Computational Design of the Electronic Response for Volatile Organic Compounds Interacting with Doped Graphene Substrates.

Changes in the work function provide a fingerprint to characterize analyte binding in charge transfer-based sensor devices. Hence, a rational sensor design requires a fundamental understanding of the microscopic factors controlling the modification of the work function. In the current investigation, we address the mechanisms behind the work function change (WFC) for the adsorption of four common volatile organic compounds (toluene, ethanol, 2-Furfurylthiol, and guaiacol) on different nitrogen-doped graphene-based 2D materials using density functional theory.

Fracture Behavior of a 2D Imine-Based Polymer.

2D polymers have emerged as a highly promising category of nanomaterials, owing to their exceptional properties. However, the understanding of their fracture behavior and failure mechanisms remains still limited, posing challenges to their durability in practical applications. This work presents an in-depth study of the fracture kinetics of a 2D polyimine film, utilizing in situ tensile testing within a transmission electron microscope (TEM).

On-Water Surface Synthesis of Vinylene-Linked Cationic Two-Dimensional Polymer Films as the Anion-Selective Electrode Coating.

Vinylene-linked two-dimensional polymers (V-2DPs) and their layer-stacked covalent organic frameworks (V-2D COFs) featuring high in-plane π-conjugation and robust frameworks have emerged as promising candidates for energy-related applications. However, current synthetic approaches are restricted to producing V-2D COF powders that lack processability, impeding their integration into devices, particularly within membrane technologies reliant upon thin films. Herein, we report the novel on-water surface synthesis of vinylene-linked cationic 2DPs films (V-C2DP-1 and V-C2DP-2) via Knoevenagel polycondensation, which serve as the anion-selective electrode coating for highly-reversible and durable zinc-based dual-ion batteries (ZDIBs).

Site-selective chemical reactions by on-water surface sequential assembly.

Controlling site-selectivity and reactivity in chemical reactions continues to be a key challenge in modern synthetic chemistry. Here, we demonstrate the discovery of site-selective chemical reactions on the water surface via a sequential assembly approach. A negatively charged surfactant monolayer on the water surface guides the electrostatically driven, epitaxial, and aligned assembly of reagent amino-substituted porphyrin molecules, resulting in a well-defined J-aggregated structure.

Enhancing the Carrier Transport in Monolayer MoS through Interlayer Coupling with 2D Covalent Organic Frameworks.

The coupling of different 2D materials (2DMs) to form van der Waals heterostructures (vdWHs) is a powerful strategy for adjusting the electronic properties of 2D semiconductors, for applications in opto-electronics and quantum computing. 2D molybdenum disulfide (MoS ) represents an archetypical semiconducting, monolayer thick versatile platform for the generation of hybrid vdWH with tunable charge transport characteristics through its interfacing with molecules and assemblies thereof. However, the physisorption of (macro)molecules on 2D MoS yields hybrids possessing a limited thermal stability, thereby jeopardizing their technological applications.

Dithienylethene-Based Single Molecular Photothermal Linear Actuator.

By employing a mechanically controllable break junction technique, we have realized an ideal single molecular linear actuator based on dithienylethene (DTE) based molecular architecture, which undergoes reversible photothermal isomerization when subjected to UV irradiation under ambient conditions. As a result, open form (compressed, UV OFF) and closed form (elongated, UV ON) of dithienylethene-based molecular junctions are achieved. Interestingly, the mechanical actuation is achieved without changing the conductance of the molecular junction around the Fermi level over several cycles, which is an essential property required for an ideal single molecular actuator.

Vinylene-Linked 2D Conjugated Covalent Organic Frameworks by Wittig Reactions.

Vinylene-linked two-dimensional covalent organic frameworks (V-2D-COFs) have shown great promise in electronics and optoelectronics. However, only a few reactions for V-2D-COFs have been developed hitherto. Besides the kinetically low reversibility of C=C bond formation, another underlying issue facing the synthesis of V-2D-COFs is the attainment of high (E)-alkene selectivity to ensure the appropriate symmetry of 2D frameworks.

Assessing the impacts of COVID-19 on activity-travel scheduling: A survey in the greater Toronto area.

The COVID-19 lockdown provided many individuals an opportunity to explore changes in their daily routines, particularly when considered in combination with an ever-changing Information and Communication Technology (ICT) landscape. These new routines and alternative activities have the potential to be continued in the post-COVID era. Transportation planners must understand how routines vary to effectively estimate activity-travel scheduling.

The contribution of intermolecular spin interactions to the London dispersion forces between chiral molecules.

Dispersion interactions are one of the components of van der Waals (vdW) forces that play a key role in the understanding of intermolecular interactions in many physical, chemical, and biological processes. The theory of dispersion forces was developed by London in the early years of quantum mechanics. However, it was only in the 1960s that it was recognized that for molecules lacking an inversion center, such as chiral and helical molecules, there are chirality-sensitive corrections to the dispersion forces proportional to the rotatory power known from the theory of circular dichroism and with the same distance scaling law R as the London energy.

Exploring the similarity of single-layer covalent organic frameworks using electronic structure calculations.

Two-dimensional Covalent Organic Frameworks (2D COFs) have attracted considerable interest because of their potential for a broad range of applications. Different combinations of the monomeric units can lead to potentially novel materials with varying physico-chemical properties. In this study, we investigate the electronic properties of various 2D COFs with square lattice topology based on a tight-binding density functional theory approach.

A Chirality-Based Quantum Leap.

There is increasing interest in the study of chiral degrees of freedom occurring in matter and in electromagnetic fields. Opportunities in quantum sciences will likely exploit two main areas that are the focus of this Review: (1) recent observations of the chiral-induced spin selectivity (CISS) effect in chiral molecules and engineered nanomaterials and (2) rapidly evolving nanophotonic strategies designed to amplify chiral light-matter interactions. On the one hand, the CISS effect underpins the observation that charge transport through nanoscopic chiral structures favors a particular electronic spin orientation, resulting in large room-temperature spin polarizations.

Combination of Knoevenagel Polycondensation and Water-Assisted Dynamic Michael-Addition-Elimination for the Synthesis of Vinylene-Linked 2D Covalent Organic Frameworks.

Vinylene-linked two-dimensional conjugated covalent organic frameworks (V-2D-COFs), belonging to the class of two-dimensional conjugated polymers, have attracted increasing attention due to their extended π-conjugation over the 2D backbones associated with high chemical stability. The Knoevenagel polycondensation has been demonstrated as a robust synthetic method to provide cyano (CN)-substituted V-2D-COFs with unique optoelectronic, magnetic, and redox properties. Despite the successful synthesis, it remains elusive for the relevant polymerization mechanism, which leads to relatively low crystallinity and poor reproducibility.

Control of Crystallinity of Vinylene-Linked Two-Dimensional Conjugated Polymers by Rational Monomer Design.

The interest in two-dimensional conjugated polymers (2D CPs) has increased significantly in recent years. In particular, vinylene-linked 2D CPs with fully in-plane sp -carbon-conjugated structures, high thermal and chemical stability, have become the focus of attention. Although the Horner-Wadsworth-Emmons (HWE) reaction has been recently demonstrated in synthesizing vinylene-linked 2D CPs, it remains largely unexplored due to the challenge in synthesis.

Morphometric study and sexual dimorphism analyses in an Iranian population of (Arachnida: Scorpionidae).

Natural selection and sexual selection are cardinal factors in shaping the body of animals such as scorpions. (Scorpiones: Scorpionidae) has a worldwide distribution. Sexual dimorphism has been reported from this species in a study in Egypt.

Multiscale Modeling Strategy of 2D Covalent Organic Frameworks Confined at an Air-Water Interface.

Two-dimensional covalent organic frameworks (2D COFs) have attracted attention as versatile active materials in many applications. Recent advances have demonstrated the synthesis of monolayer 2D COF via an air-water interface. However, the interfacial 2D polymerization mechanism has been elusive.

Predicting the bulk modulus of single-layer covalent organic frameworks with square-lattice topology from molecular building-block properties.

Two-dimensional Covalent Organic Frameworks (2D COFs) have attracted a lot of interest because of their potential for a broad range of applications. Different combinations of their molecular building blocks can lead to new materials with different physical and chemical properties. In this study, the elasticity of different single-layer tetrabenzoporphyrin (H2-TBPor) and phthalocyanine (H2-Pc) based 2D COFs is numerically investigated using a density-functional based tight-binding approach.

Synthesis of Vinylene-Linked Two-Dimensional Conjugated Polymers via the Horner-Wadsworth-Emmons Reaction.

In this work, we demonstrate the first synthesis of vinylene-linked 2D CPs, namely, 2D poly(phenylenequinoxalinevinylene)s 2D-PPQV1 and 2D-PPQV2, via the Horner-Wadsworth-Emmons (HWE) reaction of C -symmetric 1,4-bis(diethylphosphonomethyl)benzene or 4,4'-bis(diethylphosphonomethyl)biphenyl with C -symmetric 2,3,8,9,14,15-hexa(4-formylphenyl)diquinoxalino[2,3-a:2',3'-c]phenazine as monomers. Density functional theory (DFT) simulations unveil the crucial role of the initial reversible C-C single bond formation for the synthesis of crystalline 2D CPs. Powder X-ray diffraction (PXRD) studies and nitrogen adsorption-desorption measurements demonstrate the formation of proclaimed crystalline, dual-pore structures with surface areas of up to 440 m  g .

Interactions of Long-Chain Polyamines with Silica Studied by Molecular Dynamics Simulations and Solid-State NMR Spectroscopy.

The investigation of molecular interactions between silica phases and organic components is crucial for elucidating the main steps involved in the biosilica mineralization process. In this respect, the structural characterization of the organic/inorganic interface is particularly useful for a deeper understanding of the dominant mechanisms of biomineralization. In this work, we have investigated the interaction of selectively C- and N-labeled atoms of organic long-chain polyamines (LCPAs) with Si-labeled atoms of a silica layer at the molecular level.

Role of Exchange Interactions in the Magnetic Response and Intermolecular Recognition of Chiral Molecules.

The physical origin of the so-called chirality-induced spin selectivity (CISS) effect has puzzled experimental and theoretical researchers over the past few years. Early experiments were interpreted in terms of unconventional spin-orbit interactions mediated by the helical geometry. However, more recent experimental studies have clearly revealed that electronic exchange interactions also play a key role in the magnetic response of chiral molecules in singlet states.

A zinc selective oxytocin based biosensor.

Oxytocin is a peptide hormone with high affinity to both Zn and Cu ions compared to other metal ions. This affinity makes oxytocin an attractive recognition layer for monitoring the levels of these essential ions in biofluids. Native oxytocin cannot differentiate between Cu and Zn ions and hence it is not useful for sensing Zn in the presence of Cu.

Influence of Mesityl and Thiophene Peripheral Substituents on Surface Attachment, Redox Chemistry, and ORR Activity of Molecular Iron Porphyrin Catalysts on Electrodes.

Two iron porphyrin complexes with either mesityl (FeTMP) or thiophene (FeT3ThP) peripheral substituents were attached to basal pyrolytic graphite and Ag electrodes via different immobilization methods. By combining cyclic voltammetry and in-operando surface-enhanced Raman spectroscopy along with MD simulations and DFT calculations, their respective surface attachment, redox chemistry and activity toward electrocatalytic oxygen reduction was investigated. For both porphyrin complexes, it could be shown that catalytic activity is restricted to the first (few) molecular layer(s), although electrodes covered with thiophene-substituted complexes showed a better capability to consume the oxygen at a given overpotential even in thicker films.

Direct Assembly and Metal-Ion Binding Properties of Oxytocin Monolayer on Gold Surfaces.

Peptides are very common recognition entities that are usually attached to surfaces using multistep processes. These processes require modification of the native peptides and of the substrates. Using functional groups in native peptides for their assembly on surfaces without affecting their biological activity can facilitate the preparation of biosensors.

Fully sp -Carbon-Linked Crystalline Two-Dimensional Conjugated Polymers: Insight into 2D Poly(phenylenecyanovinylene) Formation and its Optoelectronic Properties.

Cyano-substituted polyphenylene vinylenes (PPVs) have been the focus of research for several decades owing to their interesting optoelectronic properties and potential applications in organic electronics. With the advent of organic two-dimensional (2D) crystals, the question arose as to how the chemical and optoelectronic advantages of PPVs evolve in 2D compared with their linear counterparts. In this work, we present the efficient synthesis of two novel 2D fully sp -carbon-linked crystalline PPVs and investigate the essentiality of inorganic bases for their catalytic formation.

ITO Work Function Tunability by Polarizable Chromophore Monolayers.

The ability to tune the electronic properties of oxide-bearing semiconductors such as Si/SiO or transparent metal oxides such as indium-tin oxide (ITO) is of great importance in both electronic and optoelectronic device applications. In this work, we describe a process that was conducted on n-type Si/SiO and ITO to induce changes in the substrate work function (WF). The substrates were modified by a two-step synthesis comprising a covalent attachment of coupling agents' monolayer followed by in situ anchoring reactions of polarizable chromophores.