Molten Metal Synthesis of Nanographenes.

This manuscript describes a simple and effective method to cyclodehydrogenate arenes using liquid alkali metals. Direct reaction between molten potassium and arenes forms 6-membered rings and zigzag edged structures within polyarenes. The approach is extended to integration of pyridinic nitrogen and 5-membered rings to arene structures and synthesis of larger, open-shell nanographenes.

Evaluating the Ability of External Electric Fields to Accelerate Reactions in Solution.

This study investigates the catalytic effects of external electric fields (EEFs) on two reactions in solution: the Menshutkin reaction and the Chapman rearrangement. Utilizing a scanning tunneling microscope-based break-junction (STM-BJ) setup and monitoring reaction rates through high-performance liquid chromatography connected to a UV detector (HPLC-UV) and ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-q-ToF-MS), we observed no rate enhancement for either reaction under ambient conditions. Density functional theory (DFT) calculations indicate that electric field-induced changes in reactant orientation and the minimization of activation energy are crucial factors in determining the efficacy of EEF-driven catalysis.

Electrochemical Doping of Two-Dimensional Superatomic Materials.

We report an electrochemical method for doping two-dimensional (2D) superatomic semiconductor ReSeCl that significantly improves the material's electrical transport while retaining the in-plane and stacking structures. The electrochemical reduction induces the complete dissociation of chloride anions from the surface of each superatomic nanosheet. After the material is dehalogenated, we observe the electrical conductivity () increases by two orders of magnitude while the 3D electron carrier density () increases by three orders of magnitude.

Effective Gating in Single-Molecule Junctions through Fano Resonances.

The successful incorporation of molecules as active circuit elements relies on the ability to tune their electronic properties through chemical design. A synthetic strategy that has been used to manipulate and gate circuit conductance involves attaching a pendant substituent along the molecular conduction pathway. However, such a chemical gate has not yet been shown to significantly modify conductance.

Near-Infrared, Organic Chiroptic Switch with High Dissymmetry Factors.

Here we unveil a chiral molecular redox switch derived from PDI-based twistacenes─ that has the remarkable attributes of high-intensity and a broadband chiral response. This material exhibits facile, stable, and reversible multistate chiroptical switching behavior over a broad active wavelength range close to 700 nm, encompassing ultraviolet, visible, and near-infrared regions. Upon reduction, exhibits a substantial increase in the amplitude of its circular dichroic response, with an outstanding |ΔΔε| > 300 M cm and a high dissymmetry factor of 3 × 10 at 960 nm.

Electron and Spin Delocalization in [Co Se (PEt ) ] Superatoms.

Molecular clusters can function as nanoscale atoms/superatoms, assembling into superatomic solids, a new class of solid-state materials with designable properties through modifications on superatoms. To explore possibilities on diversifying building blocks, here we thoroughly studied one representative superatom, Co Se (PEt ) . We probed its structural, electronic, and magnetic properties and revealed its detailed electronic structure as valence electrons delocalize over inorganic [Co Se ] core while ligands function as an insulated shell.

Interplay between Local Moment and Itinerant Magnetism in the Layered Metallic Antiferromagnet TaFeTe.

Two-dimensional antiferromagnets have garnered considerable interest for the next generation of functional spintronics. However, many bulk materials from which two-dimensional antiferromagnets are isolated are limited by their air sensitivity, low ordering temperatures, and insulating transport properties. TaFeTe aims to address these challenges with increased air stability, metallic transport, and robust antiferromagnetism.

Functional Monolayers on a Superatomic Pegboard.

We advance the chemistry of apical chlorine substitution in the 2D superatomic semiconductor ReSeCl to build functional and atomically precise monolayers on the surface of the 2D superatomic ReSe substrate. We create a functional monolayer by installing surface (2,2'-bipyridine)-4-sulfide (Sbpy) groups that chelate to catalytically active metal complexes. Through this reaction chemistry, we can create monolayers where we can control the distribution of catalytic sites.

Electric fields drive bond homolysis.

Electric fields have been used to control and direct chemical reactions in biochemistry and enzymatic catalysis, yet directly applying external electric fields to activate reactions in bulk solution and to characterize them remains a challenge. Here we utilize the scanning tunneling microscope-based break-junction technique to investigate the electric field driven homolytic cleavage of the radical initiator 4-(methylthio)benzoic peroxyanhydride at ambient temperatures in bulk solution, without the use of co-initiators or photochemical activators. Through time-dependent quantification by high performance liquid chromatography using a UV-vis detector, we find that the electric field catalyzes the reaction.

A few-layer covalent network of fullerenes.

The two natural allotropes of carbon, diamond and graphite, are extended networks of sp-hybridized and sp-hybridized atoms, respectively. By mixing different hybridizations and geometries of carbon, one could conceptually construct countless synthetic allotropes. Here we introduce graphullerene, a two-dimensional crystalline polymer of C that bridges the gulf between molecular and extended carbon materials.

Interfacial electric fields catalyze Ullmann coupling reactions on gold surfaces.

The electric fields created at solid-liquid interfaces are important in heterogeneous catalysis. Here we describe the Ullmann coupling of aryl iodides on rough gold surfaces, which we monitor using the scanning tunneling microscope-based break junction (STM-BJ) and using mass spectrometry and fluorescence spectroscopy. We find that this Ullmann coupling reaction occurs only on rough gold surfaces in polar solvents, the latter of which implicates interfacial electric fields.

Single-Handed Helicene Nanoribbons via Transfer of Chiral Information.

Here we show the access to single-handed helicene nanoribbons by utilizing a [6]helicene building block to induce diastereoselective, photochemical formation of [5]helicene units. Specifically, we have synthesized nanoribbons and with different ratios of [6]helicene "sergeants" to [5]helicene "soldiers", which on average consist of between ∼50 and 60 -annulated benzene rings. These are the longest, optically active helicene backbones that have been prepared to date.

Correction: Electric-field-induced coupling of aryl iodides with a nickel(0) complex.

Correction for 'Electric-field-induced coupling of aryl iodides with a nickel(0) complex' by Nicholas M. Orchanian , , 2022, https://doi.org/10.

Electric-field-induced coupling of aryl iodides with a nickel(0) complex.

The formation of carbon-carbon bonds with transition metal reagents serves as a cornerstone of organic synthesis. Here, we show that the reactivity of an otherwise kinetically inert transition metal complex can be induced by an external electric field to affect a coupling reaction. These results highlight the importance of electric field effects in reaction chemistry and offers a new strategy to modulate organometallic reactivity.

Inducing Singlet Fission in Perylene Thin Films by Molecular Contortion.

Singlet fission occurs only in a limited number of molecules, and expanding the molecular toolbox is necessary for progress. Here, we apply the molecular contortion strategy to tune singlet and triplet energies and observe changes in the excited-state dynamics that are consistent with singlet fission playing a role in thin films of contorted perylene. Perylene is a prototypical molecular chromophore, which does not undergo singlet fission in its planar form from its S state.

Remote Control of Dynamic Twistacene Chirality.

We report a reliable way to manipulate the dynamic, axial chirality in perylene diimide (PDI)-based twistacenes. Specifically, we reveal how chiral substituents on the imide position induce the helicity in a series of PDI-based twistacenes. We demonstrate that this remote chirality is able to control the helicity of flexible [4]helicene subunits by UV-vis, CD spectroscopy, X-ray crystallography, and TDDFT calculations.

Iterative Synthesis of Contorted Macromolecular Ladders for Fast-Charging and Long-Life Lithium Batteries.

We report here an iterative synthesis of long helical perylene diimide () nanoribbons with a length up to 16 fused benzene rings. These contorted, ladder-type conjugated, and atomically precise nanoribbons show great potential as organic fast-charging and long-lifetime battery cathodes. By tuning the length of the oligomers, we can simultaneously modulate the electrical conductivity and ionic diffusivity of the material.

Highly conducting single-molecule topological insulators based on mono- and di-radical cations.

Single-molecule topological insulators are promising candidates as conducting wires over nanometre length scales. A key advantage is their ability to exhibit quasi-metallic transport, in contrast to conjugated molecular wires which typically exhibit a low conductance that decays as the wire length increases. Here, we study a family of oligophenylene-bridged bis(triarylamines) with tunable and stable mono- or di-radicaloid character.

Broad-band Chiral Absorbance of Visible Light.

The amplification of chiral absorbance and emission is a primary figure of merit for the design of chiral chromophores. However, for dyes to be practically relevant in chiroptical applications, they must also absorb and/or emit chiral light over broad wavelength ranges. We investigate the interplay between molecular symmetry and broad-band chiral absorbance in a series of [6]helicenes.

Superatom Regiochemistry Dictates the Assembly and Surface Reactivity of a Two-Dimensional Material.

The area of two-dimensional (2D) materials research would benefit greatly from the development of synthetically tunable van der Waals (vdW) materials. While the bottom-up synthesis of 2D frameworks from nanoscale building blocks holds great promise in this quest, there are many remaining hurdles, including the design of building blocks that reliably produce 2D lattices and the growth of macroscopic crystals that can be exfoliated to produce 2D materials. Here we report the regioselective synthesis of the cluster [-CoSe(CN)(CO)], a "superatomic" building block designed to polymerize and assemble into a 2D cyanometalate lattice whose surfaces are chemically addressable.

Site-Selective Surface Modification of 2D Superatomic ReSe.

Coating two-dimensional (2D) materials with molecules bearing tunable properties imparts their surfaces with functionalities for applications in sensing, nanoelectronics, nanofabrication, and electrochemistry. Here, we report a method for the site-selective surface functionalization of 2D superatomic ReSeCl monolayers. First, we activate bulk layered ReSeCl by intercalating lithium and then exfoliate the intercalation compound LiReSeCl in -methylformamide (NMF).

High-Performance Organic Electronic Materials by Contorting Perylene Diimides.

Perylene diimide (PDI) is a workhorse of the organic electronics community. However, the vast majority of designs that include PDI substitute the core with various functional groups to encourage intimate cofacial contacts between largely planar PDIs. Over the past several years, we have observed the counterintuitive result that contorting the planar aromatic core of PDI leads to higher performing photovoltaics, photodetectors, batteries, and other organic electronic devices.

Controlling Ligand Coordination Spheres and Cluster Fusion in Superatoms.

We show that reaction pathways from a single superatom motif can be controlled through subtle electronic modification of the outer ligand spheres. Chevrel-type [CoSeL] (L = PR, CO) superatoms are used to form carbene-terminated clusters, the reactivity of which can be influenced through the electronic effects of the surrounding ligands. This carbene provides new routes for ligand substitution chemistry, which is used to selectively install cyanide or pyridine ligands which were previously inaccessible in these cobalt-based clusters.

A single-molecule blueprint for synthesis.

Chemical reactions that occur at nanostructured electrodes have garnered widespread interest because of their potential applications in fields including nanotechnology, green chemistry and fundamental physical organic chemistry. Much of our present understanding of these reactions comes from probes that interrogate ensembles of molecules undergoing various stages of the transformation concurrently. Exquisite control over single-molecule reactivity lets us construct new molecules and further our understanding of nanoscale chemical phenomena.