Simultaneously resolving BINOL and proline using a stoichiometric cocrystal switch.

We here highlight the importance of stoichiometry for simultaneous cocrystal resolution. Focusing on combining the racemates of binol and proline, we show that a 1 : 2 ratio leads to formation of a full racemic compound, whereas a 2 : 1 ratio, leads to conglomerate formation, with simultaneous resolution of both binol and proline. Playing on stoichiometry, one achieves a reversible switch between the racemic compound and conglomerate.

Synthesis, Crystal Structures, Genotoxicity, and Antifungal and Antibacterial Studies of Ni(II) and Cd(II) Pyrazole Amide Coordination Complexes.

In this study, we synthesized two coordination complexes based on pyrazole-based ligands, namely 1,5-dimethyl--phenyl-1H-pyrazole-3-carboxamide () and 1,5-dimethyl--propyl-1H-pyrazole-3-carboxamide (), with the aim to investigate bio-inorganic properties. Their crystal structures revealed a mononuclear complex [Ni()](ClO) () and a dinuclear complex [Cd()]Cl (). Very competitive antifungal and anti-Fusarium activities were found compared to the reference standard cycloheximide.

Spin-state versatility in FeII4L supramolecular cages with a pyridyl-hydrazone ligand scaffold modulated by solvents and counter anions.

Discrete spin crossover (SCO) tetranuclear cages are a unique class of materials that have potential use in next-generation molecular recognition and sensing. In this work, two new edge-bridged SCO FeII4L (L = 2,7-bis((()-pyridin-2-ylmethylene)amino)benzo[] [3,8]phenanthroline-1,3,6,8(2,7)-tetraone) supramolecular cages with different counter anions: ClO (2) and CFSO (3) were constructed subcomponent self-assembly to investigate both solvent and anion influences on their magnetic properties and compare them to cage 1 with a BF anion. Pyridyl-hydrazone bidentate ligand scaffolds were employed to replace the 'classical' imidazole/thiazolyl-imine coordination units to induce SCO behaviour in these cages.

Coordination Complexes Built from a Ditopic Triazole-Pyrazole Ligand with Antibacterial and Antifungal Performances.

Four mononuclear complexes (HO){[NiL](ClO)} (), [CoL](ClO)·2HO (), [CdLCl] () and [CuL](NO) () have been prepared employing a newly synthesized 1,2,4-triazole ligand: 3-(3,5-dimethyl-1-pyrazol-1-yl)-1-1,2,4-triazole (). The structures of the complexes, which crystallized in (), (), (), and (), are reviewed within the context of the cooperative effect of the hydrogen bonding network and counter anions on the supramolecular formations. Moreover, within the framework of biological activity examination, these compounds showed favorable antibacterial performances compared to those of various species of bacteria, including both Gram-positive and Gram-negative strains.

Modular metallotecton for engineering permanently porous frameworks: supernumerary role of ancillary ion.

The formation of robust supramolecular frameworks built from hetero-polytopic metal complexes and interacting with different ancillary ions remains a long-standing and underexplored desire. Herein, the secondary sphere interaction chemistry of [Ru(5-oxido-6-hydroxy-1,10-phenanthroline)(5,6-dihydroxy-1,10-phenanthroline)] (1) ( = 1, 3) coordination ion is reported, where the π-conjugated phenanthroline ligands are functionalized with catecholate groups used as H-bond donors and ligands. The deprotonation of the catechols is found to control the overall charge stoichiometry in 1, acting as a metallotecton to interact with anions of different basicity (Cl in 1.

Formation, Reactivity, and Catalytic Behavior of a Keggin Polyoxometalate/Bipyridine Hybrid in the Epoxidation of Cyclooctene with HO.

The present study further explores the behavior of polyoxometalate-based hybrid compounds as catalysts for liquid-phase cyclooctene epoxidation with HO. Precisely, it unveils the nature of the relevant active species derived from the hybrid based on Keggin polyoxometalate (POM) and bipyridines (bpy) of formula (2,2'-Hbpy)[PWO] (). Whereas (i) it is generally accepted that the catalytic oxidation of organic substrates by HO involving Keggin HPAs proceeds via an oxygen transfer route from a peroxo intermediate and (ii) the catalytically active peroxo species is commonly postulated to be the polyperoxotungstate {PO[W(O)(O)]} complex (PW), we show that the studied epoxidation reaction seems to be more sophisticated than commonly reported.

Revealing the reversible solid-state electrochemistry of lithium-containing conjugated oximates for organic batteries.

In the rising advent of organic Li-ion positive electrode materials with increased energy content, chemistries with high redox potential and intrinsic oxidation stability remain a challenge. Here, we report the solid-phase reversible electrochemistry of the oximate organic redox functionality. The disclosed oximate chemistries, including cyclic, acyclic, aliphatic, and tetra-functional stereotypes, uncover the complex interplay between the molecular structure and the electroactivity.

Structural insight into the magnesium borohydride - ethylenediamine solid-state Mg-ion electrolyte system.

A highly complex crystal structure of stoichiometric Mg()(BH) was solved from single crystal synchrotron X-ray diffraction and confirmed by neutron powder diffraction (NPD) on isotopically substituted Mg()(BD). We highlight the role of the amorphous Mg(BH) in the reactivity of the Mg(BH)- system and characterized a previously overlooked phase, Mg()(BH).

High performance Li-, Na-, and K-ion storage in electrically conducting coordination polymers.

Coordination polymers (CPs) made of redox-active organic moieties and metal ions emerge as an important class of electroactive materials for battery applications. However, the design and synthesis of high voltage alkali-cation reservoir anionic CPs remains challenging, hindering their practical applications. Herein, we report a family of electrically conducting alkali-cation reservoir CPs with the general formula of A-TM-PTtSA (wherein A = Li, Na, or K; TM = Fe, Co, or Mn; and PTtSA = benzene-1,2,4,5-tetra-methylsulfonamide).

Complexation: An Interesting Pathway for Combining Two APIs at the Solid State.

Combining different drugs into a single crystal form is one of the current challenges in crystal engineering, with the number of reported multi-drug solid forms remaining limited. This paper builds upon an efficient approach to combining Active Pharmaceutical Ingredients (APIs) containing carboxylic groups in their structure with APIs containing pyridine moieties. By transforming the former into their zinc salts, they can be successfully combined with the pyridine-containing APIs.

A spin crossover FeL cage based on pyridyl-hydrazone sites.

Reported here is the first Fe based supramolecular cage with pyridyl-hydrazone ligand scaffolds that exhibits temperature induced spin crossover behaviour. Density functional theory calculations were employed to investigate the cause of the occurrence of this phenomenon based on the ligand structure. These results indicate that the reported low-spin cages with pyridyl-imine sites could be reconsidered for spin crossover by carefully manipulating the functional groups in the ligand system.

Synthesis, Structure, and Thermal Stability of a Mesoporous Titanium(III) Amine-Containing MOF.

The first mesoporous bimetallic Ti/Al metal-organic framework (MOF) containing amine functionalities on its linkers has been selectively obtained by converting the cheap commercially available (TiCl)AlCl into TiAlCl(THF) and reacting this complex with 2-aminoterephthalic acid in dimethylformamide (DMF) under soft solvothermal conditions. This compound is structurally related to the previously described NH-MIL-101(M) (M = Cr, Al, and Fe) MOFs. Thermal gravimetric analyses and powder X-ray diffraction (PXRD) measurements demonstrated that this highly air-sensitive Ti-containing MOF is structurally stable up to 200 °C.

L-Proline, a resolution agent able to target both enantiomers of mandelic acid: an exciting case of stoichiometry controlled chiral resolution.

We present a thought-provoking development in chiral resolution. Using a resolving agent of a given handedness, L-proline, we show that both R- and S-enantiomers of mandelic acid can be resolved from a racemic mixture simply by varying the stoichiometry. We are the first to report this specific feature, achieved by the existence of stoichiometrically diverse cocrystal systems between R- and S-mandelic acid and L-proline.

Synthesis and cytotoxicity against tumor cells of pincer N-heterocyclic ligands and their transition metal complexes.

The complexes: [CoL](ClO) (1), [FeL](ClO) (2), [NiL](ClO) (3) and [MnLCl] (4), with L = diethyl-1,1'-(pyridine-2,6-diyl)bis(5-methyl-1-pyrazole-3-carboxylate), were synthesized and fully characterized. Structural analysis revealed two distinct patterns influenced by the counter ions where L acts as a tridentate chelating ligand. The antitumor activity of L and L' (diethyl 2,2'-(pyridine-2,6-diylbis(5-methyl-1-pyrazole-3,1-diyl)) diacetate) as well as their metal complexes, was tested by the measurement of their cytostatic and cytotoxic properties towards the blood cancer mastocytoma cell line P815.

Functionalization of Mono- and Bimetallic MIL-100(Al,Fe) MOFs by Ethylenediamine: Postfunctionalization, Brønsted Acido-Basicity, and Unusual CO Sorption Behavior.

The metal sites of MIL-100(Fe), MIL-100(Fe,Al), and MIL-100(Al) metal-organic frameworks (MOFs) were decorated with ethylenediamine (EN). Interestingly, the Al-containing MOFs presented hierarchized porosity, and their structural integrity was maintained upon functionalization. Solution and solid-state NMR confirmed the grafting efficiency in the case of MIL-100(Al) and the presence of a free amine group.

Functionalized 1,8-Diazaiptycenes as Monomers for Aromatic Oligoamide Foldamers.

Diversification of the structures and the applications possible for foldamers rely on expansion of the building block library available for their synthesis. In this work, we describe the synthesis of a range of three dimensional heteroaromatic monomers, based on iptycene scaffolds, that are suitable for the synthesis of aromatic oligoamide foldamers. These units can be obtained in gram quantities in up to 80 % yield through [4+2] cycloaddition between diester, diamine, and amino acid derivatives of 1,8-diazaanthracenes and a variety of dienophiles.

An Electrically Conducting Li-Ion Metal-Organic Framework.

Metal-organic frameworks (MOFs) have emerged as an important, yet highly challenging class of electrochemical energy storage materials. The chemical principles for electroactive MOFs remain, however, poorly explored because precise chemical and structural control is mandatory. For instance, no anionic MOF with a lithium cation reservoir and reversible redox (like a conventional Li-ion cathode) has been synthesized to date.

Correction: Water binding stabilizes stacked conformations of ferrocene containing sheet-like aromatic oligoamides.

Correction for 'Water binding stabilizes stacked conformations of ferrocene containing sheet-like aromatic oligoamides' by Ya-Zhou Liu et al., Org. Biomol.

Urea as a Cocrystal Former-Study of 3 Urea Based Pharmaceutical Cocrystals.

Cocrystallization is commonly used for its ability to improve the physical properties of APIs, such as solubility, bioavailability, compressibility, etc. The pharmaceutical industry is particularly interested in those cocrystals comprising a GRAS former in connection with the target API. In this work, we focus on the potential of urea as a cocrystal former, identifying three novel pharmaceutical cocrystal systems with catechin, 3-hydroxyl-2-naphthoic and ellagic acid.

Water binding stabilizes stacked conformations of ferrocene containing sheet-like aromatic oligoamides.

While water clusters play an essential role in the stability of biological structures, their ability to stabilize synthetic oligomers is less understood. We have synthesized a heptameric sheet-like aromatic oligoamide foldamer with ferrocene as turn unit. It shows strong interactions with water in the solid state and in solution.

A Gold(I)-Catalyzed Hydroamination/Cycloisomerization Cascade: Concise Synthesis of (±)-seco-Antofine and (±)-Septicine.

A concise and flexible procedure for the synthesis of highly functionalized N-heterocyclic 1,6-annulated 2-pyridones and 2,3-annulated 4-pyrimidinones has been elaborated through a gold-catalyzed tandem hydroamination/cycloisomerization cascade. This novel and highly efficient method allows the rapid construction of these diverse N-heterocyclic scaffolds starting from readily available building blocks, and shows a wide scope and good functional group tolerance. The total synthesis of (±)-seco-antofine and (±)-septicine were realized employing this strategy.

Combining API in a dual-drug ternary cocrystal approach.

A new strategy is developed to design multi-drug solid forms. Using an inorganic salt as the glue sticking together two different APIs in a "drug-bridge-drug" approach, we successfully created and characterized three different ternary ionic cocrystals (TICCs). The link between binary and ternary ICCs and the importance of reaction stoichiometry was investigated using ternary solid-state phase diagrams.

Improving Nefiracetam Dissolution and Solubility Behavior Using a Cocrystallization Approach.

In this work, we are the first to identify thirteen cocrystals of Nefiracetam, a poor water-soluble nootropic compound. Three of which were obtained with the biocompatible cocrystallization agents citric acid, oxalic acid, and zinc chloride. These latter have been fully structurally and physically characterized and the solubility, dissolution rate, and stability were compared to that of the initial Active Pharmaceutical Ingredient (API).

Exploring the solid-state phases and thermodynamics of calcium l-lactate.

Calcium l-lactate, an organic salt derived from l-lactic acid, is used in many fields such as food, pharmaceutical or cosmetic industry. To this date, its solid-state thermodynamics are still poorly understood: a pentahydrate crystalline and anhydrate amorphous forms were already characterized, and potential other hydrates mentioned in literature. For the development of a robust crystallization process or down-line handling of this compound, it is important to know and understand the relationship between the different solid forms to prevent uncontrolled crystallization or solid-solid transformation during storage.