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A pair of enantiopure [6]‐azairidahelicenes incorporating chirality at the metal center and on the helicenic ligand were synthesized by dynamic kinetic resolution (dkr) of a configurationally labile [4]‐helicenic ligand (4‐(2‐pyridyl)‐benzo[g]phenanthrene, L1H) using bis‐cyclometalated chiral‐at‐metal only iridium(III) precursors as chiral inductors. The origin of the observed dkr is attributed to the different conformation and stability of diastereomeric reaction intermediates formed during the cyclometalation process. The isolated enantiomers exhibited circularly polarized phosphorescence (CPP), with |gphos| values of 1.8×10−3. [ABSTRACT FROM AUTHOR]

A pair of enantiopure [6]‐azairidahelicenes incorporating chirality at the metal center and on the helicenic ligand were synthesized by dynamic kinetic resolution (dkr) of a configurationally labile [4]‐helicenic ligand (4‐(2‐pyridyl)‐benzo[g]phenanthrene, L1H) using bis‐cyclometalated chiral‐at‐metal only iridium(III) precursors as chiral inductors. The origin of the observed dkr is attributed to the different conformation and stability of diastereomeric reaction intermediates formed during the cyclometalation process. The isolated enantiomers exhibited circularly polarized phosphorescence (CPP), with |gphos| values of 1.8×10−3. [ABSTRACT FROM AUTHOR]

Chiral metallo‐supramolecular fibres can be easily obtained by mixing a chloroform solution of a phenylacetylene monomer (PA) that bears a chiral sulfoxide group as pendant, with different equivalents of a methanolic solution of AgClO4. Thus, while the PA is found molecularly dissolved in chloroform, the addition of Ag+ ions induce its aggregation through the formation of an axially chiral metallo‐supramolecular aggregate with high thermal stable properties. In this case, the ability of the metal ion to coordinate the PA triple bond, combined with the argentophilicity of the metal ion and the planarity of the phenylacetylene drives to the formation of a helical coordination polymer, whose P or M axial chirality is determined by the chirality of the sulfoxide used as substituent of the PA. Depending on the PA/Ag+ (mol/mol) ratio, it is possible to tune the morphology of the metallo‐supramolecular aggregate from chiral fibers to chiral gel. [ABSTRACT FROM AUTHOR]

Chiral metallo‐supramolecular fibres can be easily obtained by mixing a chloroform solution of a phenylacetylene monomer (PA) that bears a chiral sulfoxide group as pendant, with different equivalents of a methanolic solution of AgClO4. Thus, while the PA is found molecularly dissolved in chloroform, the addition of Ag+ ions induce its aggregation through the formation of an axially chiral metallo‐supramolecular aggregate with high thermal stable properties. In this case, the ability of the metal ion to coordinate the PA triple bond, combined with the argentophilicity of the metal ion and the planarity of the phenylacetylene drives to the formation of a helical coordination polymer, whose P or M axial chirality is determined by the chirality of the sulfoxide used as substituent of the PA. Depending on the PA/Ag+ (mol/mol) ratio, it is possible to tune the morphology of the metallo‐supramolecular aggregate from chiral fibers to chiral gel. [ABSTRACT FROM AUTHOR]

Transition metal (Ni, Pd, Pt) promoted carbocyclizations of alkenes and alkynes have been computationally investigated to rationalize the easiness or difficulty of such processes depending on the size of the forming ring. Special emphasis has been placed on measuring the activation barriers and the exo versus endo selectivities of the processes. The study leads us to propose some qualitative rules for metal controlled ring closures, noting some discrepancies with the classical Baldwin's rules for nonmetallic cyclizations. Also, some unexpected results were found, like the extremely low activation barriers for 3-exo-dig and 3-exo-trig closures, contrasting with the scarcity of such experimental procedures, which can be computationally interpreted by the reversibility and endergonicity of cyclopropane/cyclopropene ring formation in the presence of these metals. The consistency of the present rules has been further checked by introduction of selected structural variations in the substrates. [ABSTRACT FROM AUTHOR]

Described herein is a straightforward synthesis of the monocyclic triterpene achilleol A using as key step titanium(III) chemistry. This synthesis confirms the previously described structure based on spectroscopic methods. [Copyright &y& Elsevier]

Proposes a mechanism for the synthesis of cyclic terpenoids based on the radical opening of acyclic epoxypolyenes. Elimination of hydrogen in intermediate organotitanium; Cyclization of epoxide; Detection of an intermediate cyclic radicals; Formation of bicyclic products.

Helical polymers such as poly(phenylacetylene)s (PPAs) are interesting materials due to the possibility of tuning their helical scaffold (sense and elongation) once they have been prepared and by the presence of external stimuli. The main limitation in the application of PPAs is their poor photostability. These polymers degrade under visible light exposure through a photochemical electrocyclization process. In this work, it was demonstrated, through a selected example, how the photochemical degradation in PPAs is directly related to their dynamic helical behavior. Thus, while PPAs with dynamic helical structures show poor photostability under UV/Vis light exposure, poly‐(R)‐1, bearing an enantiopure sulfoxide group as pendant group and designed to have a quasi‐static helical behavior, shows a large photostability due to the restricted conformational composition at the polyene backbone, needed to orient the conjugated double bonds prior to the photochemical electrocyclization process and the subsequent degradation of the material. [ABSTRACT FROM AUTHOR]

Helical polymers such as poly(phenylacetylene)s (PPAs) are interesting materials due to the possibility of tuning their helical scaffold (sense and elongation) once they have been prepared and by the presence of external stimuli. The main limitation in the application of PPAs is their poor photostability. These polymers degrade under visible light exposure through a photochemical electrocyclization process. In this work, it was demonstrated, through a selected example, how the photochemical degradation in PPAs is directly related to their dynamic helical behavior. Thus, while PPAs with dynamic helical structures show poor photostability under UV/Vis light exposure, poly‐(R)‐1, bearing an enantiopure sulfoxide group as pendant group and designed to have a quasi‐static helical behavior, shows a large photostability due to the restricted conformational composition at the polyene backbone, needed to orient the conjugated double bonds prior to the photochemical electrocyclization process and the subsequent degradation of the material. [ABSTRACT FROM AUTHOR]

This document, published in the journal Angewandte Chemie, highlights several research findings in the field of chemistry. One study discusses the synthesis of enantiopure irida[6]helicenes, which exhibit mirrored electronic circular dichroism and circularly polarized phosphorescence signals. Another study explores the use of the CF3 group as a synthon in palladium chemistry. Additionally, researchers demonstrate a selective shift in energy storage mechanism in aqueous aluminum-ion batteries through the engineering of oxygen vacancies in the α-MoO3 structure. Lastly, a scientific perspective proposes a unified set of triple E priorities (environment, economy, equity) to guide efforts in sustainable chemistry. [Extracted from the article]

This document is a summary of various articles published in the journal Angewandte Chemie International Edition. The articles cover a range of topics including the synthesis of enantiopure irida[6]helicenes, the use of CF3 groups in palladium chemistry, the engineering of oxygen vacancies in αMoO3 for energy storage in aluminum-ion batteries, and a proposal for a unified set of priorities in sustainable chemistry. The articles are authored by various researchers and provide valuable insights into these areas of study. [Extracted from the article]

In this work a family of multidimensional (2‐(1H‐tetrazol‐5‐yl)ethyl) amino acid coordination compounds have been synthesized and thoroughly characterized. For this purpose, glycine, valine, phenylalanine and tyrosine have been selected as starting amino acids and Mn2+, Zn2+ and Cd2+ as metallic nodes. From one side, for Mn2+ based dimer magnetic resonance imaging studies have been conducted, prompted by the number and disposition of the coordinated water molecules and taking into consideration the promising future of manganese‐based coordination compounds as bio‐compatible substitutes to conventional Gd based contrast agents. From another side, d10 block metal‐based complexes allowed exploring photoluminescence properties derived by in situ synthesized ligands. Finally, amino acid preserved structural chirality allowed us to examine chiroptical properties, particularly focusing on circularly polarized luminescence. [ABSTRACT FROM AUTHOR]

Reports on the Michael reaction of stabilized carbon nucleophiles catalyzed by the ruthenium complex. Nature of the catalytic species and the essential role played by the phosphine in the reaction system; Intramolecular aldol reactions; Catalysis with other ruthenium and rhodium complexes.

Lanthanides have unique photoluminescence (PL) emission properties, including very long PL lifetimes. This makes them ideal for biological imaging applications, especially using PL lifetime imaging microscopy (PLIM). PLIM is an inherently multidimensional technique with exceptional advantages for quantitative biological imaging. Unfortunately, due to the required prolonged acquisitions times, photobleaching of lanthanide PL emission currently constitutes one of the main drawbacks of PLIM. In this study, we report a small aqueous‐soluble, lanthanide antenna, 8‐methoxy‐2‐oxo‐1,2,4,5‐tetrahydrocyclopenta[de]quinoline‐3‐phosphonic acid, PAnt, specifically designed to dynamically interact with lanthanide ions, serving as exchangeable dye aimed at mitigating photobleaching in PLIM microscopy in cellulo. Thus, self‐assembled lanthanide complexes that may be photobleached during image acquisition are continuously replenished by intact lanthanide antennas from a large reservoir. Remarkably, our self‐assembled lanthanide complex clearly demonstrated a significant reduction of PL photobleaching when compared to well‐established lanthanide cryptates, used for bioimaging. This concept of exchangeable lanthanide antennas opens new possibilities for quantitative PLIM bioimaging. [ABSTRACT FROM AUTHOR]

Lanthanides have unique photoluminescence (PL) emission properties, including very long PL lifetimes. This makes them ideal for biological imaging applications, especially using PL lifetime imaging microscopy (PLIM). PLIM is an inherently multidimensional technique with exceptional advantages for quantitative biological imaging. Unfortunately, due to the required prolonged acquisitions times, photobleaching of lanthanide PL emission currently constitutes one of the main drawbacks of PLIM. In this study, we report a small aqueous‐soluble, lanthanide antenna, 8‐methoxy‐2‐oxo‐1,2,4,5‐tetrahydrocyclopenta[de]quinoline‐3‐phosphonic acid, PAnt, specifically designed to dynamically interact with lanthanide ions, serving as exchangeable dye aimed at mitigating photobleaching in PLIM microscopy in cellulo. Thus, self‐assembled lanthanide complexes that may be photobleached during image acquisition are continuously replenished by intact lanthanide antennas from a large reservoir. Remarkably, our self‐assembled lanthanide complex clearly demonstrated a significant reduction of PL photobleaching when compared to well‐established lanthanide cryptates, used for bioimaging. This concept of exchangeable lanthanide antennas opens new possibilities for quantitative PLIM bioimaging. [ABSTRACT FROM AUTHOR]

The development of chiral compounds with enhanced chiroptical properties is an important challenge to improve device applications. To that end, an optimization of the electric and magnetic dipole transition moments of the molecule is necessary. Nevertheless, the relationship between chemical structure and such quantum mechanical properties is not always clear. That is the case of magnetic dipole transition moment (m) for which no general trends for its optimization have been suggested. In this work we propose a general rationalization for improving the magnitude of m in different families of chiral compounds. Performing a clustering analysis of hundreds of transitions, we have been able to identify a single group in which |m| value is maximized along the helix axis. More interestingly, we have found an accurate linear relationship (up to R2=0.994) between the maximum value of this parameter and the area of the inner cavity of the helix, thus resembling classical behavior of solenoids. This research provides a tool for the rationalized synthesis of compounds with improved chiroptical responses. [ABSTRACT FROM AUTHOR]

The development of chiral compounds with enhanced chiroptical properties is an important challenge to improve device applications. To that end, an optimization of the electric and magnetic dipole transition moments of the molecule is necessary. Nevertheless, the relationship between chemical structure and such quantum mechanical properties is not always clear. That is the case of magnetic dipole transition moment (m) for which no general trends for its optimization have been suggested. In this work we propose a general rationalization for improving the magnitude of m in different families of chiral compounds. Performing a clustering analysis of hundreds of transitions, we have been able to identify a single group in which |m| value is maximized along the helix axis. More interestingly, we have found an accurate linear relationship (up to R2=0.994) between the maximum value of this parameter and the area of the inner cavity of the helix, thus resembling classical behavior of solenoids. This research provides a tool for the rationalized synthesis of compounds with improved chiroptical responses. [ABSTRACT FROM AUTHOR]

A cyclophane is reported incorporating two units of a heptagon‐containing extended polycyclic aromatic hydrocarbon (PAH) analogue of the hexa‐peri‐hexabenzocoronene (HBC) moiety (hept‐HBC). This cyclophane represents a new class of macrocyclic structures that incorporate for the first time seven‐membered rings within extended PAH frameworks. The saddle curvature of the hept‐HBC macrocycle units induced by the presence of the nonhexagonal ring along with the flexible alkyl linkers generate a cavity with shape complementarity and appropriate size to enable π interactions with fullerenes. Therefore, the cyclophane forms host–guest complexes with C60 and C70 with estimated binding constants of Ka=420±2 m−1 and Ka=(6.49±0.23)×103 m−1, respectively. As a result, the macrocycle can selectively bind C70 in the presence of an excess of a mixture of C60 and C70. [ABSTRACT FROM AUTHOR]

A cyclophane is reported incorporating two units of a heptagon‐containing extended polycyclic aromatic hydrocarbon (PAH) analogue of the hexa‐peri‐hexabenzocoronene (HBC) moiety (hept‐HBC). This cyclophane represents a new class of macrocyclic structures that incorporate for the first time seven‐membered rings within extended PAH frameworks. The saddle curvature of the hept‐HBC macrocycle units induced by the presence of the nonhexagonal ring along with the flexible alkyl linkers generate a cavity with shape complementarity and appropriate size to enable π interactions with fullerenes. Therefore, the cyclophane forms host–guest complexes with C60 and C70 with estimated binding constants of Ka=420±2 m−1 and Ka=(6.49±0.23)×103 m−1, respectively. As a result, the macrocycle can selectively bind C70 in the presence of an excess of a mixture of C60 and C70. [ABSTRACT FROM AUTHOR]

Details the study of synthesis of (...)-10-epi-elemol by a highly steroselective intramolecular palladium-catalyzed coupling of an allylstannane with an allyl acetate. Reason for study conducted; Report made at end of study.

We report on the chemical design of chiral molecular junctions with stress‐dependent conductance, whose helicity is maintained during the stretching of a single molecule junction due to the stapling of both ends of the inner helix. In the reported compounds, different conductive pathways are observed, with clearly different conductance values and plateau‐length distributions, attributed to different conformations of the helical structures. The large chiro‐optical responses and the potential use of these molecules as unimolecular spin filters have been theoretically proved using state‐of‐the‐art Density Functional Theory (DFT) calculations, including a fully ab‐initio estimation of the CISS‐originating spin polarization which is done, for the first time, for a realistic molecular system. [ABSTRACT FROM AUTHOR]

We report on the chemical design of chiral molecular junctions with stress‐dependent conductance, whose helicity is maintained during the stretching of a single molecule junction due to the stapling of both ends of the inner helix. In the reported compounds, different conductive pathways are observed, with clearly different conductance values and plateau‐length distributions, attributed to different conformations of the helical structures. The large chiro‐optical responses and the potential use of these molecules as unimolecular spin filters have been theoretically proved using state‐of‐the‐art Density Functional Theory (DFT) calculations, including a fully ab‐initio estimation of the CISS‐originating spin polarization which is done, for the first time, for a realistic molecular system. [ABSTRACT FROM AUTHOR]

The present work reports on a detailed discussion about the synthesis, characterization, and luminescence properties of three pairs of enantiopure 3D metal–organic frameworks (MOFs) with general formula {[Ln2(L/D-tart)3(H2O)2]·3H2O}n (3D_Ln-L/D, where Ln = Sm(III), Eu(III) or Gd(III), and L/D-tart = L- or D-tartrate), and ten pairs of enantiopure 2D coordination polymers (CPs) with general formula [Ln(L/D-Htart)2(OH)(H2O)2]n (2D_Ln-L/D, where Ln = Y(III), Sm(III), Eu(III), Gd(III), Tb(III), Dy(III), Ho(III), Er(III), Tm(III) or Yb(III), and L/D-Htart = hydrogen L- or D-tartrate) based on single-crystal X-ray structures. Enantiopure nature of the samples has been further corroborated by Root Mean Square Deviation (RMSD) as well as by circular dichroism (CD) spectra. Solid-state emission spectra of Eu(III), Tb(III), and Dy(III)-based compounds confirm the occurrence of ligand-to-metal charge transfers in view of the characteristic emissions for these lanthanide ions, and emission decay curves were also recorded to estimate the emission lifetimes for the reported compounds. A complete theoretical study was accomplished to better understand the energy transfers occurring in the Eu-based counterparts, which allows for explaining the different performances of 3D-MOFs and 2D-layered compounds. As inferred from the colorimetric diagrams, emission characteristics of Eu-based 2D CPs depend on the temperature, so their luminescent thermometry has been determined on the basis of a ratiometric analysis between the ligand-centered and Eu-centered emission. Finally, a detailed study of the polarized luminescence intensity emitted by the samples is also accomplished to support the occurrence of chiro-optical activity. [ABSTRACT FROM AUTHOR]

Extended reach: A calculated mechanism for long‐range proton‐coupled electron transfer (PCET, see picture) through an array of structured water molecules between FeIII–FeIII complexes accounts for the reaction enthalpy and kinetic isotope effect previously measured for this reaction. This mechanism may be general and occur for other hydroxo–metal complexes. [ABSTRACT FROM AUTHOR]

The article discusses a significant advancement in quantitative PLIM bioimaging called PAnt (phosphonic acid antenna). PAnt is a small water-soluble lanthanide antenna that can self-assemble with lanthanide ions, serving as an exchangeable probe to overcome photobleaching in PLIM microscopy in cellulo. The use of PAnt allows for continuous replenishment of lanthanide complexes that may be photobleached during acquisition, resulting in remarkable photostability compared to traditional lanthanide cryptates. The research was conducted by Angel Orte, Juan A. González-Vera, and their colleagues. [Extracted from the article]

In this paper, we describe the optical and chiroptical properties of an enantiopure multipodal ortho‐oligophenylethynylene (S,S,S,S)‐1 presenting four chiral sulfoxide groups at the extremes. The presence of these groups together with alkynes allows the coordination with carbophilic Ag(I), and/or oxophilic Zn(II) cations, yielding double helical structures in an enantiopure way. In this sense, different behaviors in absorption, fluorescence, ECD and CPL spectra have been found depending on the stoichiometry and nature of the metal. We have observed that Zn(II) coordination favors an intensity increase of the electronic circular dichroism (ECD) spectra of compound (S,S,S,S)‐1 yielding an M‐helicity in the ortho‐oligophenylene ethynylene (o‐OPE) backbone. On the other hand, ECD spectra of final Ag(I) complex shows two different bands with an opposite sign to the free ligand, thus giving the P‐helical isomer. In addition, circularly polarized luminescence (CPL) exhibit an enhanced intensity and negative sign in both complexes. Computational studies were also carried out, supporting the experimental results. [ABSTRACT FROM AUTHOR]

In nature there are several terpenoids with a characteristic γ-dioxygenated system on the A ring, and many of them show interesting pharmacological properties. We have developed a novel strategy for the synthesis of these terpenoids involving three stages: (a) the selective epoxidation of commercial polyenes, (b) titanium(III)-catalyzed cyclization of the epoxypolyprenes thus obtained, and (c) Pd-mediated remote functionalization of the equatorial methyl group attached at C-4 on ring A of the cyclic terpenoid thus formed. This strategy has proved to be useful for the synthesis of the natural labdane rostratone (1) and related terpenoids, as well as for advanced synthetic approaches toward the pharmacologically active products aphidicolin (2) and pyripyropene A (3). [ABSTRACT FROM AUTHOR]

We describe a novel convergent procedure that has proved useful in the synthesis of a wide range of meroterpenoid-related structures containing a mono-, ses- qui-, or diterpenoid moiety linked to a nonfused aromatic subunit with various substitution patterns. The key steps were the Stille-type coupling of aryl stannanes and allylic carbonates, followed by the titanocene-catalyzed domino cyclization of aryl epoxypolyprenes. The coupling reaction was perfectly compatible with preformed epoxides, while the sequential cyclization, which presumably proceeded via alkyl radicals inert to benzene derivatives, selectively provided exocyclic alkenes. [ABSTRACT FROM AUTHOR]

We present results, which indicate that Pd-mediated C–H bond activation can be used under mild conditions for the remote functionalization of C-4 methyl groups of molecules with different terpenoid-like skeletons containing six- or seven-membered A rings. This procedure has allowed us to complete a novel strategy for the synthesis of γ-dioxygenated terpenoids in three stages: (i) selective epoxidation of commercial polyenes, (ii) titanium(III)-catalyzed cyclization of epoxypolyprenes, and (iii) Pd-mediated remote functionalization of equatorial methyl groups. This strategy has proved to be useful for the synthesis of the natural labdane rostratone (1). [Copyright &y& Elsevier]

We report here a novel procedure for the reduction of ketones to secondary alcohols using catalytic quantities of commercially available Cp2TiCl2, inexpensive Zn dust and water as proton source. Mechanistically the reaction presumably proceeds via titanoxy radicals. In practice this reduction process has significant advantages: it shows an interesting selectivity pattern, takes place under mild conditions using safe, cheap reagents and does not require anhydrous solvents. The proton-donor activity of water under these conditions avoids the use of the frequently poisonous hydrogen-atom donors generally required to reduce free radicals. This procedure is also highly convenient for synthesising deuterium-labelled alcohols employing relatively inexpensive D2O as deuterium source. [Copyright &y& Elsevier]

Investigates the synthesis and stereochemistry of hydroxyreynosin and eudesmanolides. Oxidation of dihydrocostunolide; Cyclizations of cyclodecenone radicals; Biological activity of terpenoid.

A series of highly emissive inert and chiral CrIII complexes displaying dual circularly polarized luminescence (CPL) within the NIR region have been prepared and characterized. The helical [Cr(dqpR)2]3+ (dqp=2,6‐di(quinolin‐8‐yl)pyridine; R=OCH3, Br or C≡CH) complexes were synthesized as racemic mixtures and resolved into their respective PP and MM enantiomers by chiral stationary phase HPLC. The corresponding enantiomers show large glum≈0.2 and high quantum yield of up to 17 %, which afford important CPL brightness of up to 170 m−1 cm−1, a key point for applications as chiral luminescent probes. Moreover, the long‐lived CP‐NIR emission provided by these chromophores (ms range) in aqueous solution opens the way toward the quantification of chiral targets in biological systems with time‐gated detection. Thus, such chiral chromophores based on earth abundant and inert 3d metals open new perspectives in the field of CPL and represent an alternative to precious 4d, 5d and to labile 4f metal‐based complexes. [ABSTRACT FROM AUTHOR]

A series of highly emissive inert and chiral CrIII complexes displaying dual circularly polarized luminescence (CPL) within the NIR region have been prepared and characterized. The helical [Cr(dqpR)2]3+ (dqp=2,6‐di(quinolin‐8‐yl)pyridine; R=OCH3, Br or C≡CH) complexes were synthesized as racemic mixtures and resolved into their respective PP and MM enantiomers by chiral stationary phase HPLC. The corresponding enantiomers show large glum≈0.2 and high quantum yield of up to 17 %, which afford important CPL brightness of up to 170 m−1 cm−1, a key point for applications as chiral luminescent probes. Moreover, the long‐lived CP‐NIR emission provided by these chromophores (ms range) in aqueous solution opens the way toward the quantification of chiral targets in biological systems with time‐gated detection. Thus, such chiral chromophores based on earth abundant and inert 3d metals open new perspectives in the field of CPL and represent an alternative to precious 4d, 5d and to labile 4f metal‐based complexes. [ABSTRACT FROM AUTHOR]

The single‐molecule conductance of a series of BN‐acene‐like derivatives has been measured by using scanning tunneling break‐junction techniques. A strategic design of the target molecules has allowed us to include azaborine units in positions that unambiguously ensure electron transport through both heteroatoms, which is relevant for the development of customized BN‐doped nanographenes. We show that the conductance of the anthracene azaborine derivative is comparable to that of the pristine all‐carbon anthracene compound. Notably, this heteroatom substitution has also allowed us to perform similar measurements on the corresponding pentacene‐like compound, which is found to have a similar conductance, thus evidencing that B–N doping could also be used to stabilize and characterize larger acenes for molecular electronics applications. Our conclusions are supported by state‐of‐the‐art transport calculations. [ABSTRACT FROM AUTHOR]

The single‐molecule conductance of a series of BN‐acene‐like derivatives has been measured by using scanning tunneling break‐junction techniques. A strategic design of the target molecules has allowed us to include azaborine units in positions that unambiguously ensure electron transport through both heteroatoms, which is relevant for the development of customized BN‐doped nanographenes. We show that the conductance of the anthracene azaborine derivative is comparable to that of the pristine all‐carbon anthracene compound. Notably, this heteroatom substitution has also allowed us to perform similar measurements on the corresponding pentacene‐like compound, which is found to have a similar conductance, thus evidencing that B–N doping could also be used to stabilize and characterize larger acenes for molecular electronics applications. Our conclusions are supported by state‐of‐the‐art transport calculations. [ABSTRACT FROM AUTHOR]

Thiele (Th) and tetrabenzo-Chichibabin (TBC) derivatives with terminal dibenzocycloheptatriene (DBHept) units were prepared. A clear correlation between their electronic and molecular structures was stablished. Insights into their closed- or open-shell ground states were gained, where particular contribution of the heptagonal carbocycles as end-groups was proved. Remarkably, a thermally accessible triplet diradical configuration was confirmed for the DBHept-TBC compound. [ABSTRACT FROM AUTHOR]

The essential oils of Cistus ladaniferus L. var. maculatus Dun. and Cistus monspeliensis L., harvested from northern Morocco, have been analyzed by GC-FID, GC/MS, and NMR techniques. The main components of C. ladaniferus were bornyl acetate, pinocarveol, and viridiflorol, whereas the main component from C. monspeliensis was the oxygenated labdane diterpenoid 13-epi-manoyl oxide. [ABSTRACT FROM AUTHOR]

A new family of distorted ribbon‐shaped nanographenes was designed, synthesized, and their optical and electrochemical properties were evaluated, pointing out an unprecedented correlation between their structural characteristics and the two‐photon absorption (TPA) responses and electrochemical band gaps. Three nanographene ribbons have been prepared: a seven‐membered‐ring‐containing nanographene presenting a tropone moiety at the edge, its full‐carbon analogue, and a purely hexagonal one. We have found that the TPA cross‐sections and the electrochemical band gaps of the seven‐membered‐ring‐containing compounds are higher and lower, respectively, than those of the fully hexagonal polycyclic aromatic hydrocarbon (PAH). Interestingly, the inclusion of additional curvature has a positive effect in terms of non‐linear optical properties of those ribbons. [ABSTRACT FROM AUTHOR]

A new family of distorted ribbon‐shaped nanographenes was designed, synthesized, and their optical and electrochemical properties were evaluated, pointing out an unprecedented correlation between their structural characteristics and the two‐photon absorption (TPA) responses and electrochemical band gaps. Three nanographene ribbons have been prepared: a seven‐membered‐ring‐containing nanographene presenting a tropone moiety at the edge, its full‐carbon analogue, and a purely hexagonal one. We have found that the TPA cross‐sections and the electrochemical band gaps of the seven‐membered‐ring‐containing compounds are higher and lower, respectively, than those of the fully hexagonal polycyclic aromatic hydrocarbon (PAH). Interestingly, the inclusion of additional curvature has a positive effect in terms of non‐linear optical properties of those ribbons. [ABSTRACT FROM AUTHOR]

Intrinsically chiral double stapled ortho-oligo phenylene ethynylenes (o-OPEs) 1 show glum values up to 5.5 × 10−2, the second highest value ever observed for a simple organic molecule (SOM). DFT calculations of molecular spectra and properties encompassing electric and magnetic dipole transition moments account for these observations. [ABSTRACT FROM AUTHOR]

In this work, we have performed an in-depth study of the photophysics and solvatofluorochromism of a red-emitting Si-xanthene dye, an analog of Tokyo Magenta (TM) historically developed by Egawa et al. (Chem. Commun. 2011 , 47 , 4162–4164). The results show a strong dependency of the emission properties of 2-Me-4-OMe-TM on the polarity of the solvent. For instance, the dye exhibited an increase in its fluorescence lifetime with the decrease in solvent polarity. Therefore, in this work, this spectral behavior has been used as a new approach for determining the intracellular microenvironment polarity through the measurement of its fluorescence lifetime by Fluorescence Lifetime Imaging Microscopy (FLIM). Our experiments confirmed the ability of the dye to detect changes in polarity between different intracellular compartments. Image 1 • A silicon-substituted xanthene dye was synthesized and its photophysics studied. • The dye shows a strong solvatochromic behavior involving two emission bands. • A strong dependency on the solvent's acidity was observed in the red-shifted band. • The dye works as an intracellular polarity fluorescence lifetime sensor. [ABSTRACT FROM AUTHOR]

A unique rippled nanographene consisting of 52 fused rings is presented in which six out‐of‐plane motifs are fully fused into a triangular aromatic surface with a size of approximately 2.5 nm. Three units of an unprecedented fully lateral π‐extended octabenzo[5]helicene together with three units of saddle‐shaped heptagonal rings are combined in a single structure, leading to a well‐soluble warped nanographene. The two diastereomeric pairs of possible enantiomers were isolated, and their linear, non‐linear, and chiroptical properties were evaluated, revealing outstanding quantum yield and brightness values at low energy, together with good chiroptical responses in both absorption and emission. [ABSTRACT FROM AUTHOR]

A unique rippled nanographene consisting of 52 fused rings is presented in which six out‐of‐plane motifs are fully fused into a triangular aromatic surface with a size of approximately 2.5 nm. Three units of an unprecedented fully lateral π‐extended octabenzo[5]helicene together with three units of saddle‐shaped heptagonal rings are combined in a single structure, leading to a well‐soluble warped nanographene. The two diastereomeric pairs of possible enantiomers were isolated, and their linear, non‐linear, and chiroptical properties were evaluated, revealing outstanding quantum yield and brightness values at low energy, together with good chiroptical responses in both absorption and emission. [ABSTRACT FROM AUTHOR]

New N,N′-dimethyl-N,N′-bis(2-pyridylmethyl)-ethane-1,2-diamine derivatives bearing covalently linked OH and (CO)NH groups have been synthesized. The coordination of those pendant hydroxyl/amide groups to a Fe(ii) metal center is demonstrated both in solution, even in the presence of chloride as the counterion, and in solid state, by means of X-ray diffraction crystal structures. As a result of this coordination, the experimental bond dissociation free energies (BDFE) of O–H and (CO)N–H bonds are remarkably diminished down to 76.0 and 80.5 kcal mol−1 respectively, which is also in agreement with DFT-based theoretical calculations. These BDFE values are in the range of commonly used hydrogen-atom donor reagents. The strategy presented here allows an unequivocal evaluation of the influence of metal coordination in X–H bond weakening in organic solvents which could be easily extended to other metal centers. [ABSTRACT FROM AUTHOR]

Here we describe a new class of CPL switches based on oxophilic interactions between chiral sulfoxide-containing ortho-phenylene ethynylene (o-OPE) foldamers and cationic metals. These systems represent a unique case combining high glum values (up to 0.7 × 10−2) and high quantum yields in both folded ON and unfolded OFF CPL states. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of an enantiopure superhelicene nanographene is reported in which two saddle‐shaped and one planar hexabenzocoronene (HBC) units are arranged in a helicoidal shape to form an undecabenzo[7]carbohelicene. The described compound is the first fully π‐extended [7]helicene. Racemic resolution of the helical nanographene permitted analysis of the chiroptical properties and revealed dissymmetry factors in the range of 2×10−3 both in the absorption and in the emission measurements. Remarkably, non‐linear photophysical analysis demonstrated a two‐photon absorption cross‐section of 870 GM at 800 nm and a perfect overlap between linear, non‐linear, and chiral emissions. A twist in the ribbon: A chiral helical nanographene with a central [7]helicene unit was synthesized and its enantiomers isolated and studied. Both enantiomers of the undecabenzo[7]superhelicene exhibit remarkable chiroptical and non‐linear optical properties, with a two‐photon absorption cross‐section of 870 GM at 800 nm and a perfect overlap between linear, non‐linear, and chiral emissions. CPL=circularly polarized luminescence. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of an enantiopure superhelicene nanographene is reported in which two saddle‐shaped and one planar hexabenzocoronene (HBC) units are arranged in a helicoidal shape to form an undecabenzo[7]carbohelicene. The described compound is the first fully π‐extended [7]helicene. Racemic resolution of the helical nanographene permitted analysis of the chiroptical properties and revealed dissymmetry factors in the range of 2×10−3 both in the absorption and in the emission measurements. Remarkably, non‐linear photophysical analysis demonstrated a two‐photon absorption cross‐section of 870 GM at 800 nm and a perfect overlap between linear, non‐linear, and chiral emissions. [ABSTRACT FROM AUTHOR]

In this manuscript, we report the first synthesis of an organic monomolecular emitter, which behaves as a circularly polarized luminescence (CPL)-based ratiometric probe. The enantiopure helical ortho-oligo(phenylene)ethynylene (o-OPE) core has been prepared by a new and efficient macrocyclization reaction. The combination of such o-OPE helical skeleton and a pyrene couple leads to two different CPL emission features in a single structure whose ratio linearly responds to silver(I) concentration. [ABSTRACT FROM AUTHOR]

Turning on the fluorescence of [3]cumulenes: we report the luminescence at room temperature upon aggregation of [3]cumulenes functionalized with propeller-like heptagon-containing polyphenylenes. These endgroups turn on the emission of a [3]cumulene by steric protection and restriction of their intramolecular rotations in the aggregates. [ABSTRACT FROM AUTHOR]