Richard J. Hooley

Labeled Protein Recognition at a Membrane Bilayer Interface by Embedded Synthetic Receptors

Co-reporter:Yoo-Jin Ghang, Jonathan J. Lloyd, Melissa P. Moehlig, Jessica K. Arguelles, Magi Mettry, Xing Zhang, Ryan R. Julian, Quan Cheng, and Richard J. Hooley

Langmuir September 2, 2014 Volume 30(Issue 34) pp:10161-10166

Publication Date(Web):August 17, 2014

DOI:10.1021/la502629d

Self-folding deep cavitands embedded in a supported lipid bilayer are capable of recognizing suitably labeled proteins at the bilayer interface. The addition of a choline derived binding “handle” to a number of different proteins allows their selective noncovalent recognition, with association constants on the order of 105 M–1. The proteins are displayed at the water:bilayer interface, and a single binding handle allows recognition of the large, charged protein by a small molecule synthetic receptor via complementary shape and charge interactions.

Stereoselective Postassembly CH Oxidation of Self-Assembled Metal–Ligand Cage Complexes

Co-reporter:Lauren R. Holloway, Paul M. Bogie, Yana Lyon, Ryan R. Julian, and Richard J. Hooley

Inorganic Chemistry September 18, 2017 Volume 56(Issue 18) pp:11435-11435

Publication Date(Web):August 25, 2017

DOI:10.1021/acs.inorgchem.7b01958

Self-assembled Fe-iminopyridine cage complexes containing doubly benzylic methylene units such as fluorene and xanthene can be selectively oxidized at the ligand backbone with tBuOOH, with no competitive oxidation observed at the metal centers. The self-assembled cage structure controls the reaction outcome, yielding oxidation products that are favored by the assembly, not by the reactants or functional groups. Whereas uncomplexed xanthene and fluorene control ligands are solely oxidized to the ketone equivalents with tBuOOH, the unfavorability of the self-assembled ketone cages forces the reaction to form the tbutyl peroxide and alcohol-containing oxidation products, respectively. In addition, the oxidation is diastereoselective, with only single isomers of the cage assemblies formed, despite the presence of as many as 10 stereocenters in the final product. The self-assembled structures exploit self-complementary hydrogen bonding and geometrical constraints to direct the postassembly reactions to outcomes not observed in free solution. This selectivity is reminiscent of the fine control of post-translational modification seen in biomacromolecules.

Site-Selective Sensing of Histone Methylation Enzyme Activity via an Arrayed Supramolecular Tandem Assay

Co-reporter:Yang Liu, Lizeth Perez, Adam D. Gill, Magi Mettry, Lin Li, Yinsheng Wang, Richard J. Hooley, and Wenwan Zhong

Journal of the American Chemical Society August 16, 2017 Volume 139(Issue 32) pp:10964-10964

Publication Date(Web):August 4, 2017

DOI:10.1021/jacs.7b05002

Arrayed deep cavitands can be coupled to a fluorescence-based supramolecular tandem assay that allows site-selective in situ monitoring of post-translational modifications catalyzed by the lysine methyltransferase PRDM9 or the lysine demethylase JMJD2E. An arrayed sensor system containing only three cavitand components can detect the specific substrates of enzyme modification, in the presence of other histone peptides in the enzyme assay, enabling investigation of cross-reactivity over multiple methylation sites and interference from nonsubstrate peptides.

Site selective reading of epigenetic markers by a dual-mode synthetic receptor array

Co-reporter:Yang Liu;Lizeth Perez;Magi Mettry;Adam D. Gill;Samantha R. Byers;Connor J. Easley;Christopher J. Bardeen;Wenwan Zhong

Chemical Science (2010-Present) 2017 vol. 8(Issue 5) pp:3960-3970

Publication Date(Web):2017/05/03

DOI:10.1039/C7SC00865A

Variably functionalized self-folding deep cavitands form an arrayed, fluorescent indicator displacement assay system for the detection of post-translationally modified (PTM) histone peptides. The hosts bind trimethyllysine (KMe3) groups, and use secondary upper rim interactions to provide more sensitive discrimination between targets with identical KMe3 binding handles. The sensor array uses multiple different recognition modes to distinguish between miniscule differences in target, such as identical lysine modifications at different sites of histone peptides. In addition, the sensor is affected by global changes in structure, so it is capable of discriminating between identical PTMs, at identical positions on amino acid fragments that vary only in peptide backbone length, and can be applied to detect non-methylation modifications such as acetylation and phosphorylations located multiple residues away from the targeted binding site. The synergistic application of multiple variables allows dual-mode deep cavitands to approach levels of recognition selectivity usually only seen with antibodies.

Selective protein recognition in supported lipid bilayer arrays by tailored, dual-mode deep cavitand hosts

Co-reporter:Lizeth Perez;Magi Mettry;Samuel S. Hinman;Samantha R. Byers;Kristy S. McKeating;Bethany G. Caulkins;Quan Cheng

Soft Matter (2005-Present) 2017 vol. 13(Issue 21) pp:3966-3974

Publication Date(Web):2017/05/31

DOI:10.1039/C7SM00192D

Self-folding deep cavitands with variably functionalized upper rims are able to selectively immobilize proteins at a biomimetic supported lipid bilayer surface. The immobilization process takes advantage of the dual-mode binding capabilities of the hosts, combining a defined binding pocket with upper rim charged/H-bonding groups. A variety of proteins can be selectively immobilized at the bilayer interface, either via complementary charge/H-bonding interactions, cavity-based molecular recognition, or a combination of both. The immobilization process can be used to bind unmodified native proteins, epitopes for bioadhesion, or proteins covalently modified with suitable RNMe3+ binding “handles” and charged groups that can either match or mismatch with the cavitand rim. The immobilization process can be monitored in real time using surface plasmon resonance (SPR) spectroscopy, and applied to the construction of cavitand:lipid arrays using the hosts and trehalose vitrified phospholipid vesicles. The selective, dual-mode protein recognition is maintained in the arrays, and can be visualized using SPR imaging.

Controlled self-sorting in self-assembled cage complexes

Co-reporter:Lauren R. Holloway;Paul M. Bogie

Dalton Transactions 2017 vol. 46(Issue 43) pp:14719-14723

Publication Date(Web):2017/11/07

DOI:10.1039/C7DT03399K

In this frontier article we highlight recent advances in subcomponent self-sorting in self-assembled metal–ligand cage complexes, with a focus on selective discrimination between ligands that contain highly similar metal-coordinating groups. Effects such as varying ligand length, coordination angle and backbone flexibility, as well as the introduction of secondary weak forces such as hydrogen bonds can be exploited to favor either narcissistic or social self-sorting. We highlight these creative solutions, and emphasize the challenges that remain in the development of functional self-assembled heterocomplexes.

Self-Aggregating Deep Cavitand Acts as a Fluorescence Displacement Sensor for Lysine Methylation

Co-reporter:Yang Liu, Lizeth Perez, Magi Mettry, Connor J. Easley, Richard J. Hooley, and Wenwan Zhong

Journal of the American Chemical Society 2016 Volume 138(Issue 34) pp:10746-10749

Publication Date(Web):August 8, 2016

DOI:10.1021/jacs.6b05897

A dual-mode aggregative host:guest indicator displacement sensing system has been created for the detection of trimethylated peptides and determination of histone demethylase activity. The combination of selective recognition of suitably sized trimethylammonium salts and reversible lipophilic aggregation of the host:guest complex provides a unique quenching mechanism that is not only dependent on affinity for sensitivity but the lipophilicity of the indicator. In addition, aggregation can be controlled by the application of chaotropic anions in the mixture, allowing a second level of discrimination between hard lysine groups and softer trimethyllysines.

Structural switching in self-assembled metal–ligand helicate complexes via ligand-centered reactions

Co-reporter:Lauren R. Holloway, Hannah H. McGarraugh, Michael C. Young, Watit Sontising, Gregory J. O. Beran and Richard J. Hooley

Chemical Science 2016 vol. 7(Issue 7) pp:4423-4427

Publication Date(Web):29 Mar 2016

DOI:10.1039/C6SC01038E

Ligand centered reactions are capable of conferring structural switching between a metastable, self-assembled Fe–iminopyridine aggregate and a stable M2L3 helicate. The reactivity is directed and accelerated by the stability of the final product structure. Under aerobic conditions, both substitution and oxidation occurs at the ligand, exploiting atmospheric oxygen as the oxidant. In the absence of air, reaction occurs more slowly, forming the less stable substitution product. Control ligands show a preference for simple substitution, but the self-assembly directs both substitution and oxidation. The metastable nature of the initial aggregate species is essential for the reaction: while the aggregate is “primed” for reaction, other analogous helicate structures are “locked” by self-assembly, preventing reactivity.

Electronic Effects on Narcissistic Self-Sorting in Multicomponent Self-Assembly of Fe-Iminopyridine meso-Helicates

Co-reporter:Calvin A. Wiley, Lauren R. Holloway, Tabitha F. Miller, Yana Lyon, Ryan. R. Julian, and Richard J. Hooley

Inorganic Chemistry 2016 Volume 55(Issue 19) pp:9805-9815

Publication Date(Web):September 13, 2016

DOI:10.1021/acs.inorgchem.6b01644

Small changes in the electron donating ability of coordinating groups have substantial effects on the multicomponent self-assembly of Fe (II)-iminopyridine-based meso-helicate complexes. Both the nature of the internal diamine core and the terminal formylpyridine reactants control the rate of the assembly process, the thermodynamic favorability of the meso-helicate products, and the selective incorporation of different aldehyde termini into the assembly. Steric congestion at the coordinating ligands can prevent assembly altogether, and favorable incorporation of electron-rich aldehyde termini is observed, even though the rate of reaction is accelerated by the use of electron-poor aldehyde reactants. NMR and electrospray ionization mass spectrometry analyses were employed to determine the synergistic nature of narcissistic self-sorting in this system, which depends on both the rigidity of the central core and the electronic donor ability of the aldehyde terminus. These experiments illustrate that significant control of self-sorting and self-assembly is possible upon extremely small variations in ligand structure, rigidity, and donor ability.

High fidelity sorting of remarkably similar components via metal-mediated assembly

Co-reporter:Lauren R. Holloway, Michael C. Young, Gregory J. O. Beran and Richard J. Hooley

Chemical Science 2015 vol. 6(Issue 8) pp:4801-4806

Publication Date(Web):02 Jun 2015

DOI:10.1039/C5SC01689D

Subtle differences in ligand coordination angle and rigidity lead to high fidelity sorting between individual components displaying identical coordination motifs upon metal-mediated self-assembly. Narcissistic self-sorting can be achieved between highly similar ligands that vary minimally in rigidity and internal coordination angle upon combination with Fe(II) ions and 2-formylpyridine. Selective, sequential cage formation can be precisely controlled in a single flask from a mix of three different core ligands (and 33 total components) differing only in the hybridization of one group that is uninvolved in the metal coordination process.

Synthesis, Guest Binding, and Metal Coordination of Functionalized Self-Folding Deep Cavitands

Co-reporter:Magi Mettry, Melissa P. Moehlig, and Richard J. Hooley

Organic Letters 2015 Volume 17(Issue 6) pp:1497-1500

Publication Date(Web):March 11, 2015

DOI:10.1021/acs.orglett.5b00383

A simple method to introduce donor functions to the upper rim of self-folding benzimidazole-based deep cavitands is described. The upper rim donors allow controlled noncovalent binding of suitably sized guest species via both self-complementary hydrogen bonding and space-filling interactions, and metal-mediated self-folding is possible if bidentate coordinators are incorporated.

Narcissistic Self-Sorting in Self-Assembled Cages of Rare Earth Metals and Rigid Ligands

Co-reporter:Amber M. Johnson;Calvin A. Wiley;Michael C. Young;Xing Zhang;Yana Lyon; Ryan R. Julian ; Richard J. Hooley

Angewandte Chemie International Edition 2015 Volume 54( Issue 19) pp:5641-5645

Publication Date(Web):

DOI:10.1002/anie.201500400

Abstract

Highly selective, narcissistic self-sorting can be achieved in the formation of self-assembled cages of rare earth metals with multianionic salicylhydrazone ligands. The assembly process is highly sensitive to the length of the ligand and the coordination geometry. Most surprisingly, high-fidelity sorting is possible between ligands of identical coordination angle and geometry, differing only in a single functional group on the ligand core, which is not involved in the coordination. Supramolecular effects allow discrimination between pendant functions as similar as carbonyl or methylene groups in a complex assembly process.

Narcissistic Self-Sorting in Self-Assembled Cages of Rare Earth Metals and Rigid Ligands

Co-reporter:Amber M. Johnson;Calvin A. Wiley;Michael C. Young;Xing Zhang;Yana Lyon; Ryan R. Julian ; Richard J. Hooley

Angewandte Chemie 2015 Volume 127( Issue 19) pp:5733-5737

Publication Date(Web):

DOI:10.1002/ange.201500400

Abstract

Highly selective, narcissistic self-sorting can be achieved in the formation of self-assembled cages of rare earth metals with multianionic salicylhydrazone ligands. The assembly process is highly sensitive to the length of the ligand and the coordination geometry. Most surprisingly, high-fidelity sorting is possible between ligands of identical coordination angle and geometry, differing only in a single functional group on the ligand core, which is not involved in the coordination. Supramolecular effects allow discrimination between pendant functions as similar as carbonyl or methylene groups in a complex assembly process.

Cell and Protein Recognition at a Supported Bilayer Interface via In Situ Cavitand-Mediated Functional Polymer Growth

Co-reporter:Lizeth Perez, Yoo-Jin Ghang, Preston B. Williams, Yinsheng Wang, Quan Cheng, and Richard J. Hooley

Langmuir 2015 Volume 31(Issue 41) pp:11152-11157

Publication Date(Web):October 5, 2015

DOI:10.1021/acs.langmuir.5b03124

Water-soluble deep cavitands embedded in a supported lipid bilayer are capable of anchoring ATRP initiator molecules for the in situ synthesis of primary amine-containing polymethacrylate patches at the water:membrane interface. These polymers can be derivatized in situ to incorporate fluorescent reporters, allow selective protein recognition, and can be applied to the immobilization of nonadherent cells at the bilayer interface.

Colorimetric barbiturate sensing with hybrid spin crossover assemblies

Co-reporter:Michael C. Young, Erica Liew and Richard J. Hooley

Chemical Communications 2014 vol. 50(Issue 39) pp:5043-5045

Publication Date(Web):02 Apr 2014

DOI:10.1039/C4CC01805B

Spin crossover complexes based on either iron(II) or iron(III) give a colorimetric response upon self-assembly with barbituric acids. They can be used as visible sensors for these narcotics, selectively detecting barbiturates in the presence of other biologically-relevant hydrogen bonding species.

Self-promoted post-synthetic modification of metal–ligand M2L3 mesocates

Co-reporter:Michael C. Young, Amber M. Johnson and Richard J. Hooley

Chemical Communications 2014 vol. 50(Issue 11) pp:1378-1380

Publication Date(Web):10 Dec 2013

DOI:10.1039/C3CC48444K

Reactive alcohol functionality has been incorporated into a self-assembled M2L3 mesocate. Post-synthetic modification of this complex with suitable isocyanates is not only possible, but is self-catalyzed by multiple internal hydrogen bonds from the self-assembly. As the metal–ligand coordination is reversible at elevated temperature, the isomeric distribution of product changes upon reaction, due to the different steric bulk conferred on the assembly after the modification.

Non-covalent self assembly controls the relaxivity of magnetically active guests

Co-reporter:Vincent Li, Yoo-Jin Ghang, Richard J. Hooley and Travis J. Williams

Chemical Communications 2014 vol. 50(Issue 11) pp:1375-1377

Publication Date(Web):11 Dec 2013

DOI:10.1039/C3CC48389D

The relaxivity of a magnetically responsive Gd complex can be controlled by non-covalent molecular recognition with a water-soluble deep cavitand. Lowered relaxivity is conferred by a self-assembled micellar “off state”, and the contrast can be regenerated by addition of a superior guest.

Anionic deep cavitands enable the adhesion of unmodified proteins at a membrane bilayer

Co-reporter:Yoo-Jin Ghang, Lizeth Perez, Melissa A. Morgan, Fang Si, Omar M. Hamdy, Consuelo N. Beecher, Cynthia K. Larive, Ryan R. Julian, Wenwan Zhong, Quan Cheng and Richard J. Hooley

Soft Matter 2014 vol. 10(Issue 48) pp:9651-9656

Publication Date(Web):31 Oct 2014

DOI:10.1039/C4SM02347A

An anionic self-folding deep cavitand is capable of immobilizing unmodified proteins and enzymes at a supported lipid bilayer interface, providing a simple, soft bioreactive surface that allows enzymatic function under mild conditions. The adhesion is based on complementary charge interactions, and the hosts are capable of binding enzymes such as trypsin at the bilayer interface: the catalytic activity is retained upon adhesion, allowing selective reactions to be performed at the membrane surface.

A Supramolecular Sorting Hat: Stereocontrol in MetalLigand Self-Assembly by Complementary Hydrogen Bonding

Co-reporter:Michael C. Young;Lauren R. Holloway;Amber M. Johnson ; Richard J. Hooley

Angewandte Chemie International Edition 2014 Volume 53( Issue 37) pp:9832-9836

Publication Date(Web):

DOI:10.1002/anie.201405242

Abstract

A combination of self-complementary hydrogen bonding and metal–ligand interactions allows stereocontrol in the self-assembly of prochiral ligand scaffolds. A unique, non-tetrahedral M₄L₆ structure is observed upon multicomponent self-assembly of 2,7-diaminofluorenol with 2-formylpyridine and Fe(ClO₄)₂. The stereochemical outcome of the assembly is controlled by self-complementary hydrogen bonding between both individual ligands and a suitably sized counterion as template. This hydrogen-bonding-mediated stereoselective metal–ligand assembly allows the controlled formation of nonsymmetric discrete cage structures from previously unexploited ligand scaffolds.

A Supramolecular Sorting Hat: Stereocontrol in MetalLigand Self-Assembly by Complementary Hydrogen Bonding

Co-reporter:Michael C. Young;Lauren R. Holloway;Amber M. Johnson ; Richard J. Hooley

Angewandte Chemie 2014 Volume 126( Issue 37) pp:9990-9994

Publication Date(Web):

DOI:10.1002/ange.201405242

Abstract

A combination of self-complementary hydrogen bonding and metal–ligand interactions allows stereocontrol in the self-assembly of prochiral ligand scaffolds. A unique, non-tetrahedral M₄L₆ structure is observed upon multicomponent self-assembly of 2,7-diaminofluorenol with 2-formylpyridine and Fe(ClO₄)₂. The stereochemical outcome of the assembly is controlled by self-complementary hydrogen bonding between both individual ligands and a suitably sized counterion as template. This hydrogen-bonding-mediated stereoselective metal–ligand assembly allows the controlled formation of nonsymmetric discrete cage structures from previously unexploited ligand scaffolds.

Labeled Protein Recognition at a Membrane Bilayer Interface by Embedded Synthetic Receptors

Co-reporter:Yoo-Jin Ghang, Jonathan J. Lloyd, Melissa P. Moehlig, Jessica K. Arguelles, Magi Mettry, Xing Zhang, Ryan R. Julian, Quan Cheng, and Richard J. Hooley

Langmuir 2014 Volume 30(Issue 34) pp:10161-10166

Publication Date(Web):August 17, 2014

DOI:10.1021/la502629d

Self-folding deep cavitands embedded in a supported lipid bilayer are capable of recognizing suitably labeled proteins at the bilayer interface. The addition of a choline derived binding “handle” to a number of different proteins allows their selective noncovalent recognition, with association constants on the order of 105 M–1. The proteins are displayed at the water:bilayer interface, and a single binding handle allows recognition of the large, charged protein by a small molecule synthetic receptor via complementary shape and charge interactions.

Selective Cavitand-Mediated Endocytosis of Targeted Imaging Agents into Live Cells

Co-reporter:Yoo-Jin Ghang ; Michael P. Schramm ; Fan Zhang ; Roger A. Acey ; Clement N. David ; Emma H. Wilson ; Yinsheng Wang ; Quan Cheng

Journal of the American Chemical Society 2013 Volume 135(Issue 19) pp:7090-7093

Publication Date(Web):April 26, 2013

DOI:10.1021/ja401273g

A water-soluble synthetic receptor molecule is capable of selective, controlled endocytosis of a specifically tagged target molecule in different types of living human cells. The presence of suitable choline-derived binding handles is essential for the molecular recognition and transport process, allowing selective guest transport and imaging of cancer cells.

Cooperative Thermodynamic Control of Selectivity in the Self-Assembly of Rare Earth Metal–Ligand Helices

Co-reporter:Amber M. Johnson ; Michael C. Young ; Xing Zhang ; Ryan R. Julian

Journal of the American Chemical Society 2013 Volume 135(Issue 47) pp:17723-17726

Publication Date(Web):November 8, 2013

DOI:10.1021/ja409882k

Metal-selective self-assembly with rare-earth cations is possible with suitable rigid, symmetrical bis-tridentate ligands. Kinetically controlled formation is initially observed, with smaller cations preferentially incorporated. Over time, the more thermodynamically favorable complexes with larger metals are formed. This thermodynamic control is a cooperative supramolecular phenomenon and only occurs upon multiple-metal-based self-assembly: single-metal ML3 analogues do not show reversible selectivity. The selectivity is dependent on small variations in lanthanide ionic radius and occurs despite identical coordination-ligand coordination geometries and minor size differences in the rare-earth metals.

Spin state modulation of iron spin crossover complexes via hydrogen-bonding self-assembly

Co-reporter:Michael C. Young, Erica Liew, Jonathan Ashby, Kelsi E. McCoy and Richard J. Hooley

Chemical Communications 2013 vol. 49(Issue 56) pp:6331-6333

Publication Date(Web):31 May 2013

DOI:10.1039/C3CC42851F

Iron complexes derived from 6-diaminotriazyl-2,2′-bipyridines display spin crossover behaviour, and hydrogen bonding-controlled self-assembly with a suitable barbiturate partner can modulate the crossover from mixed low and high spin to high spin. This system is the first to use solution-phase self-assembly of complementary hydrogen-bonding organic species to modulate spin state.

Achiral endohedral functionality provides stereochemical control in Fe(II)-based self-assemblies

Co-reporter:Michael C. Young, Amber M. Johnson, Ana S. Gamboa and Richard J. Hooley

Chemical Communications 2013 vol. 49(Issue 16) pp:1627-1629

Publication Date(Web):08 Jan 2013

DOI:10.1039/C3CC37912D

Multicomponent Fe(II)-iminopyridine-based self-assemblies have been synthesized with variably sized internal functionality. Larger internal functions provide increased strain to the complex and confer diastereocontrol upon the assembly process. Complete diastereocontrol is possible upon the introduction of large achiral groups on the cavity interior.

Reversible multicomponent self-assembly mediated by bismuth ions

Co-reporter:Amber M. Johnson, Michael C. Young and Richard J. Hooley

Dalton Transactions 2013 vol. 42(Issue 23) pp:8394-8401

Publication Date(Web):15 Apr 2013

DOI:10.1039/C3DT50578B

Bi(III) ions are capable of reversible, multicomponent self assembly with suitable tris-coordinate ligands. The nature of the self-assembled structures observed are dependent on the ligand coordination geometry, ligand protonation state and Bi concentration. These assemblies can exploit the maximum number of coordination sites at the Bi vertices (nine), and the self-assembly process has been studied by 1D NMR, Diffusion NMR, ESI-MS and X-ray crystallographic analysis. V-shaped coordinating ligands reversibly form discrete M2L4, M2L3, and M2L2 complexes dependent on ligand/bismuth concentration, whereas a linear coordinating ligand forms a single discrete M3L3 assembly.

Metal-Coordinated Water-Soluble Cavitands Act as C–H Oxidation Catalysts

Co-reporter:Katherine E. Djernes, Orly Moshe, Magi Mettry, Donald D. Richards, and Richard J. Hooley

Organic Letters 2012 Volume 14(Issue 3) pp:788-791

Publication Date(Web):January 24, 2012

DOI:10.1021/ol203243j

Cavitands can be smoothly derivatized by CuAAC chemistry to incorporate ligand species at the upper rim. These species can coordinate metal species in a number of different conformations, leading to self-assembly. The metal-coordination confers water solubility on the cavitands, and the iron-bound species are capable of catalytic C–H oxidations of fluorene under mild conditions.

Cytosine Derivatives Form Hemiprotonated Dimers in Solution and the Gas Phase

Co-reporter:Aaron R. Moehlig, Katherine E. Djernes, V. Mahesh Krishnan, and Richard J. Hooley

Organic Letters 2012 Volume 14(Issue 10) pp:2560-2563

Publication Date(Web):May 9, 2012

DOI:10.1021/ol300861r

Hemiprotonated dimers of cytosine derivatives, implicated in the formation of the i-motif of DNA, have been created in solution and the gas phase. The mechanism of dimerization has been analyzed by mass spectrometry and multidimensional NMR spectroscopy.

Hydrocarbon oxidation catalyzed by self-folded metal-coordinated cavitands

Co-reporter:Katherine E. Djernes, Melissa Padilla, Magi Mettry, Michael C. Young and Richard J. Hooley

Chemical Communications 2012 vol. 48(Issue 94) pp:11576-11578

Publication Date(Web):11 Oct 2012

DOI:10.1039/C2CC36236H

Functionalized cavitands have been shown to self-fold via coordination of Fe(II) salts and effect catalytic C–H oxidation reactions of unfunctionalized alkanes under mild aqueous conditions in the presence of tert-butyl hydroperoxide as co-oxidant. Secondary and tertiary C–H bonds can be converted to ketones and alcohols, respectively, and ethers can be converted to esters. The cavitands retain the catalytic metal throughout the reaction, and can be recovered by filtration.

A Membrane-Bound Synthetic Receptor that Promotes Growth of a Polymeric Coating at the BilayerWater Interface

Co-reporter:Ying Liu;Michael C. Young;Orly Moshe; Quan Cheng; Richard J. Hooley

Angewandte Chemie International Edition 2012 Volume 51( Issue 31) pp:7748-7751

Publication Date(Web):

DOI:10.1002/anie.201202635

Protein Recognition by a Self-Assembled Deep Cavitand Monolayer on a Gold Substrate

Co-reporter:Ying Liu, Toshiaki Taira, Michael C. Young, Dariush Ajami, Julius Rebek Jr., Quan Cheng, and Richard J. Hooley

Langmuir 2012 Volume 28(Issue 2) pp:1391-1398

Publication Date(Web):December 10, 2011

DOI:10.1021/la2039398

This paper details the first use of a self-folding deep cavitand on a gold surface. A sulfide-footed deep, self-folding cavitand has been synthesized, and its attachment to a cleaned gold surface studied by electrochemical and SPR methods. Complete monolayer formation is possible if the cavitand folding is templated by noncovalent binding of choline or by addition of space-filling thiols to cover any gaps in the cavitand adsorption layer. The cavitand is capable of binding trimethylammonium-tagged guests from an aqueous medium and can be deposited in 2 × 2 microarrays on the surface for characterization by SPR imaging techniques. When biotin-labeled guests are used, the cavitand:guest construct can recognize and immobilize streptavidin proteins from aqueous solution, acting as an effective supramolecular biosensor for monitoring protein recognition.

Synthesis and Properties of Metal–Ligand Complexes with Endohedral Amine Functionality

Co-reporter:Amber M. Johnson, Orly Moshe, Ana S. Gamboa, Brian W. Langloss, John F. K. Limtiaco, Cynthia K. Larive, and Richard J. Hooley

Inorganic Chemistry 2011 Volume 50(Issue 19) pp:9430-9442

Publication Date(Web):September 8, 2011

DOI:10.1021/ic201092s

A series of tetracationic M2L4 palladium-pyridyl complexes with endohedral amine functionality have been synthesized. The complexes were analyzed by NMR techniques (including Diffusion NMR and 2D NOESY), electrospray ionization (ESI) mass spectrometry, and X-ray crystallography. The solid state analysis shows a large change in crystal morphology upon introduction of the endohedral amine groups, caused by deleterious interactions between the amines and the triflate counterions from the coordination process. Combination of different ligands allows analysis of ligand exchange rates via NMR analysis, with half-lives on the order of 3 h, independent of the donor properties of the ligand. Self-sorting behavior is observed, with more electron-rich ligands being favored. The amine-containing and extended complexes are strongly fluorescent, giving quantum yields of up to 83%.

Protein and Small Molecule Recognition Properties of Deep Cavitands in a Supported Lipid Membrane Determined by Calcination-Enhanced SPR Spectroscopy

Co-reporter:Ying Liu ; Puhong Liao ; Quan Cheng

Journal of the American Chemical Society 2010 Volume 132(Issue 30) pp:10383-10390

Publication Date(Web):July 9, 2010

DOI:10.1021/ja102252d

This paper details the incorporation of a water-soluble deep cavitand into a membrane bilayer assembled onto a nanoglassified surface for study of molecular recognition in a membrane-mimicking setting. The cavitand retains its host properties, and real-time analysis of the host:guest properties of the membrane:cavitand complex via surface plasmon resonance and fluorescence microscopy is described. The host shows selectivity for choline-derived substrates, and no competitive incorporation of substrate is observed in the membrane bilayer. A variety of trimethylammonium-derived substrates are suitable guests, displaying varied binding affinities in a millimolar range. The membrane:cavitand:guest complexes can be subsequently used to capture NeutrAvidin protein at the membrane surface if a biotin-derived guest molecule is used. The surface coverage of NeutrAvidin is affected by the spacer used to derivatize the biotin. Increased distance from the bilayer allows a higher concentration of protein to be immobilized, suggesting a diminishing detrimental steric effect when the binding event is shifted away from the surface.

A Water-Soluble Deep Cavitand Acts as a Release Trigger for a Supramolecular Nanocap

Co-reporter:Rui Liu, Puhong Liao, Zhenyu Zhang, Richard J. Hooley, and Pingyun Feng

Chemistry of Materials 2010 Volume 22(Issue 21) pp:5797

Publication Date(Web):October 13, 2010

DOI:10.1021/cm102298y

Two-component control of guest binding in a self-assembled cage molecule

Co-reporter:Puhong Liao, Brian W. Langloss, Amber M. Johnson, Eric R. Knudsen, Fook S. Tham, Ryan R. Julian and Richard J. Hooley

Chemical Communications 2010 vol. 46(Issue 27) pp:4932-4934

Publication Date(Web):04 Jun 2010

DOI:10.1039/C0CC00234H

A self-assembled M2L4 palladium–pyridyl cluster with a “paddle-wheel” structure shows binding affinity in competitive organic solvents for neutral organic guests that possess both the correct size and electrostatic complementarity.

Two-component control of guest binding in a self-assembled cage molecule

Co-reporter:Puhong Liao, Brian W. Langloss, Amber M. Johnson, Eric R. Knudsen, Fook S. Tham, Ryan R. Julian and Richard J. Hooley

Chemical Communications 2010 - vol. 46(Issue 27) pp:NaN4934-4934

Publication Date(Web):2010/06/04

DOI:10.1039/C0CC00234H

A self-assembled M2L4 palladium–pyridyl cluster with a “paddle-wheel” structure shows binding affinity in competitive organic solvents for neutral organic guests that possess both the correct size and electrostatic complementarity.

Self-promoted post-synthetic modification of metal–ligand M2L3 mesocates

Co-reporter:Michael C. Young, Amber M. Johnson and Richard J. Hooley

Chemical Communications 2014 - vol. 50(Issue 11) pp:NaN1380-1380

Publication Date(Web):2013/12/10

DOI:10.1039/C3CC48444K

Reactive alcohol functionality has been incorporated into a self-assembled M2L3 mesocate. Post-synthetic modification of this complex with suitable isocyanates is not only possible, but is self-catalyzed by multiple internal hydrogen bonds from the self-assembly. As the metal–ligand coordination is reversible at elevated temperature, the isomeric distribution of product changes upon reaction, due to the different steric bulk conferred on the assembly after the modification.

High fidelity sorting of remarkably similar components via metal-mediated assembly

Co-reporter:Lauren R. Holloway, Michael C. Young, Gregory J. O. Beran and Richard J. Hooley

Chemical Science (2010-Present) 2015 - vol. 6(Issue 8) pp:NaN4806-4806

Publication Date(Web):2015/06/02

DOI:10.1039/C5SC01689D

Subtle differences in ligand coordination angle and rigidity lead to high fidelity sorting between individual components displaying identical coordination motifs upon metal-mediated self-assembly. Narcissistic self-sorting can be achieved between highly similar ligands that vary minimally in rigidity and internal coordination angle upon combination with Fe(II) ions and 2-formylpyridine. Selective, sequential cage formation can be precisely controlled in a single flask from a mix of three different core ligands (and 33 total components) differing only in the hybridization of one group that is uninvolved in the metal coordination process.

Colorimetric barbiturate sensing with hybrid spin crossover assemblies

Co-reporter:Michael C. Young, Erica Liew and Richard J. Hooley

Chemical Communications 2014 - vol. 50(Issue 39) pp:NaN5045-5045

Publication Date(Web):2014/04/02

DOI:10.1039/C4CC01805B

Spin crossover complexes based on either iron(II) or iron(III) give a colorimetric response upon self-assembly with barbituric acids. They can be used as visible sensors for these narcotics, selectively detecting barbiturates in the presence of other biologically-relevant hydrogen bonding species.

Achiral endohedral functionality provides stereochemical control in Fe(II)-based self-assemblies

Co-reporter:Michael C. Young, Amber M. Johnson, Ana S. Gamboa and Richard J. Hooley

Chemical Communications 2013 - vol. 49(Issue 16) pp:NaN1629-1629

Publication Date(Web):2013/01/08

DOI:10.1039/C3CC37912D

Multicomponent Fe(II)-iminopyridine-based self-assemblies have been synthesized with variably sized internal functionality. Larger internal functions provide increased strain to the complex and confer diastereocontrol upon the assembly process. Complete diastereocontrol is possible upon the introduction of large achiral groups on the cavity interior.

Spin state modulation of iron spin crossover complexes via hydrogen-bonding self-assembly

Co-reporter:Michael C. Young, Erica Liew, Jonathan Ashby, Kelsi E. McCoy and Richard J. Hooley

Chemical Communications 2013 - vol. 49(Issue 56) pp:NaN6333-6333

Publication Date(Web):2013/05/31

DOI:10.1039/C3CC42851F

Iron complexes derived from 6-diaminotriazyl-2,2′-bipyridines display spin crossover behaviour, and hydrogen bonding-controlled self-assembly with a suitable barbiturate partner can modulate the crossover from mixed low and high spin to high spin. This system is the first to use solution-phase self-assembly of complementary hydrogen-bonding organic species to modulate spin state.

Hydrocarbon oxidation catalyzed by self-folded metal-coordinated cavitands

Co-reporter:Katherine E. Djernes, Melissa Padilla, Magi Mettry, Michael C. Young and Richard J. Hooley

Chemical Communications 2012 - vol. 48(Issue 94) pp:NaN11578-11578

Publication Date(Web):2012/10/11

DOI:10.1039/C2CC36236H

Functionalized cavitands have been shown to self-fold via coordination of Fe(II) salts and effect catalytic C–H oxidation reactions of unfunctionalized alkanes under mild aqueous conditions in the presence of tert-butyl hydroperoxide as co-oxidant. Secondary and tertiary C–H bonds can be converted to ketones and alcohols, respectively, and ethers can be converted to esters. The cavitands retain the catalytic metal throughout the reaction, and can be recovered by filtration.

Structural switching in self-assembled metal–ligand helicate complexes via ligand-centered reactions

Co-reporter:Lauren R. Holloway, Hannah H. McGarraugh, Michael C. Young, Watit Sontising, Gregory J. O. Beran and Richard J. Hooley

Chemical Science (2010-Present) 2016 - vol. 7(Issue 7) pp:

Publication Date(Web):

DOI:10.1039/C6SC01038E

Non-covalent self assembly controls the relaxivity of magnetically active guests

Co-reporter:Vincent Li, Yoo-Jin Ghang, Richard J. Hooley and Travis J. Williams

Chemical Communications 2014 - vol. 50(Issue 11) pp:NaN1377-1377

Publication Date(Web):2013/12/11

DOI:10.1039/C3CC48389D

The relaxivity of a magnetically responsive Gd complex can be controlled by non-covalent molecular recognition with a water-soluble deep cavitand. Lowered relaxivity is conferred by a self-assembled micellar “off state”, and the contrast can be regenerated by addition of a superior guest.

Site selective reading of epigenetic markers by a dual-mode synthetic receptor array

Co-reporter:Yang Liu, Lizeth Perez, Magi Mettry, Adam D. Gill, Samantha R. Byers, Connor J. Easley, Christopher J. Bardeen, Wenwan Zhong and Richard J. Hooley

Chemical Science (2010-Present) 2017 - vol. 8(Issue 5) pp:

Publication Date(Web):

DOI:10.1039/C7SC00865A

Reversible multicomponent self-assembly mediated by bismuth ions

Co-reporter:Amber M. Johnson, Michael C. Young and Richard J. Hooley

Dalton Transactions 2013 - vol. 42(Issue 23) pp:NaN8401-8401

Publication Date(Web):2013/04/15

DOI:10.1039/C3DT50578B

Bi(III) ions are capable of reversible, multicomponent self assembly with suitable tris-coordinate ligands. The nature of the self-assembled structures observed are dependent on the ligand coordination geometry, ligand protonation state and Bi concentration. These assemblies can exploit the maximum number of coordination sites at the Bi vertices (nine), and the self-assembly process has been studied by 1D NMR, Diffusion NMR, ESI-MS and X-ray crystallographic analysis. V-shaped coordinating ligands reversibly form discrete M2L4, M2L3, and M2L2 complexes dependent on ligand/bismuth concentration, whereas a linear coordinating ligand forms a single discrete M3L3 assembly.

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