Dipyrenylcalix[4]arene—A Fluorescence-Based Chemosensor for Trinitroaromatic Explosives

Lee, Young Hoon,Liu, Hongguang,Lee, Jin Yong,Kim, Sang Hoon,Kim, Sung Kuk,Sessler, Jonathan L.,Kim, Yang,Kim, Jong Seung WILEY-VCH Verlag 2010 Chemistry Vol.16 No.20

<P>A new chemosensor-based approach to the detection of nitroaromatics is described. It involves the analyte-induced quenching of excimer emission of a dipyrenyl calix[4]arene (L). The chemical and photophysical properties of the complexes formed between L and mono-, di-, and trinitrobenzene, and di- and trinitrotoluene were studied in acetonitrile and chloroform by using <SUP>1</SUP>H NMR, UV/Vis, and fluorescence spectroscopy. Fluorescence spectroscopy revealed that the trinitroaromatics engendered the largest response among the various substrates tested, with the sensitivity for these analytes being correspondingly high. Quantitative analysis of the fluorescence titration profile generated from the titration of L with TNT provided evidence that this particular functionalized calix[4]arene receptor allows for the detection of TNT down to the low ppb level in CH<SUB>3</SUB>CN. A single-crystal X-ray diffraction analysis revealed that in the solid state the complex L⋅TNT consists of a supramolecular crystalline polymeric structure, the formation of which appears to be driven by intermolecular π–π interactions between two pyrene units and a TNT molecule held at a distance of 3.2–3.6 Å, as well as by intra- and intermolecular hydrogen-bonds among the amide linkages. Nevertheless, the changes in the <SUP>1</SUP>H NMR, UV/Vis, and fluorescence spectrum, including sharp color changes, are ascribed to a charge-transfer interaction arising from complementary π–π overlap between the pyrene subunits and the bound trinitroaromatic substrates. A number of ab initio calculations were also carried out and, considered in concert, they provide further support for the proposed charge-transfer interactions, particularly in the case of L⋅TNT.</P> <B>Graphic Abstract</B> <P>How to find TNT! A new chemosensor-based approach for the detection of nitrated aromatics is described. It involves the analyte-induced quenching of excimer emission of a dipyrenyl-calix[4]-arene (L; see graphic). In the solid state, the complex L⋅TNT consists of a supramolecular crystalline polymeric structure, the formation of which appears to be driven by intermolecular π–π interactions between two pyrene units and a TNT molecule held at a distance of 3.2–3.6 Å. <img src='wiley_img_2010/09476539-2010-16-20-CHEM200903439-content.gif' alt='wiley_img_2010/09476539-2010-16-20-CHEM200903439-content'> </P>

Benzene-, Pyrrole-, and Furan-Containing Diametrically Strapped Calix[4]pyrroles—An Experimental and Theoretical Study of Hydrogen-Bonding Effects in Chloride Anion Recognition

Yoon, Dae-Wi,Gross, Dustin E.,Lynch, Vincent M.,Sessler, Jonathan L.,Hay, Benjamin P.,Lee, Chang-Hee WILEY-VCH Verlag 2008 Angewandte Chemie Vol.120 No.27

<B>Graphic Abstract</B> <P>Schwach und doch wichtig: Die Bindung des Chloridanions durch Calixpyrrole mit diametraler Brücke, die eine Benzol- (siehe Struktur; grau C,H; blau N; rot O; grün Cl), Pyrrol- oder Furaneinheit enthält, wurde im Festkörper, in Lösung und mithilfe theoretischer Analysen untersucht. Die Ergebnisse sprechen dafür, dass CH⋅⋅⋅Cl<SUP>−</SUP>-Wasserstoffbrücken wichtig sind und wesentlich zur Cl<SUP>−</SUP>-Bindungsenergetik beitragen. <img src='wiley_img/00448249-2008-120-27-ANGE200801426-content.gif' alt='wiley_img/00448249-2008-120-27-ANGE200801426-content'> </P>

A Pyrrolyl-Based Triazolophane: A Macrocyclic Receptor With CH and NH Donor Groups That Exhibits a Preference for Pyrophosphate Anions

Sessler, Jonathan L.,Cai, Jiajia,Gong, Han-Yuan,Yang, Xiaoping,Arambula, Jonathan F.,Hay, Benjamin P. American Chemical Society 2010 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.132 No.40

<P>A pyrrolyl-based triazolophane, incorporating CH and NH donor groups, acts as a receptor for the pyrophosphate anion in chloroform solution. It shows selectivity for this trianion, followed by HSO<SUB>4</SUB><SUP>−</SUP> > H<SUB>2</SUB>PO<SUB>4</SUB><SUP>−</SUP> > Cl<SUP>−</SUP> > Br<SUP>−</SUP> (all as the corresponding tetrabutylammonium salts), with NH−anion interactions being more important than CH−anion interactions. In the solid state, the receptor binds the pyrophosphate anion in a clip-like slot <I>via</I> NH and CH hydrogen bonds.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2010/jacsat.2010.132.issue-40/ja107098r/production/images/medium/ja-2010-07098r_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja107098r'>ACS Electronic Supporting Info</A></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja107098r'>ACS Electronic Supporting Info</A></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja107098r'>ACS Electronic Supporting Info</A></P>

π-Extended tetrathiafulvalene BODIPY (ex-TTF-BODIPY): a redox switched “on–off–on” electrochromic system with two near-infrared fluorescent outputs

Bill, Nathan L.,Lim, Jong Min,Davis, Christina M.,Bä,hring, Steffen,Jeppesen, Jan O.,Kim, Dongho,Sessler, Jonathan L. The Royal Society of Chemistry 2014 Chemical communications Vol.50 No.51

<P>A π-extended tetrathiafulvalene-boradiazaindacene chimera, ex-TTF-BODIPY, has been prepared. The resulting system undergoes sequential one-electron oxidations, allowing access to both the mono-oxidized radical cationic and dicationic states. Additionally, ex-TTF-BODIPY displays electrochromic and electrofluorochromic behaviour in the near-IR portion of the electromagnetic spectrum and functions as a redox switched “on–off–on” emissive system.</P> <P>Graphic Abstract</P><P>Ex-TTF-BODIPY functions as a near-IR electrochromic and electrofluorochromic switch, displaying redox controlled “on–off–on” emission features. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4cc02567a'> </P>

Oxoanion recognition by benzene-based tripodal pyrrolic receptors

Bill, Nathan L.,Kim, Dae-Sik,Kim, Sung Kuk,Park, Jung Su,Lynch, Vincent M.,Young, Neil J.,Hay, Benjamin P.,Yang, Youjun,Anslyn, Eric V.,Sessler, Jonathan L. Informa UK (TaylorFrancis) 2012 Supramolecular chemistry Vol.24 No.1

Disulfide-Based Multifunctional Conjugates for Targeted Theranostic Drug Delivery

Lee, Min Hee,Sessler, Jonathan L.,Kim, Jong Seung American Chemical Society 2015 Accounts of chemical research Vol.48 No.11

<title>Conspectus</title><P>Theranostics, chemical entities designed to combine therapeutic effects and imaging capability within one molecular system, have received considerable attention in recent years. Much of this interest reflects the promise inherent in personalized medicine, including disease-targeted treatments for cancer patients. One important approach to realizing this latter promise involves the development of so-called theranostic conjugates, multicomponent constructs that selectively target cancer cells and deliver cytotoxic agents while producing a readily detectable signal that can be monitored both <I>in vitro</I> and <I>in vivo</I>. This requires the synthesis of relatively complex systems comprising imaging reporters, masked chemotherapeutic drugs, cleavable linkers, and cancer targeting ligands. Ideally, the cleavage process should take place within or near cancer cells and be activated by cellular components that are associated with cancer states or specifically expressed at a higher level in cancer cells. Among the cleavable linkers currently being explored for the construction of such localizing conjugates, disulfide bonds are particularly attractive. This is because disulfide bonds are stable in most blood pools but are efficiently cleaved by cellular thiols, including glutathione (GSH) and thioredoxin (Trx), which are generally found at elevated levels in tumors. When disulfide bonds are linked to fluorophores, changes in emission intensity or shifts in the emission maxima are typically seen upon cleavage as the result of perturbations to internal charge transfer (ICT) processes. In well-designed systems, this allows for facile imaging. In this Account, we summarize our recent studies involving disulfide-based fluorescent drug delivery conjugates, including preliminary tests of their biological utility <I>in vitro</I> and <I>in vivo</I>.</P><P>To date, a variety of chemotherapeutic agents, such as doxorubicin, gemcitabine, and camptothecin, have been used to create disulfide-based conjugates, as have a number of fluorophores, including naphthalimide, coumarin, BODIPY, rhodol, and Cy7. The resulting theranostic core (drug–disulfide–fluorophore) can be further linked to any of several site-localizing entities, including galactose, folate, biotin, and the RGD (Arg-Gly-Asp) peptide sequence, to create systems with an intrinsic selectivity for cancer cells over normal cells. Site-specific cleavage by endogenous thiols serves to release the cytotoxic drug and produce an easy-to-monitor change in the fluorescence signature of the cell. On the basis of the results summarized in this Account, we propose that disulfide-based cancer-targeting theranostics may have a role to play in advancing drug discovery efforts, as well as improving our understanding of cellular uptake and drug release mechanisms.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/achre4/2015/achre4.2015.48.issue-11/acs.accounts.5b00406/production/images/medium/ar-2015-00406b_0018.gif'></P>

Bismuth– and lead–texaphyrin complexes: towards potential α-core emitters for radiotherapy

Preihs, Christian,Arambula, Jonathan F.,Lynch, Vincent M.,Siddik, Zahid H.,Sessler, Jonathan L. The Royal Society of Chemistry 2010 Chemical communications Vol.46 No.42

<P>Lead(<SMALL>II</SMALL>)–texaphyrins and the first discrete binuclear μ–oxo bismuth(<SMALL>III</SMALL>)–texaphyrin are reported. The latter was characterized <I>via</I>single crystal X-ray diffraction analysis. Cell proliferation assays using the A2780 ovarian cancer cell line were used to determine the cytotoxicity of the complexes.</P> <P>Graphic Abstract</P><P>Bismuth(<SMALL>III</SMALL>)– and lead(<SMALL>II</SMALL>)–texaphyrins have been synthesized with Bi(<SMALL>III</SMALL>) residing in a unique binuclear μ–oxo coordination sphere. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0cc03528a'> </P>

Ion pair receptors

Kim, Sung Kuk,Sessler, Jonathan L. Royal Society of Chemistry 2010 Chemical Society reviews Vol.39 No.10

<P>Compared with simple ion receptors, which are able to bind either a cation or an anion, ion pair receptors bearing both a cation and an anion recognition site offer the promise of binding ion pairs or pairs of ions strongly as the result of direct or indirect cooperative interactions between co-bound ions. This critical review focuses on the recent progress in the design of ion pair receptors and summarizes the various binding modes that have been used to accommodate ion pairs (110 references).</P>

Recent Developments in Texaphyrin Chemistry and Drug Discovery

Preihs, Christian,Arambula, Jonathan F.,Magda, Darren,Jeong, Heeyeong,Yoo, Dongwon,Cheon, Jinwoo,Siddik, Zahid H.,Sessler, Jonathan L. American Chemical Society 2013 Inorganic chemistry Vol.52 No.21

<P>Texaphyrins are pentaaza expanded porphyrins with the ability to form stable complexes with a variety of metal cations, particularly those of the lanthanide series. In biological milieus, texaphyrins act as redox mediators and mediate the production of reactive oxygen species (ROS). In this review, newer studies involving texaphyrin complexes targeting several different applications in anticancer therapy are described. In particular, the preparation of bismuth and lead texaphyrin complexes as potential α-core emitters for radiotherapy is detailed, as are gadolinium texaphyrin functionalized magnetic nanoparticles with features that make them of interest as dual-mode magnetic resonance imaging contrast agents and as constructs with anticancer activity mediated through ROS-induced sensitization and concurrent hyperthermia. Also discussed are gadolinium texaphyrin complexes as possible carrier systems for the targeted delivery of platinum payloads.</P><P>Texaphyrins are pentaaza expanded porphyrins with the ability to form stable complexes with a variety of metal cations, particularly those of the lanthanide series. In biological milieus, texaphyrins act as redox mediators and mediate the production of reactive oxygen species. In this review, newer studies involving texaphyrin complexes targeting several different applications in anticancer therapy are described.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/inocaj/2013/inocaj.2013.52.issue-21/ic400226g/production/images/medium/ic-2013-00226g_0016.gif'></P>

A Calix[4]arene Strapped Calix[4]pyrrole: An Ion-Pair Receptor Displaying Three Different Cesium Cation Recognition Modes

Kim, Sung Kuk,Sessler, Jonathan L.,Gross, Dustin E.,Lee, Chang-Hee,Kim, Jong Seung,Lynch, Vincent M.,Delmau, Lætitia H.,Hay, Benjamin P. American Chemical Society 2010 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.132 No.16

<P>An ion-pair receptor, the calix[4]pyrrole-calix[4]arene pseudodimer <B>2</B>, bearing a strong anion-recognition site but not a weak cation-recognition site, has been synthesized and characterized by standard spectroscopic means and <I>via</I> single-crystal X-ray diffraction analysis. In 10% CD<SUB>3</SUB>OD in CDCl<SUB>3</SUB> (v/v), this new receptor binds neither the Cs<SUP>+</SUP> cation nor the F<SUP>−</SUP> anion when exposed to these species in the presence of other counterions; however, it forms a stable 1:1 solvent-separated CsF complex when exposed to these two ions in concert with one another in this same solvent mixture. In contrast to what is seen in the case of a previously reported crown ether “strapped” calixarene−calixpyrrole ion-pair receptor <B>1</B> (J. Am. Chem. Soc. 2008, 130, 13162−<lpage>13166</lpage>), where Cs<SUP>+</SUP> cation recognition takes place within the crown, in <B>2</B>·CsF cation recognition takes place within the receptor cavity itself, as inferred from both single-crystal X-ray diffraction analyses and <SUP>1</SUP>H NMR spectroscopic studies. This binding mode is supported by calculations carried out using the MMFF94 force field model. In 10% CD<SUB>3</SUB>OD in CDCl<SUB>3</SUB> (v/v), receptor <B>2</B> shows selectivity for CsF over the Cs<SUP>+</SUP> salts of Cl<SUP>−</SUP>, Br<SUP>−</SUP>, and NO<SUB>3</SUB><SUP>−</SUP> but will bind these other cesium salts in the absence of fluoride, both in solution and in the solid state. In the case of CsCl, an unprecedented 2:2 complex is observed in the solid state that is characterized by two different ion-pair binding modes. One of these consists of a contact ion pair with the cesium cation and chloride anion both being bound within the central binding pocket and in direct contact with one another. The other mode involves a chloride anion bound to the pyrrole NH protons of a calixpyrrole subunit and a cesium cation sandwiched between two cone shaped calix[4]pyrroles originating from separate receptor units. In contrast to what is seen for CsF and CsCl, single-crystal X-ray structural analyses and <SUP>1</SUP>H NMR spectroscopic studies reveal that receptor <B>2</B> forms a 1:1 complex with CsNO<SUB>3</SUB>, with the ions bound in the form of a contact ion pair. Thus, depending on the counteranion, receptor <B>2</B> is able to stabilize three different ion-pair binding modes with Cs<SUP>+</SUP>, namely solvent-bridged, contact, and host-separated.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2010/jacsat.2010.132.issue-16/ja100715e/production/images/medium/ja-2010-00715e_0014.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja100715e'>ACS Electronic Supporting Info</A></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja100715e'>ACS Electronic Supporting Info</A></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja100715e'>ACS Electronic Supporting Info</A></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja100715e'>ACS Electronic Supporting Info</A></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja100715e'>ACS Electronic Supporting Info</A></P>