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Organofluorines have a broad range of industrial applications, such as pharmaceuticals, liquid crystal displays (LCDs), solar cells, textiles, and construction coatings, and are used in peptidomimetics, surfactants, refrigerants, anesthetics, and agrochemicals. Among them are versatile monofluoroalkenes that play a crucial role in medicinal and synthetic chemistry. The synthetic strategies for this class of molecules are limited, and prior efforts frequently suffered from poor atom- and step-economies. As a surrogate pathway for traditional cross-coupling transformations, transition metal (TM)-catalyzed C-H direct α-fluoroalkenylation overcomes these obstacles and provides straightforward techniques to access monofluoroalkenes. Nevertheless, substrate scope is still a challenge for catalysis, where gem -bromofluoroalkene synthons are applicable with electronically biased substrates such as azoles, while gem -difluoroalkene-based strategies are limited to substrates containing N-based directing groups. Herein, we review the cutting-edge fluoroalkenylation research for direct synthesis of monofluoroalkenes achieved during the last decade (2013-2023). This review is divided into two main parts: the first part discusses TM-catalyzed direct α-fluoroalkenylation via the merging of C-H activation and C(sp 2 )-Br cleavage strategies using gem -bromofluoroalkenes, and the second part describes the same reaction, albeit with C(sp 2 )-F cleavage of highly explored gem -difluoroolefins. Our review surveys all previously reported monofluoroalkenes in this research area, including their preparation techniques, stereoselectivity, and yield percentages. Furthermore, optimal conditions, reactant scope, mechanistic investigations, synthetic applications, benefits, and drawbacks of each presented methodology are critically discussed.

Chiral 1D tin iodides EBASnI 3 were synthesized while incorporating enantiomerically pure and racemic ethylbenzylammonium (EBA) cations between the 1D shared inorganic corners. The dimensionality was reduced to 0D when replacing iodine with bromine. In all the cases, the presence of hydrogen bonds was observed between the organic part and the inorganic part, while transfer of chirality was evidenced for the EBASnI 3 enantiomerically pure compounds.

Herein, initially, we present a general overview of the global financial support for chemistry devoted to materials science, specifically intercalation layered compounds (ILCs). Subsequently, the strategies to synthesise these host structures and the corresponding guest-host hybrid assemblies are exemplified on the basis of some families of materials, including pillared clays (PILCs), porous clay heterostructures (PCHs), zirconium phosphate (ZrP), layered double hydroxides (LDHs), graphite intercalation compounds (GICs), graphene-based materials, and MXenes. Additionally, a non-exhaustive survey on their possible application in the field of energy through electrochemical storage, mostly as electrode materials but also as electrolyte additives, is presented, including lithium technologies based on lithium ion batteries (LIBs), and beyond LiBs with a focus on possible alternatives such XIBs (X = Na (NIB), K (KIB), Al (AIB), Zn (ZIB), and Cl (CIB)), reversible Mg batteries (RMBs), dual-ion batteries (DIBs), Zn-air and Zn-sulphur batteries and supercapacitors as well as their relevance in other fields related to (opto)electronics. This selective panorama should help readers better understand the reason why ILCs are expected to meet the challenge of tomorrow as electrode materials.

Intercalation compounds represent a unique class of materials that can be anisotropic (1D and 2D-based topology) or isotropic (3D) through their guest/host superlattice repetitive organisation. Intercalation refers to the reversible introduction of guest species with variable natures into a crystalline host lattice. Different host lattice structures have been used for the preparation of intercalation compounds, and many examples are produced by exploiting the flexibility and the ability of 2D-based hosts to accommodate different guest species, ranging from ions to complex molecules. This reaction is then carried out to allow systematic control and fine tuning of the final properties of the derived compounds, thus allowing them to be used for various applications. This review mainly focuses on the recent applications of intercalation layered compounds (ILCs) based on layered clays, zirconium phosphates, layered double hydroxides and graphene as heterogeneous catalysts, for environmental and health purposes, aiming at collecting and discussing how intercalation processes can be exploited for the selected applications.

Spin-state switching in iron(II) complexes composed of ligands featuring moderate ligand-field strength-for example, 2,6-bi(1 H -pyrazol-1-yl)pyridine (BPP)-is dependent on many factors. Herein, we show that spin-state switching in isomeric iron(II) complexes composed of BPP-based ligands-ethyl 2,6-bis(1 H -pyrazol-1-yl)isonicotinate (BPP-COOEt, L1) and (2,6-di(1 H -pyrazol-1-yl)pyridin-4-yl)methylacetate (BPP-CH 2 OCOMe, L2)-is dependent on the nature of the substituent at the BPP skeleton. Bi-stable spin-state switching-with a thermal hysteresis width (Δ T 1/2 ) of 44 K and switching temperature ( T 1/2 ) = 298 K in the first cycle-is observed for complex 1·CH 3 CN composed of L1 and BF 4 - counter anions. Conversely, the solvent-free isomeric counterpart of 1·CH 3 CN-complex 2a, composed of L2 and BF 4 - counter anions-was trapped in the high-spin (HS) state. For one of the polymorphs of complex 2b·CH 3 CN-2b·CH 3 CN-Y, Y denotes yellow colour of the crystals-composed of L2 and ClO 4 - counter anions, a gradual and non-hysteretic SCO is observed with T 1/2 = 234 K. Complexes 1·CH 3 CN and 2b·CH 3 CN-Y also underwent light-induced spin-state switching at 5 K due to the light-induced excited spin-state trapping (LIESST) effect. Structures of the low-spin (LS) and HS forms of complex 1·CH 3 CN revealed that spin-state switching goes hand-in-hand with pronounced distortion of the trans-N {pyridyl}-Fe-N{pyridyl} angle ( ϕ ), whereas such distortion is not observed for 2b·CH 3 CN-Y. This observation points that distortion is one of the factors making the spin-state switching of 1·CH 3 CN hysteretic in the solid state. The observation of bi-stable spin-state switching with T 1/2 centred at room temperature for 1·CH 3 CN indicates that technologically relevant spin-state switching profiles based on mononuclear iron(II) complexes can be obtained.

In order to prepare self-standing and flexible slow neutron reflectors made of graphite fluoride (GF) with high contents of (C 2 F) n structural phase, graphite foils of different thicknesses were used as starting materials for gas (F 2 )/solid fluorination. The maximal interlayer distance of GF was obtained with this phase thanks to the stacking sequence FCCF/FCCF; this is mandatory for the efficient reflection of slow neutrons. 71 and 77% of the (C 2 F) n phase were achieved for graphite foils with thicknesses of 1.0 and 0.1 mm, respectively. The interlayer distances were 8.6 Å as expected. The fluorination conditions (static mode, a long duration of 24 h, annealing in pure F 2 gas for 24 h, and temperatures in the 390-460 °C range) were adapted to large pieces of graphite foils (7 × 7 cm 2 ) in order to both avoid exfoliation and achieve a homogeneous dispersion of fluorine atoms. This process was also efficient for thinner (0.01 mm thick) graphitized graphene oxide foil. 56% of the (C 2 F) n phase and an interlayer of 8.6 Å were achieved for this foil when fluorination was performed at 430 °C. Whatever the nature and the thickness of the foil, their flexibilities are maintained.

The impact of isomerism of pyrimidine-based ligands and their rhodium(III) complexes with regard to their structures and properties was investigated. Two isomeric ligands, 4-(3,5-dimethyl-1 H -pyrazol-1-yl)-2,5-diphenylpyrimidine (HL2,5) and 4-(3,5-dimethyl-1 H -pyrazol-1-yl)-2,6-diphenylpyrimidine (HL2,6), were synthesized. The ligands differ by the degree of steric bulk: the molecular structure of HL2,5 is more distorted due to presence of pyrazolyl and phenyl groups in the neighbouring positions 4 and 5 of the pyrimidine ring. The complexation of HL2,5 and HL2,6 with RhCl 3 leads to the sp 2 C-H bond activation, resulting in the isolation of two complexes, [RhL2,5(Solv)Cl2]·nEtOH and [RhL2,6(Solv)Cl2]·nEtOH (Solv = H 2 O, EtOH), with the deprotonated forms of the pyrazolylpyrimidine molecules which coordinate the Rh 3+ ion as N^N^C-tridentate ligands. According to DFT modelling, the mechanism of the deprotonation involves (i) the C-H bond breaking in the 2-phenyl group followed by the coordination of the C atom to the Rh atom, (ii) the protonation of coordinated chlorido ligand, (iii) the ejection of the HCl molecule and (iv) the coordination of the H 2 O molecule. The ligand isomerism has an impact on emission properties and cytotoxicity of the complexes. Although the excited states of the complexes effectively deactivate through S 0 /T 1 and S 0 /S 1 crossings associated with the cleavage of the weak H 2 O ligands upon excitation, the [RhL2,5(Solv)Cl2]·nEtOH complex appeared to be emissive in the solid state, while [RhL2,6(Solv)Cl2]·nEtOH is non-emissive at all. The complexes show significant cytotoxic activity against cancerous HepG2 and Hep2 cell lines, with the [RhL2,6(Solv)Cl2]·nEtOH complex being more active than its isomer [RhL2,5(Solv)Cl2]·nEtOH. On the other hand, noticeable cytotoxicity of the latter against HepG2 is supplemented by its non-toxicity against non-cancerous MRC-5 cells.

In this study, the insertion of fluorine into LiFePO 4 was carried out under molecular fluorine F 2 at different temperatures. The reactivity strongly depends on the applied fluorination temperature, leading to very different products: core delithiation of the material is observed at low temperatures with the formation of a LiF shell around particles, while the material decomposes to gradually form a mixture of α-FeF 3 and α-Li 3 FeF 6 iron fluorides at higher temperatures. A second thermal treatment under N 2 leads to the formation of LiFePO 4 F in a new way that has not been reported before. Supported by X-ray diffraction, Raman, infrared, Mössbauer spectroscopies, 7 Li nuclear magnetic resonance and electrochemical characterization of the different materials, this report demonstrates various fluorination mechanisms for LiFePO 4 , from chemical delithiation to the stable pure fluorinated form LiFePO 4 F and illustrates an innovative method that can be extended to obtain the triphylite form of NaFePO 4 .

The advancement of lithium-ion batteries (LIBs) with high performance is crucial across various sectors, notably in space exploration. This advancement hinges on the development of innovative cathode materials. Our research is dedicated to pioneering a new category of cathodes using fluorinated multimetallic materials, with a specific focus on diverging from the traditional Ni, Co, and Mn-based NMC chemistries by substituting nickel and manganese with copper and iron which are more sustainable elements. Our goal is also to enhance the robustness of cathodes upon cycling by substituting oxygen with fluorine as the metal-ligand. To achieve this, an intimate composite blend of CuF 2 and FeF 3 , through the multi-metallic template fluorination (MMTF) methodology using a layered double hydroxide (LDH) as a precursor has been designed. Each of these components was carefully selected for its distinct attributes, including high redox potential, elevated energy density, substantial theoretical capacity, and improved cyclability. The composition denoted as (Cu 1.5 Co 0.5 ) 2+ (Fe 0.75 Al 0.25 ) 3+ has been selected for fluorination because it maximizes Fe 3+ and Cu 2+ amount in the screened LDHs. Subsequently, this particular LDH was fluorinated through solid-gas fluorination at different temperatures (200, 350, and 500 °C) using gaseous molecular fluorine (F 2 ). A comprehensive characterization of these materials using various techniques, including X-ray diffraction (XRD), 57 Fe Mössbauer spectrometry, scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX), and inductively coupled plasma analyses (ICP-AES) was conducted, and the evolution of LDH upon fluorination has revealed an intermediate porous texture particularly sensitive to hydration. Two original crystallographic phases are else obtained by fluorination: one formed by the hydration of the amorphous intermediate compound: Cu 3 Fe 1.5 Al 0.5 F 12 (H 2 O) 12 an anti-perovskite structure and another stabilized through the combination of solid gas fluorination and LDH precursor yielding an original CoFeF 5 -type phase. Raman operando during cyclic voltammetry measurement applied on a sample fluorinated at 500 °C and used as a cathode in front of lithium metal was finally conducted to validate redox activity and mechanism.

The synthesis of [6]helicene para -quinone starting from the 1,4-dimethoxy-[6]helicene derivative is presented. The demethylation reaction with boron tribromide led to unexpected results. Instead of the expected para -hydroquinone, the diketone tautomeric form was isolated. In contrast to the 1,4-hydroquinone and 1,4-dihydroxynaphthalene, the stable tautomers for the [4] and [6]helicenes were the aromatic diketones. These experimental results were corroborated by calculations. Additional calculations showed that these tautomeric species were indeed the stable forms of 1,4 and 1,3-hydroquinones when present in larger aromatics, in drastic contrast with 1,2-dihydroxy-aromatics (known as catechol)., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Two different alkynyl-substituted C 3 -symmetric cyclotribenzylenes (CTB) were synthesized in racemic and enantiomerically pure forms, and six gold(I) phosphine complexes differing by the nature of the CTB and the phosphine were prepared and characterized, in particular by NMR spectroscopy, DOSY, electronic circular dichroism (ECD), and electrospray ionization mass spectrometry (ESI-MS). Their ECD patterns depended on the substitution of the starting CTBs and were shifted bathochromically by comparison with the latter. ESI-MS in the presence of HCO 2 H allowed us to detect the complexes as proton adducts. The intensities of the signals were stronger when the phosphine was more electron-rich. This technique was also used to investigate the exchange of phosphine betweeen pairs of CTB complexes. The scrambling reaction was demonstrated by the higher intensity of the signals of the complexes subjected to the exchange of a single phosphine ligand by comparison with the intensity of the signals of the starting complexes.

Molecular triangles with competing Heisenberg interactions and significant Dzyaloshinskii-Moriya interactions (DMI) exhibit high environmental sensitivity, making them potential candidates for active elements for quantum sensing. Additionally, these triangles exhibit magnetoelectric coupling, allowing their properties to be controlled using electric fields. However, the manipulation and deposition of such complexes pose significant challenges. This work explores a solution by embedding iron-based molecular triangles in a polymer matrix, a strategy that offers various deposition methods. We investigate how the host matrix alters the magnetic properties of the molecular triangle, with specific focus on the magnetic anisotropy, aiming to advance its practical applications as quantum sensors.

The design of enantiomerically pure circularly polarized luminescent (CPL) emitters would enormously benefit from the accurate and in-depth interpretation of the chiroptical properties by means of jointly (chiroptical) photophysical measurements and state-of-the-art theoretical investigation. Herein, computed and experimental (chiro-)optical properties of a series of eight enantiopure phosphorescent rhenium(I) tricarbonyl complexes are systematically compared in terms of electronic circular dichroism (ECD) and CPL. The compounds have general formula fac -[ReX(CO) 3 (N^C NHC )], where N^C NHC is a pyridyl benzannulated N-heterocyclic carbene deriving from a (substituted) 2-(pyridin-2-yl)imidazo[1,5- a ]pyridin-2-ium proligand and X = Cl, Br and I, and display structured red phosphorescence with long-lived ( τ = 7.0-19.1 μs) excited-state lifetime and dissymmetry factors | g Lum | up to 4 × 10 -3 . The mixing of the character of the lowest-lying emitting triplet excited state is finely modulated between ligand centred ( 3 LC), metal-to-ligand charge transfer ( 3 MLCT) and halogen-to-ligand charge transfer ( 3 XLCT) by the nature of the ancillary halogen and the chromophoric N^C NHC ligand. The study unravels the effect exerted by the nature of the excited state onto the ECD and CPL activity and will help to pave the way to construct efficient CPL emitters by chemical design.

We developed a chemoselective metal-free access for the 1,2- and 2,3-semireduction of CF 3 - N -allenamides. The enamide functionality of CF 3 -substituted N -allenamides could be efficiently reduced by Et 3 SiH/BF 3 ·OEt 2 in total regioselectivity and good stereoselectivity, whereas DBU promoted the isomerization of the resulting allyl amide leading exclusively to the E -configurated enamide.

Reaction of a trinuclear triangular macrocyclic complex Pb 3 L(CF 3 SO 3 ) 6 with bidentate linkers in a ratio of 3 equiv. of linker per 2 equiv. of complex, produces a prismatic structure with 4,4'-dipyridyl, and two unprecedented, extended 3D frustum-like structures with 1,2-di(4-pyridyl)ethylene and 1,4-di(4-pyridyl)benzene. The cavities of these structures encapsulate triflate anions.

The synthesis of several new compounds containing a chromophore and a helicenic moiety is reported. The preparation, characterisation and some physico-chemical studies are detailed. In particular, the two enantiomers of several chiral molecules of this type were separated by chiral HPLC (both analytically and in a preparative way) and their racemisation rates were determined for short-lived species. Electronic circular dichroism (ECD) and circular polarised luminescence (CPL) measurements were performed for the compounds with a very long racemisation half-life. Chiral porphyrins and Bodipys both gave ECD and CPL responses over a large area of the visible spectrum.

The chelator diacetyl-bis( N 4-methylthiosemicarbazone) (ATSM) and its complexes with Cu II and Zn II are becoming increasingly investigated for medical applications such as PET imaging for anti-tumour therapy and the treatment of amyotrophic lateral sclerosis. However, the solubility in water of both the ligand and the complexes presents certain limitations for in vitro studies. Moreover, the stability of the Cu II and Zn II complexes and their metal exchange reaction against the potential biological competitor human serum albumin (HSA) has not been studied in depth. In this work it was observed that the ATSM with an added carboxylic group into the structure increases its solubility in aqueous solutions without altering the coordination mode and the conjugated system of the ligand. The poorly water-soluble Cu II - and Zn II -ATSM complexes were prevented from precipitating due to the binding to HSA. Both HSA and ATSM show a similar thermodynamic affinity for Zn II . Finally, the Cu II -competition experiments with EDTA and the water-soluble ATSM ligands yielded an apparent log  K d at pH 7.4 of about -19. When ATSM was added to Cu II - and Zn II -loaded HSA, withdrawing of Zn II was kinetically favoured, but this metal is slowly substituted by the Cu II afterwards taken from HSA so that this protein could be considered as a source of Cu II for ATSM.

Selective P-glycoprotein (P-gp)-targeted fluorescent conjugates are desirable tools to investigate the role of P-gp, a protein strongly implicated in mediating multidrug resistance and a major cause of chemotherapy failure. Herein, we report the development of 25 novel fluorescent small-molecule conjugates with varying physicochemical and optical properties, and their biological evaluation in a cell model as P-gp targeted constructs. This investigation revealed relationships between molecular structure and cell behavior and uncovered the capacity of conjugates with varying fluorophores to selectively target P-gp. Sulfocyanine 3 labeled conjugates (5, 10, 24, 29, 34) showed a particular intracellular staining pattern. Other conjugates bearing a boron dipyrromethene (BODIPY) core (3, 8, 13, 22, 27 (BODIPY FL), 12 (BODIPY 564/570) and 4, 9 (BODIPY 650/665)) or a 7-nitrobenz-2-oxa-1,3-diazole (NBD) core (11, 30) showed potential for global P-gp direct detection and quantification. These fluorescent conjugates holds key advantages over existing methods for drug resistance evaluation with regards to P-gp expression and could be used as innovative tools in preclinical assays and clinical diagnosis., Competing Interests: The authors declare the following competing financial interest(s): P. D., A. G., C. D., F. P. L., M. B. and E. M. are co-inventors on a patent application covering the method of P-gp detection, localization and quantification reported herein and as such may be entitled to a portion of any licensing fees and royalties generated by this technology. The authors declare no other potential conflict of interest relevant to this article., (This journal is © The Royal Society of Chemistry.)

The absorption spectrum of [Pt(dpybMe)Cl] (dpyb = 2,6-di-(2-pyridyl)benzene), representative of luminescent halide-substituted tridentate cyclometalated square planar Pt(II) neutral complexes, has been revisited by means of non-adiabatic wavepacket quantum dynamics. The early photophysics has been investigated on the basis of four singlet and five triplet excited states, namely nineteen "spin-orbit states", coupled with both vibronic and spin-orbit couplings, and includes eighteen normal modes. It is shown that in-plane scissoring and rocking normal modes of the cyclometalated tridentate ligand are responsible for the vibronic structure observed at around 400 nm in the experimental spectrum of the complex. The ultrafast decay of [Pt(dpybMe)Cl], within 1 ps, follows a spin-vibronic mechanism governed by excited state electronic characters, spin-orbit, and active tuning mode interplay. Both spin-orbit coupling and Pt(II) coordination sphere stretching modes and in-plane scissoring/rocking of the cyclometalated ligand activate the ultrafast decay within 20 fs of absorption. At longer time-scales (>100 fs) an asynchronous stretching of the Pt-C and Pt-N bonds activates the depopulation of the upper "reservoir" electronic states to populate the two lowest luminescent T1 and T2 electronic states. The in-plane rocking motion of the ligand controls the T1/T2 population exchange which is equilibrated at about 1 ps. Stabilization of the upper non-radiative metal-centered (MC) states by out-of-plane ligand distortion of low frequency is not competitive with the ultrafast spin-vibronic mechanism discovered here for [Pt(dpybMe)Cl]. Modifying the Pt-C covalent bond position and rigidifying the cyclometalated ligand will have a dramatic influence on the spin-vibronic mechanism and consequently on the luminescence properties of this class of molecules.

The conformational preference of a cavity-based biaryl phosphine, namely 5-(2-diphenylphosphinyl-phenyl)-25,26,27,28-tetrapropyloxycalix[4]arene (L) has been investigated by density functional theory calculations. The analysis showed that the barrier to rotation about the C-C axle of the biaryl unit is only 10.7 kcal mol -1 , this rendering possible access to conformers of two types, those in which the P lone pair sits at the cavity entrance and points to the calixarene interior, others with a more open structure where the P atom is located outside the cavity. As revealed by a single crystal X-ray diffraction study, the biaryl phosphine appears virtually as an atropisomer in the solid state in which the phosphorus atom lies totally out of the cavity defined by the four phenoxy rings.

In the field of noncovalent interactions, chalcogen bonding (ChB) involving the tellurium atom is currently attracting much attention in supramolecular chemistry and in catalysis. However, as a prerequisite for its application, the ChB should be studied in solution to assess its formation and, if possible, to evaluate its strength. In this context, new tellurium derivatives bearing CH 2 F and CF 3 groups were designed to exhibit Te⋯F ChB and were synthesized in good to high yields. In both types of compounds, Te⋯F interactions were characterized in solution by combining 19 F, 125 Te and HOESY NMR techniques. These Te⋯F ChBs were shown to contribute to the overall J Te-F coupling constants (94-170 Hz) measured in the CH 2 F- and CF 3 -based tellurium derivatives. Finally, a variable temperature NMR study allowed us to approximate the energy of the Te⋯F ChB, from 3 kJ mol -1 for the compounds with weak Te σ-holes to 11 kJ mol -1 for Te σ-holes activated by the presence of strong electron withdrawing substituents., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

A bipyridine-strapped porphyrin was prepared using a remote template effect of alkali or transition metal cations in the bipyridine subunit to enhance the yield 10-fold. The flexibility of the bipyridine-strap also allowed the synthesis of a doubly strapped porphyrin.

Metal-mediated assembly allows us to combine an achiral emissive ligand A with different chiral ligands (such as B) in a non-statistical fashion, obtaining Pd 2 A 2 B 2 heteroleptic cages showing circularly polarized luminescence (CPL). By using the 'shape complementary assembly' (SCA) strategy, the cages are exclusively obtained as cis -Pd 2 A 2 B 2 stereoisomers, as confirmed by NMR, MS and DFT analyses. Their unique chiroptical properties derive from the synergy of all the building blocks. Ligand B imparts the chiral information of its aliphatic backbone, comprising two stereogenic sp 3 carbon centres, to the overall structure, causing CD and CPL signal induction for the chromophore on ligand A. The heteroleptic cage shows CPL with a | g lum | value of 2.5 × 10 -3 , which is 3-times higher than that for a progenitor based on aromatic helical building block H, thus opening a rational route towards optimizing the CPL properties of self-assembled nanostructures in a modular way.

Metal ions play a very important role in nature and their homeostasis is crucial. A lot of metal-related chemical research activities are ongoing that concern metal-based drugs or tools, such as chelation therapy, metal- and metabolite sensors, metallo-drugs and prodrugs, PET and MRI imaging agents, etc . In most of these cases, the applied chelator/ligand (L) or metal-ligand complex (M-L) has at least to pass the blood plasma to reach the target. Hence it is exposed to several metal-binding proteins (mainly serum albumin and transferrin) and to all essential metal ions (zinc, copper, iron, etc .). This holds also for studies in cultured cells when fetal calf serum is used in the medium. There is a risk that the applied compound (L or M-L) in the serum is transformed into a different entity, due to trans-metallation and/or ligand exchange reactions. This depends on the thermodynamics and kinetics. For kinetically-labile complexes, the complex stability with all the ligands and all metal ions present in serum is decisive in evaluating the thermodynamic driving force towards a certain fate of the chelator or metal-ligand complex. To consider that, an integrative view is needed on the stability constants, by taking into account all the metal ions present and all the main proteins to which they are bound, as well as the non-occupied metal binding site in proteins. Only then, a realistic estimation of the complex stability, and hence its potential fate, can be done. This perspective aims to provide a simple approach to estimate the thermodynamic stability of labile metal-ligand complexes in a blood plasma/serum environment. It gives a guideline to obtain an estimation of the plasma and serum complex stability and metal selectivity starting from the chemical stability constants of metal-ligand complexes. Although of high importance, it does not focus on the more complex kinetic aspects of metal-transfer reactions. The perspective should help for a better design of such compounds, to perform test tube assays which are relevant to the conditions in the plasma/serum and to be aware of the importance of ternary complexes, kinetics and competition experiments.

Nickel(0) nanoparticles coordinated to NHC ligands bearing N-coordinated cinnamyl moieties were readily prepared by reduction of a [NiCpBr(NHC-cinnamyl)] complex with methyl magnesium bromide. The combination of a strong σ-donor NHC ligand with a π-coordinating appended cinnamyl moiety likely prevents nickel(0) nanoparticle aggregation to larger inactive species, and allows the effective and ( Z )-selective semi-hydrogenation of alkynes and ynamides .

Bioactive glass-based organic/inorganic hybrids are a family of materials holding great promise in the biomedical field. Developed from bioactive glasses following recent advances in sol-gel and polymer chemistry, they can overcome many limitations of traditional composites typically used in bone repair and orthopedics. Thanks to their unique molecular structure, hybrids are often characterized by synergistic properties that go beyond a mere combination of their two components; it is possible to synthesize materials with a wide variety of mechanical and biological properties. The polymeric component, in particular, can be tailored to prepare tough, load-bearing materials, or rubber-like elastomers. It can also be a key factor in the determination of a wide range of interesting biological properties. In addition, polymers can also be used within hybrids as carriers for therapeutic ions (although this is normally the role of silica). This review offers a brief look into the history of hybrids, from the discovery of bioactive glasses to the latest developments, with a particular emphasis on polymer design and chemistry. First the benefits and limitations of hybrids will be discussed and compared with those of alternative approaches (for instance, nanocomposites). Then, key advances in the field will be presented focusing on the polymeric component: its chemistry, its physicochemical and biological advantages, its drawbacks, and selected applications. Comprehensive tables summarizing all the polymers used to date to fabricate sol-gel hybrids for biomedical applications are also provided, to offer a handbook of all the available candidates for hybrid synthesis. In addition to the current trends, open challenges and possible avenues of future development are proposed.

Implementing transient processes in networks of dynamic molecules holds great promise for developing new functional behaviours. Here we report that trichloroacetic acid can be used to temporarily rearrange networks of dynamic imine-based metal complexes towards new equilibrium states, forcing them to express complexes otherwise unfavourable in their initial equilibrium states. Basic design principles were determined for the creation of such networks. Where a complex distribution of products was obtained in the initial equilibrium state of the system, the transient rearrangement temporarily yielded a simplified output, forcing a more structured distribution of products. Where a single complex was obtained in the initial equilibrium state of the system, the transient rearrangement temporarily modified the properties of this complex. By doing so, the mechanical properties of an helical macrocyclic complex could be temporarily altered by rearranging it into a [2]catenane., Competing Interests: The authors declare no conflicts of interest., (This journal is © The Royal Society of Chemistry.)

In this paper, the history, present status, and future of density-functional theory (DFT) is informally reviewed and discussed by 70 workers in the field, including molecular scientists, materials scientists, method developers and practitioners. The format of the paper is that of a roundtable discussion, in which the participants express and exchange views on DFT in the form of 302 individual contributions, formulated as responses to a preset list of 26 questions. Supported by a bibliography of 777 entries, the paper represents a broad snapshot of DFT, anno 2022.

The two-faced reactivity of N -allenamides allows regio- and stereo-controlled functionalization at the α-, β- and γ-positions of the nitrogen atom. The contingency to obtain either proximal or distal adducts makes these substrates essential for the construction of complex heterocyclic scaffolds. This review covers the recent advances made in the development of new methods involving amination and alkoxylation reactions on N -allenamides leading to a broad array of N-heterocycles. The syntheses reported herein are classified based on their reaction type. In addition, mechanistic perceptions are provided for the majority of the discussed transformations.

The mean square displacement 〈( x ( t ) - x (0)) 2 〉 of the position x of a CO molecule adsorbed at thermal equilibrium on a Cu(100) substrate and moving along the 〈100〉 direction is evaluated quantum mechanically. The problem is treated in the independent particle formalism via the numerical solution of the time dependent Schrödinger equation with an initial thermal wave packet. The results are discussed in relation to observables from neutron scattering or helium-3 spin-echo experiments, and their interpretation in terms of classical or quantum mechanical expressions for the mean square displacement.

While much progress has been made on the modeling of swelling clays at the molecular scale in recent decades, up-scaling to the macroscopic scale remains a challenge, in particular because the mesoscopic scale (between a few nanometers and a few hundreds of nanometers) is still poorly understood. In this article, we propose a new 2D granular model of clay at the mesoscale. This model is adapted to the modeling of a dense clay matrix representing geomechanical conditions (up to pressures of 10-100 MPa). Some salient features of this model with respect to the existing literature are: (1) its ability to capture hydration transitions occurring at small basal spacings (essential to model complex hydro-mechanical behaviors such as drying shrinkage), (2) the flexibility of the clay layers that becomes important at pressures exceeding 1 MPa, and (3) the control of the inter-layer shear strength critical to model plasticity. The model calibration is purely bottom-up, based on molecular modeling results only. The case of Na-montmorillonite (Na-Mnt) is investigated in detail, regarding isotropic compression (elasticity and plasticity), yield surface and desiccation. The behavior of the granular model appears well consistent with what is known experimentally for pure Na-Mnt, and offers valuable insight into meso-scale processes that could not be reached so far (role of hydration transition, layer flexibility, and impact of loading history). This granular model is a first step toward quantitative up-scaling of molecular modeling of swelling clay for geomechanical applications.

The metastable trilacunary heteropolyoxomolybdate [PMo 9 O 31 (py) 3 ] 3- - {PMo 9 }; py = pyridine) and the ditopic pyridyl bearing diarylethene (DAE) (C 25 H 16 N 2 F 6 S 2 ) self-assemble via a facile ligand replacement methodology to yield the photo-active molecular capsule [(PMo 9 O 31 ) 2 (DAE) 3 ] 6- . The spatial arrangement and conformation of the three DAE ligands are directed by the surface chemistry of the molecular metal oxide precursor with exclusive ligation of the photo-active antiparallel rotamer to the polyoxometalate (POM) while the integrity of the assembly in solution has been verified by a suite of spectroscopic techniques. Electrocyclisation of the three DAEs occurs sequentially and has been investigated using a combination of steady-state and time-resolved spectroscopies with the discovery of a photochemical cascade whereby rapid photoinduced ring closure is followed by electron transfer from the ring-closed DAE to the POM in the latent donor-acceptor system on subsequent excitation. This interpretation is also supported by computational and detailed spectroelectrochemical analysis. Ring-closing quantum yields were also determined using a custom quantum yield determination setup (QYDS), providing insight into the impact of POM coordination on these processes., Competing Interests: The authors declare no conflict of interests., (This journal is © The Royal Society of Chemistry.)

Metal ions (Ag + , Cd 2+ , Eu 3+ , Sm 3+ ) and protons can, through coordination and protonation, modulate in three specific ways the structural information contained in the pyrazine-based heterocyclic strand L (obtained from 2,5-bis(methylhydrazino)pyrazine and 2 equivalents of 2-pyridinecarboxaldehyde), thus generating two linear rod-like conformations and a bent one. This conformational diversity is associated with a structural one that consists of two diprotonated forms (H 2 L(PF 6 ) 2 and H 2 L(CF 3 SO 3 ) 2 ), a polymeric architecture [AgL] n (CF 3 SO 3 ) n , two rack-like complexes ([Eu 2 H 2 L 3 (CF 3 SO 3 ) 6 ](PF 6 ) 2 and [Sm 2 H 2 L 3 (CF 3 SO 3 ) 6 ](PF 6 ) 2 ) and a grid-like structure ([Cd 4 L 4 ](CF 3 SO 3 ) 8 ).

Upon gold catalysis, the 2,3-dihydropyrrolo[1,2- a ]indole motif, encountered in few but interesting bioactive natural products, was efficiently obtained from N -aryl 2-alkynylazetidine derivatives. In an attempt to apply this methodology to the synthesis of harmalidine, isolated from the seeds of Peganum harmala , advanced amino 2,3-hydropyrrolo[1,2- a ]indol(one) derivatives were readily obtained in only 11 steps from but-3-yn-1-ol. While the reported structure of harmalidine could not be reached from these intermediates, a surprising 12-membered diimino dimer was isolated. Extensive comparison of the reported harmalidine NMR data to the experimental and calculated data of our synthetic molecules, harmaline or the synthetised N -methylharmaline show discrepancies with the proposed natural product structure., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Copper (Cu) in its ionic forms is an essential element for mammals and its homeostasis is tightly controlled. Accordingly, Cu-dyshomeostasis can be lethal as is the case in the well-established genetic Wilson's and Menkes diseases. In Alzheimer's disease (AD), Cu-accumulation occurs in amyloid plaques, where it is bound to the amyloid-beta peptide (Aβ). In vitro , Cu-Aβ is competent to catalyze the production of reactive oxygen species (ROS) in the presence of ascorbate under aerobic conditions, and hence Cu-Aβ is believed to contribute to the oxidative stress in AD. Several molecules that can recover extracellular Cu from Aβ and transport it back into cells with beneficial effects in cell culture and transgenic AD models were identified. However, all the Cu-shuttles currently available are not satisfactory due to various potential limitations including ion selectivity and toxicity. Hence, we designed a novel peptide-based Cu shuttle with the following properties: (i) it contains a Cu(ii)-binding motif that is very selective to Cu(ii) over all other essential metal ions; (ii) it is tagged with a fluorophore sensitive to Cu(ii)-binding and release; (iii) it is made of a peptide platform, which is very versatile to add new functions. The work presented here reports on the characterization of AKH-αR5W4 NBD , which is able to transport Cu ions selectively into PC12 cells and the imported Cu appeared bioavailable, likely via reductive release induced by glutathione. Moreover, AKH-αR5W4 NBD was able to withdraw Cu from the Aβ 1-16 peptide and consequently inhibited the Cu-Aβ based reactive oxygen species production and related cell toxicity. Hence, AKH-αR5W4 NBD could be a valuable new tool for Cu-transport into cells and suitable for mechanistic studies in cell culture, with potential applications in restoring Cu-homeostasis in Cu-related diseases such as AD., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

Covering: 1972 to 2021The rhazinilam family of natural products exhibits a main structure with a stereogenic quaternary carbon and a tetrahydroindolizine core imbedded within a 9-membered macrocycle, imposing axial chirality. This unique architecture combined with their taxol-like antimitotic activities have attracted various attention, especially from synthetic chemists, notably in the past decade. The present review describes the known total and formal syntheses of the members of the rhazinilam family (rhazinilam, rhazinal, leuconolam and kopsiyunnanines), according to the strategy developed.

The presence of a permethylated α-cyclodextrin (α-CD) cavity in a chelating P,N ligand promotes exclusive formation of 1 : 1 ligand/metal complexes. In MX 2 complexes, one of the two halido ligands is forced to reside inside the CD hollow while the second one is pointing outside. Unlike its cavity-free analogue, a Ni(II) complex of the CD ligand is a highly selective precatalyst for ethylene dimerisation (96% C 4 selectivity with up to 95% of 1-butene within the C 4 fraction).

In the screening of compounds for singlet fission, the relative energies of the constitutive units are decisive to fulfil the thermodynamic rules. From a model Hamiltonian constructed on the local spin states of an active chromophore and its environment, it is suggested that embedding greatly influences the energy differences of the active monomer spin states. Even in the absence of charge transfer, the field generated by a singlet environment produces an increase of the [ E (S 1 ) - E (S 0 )]/[ E (T 1 ) - E (S 0 )] critical ratio by up to 6% as compared to the one of a free chromophore. Besides, variations are observed when the intimate electronic structure of the singlet environment is modified. This propensity towards singlet fission is even more pronounced (10%) when the environment is switched to the triplet state. Finally, the embedding is likely to reverse the spin state ordering in the limit of vanishing atomic orbital overlaps. Despite its simplicity, the model stresses the importance of the environment spin nature in the quest for singlet fission candidates, and more generally in spectroscopy analysis.

Well-defined π-conjugated thiophene donor-acceptor molecules play an important role in different fields ranging from synthetic chemistry to materials science. Their chemical structure provides specific electronic and physicochemical properties, which can be further tuned by the introduction of functional groups. Herein, we design and synthesize two novel thiophene-based π-conjugated donor-acceptor molecules TDA-1 and TDA-2 through Aldol and Knoevenagel condensations. In our proof-of-concept study we report for the first time on the use of small organic molecules employed in aqueous zinc-ion hybrid supercapacitors (Zn-HSCs),which exhibit capacitance as high as 206.7 and 235.2 F g -1 for TDA-1, and TDA-2, respectively.

The preparation of several covalently linked [6]-helicene-porphyrins is reported. A fused [6]-helicene-porphyrin π-extended aromatic system was isolated, the enantiomers separated and the chiroptical properties determined. The oxidative cyclodehydrogenation proved to be very effective for six-membered fused helical systems, but not suited for the formation of five-membered fused systems.

The one-dimensional coordination polymers {[Cu II (hfac) 2 ] 3 ( m -BNN)} n · n CH 2 Cl 2 (1 ·CH 2 Cl 2 , P 1̄) and {[Cu II (hfac) 2 ] 3 ( m -BNN)} n (1', P 2/ n ), hfac = hexafluoroacetylacetonate and m -BNN = meta -phenylene bis(nitronyl-nitroxide), were obtained from CH 2 Cl 2 and CHCl 3 , respectively. 1 ·CH 2 Cl 2 is transformed to 1 at 335 K. Their magnetic susceptibilities differ in both magnitude and temperature dependence behavior. 1 and 1' undergo a ferroelastic-like phase transition at 110 K and an unidentified one at 37 K. There is a subtle long relaxation of this ferroelastic-like ordered state.

The treatment of osteomyelitis, a destructive inflammatory process caused by bacterial infections to bone tissue, is one of the most critical challenges of orthopedics and bone regenerative medicine. The standard treatment consists of intense antibiotic therapies combined with tissue surgical debridement and the application of a bone defect filler material. Unfortunately, commercially available candidates, such as gentamicin-impregnated polymethylmethacrylate cements, possess very poor pharmacokinetics ( i.e. , 24 hours burst release) and little to no regenerative potential. Fostered by the intrinsic limitations associated with conventional treatments, alternative osteostimulative biomaterials with local drug delivery have recently started to emerge. In this study, we propose the use of a polycaprolactone-silica sol-gel hybrid material as carrier for the delivery of rifampicin, an RNA-polymerase blocker often used to treat bone infections, and of osteostimulative silicate ions. The release of therapeutic agents from the material is dual, offering two separate and simultaneous effects, and decoupled, meaning that the kinetics of rifampicin and silicate releases are independent from each other. A series of hybrid formulations with increasing amounts of rifampicin was prepared. The antibiotic loading efficacy, as well as the release profiles of rifampicin and silicates were measured. The characterization of cell viability and differentiation of rat primary osteoblasts and antibacterial performance were also performed. Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa and Escherichia coli were selected due to their high occurrence in bone infections. Results confirmed that rifampicin can be successfully loaded within the hybrids without significant degradation and that it is possible to tailor the antibiotic release according to need. Once in a physiological environment, the rapid release of silicates was associated with optimal cell proliferation and the overexpression of osteoblastic differentiation. Simultaneously, rifampicin is delivered over the course of several weeks with significant inhibition of all tested strains. In particular, the materials caused a growth reduction of 7-10 orders of magnitude in Staphylococcus aureus , the major strain responsible for osteomyelitis worldwide. Our data strongly suggest that PCL/silica hybrids are a very promising candidate to develop bone fillers with superior biological performance compared to currently available options. Thanks to their unique synthesis route and their dual tailored release they can promote bone regeneration while reducing the risk of infection for several weeks upon implantation.

The ability of [Ru(bpy) 2 (bpym)] 2+ (bpy = 2,2'-bipyridine; bpym = 2,2'-bipyrimidine) to probe specifically heavy cations has been investigated by means of density functional theory for transition metals, group 12 elements and Pb 2+ . On the basis of the calculated Gibbs free energies of complexation in water it is shown that all reactions are favorable with negative enthalpies except for Hg 2+ , with the transition metal cations forming stable bi-metallic complexes by coordination to the bpym ligand. Comparison between the optical and photophysical properties of the Ru 2+ probe and those of the coordination compounds does not demonstrate a high selectivity due to very similar characteristics of the absorption and emission spectra. Whereas by complexation the lowest metal-to-ligand-charge-transfer (MLCT) shoulder of [Ru(bpy) 2 (bpym)] 2+ at 462 nm is more or less shifted to the red as a function of the cation, the second MLCT band at 415 nm, less sensitive to the complexation, gains in intensity and is slightly blue-shifted. The visible MLCT emission of [Ru(bpy) 2 (bpym)] 2+ at 706 nm is altered by complexation leading to near IR (800-900 nm) emission in most of the coordination compounds. Complexation to some transition metal cations (Fe, Co, Rh and Pd) generates low-lying metal-centered (MC) excited states that quench luminescence. In contrast to the conclusion of experimental findings by Kumar et al. ( Chem. Commun. 2014, 50 , 8488-8490), [Ru(bpy) 2 (bpym)] 2+ cannot be proposed as a fast and selective probe for monitoring Pd 2+ in aqueous media. Indeed, it does not possess the optical and photophysical characteristics necessary to discriminate Pd 2+ ions over a variety of other cations.

The use of Pd(OAc) 2 as the catalyst and AgOAc as the oxidant enabled the direct regioselective oxidative C-H/C-H cross-coupling of pyrazolo[1,5- a ]pyrimidines or pyrazolo[1,5- a ]pyridines with various five-membered heteroarenes without the need of pre-activation and/or directing groups. Successful coupling partners include thiophenes, benzothiophenes, thiazoles, furans, oxazoles, indoles and imidazo[1,2- a ]pyridines.

FID-detected nutations of the antiferromagnetic crystal form of [Y(pc) 2 ]˙ demonstrated that its radical spin can be coherently driven in its magnetically condensed undeuterated phase and at room temperature. Liquid-helium nutations revealed additional Rabi oscillations assigned to transitions within higher-multiplicity states of finite-sized chain fragments.