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An anion radical salt of 7,7,8,8-tetracyanoquinodimethane (TCNQ) with the complex composition (N–Me–DABCO)(TCNQ)2 (1) has been synthesized. The crystal structure 1 has been characterized by X-ray diffraction. The structure of this salt consists of almost homogeneous stacks of TCNQ particles separated by cation layers. Interplanar spacings of 3.25 and 3.29 Å alternate in the stacks. Due to the alternating distances and uniform charge distribution in the stacks, conducting channels are formed in the structure, which determine the properties of an organic metal or a narrow-gap semiconductor, as confirmed by IR spectra containing electron-phonon interaction-related features. In particular, vibrational lines against the continuous absorption background are observed: the band gap does not exceed 0.06 eV. As a result lines of totally symmetric vibrations appear (without the electron-phonon interaction, these lines are forbidden in the IR spectra). [ABSTRACT FROM AUTHOR]

An anion radical salt of 7,7,8,8-tetracyanoquinodimethane (TCNQ) with the complex composition (N–Me–DABCO)(TCNQ)2 (1) has been synthesized. The crystal structure 1 has been characterized by X-ray diffraction. The structure of this salt consists of almost homogeneous stacks of TCNQ particles separated by cation layers. Interplanar spacings of 3.25 and 3.29 Å alternate in the stacks. Due to the alternating distances and uniform charge distribution in the stacks, conducting channels are formed in the structure, which determine the properties of an organic metal or a narrow-gap semiconductor, as confirmed by IR spectra containing electron-phonon interaction-related features. In particular, vibrational lines against the continuous absorption background are observed: the band gap does not exceed 0.06 eV. As a result lines of totally symmetric vibrations appear (without the electron-phonon interaction, these lines are forbidden in the IR spectra). [ABSTRACT FROM AUTHOR]

Photolysis of aryl azides typically involves multiple reaction pathways. This study designed and synthesized an aryl azide rotamer with two conformations. In aqueous media, its photolysis yields two main products. However, when stabilized in one conformation within the cucurbit[8]uril (CB8) host, the photoreaction selectively produces a single product.

Photolysis of aryl azides is a convenient method to approach more functionalized systems in chemical biology. Here, we present a set of photoactivatable aryl azides that undergo controlled reaction pathways within the cucurbit[7]uril (CB7) cavity upon photolysis. The fluorescence turn-on process is utilized for bioimaging.

A novel dinuclear silylene cobalt complex [((Me 3 P) 2 Co)(PMe 2 )(CoCl(PMe 3 ))(Si(NCH 2 PPh 2 ) 2 C 6 H 4 )] ( 1 ) supported by the [PSi(silylene)P] ligand was prepared through the reaction of N-heterocyclic [PSiP] pincer ligand L1 (HSiCl(NCH 2 PPh 2 ) 2 C 6 H 4 ) with Co(PMe 3 ) 4 . Complex [((Me 3 P) 2 Co) 2 (Si(NCH 2 PPh 2 ) 2 C 6 H 4 )] ( 2 ) was formed through the reaction of complex 1 with MeLi. To the best of our knowledge, complexes 1 and 2 are the first examples of dinuclear silylene cobalt complexes supported by the [PSi(silylene)P] ligand. A new preligand L2 (SiCl 2 (NCH 2 PPh 2 ) 2 C 6 H 4 ) was synthesized, and the reaction of preligand L2 with Co(PMe 3 ) 4 afforded silyl cobalt complex [((Me 3 P) 2 Co)(SiCl(NCH 2 PPh 2 ) 2 C 6 H 4 )] ( 3 ). The reaction of 3 with CO delivered cobalt carbonyl complex [((Me 3 P)(CO)Co)(Si(NCH 2 PPh 2 ) 2 C 6 H 4 )] 2 O ( 4 ). The catalytic activity of cobalt complexes 1-4 on the hydrosilylation of alkenes was explored. Among the four complexes, complex 1 has the best catalytic activity. The catalytic process could be promoted with NaBHEt 3 as an additive, and a complete conversion with an excellent selectivity of 98:2 (b/l) could be reached at 120 °C within 8 min for aryl alkenes. A possible catalytic cycle was proposed on the basis of the experimental results and literature reports, with a cobalt hydride complex as an active intermediate. The molecular structure of complexes 1-4 was determined by single-crystal X-ray diffraction analysis.

The emergence of highly wavelength resolved reactivity information for complex photochemical reaction processes allows the establishment of multi-color reaction modes. One particularly powerful mode is the synergistic two-color reaction, where two colors of light have to be present in the same volume element to either enable or enhance photochemical reactivity that leads to a specific photoproduct. Herein, we introduce a two-color synergistic photochemical reaction system based on a diaryl indenone epoxide (DIO) photoswitch and the cis-to-trans isomerization of a bridged ring-strained azobenzene (SA), which respond to ultraviolet (365 nm) and visible light (430 nm), respectively, with different rates, forming a well-defined heterocyclic photoadduct, DIOSA, that we structurally confirm via single crystal x-ray diffraction (SXRD). To quantitatively capture the effectiveness of the dual-color irradiation as a function of the reaction conditions such as light intensity and starting material ratio as a function of product yield, we introduce a parameter, the photochemical synergistic ratio. A reduced synergistic ratio - that extrapolates to conditions of infinitesimal conversions - allows to compare the efficiency of the synergistic photochemistry at varying reaction conditions., (© 2024 Wiley‐VCH GmbH.)

Coordination complexes of rare-earth ions (REI) show optical transitions with narrow linewidths enabling the creation of coherent light-matter interfaces for quantum information processing (QIP) applications. Among the REI-based complexes, Eu(III) complexes showing the 5 D 0 → 7 F 0 transition are of interest for QIP applications due to the narrow linewidths associated with the transition. Herein, we report on the synthesis, structure, and optical properties of a novel Eu(III) complex and its Gd(III) analogue composed of 2,9-bis(pyrazol-1-yl)-1,10-phenanthroline (dpphen) and three nitrate (NO 3 ) ligands. The Eu(III) complex-[Eu(dpphen)(NO 3 ) 3 ]-showed sensitized metal-centred emission ( 5 D 0 → 7 F J ; J=0,1,2,3, 4, 5, or 6) in the visible region, upon irradiation of the ligand-centred band at 369 nm, with the 5 D 0 → 7 F 0 transition centred at 580.9 nm. Spectral hole-burning (SHB) studies of the complex with stoichiometric Eu(III) concentration revealed a narrow homogeneous linewidth (Γ h ) of 1.55 MHz corresponding to a 0.205 μs long optical coherence lifetime (T 2opt ). Remarkably, long nuclear spin lifetimes (T 1spin ) of up to 41 s have been observed for the complex. The narrow optical linewidths and long T 1spin lifetimes obtained for the Eu(III) complex showcase the utility of Eu(III) complexes as tuneable, following molecular engineering principles, coherent light-matter interfaces for QIP applications., (© 2024 The Authors. ChemPhysChem published by Wiley-VCH GmbH.)

This works describes a new step into the assembly of molecular textiles by the use of covalent templating. To establish a well-founded base and to tackle pre-mature obstacles, expected during the fabrication of the desired 2D-material, we opted to investigate the in-solution synthesis of molecular patches e.g. cut-outs of a textile. A bi-functional cross-shaped monomer was designed, synthesized and was in-detail characterized by means of 1H-NMR and chiro-optical spectroscopy. In addition, x-ray structure crystallography was used to assess the absolute configuration. The monomer was used in an in-solution oligomerization to assemble the molecular patches via imine condensation, which revealed the formation of predominately dimeric patches.  The imine-oligomer mixtures were further analyzed by reduction and cleaved to investigate the conditions required post mono-layer assembly. All reaction stages were followed by FT-IR and 1H-NMR analysis. Finally, we address the adsorption of the cross-shaped monomer onto a Au(111) surface, via high vacuum electrospray deposition. The subsequent annealing of the interface induced the on-surface imine condensation reaction, leading to unidimensional oligomers co-adsorbed with clusters of cyclic-dimers. Nc-AFM analysis revealed the tridimensional molecular structures, and together with electrospray deposition technique showed to be a promising pathway to investigate potential monomer candidates., (© 2024 Wiley‐VCH GmbH.)

An asymmetrical dysprosium trimer with a molecular formula of [Dy 3 (hq) 7 (hqH)(NO O and 8-quinolinoline as ligand. Magnetic susceptibility investigations show the system to be an SMM, which was corroborated by sub-Kelvin μSQUID studies. Upon cooling, the magnetic susceptibility also exhibits a decrease in the 3 ) 2 (H 2 O)] was obtained through a reflux reaction employing as starting material Dy(NO 3 ) 3 · n H 2 O and 8-quinolinoline as ligand. Magnetic susceptibility investigations show the system to be an SMM, which was corroborated by sub-Kelvin μSQUID studies. Upon cooling, the magnetic susceptibility also exhibits a decrease in the χ M T product, which was confirmed to be due to intramolecular antiferromagnetic interactions. μSQUID measurements, moreover, reveal a marked magnetic behaviour in the angular dependence of the hysteresis loops. The latter is a direct consequence of the non-colinear spin arrangement of the anisotropy axes of each Dy(III) ion in [Dy 3 (hq) 7 (hqH)(NO 3 ) 2 (H 2 O)] and the interaction between the ions, as also evidenced by CASSCF calculations. Our results evidence the effect of spin canting along with the intramolecular interactions, which can induce non-trivial magnetic behaviour in SMMs.

A novel mononuclear Cu(I) complex was synthesized via coordination with a benzoquinoxalin-2'-one-1,2,3-triazole chelating diimine and the bis[(2-diphenylphosphino)phenyl] ether (DPEPhos), to target a new and efficient photosensitizer for photocatalytic CO 2 reduction. The Cu(I) complex absorbs in the blue-green region of the visible spectrum, with a broad band having a maximum at 475 nm (ϵ =4500 M -1  cm -1 ), which is assigned to the metal-to-ligand charge transfer (MLCT) transition from the Cu(I) to the benzoquinoxalin-2'-one moiety of the diimine. Surprisingly, photo-driven experiments for the CO 2 reduction showed that this complex can undergo a photoinduced electron transfer with a sacrificial electron donor and accumulate electrons on the diimine backbone. Photo-driven experiments in a CO 2 atmosphere revealed that this complex can not only act as a photosensitizer, when combined with an Fe(III)-porphyrin, but can also selectively produce CO from CO 2 . Thus, owing to its charge-accumulation properties, the non-innocent benzoquinoxalin-2-one based ligand enabled the development of the first copper(I)-based photocatalyst for CO 2 reduction., (© 2024 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

In this report, a new series of mono-, di-, tri-, and tetra-cationic pyridinium and vinyl pyridinium-modified [2.2]paracyclophanes as useful molecular tectons for supramolecular systems are described. Regioselective functionalization at specific positions, followed by resolution step and successive transformations through Pd-catalyzed Suzuki-Miyaura and Mizoroki-Heck cross-coupling chemistry furnish a series of modular PCP scaffolds. In our proof-of-concept study, on N-methylation, the PCPs bearing (cationic) pyridyl functionalities were demonstrated as useful molecular receptors in host-guest supramolecular assays. The PCPs on grafting with light-responsive azobenzene (-N=N-) functional core as side-groups impart photosensitivity that can be remotely transformed on irradiation, offering photo-controlled smart molecular functions. Furthermore, the symmetrical PCPs bearing bi-, and tetra-pyridyl functionalities at the peripheries have enormous potential to serve as ditopic and tetratopic 3D molecular tectons for engineering non-covalent supramolecular assemblies with new structural and functional attributes., (© 2024 The Authors. ChemistryOpen published by Wiley-VCH GmbH.)

A synthesis route to access triazole-pyrazole hybrids via triazenylpyrazoles was developed. Contrary to existing methods, this route allows the facile N -functionalization of the pyrazole before the attachment of the triazole unit via a copper-catalyzed azide-alkyne cycloaddition. The developed methodology was used to synthesize a library of over fifty new multi-substituted pyrazole-triazole hybrids. We also demonstrate a one-pot strategy that renders the isolation of potentially hazardous azides obsolete. In addition, the compatibility of the method with solid-phase synthesis is shown exemplarily., (Copyright © 2024, Gräßle et al.)

Macrocyclic hosts, such as cucurbit[8]uril (CB8), can significantly influence the outcomes of chemical reactions involving encapsulated reactive guests. In this study, we demonstrate that CB8 completely reverses the stereoselectivity of intramolecular [2+2] photo-cycloaddition reactions. Notably, it was also found that CB8 can trigger the unreactive diene to be reactive.

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 g abs 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., (© 2024 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

A series of monometallic Ag(I) and Cu(I) halide complexes bearing 2-(diphenylphosphino)pyridine (PyrPhos, L) as a ligand were synthesized and spectroscopically characterized. The structure of most of the derivatives was unambiguously established by X-ray diffraction analysis, revealing the formation of mono-, di-, and tetranuclear complexes having general formulas MXL 3 (M = Cu, X = Cl, Br; M = Ag, X = Cl, Br, I), Ag 2 X 2 L 3 (X = Cl, Br), and Ag 4 X 4 L 4 (X = Cl, Br, I). The Ag(I) species were compared to the corresponding Cu(I) analogues from a structural point of view. The formation of Cu(I)/Ag(I) heterobimetallic complexes MM'X 2 L 3 (M/M' = Cu, Ag; X = Cl, Br, I) was also investigated. The X-ray structure of the bromo-derivatives revealed the formation of two possible MM'Br 2 L 3 complexes with Cu/Ag ratios, respectively, of 7:1 and 1:7. The ratio between Cu and Ag was studied by scanning electron microscopy-energy-dispersive X-ray analysis (SEM-EDX) measurements. The structure of the binuclear homo- and heterometallic derivatives was investigated using density functional theory (DFT) calculations, revealing the tendency of the PyrPhos ligands not to maintain the bridging motif in the presence of Ag(I) as the metal center., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Thiazole and thiazolidinone recur in a wide range of biologically active compounds that reach different targets within the context of tumors and represent a promising starting point to access potential candidates for treating metastatic cancer. Therefore, searching for new lead compounds that show the highest anticancer potency with the fewest adverse effects is a major drug-discovery challenge. Because the thiazole ring is present in dasatinib, which is currently used in anticancer therapy, it is important to highlight the ring. In this study, cycloalkylidenehydrazinecarbothioamides (cyclopentyl, cyclohexyl, cyclooctyl, dihydronapthalenylidene, flurine-9-ylidene, and indolinonyl) reacted with 2-bromoacetophenone and diethylacetylenedicarboxylate to yield thiazole and 4-thiazolidinone derivatives. The structure of the products was confirmed by using infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry, and single-crystal X-ray analyses. The antiproliferative activity of the newly synthesized compounds was evaluated. The most effective inhibitory compounds were further tested in vitro against both epidermal growth factor receptor (EGFR) and B-Raf proto-oncogene, serine/threonine kinase (BRAF V600E ) targets. Additionally, molecular docking analysis examined how these molecules bind to the active sites of EGFR and BRAF V600E .

Developing efficient catalysts for reducing carbon dioxide, a highly stable combustion waste product, is a relevant task to lower the atmospheric concentration of this greenhouse gas by upcycling. Selectivity towards CO 2 -reduction products is highly desirable, although it can be challenging to achieve since the metal-hydrides formation is sometimes favored and leads to H 2 evolution. In this work, we designed a cobalt-based catalyst, and we present herein its physicochemical properties. Moreover, we tailored a fully earth-abundant photocatalytic system to achieve specifically CO 2 reduction, optimizing efficiency and selectivity. By changing the conditions, we enhanced the turnover number (TON) of CO production from only 0.5 to more than 60 and the selectivity from 6% to 97% after four hours of irradiation at 420 nm. Further efficiency enhancement was achieved by adding 1,1,1,3,3,3-hexafluoropropan-2-ol, producing CO with a TON up to 230, although at the expense of selectivity (54%)., (Copyright © 2023, Gracia et al.)

The pro-oncogenic activities of estrogen receptor alpha (ERα) drive breast cancer pathogenesis. Endocrine therapies that impair the production of estrogen or the action of the ERα are therefore used to prevent primary disease metastasis. Although recent successes with ERα degraders have been reported, there is still the need to develop further ERα antagonists with additional properties for breast cancer therapy. We have previously described a benzothiazole compound A4B17 that inhibits the proliferation of androgen receptor-positive prostate cancer cells by disrupting the interaction of the cochaperone BAG1 with the AR. A4B17 was also found to inhibit the proliferation of estrogen receptor-positive (ER + ) breast cancer cells. Using a scaffold hopping approach, we report here a group of small molecules with imidazopyridine scaffolds that are more potent and efficacious than A4B17. The prototype molecule X15695 efficiently degraded ERα and attenuated estrogen-mediated target gene expression as well as transactivation by the AR. X15695 also disrupted key cellular protein-protein interactions such as BAG1-mortalin (GRP75) interaction as well as wild-type p53-mortalin or mutant p53-BAG2 interactions. These activities together reactivated p53 and resulted in cell-cycle block and the induction of apoptosis. When administered orally to in vivo tumor xenograft models, X15695 potently inhibited the growth of breast tumor cells but less efficiently the growth of prostate tumor cells. We therefore identify X15695 as an oral selective ER degrader and propose further development of this compound for therapy of ER + breast cancers., Significance: An imidazopyridine that selectively degrades ERα and is orally bioavailable has been identified for the development of ER + breast cancer therapeutics. This compound also activates wild-type p53 and disrupts the gain-of-function tumorigenic activity of mutant p53, resulting in cell-cycle arrest and the induction of apoptosis., (© 2023 The Authors; Published by the American Association for Cancer Research.)

Heteroleptic copper(I) complexes, with a diimine as a chromophoric unit and a bulky diphosphine as an ancillary ligand, have the advantage of a reduced pseudo Jahn-Teller effect in their excited state over the corresponding homoleptic bis(diimine) complexes. Nevertheless, their lowest absorption lies generally between 350 to 500 nm. Aiming at a strong absorption in the visible by stable heteroleptic Cu(I) complexes, we designed a novel diimine based on 4-(benzo[ g ]quinoxal-2'-yl)-1,2,3-triazole derivatives. The large π-conjugation of the benzoquinoxaline moiety shifted bathochromically the absorption with regard to other diimine-based Cu(I) complexes. Adding another Cu(I) core broadened the absorption and extended it to considerably longer wavelengths. Moreover, by fine-tuning the structure of the dichelating ligand, we achieved a panchromatic absorption up to 700 nm with a high molar extinction coefficient of 8000 M -1 cm -1 at maximum ( λ = 570 nm), making this compound attractive for light-harvesting antennae.

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 sp 2 hybridized. Both helical structures were fully characterized and chirally resolved. Assignment of the enantiomers was achieved by simulation of chiroptical properties and enantiopure synthesis., (© 2022 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

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 ., (© 2022 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

The conversion of tetrazolo[1,5- a ]quinoxalines to 1,2,3-triazoloquinoxalines and triazoloimidazoquinoxalines under typical conditions of a CuAAC reaction has been investigated. Derivatives of the novel compound class of triazoloimidazoquinoxalines (TIQ) and rhenium(I) triazoloquinoxaline complexes as well as a new TIQ rhenium complex were synthesized. As a result, a small 1,2,3-triazoloquinoxaline library was obtained and the method could be expanded towards 4-substituted tetrazoloquinoxalines. The compatibility of various aliphatic and aromatic alkynes towards the reaction was investigated and the denitrogenative annulation towards imidazoloquinoxalines could be observed as a competing reaction depending on the alkyne concentration and the substitutions at the quinoxaline., (Copyright © 2022, Holzhauer et al.)

The recent outbreak of coronavirus disease (COVID-19) has rampaged the world with more than 236 million confirmed cases and over 4.8 million deaths across the world reported by the world health organization (WHO) till Oct 5, 2021. Due to the advent of different variants of coronavirus, there is an urgent need to identify effective drugs and vaccines to combat rapidly spreading virus varieties across the globe. Ferrocene derivatives have attained immense interest as anticancer, antifungal, antibacterial, and antiparasitic drug candidates. However, the ability of ferrocene as anti-COVID-19 is not yet explored. Therefore, in the present work, we have synthesized four new ferrocene Schiff bases (L1-L4) to understand the active sites and biological activity of ferrocene derivatives by employing various molecular descriptors, frontier molecular orbitals (FMO), electron affinity, ionization potential, and molecular electrostatic potential (MEP). A theoretical insight on synthesized ferrocene Schiff bases was accomplished by molecular docking, frontier molecular orbitals energies, active sites, and molecular descriptors which were further compared with drugs being currently used against COVID-19, i.e., dexamethasone, hydroxychloroquine, favipiravir (FPV), and remdesivir (RDV). Moreover, through the molecular docking approach, we recorded the inhibitions of ferrocene derivatives on core protease (6LU7) protein of SARS-CoV-2 and the effect of substituents on the anti-COVID activity of these synthesized compounds. The computational outcome indicated that L1 has a powerful 6LU7 inhibition of SARS-CoV-2 compared to the currently used drugs. These results could be helpful to design new ferrocene compounds and explore their potential application in the prevention and treatment of SARS-CoV-2., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 Elsevier B.V. All rights reserved.)

Rare-earth ions (REIs) are promising solid-state systems for building light-matter interfaces at the quantum level 1,2 . This relies on their potential to show narrow optical and spin homogeneous linewidths, or, equivalently, long-lived quantum states. This enables the use of REIs for photonic quantum technologies such as memories for light, optical-microwave transduction and computing 3-5 . However, so far, few crystalline materials have shown an environment quiet enough to fully exploit REI properties. This hinders further progress, in particular towards REI-containing integrated nanophotonics devices 6,7 . Molecular systems can provide such capability but generally lack spin states. If, however, molecular systems do have spin states, they show broad optical lines that severely limit optical-to-spin coherent interfacing 8-10 . Here we report on europium molecular crystals that exhibit linewidths in the tens of kilohertz range, orders of magnitude narrower than those of other molecular systems. We harness this property to demonstrate efficient optical spin initialization, coherent storage of light using an atomic frequency comb, and optical control of ion-ion interactions towards implementation of quantum gates. These results illustrate the utility of rare-earth molecular crystals as a new platform for photonic quantum technologies that combines highly coherent emitters with the unmatched versatility in composition, structure and integration capability of molecular materials., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Three novel iron dinitrogen hydrides, [FeH( i Pr-PSi Me P)(N 2 )(PMe 3 )] (1), [FeH( i Pr-PSi Ph P)(N 2 )(PMe 3 )] (2), and [FeH( i Pr-PSi Ph )(N 2 )(PMe 3 )] (3), supported by a silyl ligand are synthesized for the first time by changing the electronic effect and steric hindrance of the ligands through the reaction of ligands L1-L3 with Fe(PMe 3 ) 4 in a nitrogen atmosphere. The ligands containing an electron-donating group with large steric hindrance on the phosphorus atom are beneficial for the formation of dinitrogen complexes. A penta-coordinate iron hydride [FeH( i Pr-PSi Ph )(PMe 3 ) 2 ] (4) was formed through the reaction of ligand L3 with Fe(PMe 3 ) 4 in an argon atmosphere under the same conditions. The reactions between complexes 1-3 with an atmospheric pressure of dihydrogen gas resulted in Fe(II) dihydrides, [( i Pr-PSi Me (μ-H)P)Fe(H) 2 (PMe 3 )] (5), [( i Pr-PSi Ph (μ-H)P)Fe(H) 2 (PMe 3 )] (6) and [(iPr-PSi Ph (μ-H))Fe(H) 2 (PMe 3 ) 2 ] (7), with an η 2 -(Si-H) coordination. The isolation of dihydrides 5-7 demonstrates the ability of the dinitrogen complexes 1-3 to realize the activation of dihydrogen under ambient temperature and pressure. The molecular structures of complexes 1-7 were elucidated by single crystal X-ray diffraction analysis. The iron dinitrogen hydrides 1-3 are effective catalysts for the silylation of dinitrogen under ambient conditions and among them 3 is the best catalyst.

Conjugation-extended carbazolophane donors, dicarbazolophanes ( DCzp ), were designed and synthesized using a multifold stepwise Pd-catalyzed Buchwald-Hartwig amination/ring cyclization process. Furthermore, elaboration of the DCzp core is possible with the introduction of pendant carbazole derivative groups. This provides a way to tune the optoelectronic properties of the thermally activated delayed fluorescence (TADF) compounds DCzpTRZtBu , dtBuCzDCzpTRZtBu , and dMeOCzDCzpTRZtBu . Solution-processed organic light-emitting diodes (OLEDs) were fabricated and achieved a maximum external quantum efficiency (EQE max ) of 8.2% and an EQE of 7.9% at 100 cd/m 2 .

Six silyl cobalt(III) hydrides 1 - 6 with [PSiP] pincer ligands having different substituents at the P and Si atoms ([(2-Ph 2 PC 6 H 4 ) 2 MeSiCo(H)(Cl)(PMe 3 )] ( 1 ), [(2-Ph 2 PC 6 H 4 ) 2 HSiCo(H)(Cl)(PMe 3 )] ( 2 ), [(2-Ph 2 PC 6 H 4 ) 2 PhSiCo(H)(Cl)(PMe 3 )] ( 3 ), [(2- i Pr 2 PC 6 H 4 ) 2 HSiCo(H)(Cl)(PMe 3 )] ( 4 ), [(2- i Pr 2 PC 6 H 4 ) 2 MeSiCo(H)(Cl)(PMe 3 )] ( 5 ), and [(2- i Pr 2 PC 6 H 4 ) 2 PhSiCo(H)(Cl)(PMe 3 )] ( 6 )) were synthesized through the reactions of the ligands ( L1 - L6 ) with CoCl(PMe 3 ) 3 via Si-H bond cleavage. Compounds 1 - 6 have catalytic activity for alkene hydrosilylation, and among them, complex 3 is the best catalyst with excellent anti -Markovnikov regioselectivity. A silyl dihydrido cobalt(III) complex 7 from the reaction of 3 with Ph 2 SiH 2 was isolated, and its catalytic activity is equivalent to that of complex 3 . Complex 7 and its derivatives 10 - 12 could also be obtained through the reactions of complexes 3 , 1 , 4 , and 5 with NaBHEt 3 . The molecular structure of 7 was indirectly verified by the structures of 10 - 12 . To our delight, the addition of pyridine N-oxide reversed the selectivity of the reaction, from anti -Markovnikov to Markovnikov addition. At the same time, the reaction temperature was reduced from 70 to 30 °C on the premise of high yield and excellent selectivity. However, this catalytic system is only applicable to aromatic alkenes. On the basis of the experimental information, two reaction mechanisms are proposed. The molecular structures of cobalt(III) complexes 3 - 6 and 10 - 12 were determined by single crystal X-ray diffraction analysis.

To develop new and flexible Cu I containing luminescent substances, we extend our previous investigations on two metal-centered species to four metal-centered complexes. These complexes could be a basis for designing new organic light-emitting diode (OLED) relevant species. Both the synthesis and in-depth spectroscopic analysis, combined with high-level theoretical calculations are presented on a series of tetranuclear Cu I complexes with a halide containing Cu 4 X 4 core (X=iodide, bromide or chloride) and two 2-(diphenylphosphino)pyridine bridging ligands with a methyl group in para (4-Me) or ortho (6-Me) position of the pyridine ring. The structure of the electronic ground state is characterized by X-ray diffraction, NMR, and IR spectroscopy with the support of theoretical calculations. In contrast to the para system, the complexes with ortho-substituted bridging ligands show a remarkable and reversible temperature-dependent dual phosphorescence. Here, we combine for the first time the luminescence thermochromism with time-resolved FTIR spectroscopy. Thus, we receive experimental data on the structures of the two triplet states involved in the luminescence thermochromism. The transient IR spectra of the underlying triplet metal/halide-to-ligand charge transfer ( 3 M/XLCT) and cluster-centered ( 3 CC) states were obtained and interpreted by comparison with calculated vibrational spectra. The systematic and significant dependence of the bridging halides was analyzed., (© 2020 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

The well-known system of dinuclear Cu(I) complexes bridged by 2-(diphenylphosphino)pyridine (PyrPhos) derivatives Cu 2 X 2 L 3 and Cu 2 X 2 LP 2 (L = bridging ligand, P = ancillary ligand) goes along with endless variation options for tunability. In this work, the influence of substituents and modifications on the phosphine moiety of the NP-bridging ligand was investigated. In previous studies, the location of the lowest unoccupied molecular orbital (LUMO) of the copper complexes of the PyrPhos family was found to be located on the NP-bridging ligand and enabled color tuning in the whole visible spectrum. A multitude of dinuclear Cu(I) complexes based on the triple methylated 2-(bis(4-methylphenyl)phosphino)-4-methylpyridine ( Cu-1b-H , Cu-1b-MeO , and Cu-1b-F ) up to complexes bearing 2-(bis(4-fluorophenyl)phosphino)pyridine ( Cu-6a-H ) with electron-withdrawing fluorine atoms over many other variations on the NP-bridging ligands were synthesized. Almost all copper complexes were confirmed via single crystal X-ray diffraction analysis. Besides theoretical TDDFT-studies of the electronic properties and photophysical measurements, the majority of the phosphino-modified Cu(I) complexes was tested in solution-processed organic light-emitting diodes (OLEDs) with different heterostructure variations. The best results of the OLED devices were obtained with copper emitter Cu-1b-H in a stack architecture of ITO/PEDOT-PSS (50 nm)/poly-TPD (15 nm)/20 wt % Cu(I) emitter:CBP:TcTA(7:3) (45 nm)/TPBi (30 nm)/LiF(1 nm)/Al (>100 nm) with a high brightness of 5900 Cd/m 2 and a good current efficiency of 3.79 Cd/A.

Differently functionalized porphyrin linkers represent the key compounds for the syntheses of new porphyrin-based metal-organic frameworks (MOFs), which have gathered great interest within the last two decades. Herein we report the synthesis of a large range of 5,15-bis(4-ethoxycarbonylphenyl)porphyrin derivatives, through Suzuki and Sonogashira cross-coupling reactions of an easily accessible corresponding meso-dibrominated trans-A 2 B 2 -porphyrin with commercially available boronic acids or terminal alkynes. The resulting porphyrins were fully characterized through NMR, MS, and IR spectroscopy and systematically investigated through UV/Vis absorption. Finally, selected structures were saponified to the corresponding carboxylic acids and subsequently proven to be suitable for the synthesis of surface-anchored MOF thin films., (© 2020 The Authors. Published by Wiley-VCH GmbH.)

Porphyrin cyclophane 1 , consisting of two rigidly fixed but still movable cofacial porphyrins and exposing acetate-masked thiols in opposed directions of the macrocycle, is designed, synthesized, and characterized. The functional cyclophane 1 , as pioneer of mechanosensitive 3D materials, forms stable single-molecule junctions in a mechanically controlled break-junction setup. Its reliable integration in a single-molecule junction is a fundamental prerequisite to explore the potential of these structures as mechanically triggered functional units and devices.