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Chiral organic molecules possessing high quantum yields, circular dichroism, and circularly polarized luminescence values have great potential as optically active materials for future applications. Recently, the identification of a promising class of inherently chiral compounds was reported, namely macrocyclic 1,3‐butadiyne‐linked pseudo‐meta[2.2]paracyclophanes, displaying high circular dichroism and related gabs values albeit modest quantum yields. Increasing the quantum yields in an attempt to get bright circularly polarized light emitters, the high‐yielding heterocyclization of those 1,3‐butadiyne bridges resulting in macrocyclic 2,5‐thienyls‐linked pseudo‐meta [2.2]paracyclophanes is herein described. The chiroptical properties of both, the previously reported 1,3‐butadiyne, and the novel 2,5‐thienyl bridged macrocycles of various sizes, are experimentally recorded, and theoretically described using density‐functional theory. [ABSTRACT FROM AUTHOR]

The development of water‐soluble hosts for the selective recognition of aromatic amino acids is highly desirable and may serve as a tool to facilitate drug discovery and enable fabrication of sensors for point‐of‐care monitoring in the context of phenylketonuria disease. This paper presents the synthesis and characterization of a water‐soluble molecular cleft which is demonstrated to selectively bind aromatic amino acid guests over other amino acids in aqueous medium, favoring ʟ‐Trp over ʟ‐Phe and ʟ‐Tyr by a factor of approximately five. Host/guest‐interaction forces were studied by 1H‐NMR titrations complemented by fluorescence titrations and isothermal titration calorimetry. The here presented results provide a starting point for future optimizations in our efforts to selectively identify and quantify individual aromatic amino acids in aqueous medium. [ABSTRACT FROM AUTHOR]

Control over the electrical contact to an individual molecule is one of the biggest challenges in molecular optoelectronics. The mounting of individual chromophores on extended tripodal scaffolds enables both efficient electrical and mechanical decoupling of individual chromophores from metallic leads. Core-substituted naphthalene diimides fixed perpendicular to a gold substrate by a covalently attached extended tripod display high stability with well-defined and efficient electroluminescence down to the single-molecule level. The molecularly controlled spatial arrangement balances the electric conduction for electroluminescence and the insulation to avoid non-radiative carrier recombination, enabling the spectrally and spatially resolved electroluminescence of individual self-decoupled chromophores in a scanning tunneling microscope. Hot luminescence bands are even visible in single self-decoupled chromophores, documenting the mechanical decoupling between the vibrons of the chromophore and the substrate. A fundamental challenge for molecular electronics is the change in photophysical properties of molecules upon direct electrical contact. Here, the authors observe hot luminescence emitted by single-molecule chromophores that are electrically and mechanically self-decoupled by a tripodal scaffold. [ABSTRACT FROM AUTHOR]

Microfluidic systems are widely used in fundamental research and industrial applications due to their unique behavior, enhanced control, and manipulation opportunities of liquids in constrained geometries. In micrometer-sized channels, electric fields are efficient mechanisms for manipulating liquids, leading to deflection, injection, poration or electrochemical modification of cells and droplets. While PDMS-based microfluidic devices are used due to their inexpensive fabrication, they are limited in terms of electrode integration. Using silicon as the channel material, microfabrication techniques can be used to create nearby electrodes. Despite the advantages that silicon provides, its opacity has prevented its usage in most important microfluidic applications that need optical access. To overcome this barrier, silicon-on-insulator technology in microfluidics is introduced to create optical viewports and channel-interfacing electrodes. More specifically, the microfluidic channel walls are directly electrified via selective, nanoscale etching to introduce insulation segments inside the silicon device layer, thereby achieving the most homogeneous electric field distributions and lowest operation voltages feasible across microfluidic channels. These ideal electrostatic conditions enable a drastic energy reduction, as effectively shown via picoinjection and fluorescence-activated droplet sorting applications at voltages below 6 and 15 V, respectively, facilitating low-voltage electric field applications in next-generation microfluidics. [ABSTRACT FROM AUTHOR]

A molecular cage encapsulating gold nanoparticles is presented. Six benzylic thioethers are pointing into its cavity, stabilizing the particles in a 1 : 1 ligand-to-particle-ratio in excellent yields. They are bench-stable for several months and can withstand unprecedented thermal stress of up to 130 °C, documenting the advantages of the cage-type stabilization over open-chain analogues. [ABSTRACT FROM AUTHOR]

The exploration of new materials is timeless. Especially 2D‐materials have gotten much interest in the last decades. This work proposes a new route towards a fascinating class of 2D materials: molecular textiles. The suggested bottom‐up approach focuses on the 2D self‐assembly of a cross‐shaped monomer at the water/air interface. A 3D cross‐shaped motive was designed, synthesized, and characterized, which exhibits the required structural features, i. e., static and dynamic control. Analysis of the cross‐shaped motive by 1H‐NMR spectroscopy, X‐ray structure, and chiral stationary phase HPLC proved the rigidity and stability of the system, and thus also its potential for the here suggested new strategy towards molecular textiles. Three variants of a Schiff‐base precursor pair functionalized monomer were synthesized and characterized by 1H‐NMR spectroscopy, 13C‐NMR spectroscopy, and mass spectrometry. Finally, the network formation of the monomer is shown to be triggered by deprotonation of its ammonium salt, corroborated with FT‐IR analysis. [ABSTRACT FROM AUTHOR]

Orthogonal joints, understood as connections with an angle of 90°, were introduced in the design of the "Geländer" model compounds 1 and 2. The banister, consisting of a conjugated carbazole dimer linked by either 1,3‐butadiyne (2) or a single thiophene (1), wraps around an axis composed of a phthalimide dimer due to the dimensional mismatch of both subunits, which are interconnected by phenylene rungs. The "Geländer" structure was assembled from a monomer comprising the 1,4‐diaminobenzene rung with one amino substituent as part of a 4‐bromo phthalimide subunit forming the orthogonal junction to the axis, and the other as part of a masked 2‐ethynyl carbazole as orthogonal joint to the banister. The macrocycle was obtained by two sequential homocoupling steps. A first dimerization by a reductive homocoupling assembled the axis, while an oxidative acetylene coupling served as ring‐closing reaction. The formed butadiyne was further derivatized to a thiophene, rendering all carbons of the model compound sp2 hybridized. Both helical structures were fully characterized and chirally resolved. Assignment of the enantiomers was achieved by simulation of chiroptical properties and enantiopure synthesis. [ABSTRACT FROM AUTHOR]

The synthetic access to macrocyclic molecular topologies with interesting photophysical properties has greatly improved thanks to the successful implementation of organic and inorganic corner units. Based on recent reports, we realized that pseudo‐meta [2.2]paracyclophanes (PCPs) might serve as optimal corner units for constructing 3D functional materials, owing to their efficient electronic communication, angled substituents and planar chirality. Herein, we report the synthesis, characterization and optical properties of four novel all‐carbon enantiopure macrocycles bearing three to six pseudo‐meta PCPs linked by 1,3‐butadiyne units. The macrocycles were obtained by a single step from enantiopure, literature‐known dialkyne pseudo‐meta PCP and were unambiguously identified and characterized by state of the art spectroscopic methods and in part even by x‐ray crystallography. By comparing the optical properties to relevant reference compounds, it is shown that the pseudo‐meta PCP subunit effectively elongates the conjugated system throughout the macrocyclic backbone, such that already the smallest macrocycle consisting of only three subunits reaches a polymer‐like conjugation length. Additionally, it is shown that the chiral pseudo‐meta PCPs induce a remarkable chiroptical response in the respective macrocycles, reaching unprecedented high molar circular dichroism values for all‐carbon macrocycles of up to 1307 L mol−1 cm−1. [ABSTRACT FROM AUTHOR]

Ablation of materials in combination with element‐specific analysis of the matter released is a widely used method to accurately determine a material's chemical composition. Among other methods, repetitive ablation using femto‐second pulsed laser systems provides excellent spatial resolution through its incremental removal of nanometer thick layers. The method can be combined with high‐resolution mass spectrometry, for example, laser ablation ionization mass spectrometry, to simultaneously analyze chemically the material released. With increasing depth of the volume ablated, however, secondary effects start to play an important role and the ablation geometry deviates substantially from the desired cylindrical shape. Consequently, primarily conical but sometimes even more complex, rather than cylindrical, craters are created. Their dimensions need to be analyzed to enable a direct correlation with the element‐specific analytical signals. Here, a post‐ablation analysis method is presented that combines generic polydimethylsiloxane‐based molding of craters with the volumetric reconstruction of the crater's inverse using X‐ray computed tomography. Automated analysis yields the full, sub‐micron accurate anatomy of the craters, thereby a scalable and generic method to better understand the fundamentals underlying ablation processes applicable to a wide range of materials. Furthermore, it may serve toward a more accurate determination of heterogeneous material's composition for a variety of applications without requiring time‐ and labor‐intensive analyses of individual craters. [ABSTRACT FROM AUTHOR]

We report the design of a synthetically easy accessible axial chirality-inducing framework for a chromophore of choice. The scaffold consists of two basic para-phenylene-ethynylene backbones separated by laterally placed corner units. Substitution with an inherently achiral chromophore at the 2 and 5 positions of the central phenylene excitonically couples the chromophore associated transition and thereby results in chiroptical properties. Using 6-methoxynaphthalene as a model chromophore, we present the synthesis, structural analysis and spectroscopic investigation of the framework. The chiral framework was synthesized in three straightforward synthetic steps and fully characterized. The obtained racemic compounds were resolved using HPLC and assignment of the absolute configuration was performed using the exciton chirality method, crystallography and DFT calculations. This simple yet potent framework might prove useful to enrich the structural diversity of chiral materials. [ABSTRACT FROM AUTHOR]

A new type of "Geländer" molecule based on a ortho‐tetraphenylene core is presented. The central para‐quaterphenyl backbone is wrapped by a 4,4'‐di((Z)‐styryl)‐1,1'‐biphenyl banister, with its aryl rings covalently attached to all four phenyl rings of the backbone. The resulting helical chiral bicyclic architecture consists exclusively of sp2‐hybridized carbon atoms. The target structure was assembled by expanding the central ortho‐tetraphenylene subunit with the required additional phenyl rings followed by a twofold macrocyclization. The first macrocyclization attempts based on a twofold McMurry coupling were successful but low yielding; the second strategy, profiting from olefin metathesis, provided satisfying yields. Hydrogenation of the olefins resulted in a saturated derivative of similar topology, thereby allowing the interdependence between saturation and physico‐chemical properties to be studied. The target structures, including their solid‐state structures, were fully characterized. The helical chiral bicycle was synthesized as a racemate and separated into pure enantiomers by HPLC on a chiral stationary phase. Comparison of recorded and simulated chiroptical properties allowed the enantiomers to be assigned. [ABSTRACT FROM AUTHOR]

This paper reports the efficient synthesis, absorption and emission spectra, and the electrochemical properties of a series of 2,6‐disubstituted naphthalene‐1,4,5,8‐tetracarboxdiimide (NDI) tripodal molecules with thioacetate anchors for their surface investigations. Our studies showed that, in particular, the pyrrolidinyl group with its strong electron‐donating properties enhanced the fluorescence of such core‐substituted NDI chromophores and caused a significant bathochromic shift in the absorption spectrum with a correspondingly narrowed bandgap of 1.94 eV. Cyclic voltammetry showed the redox properties of NDIs to be influenced by core substituents. The strong electron‐donating character of pyrrolidine substituents results in rather high HOMO and LUMO levels of ‐5.31 and ‐3.37 eV when compared with the parental unsubstituted NDI. UHV‐STM measurements of a sub‐monolayer of the rigid tripodal NDI chromophores spray deposited on Au(111) show that these molecules mainly tend to adsorb flat in a pairwise fashion on the surface and form unordered films. However, the STML experiments also revealed a few molecular clusters, which might consist of upright oriented molecules protruding from the molecular island and show electroluminescence photon spectra with high electroluminescence yields of up to 6×10−3. These results demonstrate the promising potential of the NDI tripodal chromophores for the fabrication of molecular devices profiting from optical features of the molecular layer. [ABSTRACT FROM AUTHOR]

Nanopatterned surfaces enhance incident electromagnetic radiation and thereby enable the detection and characterization of self‐assembled monolayers (SAMs), for instance in surface‐enhanced Raman spectroscopy (SERS). Herein, Au nanohole arrays, developed and characterized as SERS substrates, are exemplarily used for monitoring a solid‐phase deprotection and a subsequent copper(I)‐catalyzed azide–alkyne cycloaddition "click" reaction, performed directly on the corresponding SAMs. The SERS substrate was found to be highly reliable in terms of signal reproducibility and chemical stability. Furthermore, the intermediates and the product of the solid‐phase synthesis were identified by SERS. The spectra of the immobilized compounds showed minor differences compared to spectra of the microcrystalline solids. With its uniform SERS signals and the high chemical stability, the platform paves the way for monitoring molecular manipulations in surface functionalization applications. [ABSTRACT FROM AUTHOR]

Copyright of Angewandte Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The novel diacetylene bridged terphenylic macrocycle 1 is presented and discussed in the context of rotationally restricted "Geländer" oligomers. The 1,4‐bis(phenylbuta‐1,3‐diyn‐1‐yl) benzene bridge of diacetylene 1 is significantly longer than its terphenyl backbone, forcing the bridge to bend around the central pylon. The synthesis of molecule 1 is based to a large extent on acetylene scaffolding strategies, profiting from orthogonal alkyne protection groups to close both macrocyclic subunits by oxidative acetylene coupling sequentially. The spatial arrangement and the dynamic enantiomerization process of the bicyclic target structure 1 are analyzed. In‐depth NMR investigations not only reveal an unexpected spatial arrangement with both oligomer strands bent alongside the backbone, but also display the limited stability of the model compound in the presence of molecular oxygen. [ABSTRACT FROM AUTHOR]

Functional molecular groups mounted on specific foot structures are ideal model systems to study intermolecular interactions, due to the possibility to separate the functionality and the adsorption mechanism. Here, we report on the rotational switching of a thioacetate group mounted on a tripodal tetraphenylmethane (TPM) derivative adsorbed in ordered islands on a Au(111) surface. Using low temperature scanning tunnelling microscopy, individual freestanding molecular groups of the lattice can be switched between two bistable orientations. The functional dependence of this rotational switching on the sample bias and tip–sample distance allows us to model the energy landscape of this molecular group as an electric dipole in the electric field of the tunnelling junction. As expected for the interaction of two dipoles, we found states of neighbouring molecules to be correlated. [ABSTRACT FROM AUTHOR]

The coordination sphere of the Fe(II) terpyridine complex 1 is rigidified by fourfold interlinking of both terpyridine ligands. Profiting from an octa‐aldehyde precursor complex, the ideal dimensions of the interlinking structures are determined by reversible Schiff‐base formation, before irreversible Wittig olefination provided the rigidified complex. Reversed‐phase HPLC enables the isolation of the all‐trans isomer of the Fe(II) terpyridine complex 1, which is fully characterized. While temperature independent low‐spin states were recorded with superconducting quantum interference device (SQUID) measurements for both, the open precursor 8 and the interlinked complex 1, evidence of the increased rigidity of the ligand sphere in 1 was provided by proton T2 relaxation NMR experiments. The ligand sphere fixation in the macrocyclized complex 1 even reaches a level resisting substantial deformation upon deposition on an Au(111) surface, as demonstrated by its pristine form in a low temperature ultra‐high vacuum scanning tunneling microscope experiment. [ABSTRACT FROM AUTHOR]

The coordination sphere of the Fe(II) terpyridine complex 1 is rigidified by fourfold interlinking of both terpyridine ligands. Profiting from an octa‐aldehyde precursor complex, the ideal dimensions of the interlinking structures are determined by reversible Schiff‐base formation, before irreversible Wittig olefination provided the rigidified complex. Reversed‐phase HPLC enables the isolation of the all‐trans isomer of the Fe(II) terpyridine complex 1, which is fully characterized. While temperature independent low‐spin states were recorded with superconducting quantum interference device (SQUID) measurements for both, the open precursor 8 and the interlinked complex 1, evidence of the increased rigidity of the ligand sphere in 1 was provided by proton T2 relaxation NMR experiments. The ligand sphere fixation in the macrocyclized complex 1 even reaches a level resisting substantial deformation upon deposition on an Au(111) surface, as demonstrated by its pristine form in a low temperature ultra‐high vacuum scanning tunneling microscope experiment. [ABSTRACT FROM AUTHOR]

Using a tripodal, thioether‐based ligand comprising a remote protected acetylene, we efficiently stabilize small gold nanoparticles (Ø ≈ 1.2 nm) which are isolated and purified by chromatography. The 1:1 ligand‐to‐particle ratio is obtained by comparing the particles' dimensions measured by transmission electron microscopy with the weight fraction of the coating ligand determined by thermogravimetric analysis. The single ligand coating of the gold particle guarantees the presence of a single masked alkyne per particle. It can be addressed by wet chemical protocols providing the particles with the properties of "massive molecules". The "massive molecule" nature of the particles is demonstrated by involving them in wet chemical coupling protocols like oxidative acetylene coupling providing gold nanoparticle dimers (34 % isolated yield) or alkyne‐azide "click"‐chemistry with a suitable triazide, giving trimeric particle architectures (30 % determined by transmission electron microscopy). The particle stabilization obtained by the coating ligand allows, for the first time, to treat these multi‐particle architectures by size exclusion chromatography. [ABSTRACT FROM AUTHOR]

Studies of neutral biomolecules in the gas phase allow for the study of molecular properties in the absence of solvent and charge effects, thus complementing spectroscopic and analytical methods in solution or in ion traps. Some properties, such as the static electronic susceptibility, are best accessed in experiments that act on the motion of the neutral molecules in an electric field. Here, we screen seven peptides for their thermal stability and electron impact ionizability. We identify two tripeptides as sufficiently volatile and thermostable to be evaporated and interfered in the long‐baseline universal matter‐wave interferometer. Monitoring the deflection of the interferometric molecular nanopattern in a tailored external electric field allows us to measure the static molecular susceptibility of Ala–Trp–Ala and Ala–Ala–Trp bearing fluorinated alkyl chains at C‐ and N‐termini. The respective values are 4πε0×330±150Å3 and 4πε0×270±80Å3. [ABSTRACT FROM AUTHOR]

Achiral chromophoric hosts, i.e. acyclic cucurbit[n]urils and molecular tweezers, were found to respond with characteristic Circular Dichroism (CD) spectra to the presence of micromolar concentrations of chiral hydrocarbons, terpenes, steroids, amino acids and their derivates, and drugs in water. In favourable cases, this allows for analyte identification or for reaction monitoring. [ABSTRACT FROM AUTHOR]

The development of molecular materials for conversion of solar energy into electricity and fuels is one of the most active research areas, in which the light absorber plays a key role. While copper(I)‐bis(diimine) complexes [CuI(L)2]+ are considered as potent substitutes for [RuII(bpy)3]2+, they exhibit limited structural integrity as ligand loss by substitution can occur. In this article, we present a new concept to stabilize copper bis(phenanthroline) complexes by macrocyclization of the ligands which are preorganized around the CuI ion. Using oxidative Hay acetylene homocoupling conditions, several CuI complexes with varying bridge length were prepared and analyzed. Absorption and emission properties are assessed; rewardingly, the envisioned approach was successful since the flexible 1,4‐butadiyl‐bridged complex does show enhanced MLCT absorption and emission, as well as improved photostability upon irradiation with a blue LED compared to a reference complex. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis of the enantiomers of trinorbornane, a tetracyclic saturated hydrocarbon with the chemical formula C11H16. The preparation of these rigid carbon scaffolds was enabled by the successful chiral separation of its tricyclic precursor, thus allowing the enantiomers to be synthesized through a reductive radical cyclization reaction. Assignment of the absolute conformation of the enantiomers was achieved through VCD experiments. Further, we report an alternative cyclization procedure providing access to hydroxyl and phenyl sulfone functionalized trinorbornanes. [ABSTRACT FROM AUTHOR]

Copyright of Synthesis is the property of Georg Thieme Verlag Stuttgart and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A method for the transformation of organic thioacetates, a widely used functionality for the preparation of self‐assembled monolayers on gold surfaces, into unsymmetrical disulfides is reported. Disulfides are readily immobilized on gold in contrast to thioacetates, which usually require a deprotection step prior to bonding to the metal surface. The potential of the method for the controlled preparation of unsymmetrical disulfides has been demonstrated with model compounds comprising several thioacetates, which were readily converted into the corresponding unsymmetrical disulfides. [ABSTRACT FROM AUTHOR]

Charge reduction and neutralization of electro-sprayed peptides are realized by selective gas-phase photocleavage of tailored covalent tags. The concept is demonstrated with four model peptides in positive and negative ion modes and tagged insulin as the largest construct. [ABSTRACT FROM AUTHOR]

A new concept to improve the reliability of functional single molecule junctions is presented using the E‐field triggered switching of FeIIbis‐terpyridine complexes in a mechanically controlled break junction experiment as model system. The complexes comprise a push‐pull ligand sensing the applied E‐field and the resulting distortion of the FeII ligand field is expected to trigger a spin‐crossover event reflected in a sudden jump of the transport current. By molecular engineering, the active centre of the complex is separated from the gold electrodes in order to eliminate undesired side‐effects. Two aspects are considered to isolate the central metal ion, namely the spacing by introducing additional alkynes, and the steric shielding achieved by bulky isopropyl groups. With this small series of model complexes, a pronounced correlation is observed between the occurrence of bistable junctions and the extent of separation of the central metal ion, affirming the hypothesized Enhanced Separation Concept (ESC). [ABSTRACT FROM AUTHOR]

The synthesis of two water‐soluble oligophenylene‐ethynylene (OPE)‐rods with substituted iso‐ and terephthalate end groups is presented. Both undergo slow association with a Diederich‐type cyclophane in aqueous solution. Formation of [2]pseudorotaxanes occurs with reaction half‐lives of several hours. Characterization of the supermolecules by 1H‐NMR spectroscopy reveals a high thermodynamic stability and kinetic inertness of the pseudorotaxanes. The phthalate precursors are functionalized with peripheral azide groups, which make them modular precursors for construction of mechanically interlocked molecules in water. [ABSTRACT FROM AUTHOR]

[2.2]Paracyclophane is the prototypical layered hydrocarbon and has been essential for investigations of through‐space electronic interactions. Over the last years more examples of tetrasubstituted derivatives have been reported. This minireview discusses the synthetic approaches towards various substitution patterns and provides a survey over different approaches used to achieve and derivatize symmetric tetrasubstitution. The first two sections of this work present homo‐tetrasubstituted derivatives, while the third section gives insight into symmetrically hetero‐tetrasubstituted analogues. These approaches are briefly discussed, the resulting structures are presented in detail, and their specific properties resulting from the incorporation of [2.2]paracyclophane are elucidated. [ABSTRACT FROM AUTHOR]

Four molecules containing identical tripodal anchors and p-oligophenylene molecular wires of increasing length were used to demonstrate tuning of the asymmetric molecular junction to the desired geometry by probabilistic mapping of single molecule junction configurations in a scanning tunnelling microscopy break junction experiment. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of zwitterionic molecular [c2]‐ and [a2]‐daisy chains are described, relying on recognition of a positively charged cyclophane and a negatively charged oligo(phenylene‐ethynylene) (OPE) rod in aqueous medium. For this purpose, syntheses of an acetylene‐functionalized macrocyclic receptor and a water‐soluble OPE‐rod as the guest component are presented, from which a heteroditopic daisy chain monomer was prepared. This monomer aggregated strongly in water/methanol 4:1 and formed molecular daisy chains, which were isolated as interlocked species from a stoppering reaction at 1 mm concentration. The cyclic dimer [c2] was the main product with an isolated yield of 30 % and consisted of a mixture of diastereomers, as evidenced by 1H NMR spectroscopy. Assembling daisy chains: Synthesis and characterization of interlocked zwitterionic molecular [c2]‐ and [a2]‐daisy chains are described. The daisy chains were obtained by assembly in aqueous medium of a stopper unit and a heteroditopic monomer, which was prepared by reacting an acetylene‐functionalized cyclophane and a water‐soluble oligo(phenylene‐ethynylene) rod. [ABSTRACT FROM AUTHOR]

Macrocycle 1 is assembled as smallest member of a series of “Geländer” oligomers with a conjugated banister comprising exclusively sp2‐ and sp‐hybridized carbon atoms. The synthesis of 1 is based on an acetylene scaffolding approach, comprising Sonogashira cross‐coupling reactions in combination with protection group strategies and a final cyclization based on an oxidative acetylene coupling using Eglinton‐Breslow reaction conditions. Macrocycle 1 serves as model compound for the investigation of the structural integrity of the strained 1,3‐diyne subunit. An enhanced reactivity of the strained 1,3‐diyne subunit is documented by its engagement in Huisgen's (2+3) cycloaddition when exposed to an azide at elevated temperature. Both structures, macrocycle 1 and cycloaddition‐product 2, are fully characterized including their solid‐state structure obtained by X‐ray diffraction analysis. [ABSTRACT FROM AUTHOR]

Abstract: In order to coat the entire surface of gold nanoparticles (AuNPs) by a single ligand, tripodal macromolecules comprising benzylic thioethers coordinating to the AuNP surface are synthesized and their abilities to stabilize AuNPs are investigated. Out of the five studied ligands 1–5, the tetraphenylmethane‐based oligomers 4 and 5 display excellent AuNP coating features. Both ligand structures are able to control the dimensions of the AuNPs by stabilizing particles of narrow size distributions during their syntheses (1.05 ± 0.28 nm for Au‐4, and 1.15 ± 0.34 nm for Au‐5). Closer inspection of these AuNPs by transmission electron microscopy and thermogravimetric analyses suggests that single ligands 4 and 5 are able to stabilize entire AuNPs. These particles Au‐4 and Au‐5 are obtained in good yields and display promising thermal stabilities (110 °C for Au‐4, and 95 °C for Au‐5), making them interesting nanoscale inorganic–organic building blocks for further functionalization/processing by wet chemistry. [ABSTRACT FROM AUTHOR]