Partially Sulfated Pillar[5]Arenes: Synthesis and Molecular Recognition Properties.

We report the synthesis and characterization of sulfated pillar[5]arene hosts (P5S-P5S) that differ in the number of sulfate substituents. All five P5S hosts display high solubility in water (73-131 mM) and do not undergo significant self-association according to H NMR dilution experiments. The x-ray crystal structures of P5S, P5S ⋅ MeHDA, P5S ⋅ MeHDA, and P5S ⋅ MeHDA reveal one intracavity molecule of MeHDA and several external molecules of MeHDA which form a network of close methonium ⋅ ⋅ ⋅ sulfate interactions.

Insoluble Acyclic Cucurbit[n]uril-Type Receptors Capture Iodine from the Vapor Phase.

Nuclear energy makes large contributions toward meeting global energy needs, but societal concerns remain high given the impacts of the intended release of radioactive materials including I and I. In this paper we explore the use of a homologous series of acyclic CB[n] type hosts (H1-H4) as adsorbents of iodine from the vapor phase. We find that H2-H4, but not H1 - perform well in this application with uptake capacities of 2.

Structural Diversity in 2-(2-Aminoethyl)pyridine-Based Lead Iodide Hybrids.

While 2D metal-organic hybrids have emerged as promising solar absorbers due to their improved moisture stability, their inferior transport properties limit their potential translation into devices. We report a new hybrid containing 2-(2-ammonioethyl)pyridine [(2-AEP)], forming a 2D hybrid with the composition (2-AEP)PbI. The organic bilayer comprises of (2-AEP), which is arranged in a face-to-face stacking that promotes π-π interactions between neighboring pyridyl rings.

Acyclic Cucurbit[n]uril Receptors Function as Solid State Sequestrants for Organic Micropollutants.

The accumulation of organic micropollutants (OMP) in aquatic systems is a major societal problem that can be addressed by approaches including nanofiltration, flocculation, reverse osmosis and adsorptive methods using insoluble materials (e.g. activated carbon, MOFs, nanocomposites).

Thermodynamics of Pillararene•Guest Complexation: Blinded Dataset for the SAMPL9 Challenge.

We report an investigation of the complexation between a water soluble pillararene host (WP6) and a panel of hydrophobic cationic guests (G1 - G20) by a combination of H NMR spectroscopy and isothermal titration calorimetry in phosphate buffered saline. We find that WP6 forms 1:1 complexes with K values in the 10 - 10 M range driven by favorable enthalpic contributions. This thermodynamic dataset serves as blinded data for the SAMPL9 challenge.

Contrasting Bonding Extremes in Two [Ge] Complexes: A Wadian Polyhedron ( = 2) versus a Hydrocarbon-like 2c-2e Polygermanide ( = 12).

[Nb(η-CHMe)] reacts with ethylenediamine (en) solutions of KGe in the presence of 18-crown-6 to give [(η-CHMe)NbHGe] () and [(η-CHMe)NbGeNb(η-CHMe)] () as their corresponding [K(18-crown-6)] salts. The crystalline solids are dark brown, air-sensitive, and sparingly soluble or insoluble in most solvents. The [K(18-crown-6)] salts of cluster ions and have been characterized by energy-dispersive X-ray (EDX) analysis, NMR studies, single-crystal X-ray diffraction, and electrospray ionization time-of-flight (ESI-TOF) mass spectrometry studies.

Orbital Contribution to Paramagnetism and Noninnocent Thiophosphate Anions in Layered LiMPS Where M = Fe and Co.

Transition-metal thiophosphates and selenophosphates are layered systems with the potential for displaying two-dimensional (2D) magnetic phenomena. We present the crystal structures and magnetic properties of two lithium transition-metal thiophosphates, LiCoPS and LiFePS. The previously unreported LiCoPS crystallizes in the trigonal space group 31 with lattice parameters = 6.

Fe-catalyzed three-component dicarbofunctionalization of unactivated alkenes with alkyl halides and Grignard reagents.

A highly chemoselective iron-catalyzed three-component dicarbofunctionalization of unactivated olefins with alkyl halides (iodides and bromides) and sp-hybridized Grignard reagents is reported. The reaction operates under fast turnover frequency and tolerates a diverse range of sp-hybridized nucleophiles (electron-rich and electron-deficient (hetero)aryl and alkenyl Grignard reagents), alkyl halides (tertiary alkyl iodides/bromides and perfluorinated bromides), and unactivated olefins bearing diverse functional groups including tethered alkenes, ethers, protected alcohols, aldehydes, and amines to yield the desired 1,2-alkylarylated products with high regiocontrol. Further, we demonstrate that this protocol is amenable for the synthesis of new (hetero)carbocycles including tetrahydrofurans and pyrrolidines a three-component radical cascade cyclization/arylation that forges three new C-C bonds.

Microwave-Assisted Synthesis of Organometallic Rhenium (I) Pentylcarbonato Complexes: New Synthon for Carboxylato, Sulfonato and Chlorido Complexes.

Tricarbonylrhenium(I)(α-diimine) complexes are of importance because of their strong cytotoxic and fluorescence properties. Syntheses of such complexes were achieved through a two-step process. First, the pentylcarbonato complexes, -(CO)(α-diimine)ReOC(O)OCH were synthesized through a microwave-assisted reaction of Re(CO), α-diimine, 1-pentanol and CO in a few hours.

[Cp*RuPb] and [Cu@Cp*RuPb]: centered and non-centered transition-metal substituted zintl icosahedra.

Cluster anions [Cp*RuPb] (1) and [Cu@Cp*RuPb] (2) represent the first vertex-substituted zintl icosahedra and 1 is the first non-centered zintl icosahedron isolated in the condensed phase. Complexes 1 and 2 are both 12-vertex, 26-electron closo-clusters with C point symmetry and are static on the Pb NMR time scale in solution.

Acyclic Cucurbit[n]uril-Type Receptors: Aromatic Wall Extension Enhances Binding Affinity, Delivers Helical Chirality, and Enables Fluorescence Sensing.

We report the linear extension from M1 to M2 to anthracene walled M3 which adopts a helical conformation (X-ray) to avoid unfavorable interactions between sidewalls. M3 is water soluble (=30 mm) and displays enhanced optical properties (ϵ=1.28×10  m  cm , λ =370 nm) relative to M2.

Acyclic Cucurbit[]uril-Type Receptors: Optimization of Electrostatic Interactions for Dicationic Guests.

The synthesis of acyclic CB[]-type host () is reported. By optimizing the placement of the sulfate groups nearby the electrostatically negative ureidyl C═O portals, the binding affinity of this class of receptors toward hydrophobic (di)ammonium guest molecules (-) is maximized. The X-ray crystal structures of and · are reported.

Oxidation of 8-thioguanosine gives redox-responsive hydrogels and reveals intermediates in a desulfurization pathway.

A disulfide made by oxidation of 8-thioguanosine is a supergelator. The hydrogels are redox-responsive, as they disassemble upon either reduction or oxidation of the S-S bond. We also identified this disulfide, and 2 other compounds, as intermediates in oxidative desulfurization of 8-thioG to guanosine.

Pillar[n]MaxQ: A New High Affinity Host Family for Sequestration in Water.

We report the synthesis, X-ray crystal structure, and molecular recognition properties of pillar[n]arene derivative P[6]AS, which we refer to as Pillar[6]MaxQ along with analogues P[5]AS and P[7]AS toward guests 1-18. The ultratight binding affinity of P[5]AS and P[6]AS toward quaternary (di)ammonium ions renders them prime candidates for in vitro and in vivo non-covalent bioconjugation, for imaging and delivery applications, and as in vivo sequestration agents.

Triptycene Walled Glycoluril Trimer: Synthesis and Recognition Properties.

We report the synthesis of a new acyclic CB[n]-type host (1) that features a central glycoluril trimer capped by triptycene sidewalls. Host 1 has good solubility in water (≈ 3 mM) and does not undergo strong self-association (K = 480 M). We probed the geometry of the complexes by analyzing the complexation induced changes in the H NMR spectra and measured the complexation thermodynamics by isothermal titration calorimetry.

An Electron-Poor Dioxa-[2.1.1]-(2,6)-pyridinophane Ligand and Its Application in Cu-Catalyzed Olefin Aziridination.

A novel macrocyclic 1,7-dioxa-[2.1.1]-(2,6)-pyridinophane ligand has been synthesized and crystallographically characterized.

Drawing with Iron on a Gel Containing a Supramolecular Siderophore.

Guanosine-5'-hydroxamic acid (3) forms hydrogels when mixed with guanosine (1) and KCl. The 5'-hydroxamic acid (HA) unit is pH-responsive and also chelates Fe . When gels are prepared under basic conditions, the 5'-HA groups are deprotonated and the anionic hydrogel binds cationic thiazole orange (TO), signaled by enhanced fluorescence.

Identifying the components of the solid-electrolyte interphase in Li-ion batteries.

The importance of the solid-electrolyte interphase (SEI) for reversible operation of Li-ion batteries has been well established, but the understanding of its chemistry remains incomplete. The current consensus on the identity of the major organic SEI component is that it consists of lithium ethylene di-carbonate (LEDC), which is thought to have high Li-ion conductivity, but low electronic conductivity (to protect the Li/C electrode). Here, we report on the synthesis and structural and spectroscopic characterizations of authentic LEDC and lithium ethylene mono-carbonate (LEMC).

Triazole functionalized acyclic cucurbit[n]uril-type receptors: host·guest recognition properties.

We report the synthesis of three new triazole functionalized acyclic CB[n]-type receptors (2-4) by click chemistry. The compounds have good solubility in water (≥8 mM) and do not undergo strong self-association (Ks ≤ 903 M-1). We measured the binding constants of 2-4 toward guests 9-24 and compared the results to those obtained for the prototypical acyclic CB[n]-type receptor 1.

Acyclic Cucurbit[n]uril Type Receptors: Secondary Versus Tertiary Amide Arms.

Two acyclic CB[]-type hosts ( and ) which possess four 2° or 3° amide arms are reported; and are slightly soluble in water and do not self-associate. Host has four 3° amide arms that exist as a mixture of E- and Z-isomers. H NMR was used to qualitatively investigate the binding properties of and which indicates they retain the essential binding features of macrocyclic CB[] hosts (e.

Two- and three-dimensional coordination polymers based on zinc(II) and furan-2,5-dicarboxylic acid: structure variation due to metal-to-linker ratio.

Two Zn-based coordination polymers (CPs) were synthesized by the hydrothermal method, using Zn(NO)·6HO and furan-2,5-dicarboxylic acid (FDCA) in dimethylformamide (DMF) solvent, at 95 °C. Poly[tetrakis(dimethylazanium) [tetrakis(μ-furan-2,5-dicarboxylato-κO:O)dizinc(II)]], {(CHN)[Zn(CHO)]} or {[DMA][Zn(FDC)]} (DMA = dimethylazanium and FDC = furan-2,5-dicarboxylate), (1), was obtained with a 1:1 molar ratio of Zn and FDCA. It crystallized in the monoclinic space group C2/c.

Two furan-2,5-dicarboxylic acid solvates crystallized from dimethylformamide and dimethyl sulfoxide.

Furan-2,5-dicarboxylic acid (FDCA) has been ranked among the top 12 bio-based building-block chemicals by the Department of Energy in the US. The molecule was first synthesized in 1876, but large-scale production has only become possible since the development of modern bio- and chemical catalysis techniques. The structures of two FDCA solvates, namely, FDCA dimethylformamide (DMF) disolvate, CHO·2CHNO, (I), and FDCA dimethyl sulfoxide (DMSO) monosolvate, CHO·CHOS, (II), are reported.

Hybrid Molecular Container Based on Glycoluril and Triptycene: Synthesis, Binding Properties, and Triggered Release.

We designed and synthesized a "hybrid" molecular container 1, which is structurally related to both cucurbit[n]uril (CB[n]) and pillar[n]arene type receptors. Receptor 1 was fully characterized by H NMR, C NMR, IR, MS and X-ray single crystal diffraction. The self-association behavior, host-guest recognition properties of 1, and the [salt] dependence of K were investigated in detail by H NMR and isothermal titration calorimetry (ITC).

Crystal structures of 5,5'-bis(-hydroxy-methyl)-3,3'-biisoxazole and 4,4',5,5'-tetrakis-(hydroxy-methyl)-3,3'-biisoxazole.

The mol-ecular structure of 5,5'-bis(-hydroxy-methyl)-3,3'-biisoxazole, CHNO (), is composed of two planar isoxazole rings [r.m.s deviation = 0.

Blurring the Lines between Host and Guest: A Chimeric Receptor Derived from Cucurbituril and Triptycene.

We report the synthesis and X-ray crystal structure of a cucurbituril-triptycene chimeric receptor (1). Host 1 binds to guests typical of CB[6]-CB[8], but also binds to larger guests such as blue box (20) and the Fujita square (22). Intriguingly, the geometries of the 1⋅20 and 1⋅22 complexes blur the lines between host and guest in that both components fulfill both roles within each complex.