by 37 publications

(12 citation statements)

References 44 publications

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“…However, surprisingly little effort has been made so far to build on this promising foundation by designing more complex quinones and quinols for use in the modular construction of new molecular materials. − Moreover, the chemistry of 1,4-benzoquinones and hydroquinones has been explored much more extensively than that of the isomeric 1,2-benzoquinones and their reduced forms, despite the potential of all of these compounds to engage in similar intermolecular interactions and to serve as modules in supramolecular construction. , In particular, the historic work of Wöhler provides a strong motivation for studying the cocrystallization of 1,2-benzoquinones with catechols, but little work of this type has been reported. , We have therefore undertaken a study to assess the utility of 1,2-benzoquinones and the corresponding catechols in the modular assembly of complex redox-active molecular structures held together by hydrogen bonds, charge-transfer interactions, and other forces. Of particular interest is the possibility of using such modules to make porous crystalline solids for use as electrodes in carbon-based batteries. − …”

Section: Introductionmentioning

confidence: 99%

“…19−21 However, surprisingly little effort has been made so far to build on this promising foundation by designing more complex quinones and quinols for use in the modular construction of new molecular materials. 22−26 Moreover, the chemistry of 1,4benzoquinones and hydroquinones has been explored much more extensively than that of the isomeric 1,2-benzoquinones and their reduced forms, 27 despite the potential of all of these compounds to engage in similar intermolecular interactions and to serve as modules in supramolecular construction. 28,29 In particular, the historic work of Woḧler provides a strong motivation for studying the cocrystallization of 1,2-benzoqui-nones with catechols, but little work of this type has been reported.…”

Section: ■ Introductionmentioning

confidence: 99%

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Triptycene 1,2-Quinones and Quinols: Permeable Crystalline Redox-Active Molecular Solids

2018

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Suitably designed quinones and quinols are promising modules for the programmed construction of ordered redox-active molecular solids. To explore this potential, we have synthesized compounds 1–4, in which multiple 1,2-benzoquinone and 1,2-quinol units are attached to a triptycene core. The resulting molecules have topologies that disfavor efficient packing, and structural studies show that they crystallize to form open networks held together by characteristic attractive intermolecular forces, including O–H···O hydrogen bonds, C–H···O interactions, π-stacking, and dipolar interactions. Remarkably, the resulting solids are permeable and can undergo reversible redox reactions without loss of crystallinity. Our work may thereby help lead to the design of robust carbon-based batteries with electrodes derived from quinones, quinols, and other redox-active molecules abundantly produced by nature.

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Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Triptycene 1,2-Quinones and Quinols: Permeable Crystalline Redox-Active Molecular Solids

2018

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“…Although the steps shown subsequent to metabolic dealkylation might be considered to occur spontaneously, − we have not found any evidence to support this toxic series of conversions in the case of PPAR ligands like cardarine or even within the chemical literature associated with any of the simpler 2-(4-X-phenoxy)acetic acid compounds. Thus if quinone-like materials are formed at some low level, then this is likely prompted by some additional biochemical interaction if not by another complete biotransformation step such as the previously mentioned possibility for aromatic hydroxylation leading to catechol-like arrangements wherein redox chemistry becomes applicable ,, (Figure B, lower arrow). One can imagine that the metabolite resulting from a common CYP-450-mediated X-dealkylation for any of the three heteroatom substitutions could also follow the proposed toxic pathways shown in Figure B.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Evaluation of PPARδ Agonists That Promote Osteogenesis in a Human Mesenchymal Stem Cell Culture and in a Mouse Model of Human Osteoporosis

et al. 2021

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We synthesized a directed library of compounds to explore the structure−activity relationships of peroxisome proliferator-activated receptor δ (PPARδ) activation relative to mesenchymal stem cell (MSC) osteogenesis. Our scaffold used para-substituted cinnamic acids as a polar headgroup, a heteroatom and heterocycle core connecting units, and substituted phenyl groups for the lipophilic tail. Compounds were screened for their ability to increase osteogenesis in MSCs, and the most promising were examined for subunit specificity using a quantitative PPAR transactivation assay. Six compounds were selected for in vivo studies in an ovariectomized mouse model of human postmenopausal osteoporosis. Four compounds improved bone density in vivo, with two (12d and 31a) having activity comparable to that of GW0742, a wellstudied PPARδ-selective agonist. 31a (2-methyl-4-[N-methyl-N-[5methylene-4-methyl-2-[4-(trifluoromethyl)phenyl]thiazole]]aminocinnamic acid) had the highest selectivity for PPARδ compared to other subtypes, its selectivity far exceeding that of GW0742. Our results confirm that PPARδ is a new drug target for possible treatment of osteoporosis via in situ manipulation of MSCs.

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“…[11][12][13] The most attractive feature of catechol ligands is their rich electrochemistry, with facile and reversible oxidation to semiquinone and quinone forms, together with the strong interplay between catechol and metal-based orbitals frequently resulting in transition metal complexes which display 'non-innocent' behaviour. 14,15 Whilst transition metal catecholates have been widely studied, Pt(II) catecholate chemistry has been rather less explored. [16][17][18][19][20][21][22][23][24][25] Previously reported Pt(II) catecholates commonly feature α,α′-diimines such as substituted bipyridines or phenanthrolines, in conjunction with simple dioxolenes, for example pyrocatechol, 3,5-di-tert-butyl catechol or 4-tert-butyl catechol.…”

Section: Introductionmentioning

confidence: 99%

Exploring excited states of Pt(ii) diimine catecholates for photoinduced charge separation

et al. 2015

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The intense absorption in the red part of the visible range, and the presence of a lowest charge-transfer excited state, render Platinum(II) diimine catecholates potentially promising candidates for light-driven applications. Here, we test their potential as sensitisers in dye-sensitised solar cells and apply, for the first time, the sensitive method of photoacoustic calorimetry (PAC) to determine the efficiency of electron injection in the semiconductor from a photoexcited Pt(II) complex. Pt(II) catecholates containing 2,2′-bipyridine-4,4′-di-carboxylic acid (dcbpy) have been prepared from their parent iso-propyl ester derivatives, complexes of 2,2′-bipyridine-4,4′-di-C(O)OiPr, (COOiPr)2bpy, and their photophysical and electrochemical properties studied. Modifying diimine Pt(II) catecholates with carboxylic acid functionality has allowed for the anchoring of these complexes to thin film TiO2, where steric bulk of the complexes (3,5-di(t)Bu-catechol vs. catechol) has been found to significantly influence the extent of monolayer surface coverage. Dye-sensitised solar cells using Pt(dcbpy)((t)Bu2Cat), 1a, and Pt(dcbpy)(pCat), 2a, as sensitisers, have been assembled, and photovoltaic measurements performed. The observed low, 0.02–0.07%, device efficiency of such DSSCs is attributed at least in part to the short excited state lifetime of the sensitisers, inherent to this class of complexes. The lifetime of the charge-transfer ML/LLCT excited state in Pt((COO(I)Pr)2bpy)(3,5-di-(t)Bu-catechol) was determined as 250 ps by picosecond time-resolved infrared spectroscopy, TRIR. The measured increase in device efficiency for 2a over 1a is consistent with a similar increase in the quantum yield of charge separation (where the complex acts as a donor and the semiconductor as an acceptor) determined by PAC, and is also proportional to the increased surface loading achieved with 2a. It is concluded that the relative efficiency of devices sensitised with these particular Pt(II) species is governed by the degree of surface coverage. Overall, this work demonstrates the use of Pt(diimine)(catecholate) complexes as potential photosensitizers in solar cells, and the first application of photoacoustic calorimetry to Pt(II) complexes in general.

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Recent advances in dioxolene chemistry

Cited by 37 publications

References 44 publications

Triptycene 1,2-Quinones and Quinols: Permeable Crystalline Redox-Active Molecular Solids

Triptycene 1,2-Quinones and Quinols: Permeable Crystalline Redox-Active Molecular Solids

Synthesis and Evaluation of PPARδ Agonists That Promote Osteogenesis in a Human Mesenchymal Stem Cell Culture and in a Mouse Model of Human Osteoporosis

Exploring excited states of Pt(ii) diimine catecholates for photoinduced charge separation

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