Squeezing formaldehyde into C fullerene.

The cavity inside fullerene C provides a highly symmetric and inert environment for housing atoms and small molecules. Here we report the encapsulation of formaldehyde inside C by molecular surgery, yielding the supermolecular complex CHO@C, despite the 4.4 Å van der Waals length of CHO exceeding the 3.

Atomic-Scale Time-Resolved Imaging of Krypton Dimers, Chains and Transition to a One-Dimensional Gas.

Single-atom dynamics of noble-gas elements have been investigated using time-resolved transmission electron microscopy (TEM), with direct observation providing for a deeper understanding of chemical bonding, reactivity, and states of matter at the nanoscale. We report on a nanoscale system consisting of endohedral fullerenes encapsulated within single-walled carbon nanotubes ((Kr@C)@SWCNT), capable of the delivery and release of krypton atoms on-demand, via coalescence of host fullerene cages under the action of the electron beam () or heat (). The state and dynamics of Kr atoms were investigated by energy dispersive X-ray spectroscopy (EDS), electron energy loss spectroscopy (EELS), and X-ray photoelectron spectroscopy (XPS).

Structure-Reactivity Studies of 2-Sulfonylpyrimidines Allow Selective Protein Arylation.

Protein arylation has attracted much attention for developing new classes of bioconjugates with improved properties. Here, we have evaluated 2-sulfonylpyrimidines as covalent warheads for the mild, chemoselective, and metal free cysteine -arylation. 2-Sulfonylpyrimidines react rapidly with cysteine, resulting in stable -heteroarylated adducts at neutral pH.

Isocyanides as Catalytic Electron Acceptors in the Visible Light Promoted Oxidative Formation of Benzyl and Acyl Radicals.

The recent disclosure of the ability of aromatic isocyanides to harvest visible light and act as single electron acceptors when reacting with tertiary aromatic amines has triggered a renewed interest in their application to the development of green photoredox catalytic methodologies. Accordingly, the present work explores their ability to promote the generation of both alkyl and acyl radicals starting from radical precursors such as Hantzsch esters, potassium alkyltrifluoroborates, and α-oxoacids. Mechanistic studies involving UV-visible absorption and fluorescence experiments, electrochemical measurements of the ground-state redox potentials along with computational calculations of both the ground- and the excited-state redox potentials of a set of nine different aromatic isocyanides provide key insights to promote a rationale design of a new generation of isocyanide-based organic photoredox catalysts.

Correction: Terahertz spectroscopy of the helium endofullerene He@C.

Correction for 'Terahertz spectroscopy of the helium endofullerene He@C' by Tanzeeha Jafari , , 2022, , 9943-9952, https://doi.org/10.1039/D2CP00515H.

Ne, Ar, and Kr oscillators in the molecular cavity of fullerene C60.

We used THz (terahertz) and INS (inelastic neutron scattering) spectroscopies to study the interaction between an endohedral noble gas atom and the C60 molecular cage. The THz absorption spectra of powdered A@C60 samples (A = Ar, Ne, Kr) were measured in the energy range from 0.6 to 75 meV for a series of temperatures between 5 and 300 K.

A combined inelastic neutron scattering and simulation study of the He@C endofullerene.

The He@C endofullerene consists of a single He atom entrapped inside a C fullerene cage. The confining potential, arising from the non-covalent interaction between the enclosed He atom and the C atoms of the cage, is investigated by inelastic neutron scattering. These measurements allow us to obtain information in both energy () and momentum () transfers in the form of the dynamical structure factor (, ).

Double Click: Unexpected 1:2 Stoichiometry in a Norbornene-Tetrazine Reaction.

We report a new reactivity for the inverse electron demand Diels-Alder (iEDDA) reaction between norbornene and tetrazine. Instead of simple 1:1 condensation between norbornene- and tetrazine-conjugated biomolecules, we observed that dimeric products were preferentially formed. As such, an olefinic intermediate formed after the addition of the first tetrazine unit to norbornene rapidly undergoes a consecutive cycloaddition reaction with a second tetrazine unit to result in a conjugate with a 1:2 stoichiometric ratio.

Synthesis of endohedral fullerenes by molecular surgery.

Encapsulation of atoms or small molecules inside fullerenes provides a unique opportunity for study of the confined species in the isolated cavity, and the synthesis of closed C or C fullerenes with enclosed atoms or molecules has recently developed using the method of 'molecular surgery'; in which an open-cage intermediate fullerene is the host for encapsulation of a guest species, before repair of the cage opening. In this work we review the main methods for cage-opening and closure, and the achievements of molecular surgery to date.

Pharmaceutical innovation and access to financial markets.

While prior research shows that pharmaceutical innovation generates measurable benefits for society, over the last 70 years, the innovative activities of pharmaceutical firms have dramatically declined. In this study, we develop and test the hypothesis that to innovate, pharmaceutical firms must have access to capital through well-developed financial markets. Using a broad cross-country sample from 1989 to 2016, we document that financial market development is associated with greater levels of pharmaceutical innovation.

A practical flow synthesis of 1,2,3-triazoles.

A robust and versatile protocol for synthesis of 1-monosubstituted and 1,4-disubstituted 1-1,2,3-triazoles was established under continuous flow conditions using copper-on-charcoal as a heterogeneous catalyst. This methodology allowed for the synthesis of a diverse set of substituted 1,2,3-triazoles with good functional group tolerance and high yields. 2-Ynoic acids were also used as small-chain alkyne donors in a decarboxylation/cycloaddition cascade, allowing gaseous reagents to be bypassed, delivering desired triazoles in high yields.

Synthesis and Kr NMR spectroscopy of Kr@C.

Synthesis of Kr@C is achieved by quantitative high-pressure encapsulation of the noble gas into an open-fullerene, and subsequent cage closure. Krypton is the largest noble gas entrapped in C using 'molecular surgery' and Kr@C is prepared with >99.4% incorporation of the endohedral atom, in 4% yield from C.

Lobbying and lending by banks around the financial crisis by.

Despite the unprecedented levels of liquidity provided by the Federal Reserve to banks during the 2007-2008 financial crisis, lending by banks slowed dramatically during and after that global episode. In this study, we propose that, given capital constraints, the lobbying expenditures by banks to combat Dodd-Frank might have crowded out lending activity. A variety of univariate and multivariate tests show that while lending by banks fell significantly around the financial crisis, lobbying rose dramatically.

Terahertz spectroscopy of the helium endofullerene He@C.

We studied the quantized translational motion of single He atoms encapsulated in molecular cages by terahertz absorption. The temperature dependence of the THz absorption spectra of He@C and He@C crystal powder samples was measured between 5 and 220 K. At 5 K there is an absorption line at 96.

Experimental determination of the interaction potential between a helium atom and the interior surface of a C fullerene molecule.

The interactions between atoms and molecules may be described by a potential energy function of the nuclear coordinates. Nonbonded interactions between neutral atoms or molecules are dominated by repulsive forces at a short range and attractive dispersion forces at a medium range. Experimental data on the detailed interaction potentials for nonbonded interatomic and intermolecular forces are scarce.

Chemical shielding of HO and HF encapsulated inside a C cage.

Molecular surgery provides the opportunity to study relatively large molecules encapsulated within a fullerene cage. Here we determine the location of an HO molecule isolated within an adsorbed buckminsterfullerene cage, and compare this to the intrafullerene position of HF. Using normal incidence X-ray standing wave (NIXSW) analysis, coupled with density functional theory and molecular dynamics simulations, we show that both HO and HF are located at an off-centre position within the fullerene cage, caused by substantial intra-cage electrostatic fields generated by surface adsorption of the fullerene.

Infrared spectroscopy of an endohedral water in fullerene.

An infrared absorption spectroscopy study of the endohedral water molecule in a solid mixture of HO@C and C was carried out at liquid helium temperature. From the evolution of the spectra during the ortho-para conversion process, the spectral lines were identified as para-HO and ortho-HO transitions. Eight vibrational transitions with rotational side peaks were observed in the mid-infrared: ω, ω, ω, 2ω, 2ω, ω + ω, ω + ω, and 2ω + ω.

On the Ethics of "Non-Corporate" Insider Trading.

The ethical considerations of insider trading have been widely debated in the academic literature (see e.g., Moore in J Bus Ethics 9(3):171-182, 1990).

A Solid-State Intramolecular Wittig Reaction Enables Efficient Synthesis of Endofullerenes Including Ne@C , He@C , and HD@C.

An open-cage fullerene incorporating phosphorous ylid and carbonyl group moieties on the rim of the orifice can be filled with gases (H , He, Ne) in the solid state, and the cage opening then contracted in situ by raising the temperature to complete an intramolecular Wittig reaction, trapping the atom or molecule inside. Known transformations complete conversion of the product fullerene to C containing the endohedral species. As well as providing an improved synthesis of large quantities of He@C , H @C , and D @C , the method allows the efficient incorporation of expensive gases such as HD and He, to prepare HD@C and He@C .

Enantiomer-specific activities of an LRH-1 and SF-1 dual agonist.

Chirality is an important consideration in drug development: it can influence recognition of the intended target, pharmacokinetics, and off-target effects. Here, we investigate how chirality affects the activity and mechanism of action of RJW100, a racemic agonist of the nuclear receptors liver receptor homolog-1 (LRH-1) and steroidogenic factor-1 (SF-1). LRH-1 and SF-1 modulators are highly sought as treatments for metabolic and neoplastic diseases, and RJW100 has one of the few scaffolds shown to activate them.

Rotational coherence of encapsulated ortho and para water in fullerene-C revealed by time-domain terahertz spectroscopy.

We resolve the real-time coherent rotational motion of isolated water molecules encapsulated in fullerene-C cages by time-domain terahertz (THz) spectroscopy. We employ single-cycle THz pulses to excite the low-frequency rotational motion of water and measure the subsequent coherent emission of electromagnetic waves by water molecules. At temperatures below ~ 100 K, C lattice vibrational damping is mitigated and the quantum dynamics of confined water are resolved with a markedly long rotational coherence, extended beyond 10 ps.

An Internuclear -Coupling of He Induced by Molecular Confinement.

The solution-state C NMR spectrum of the endofullerene He@C displays a doublet structure due to a -coupling of magnitude 77.5 ± 0.2 mHz at 340 K between the He nucleus and a C nucleus of the enclosing carbon surface.

Bond Dissociation and Reactivity of HF and HO in a Nano Test Tube.

Molecular motion and bond dissociation are two of the most fundamental phenomena underpinning the properties of molecular materials. We entrapped HF and HO molecules within the fullerene C cage, encapsulated within a single-walled carbon nanotube (X@C)@SWNT, where X = HF or HO. (X@C)@SWNT represents a class of molecular nanomaterial composed of a guest within a molecular host within a nanoscale host, enabling investigations of the interactions of isolated single di- or triatomic molecules with the electron beam.

Synthesis of Ar@C using molecular surgery.

Synthesis of Ar@C60 is described, using a route in which high-pressure argon filling of an open-fullerene and photochemical desulfinylation are the key steps for >95% encapsulation of the noble gas. Enrichment by recycling HPLC leads to quantitative incorporation of argon in the product endofullerene, with a mass recovery of tens of milligrams, allowing the first characterisation of fine structure in the solution 13C NMR spectrum.

Fine structure in the solution state C-NMR spectrum of C and its endofullerene derivatives.

The C NMR spectrum of fullerene C in solution displays two small "side peaks" on the shielding side of the main C peak, with integrated intensities of 1.63% and 0.81% of the main peak.