Mono- to Tetra-nuclear Iron Dichloride Complexes Bearing -(Fluoro)-aryl-Substituted Iminopyridine Ligands: Synthesis, Structures, Magnetic Properties, and Polymerization of Isoprene.

The reaction of FeCl with the iminopyridine ligand containing fluorinated -aryl groups {2-[(Ar)N = C(R)]CHN, where Ar = 3,5-(CF)CH and R = H () or CH (); Ar = CF and R = H () or CH (); and iminoquinoline 2-[(3,5-(CF)(CH)N = CH)]CHN ()} resulted in distinct iron coordination complexes whose structures were determined by single-crystal X-ray diffraction. Ligands and yielded mononuclear bis-ligated iron dichlorides ( or )FeCl (complexes and ), while and formed dinuclear complexes ( or )Fe(μ-Cl)FeCl (complexes and ). Ligand produced an unprecedented tetranuclear dimer [()FeCl(μ-Cl)FeCl] (complex ).

Crystal structure and Hirshfeld surface analyses, inter-action energy calculations and energy frameworks of methyl 2-[(4-cyano-phen-yl)meth-oxy]quinoline-4-carboxyl-ate.

The title compound, CHNO, features competition and inter-play of a range of weak inter-actions, which actualize under the absence of conventional hydrogen-bond donors. Two kinds of stacking inter-actions, namely slipped anti-parallel inter-actions of cyano-phenyl groups as well as quinoline and carb-oxy groups, are primarily important. In combination with relatively short tetrel OCH⋯N≡C bonds [C⋯N = 3.

Amide Chemistry Enables Redox Locking of Cyclic Disulfides for Polypeptide Assembly.

A practical strategy in synthetic organic chemistry for shutting down temporarily the nucleophilicity of thiols is to exploit their redox properties by converting them into disulfides. The stability of such a thiol protection in reductive medium can be sensitive to microenvironmental changes, including chemical modifications occurring nearby. Although difficult to achieve, large shifts in disulfide stability might provide a practical mean for bringing selectivity in a reacting system comprising multiple thiol functionalities.

Synthesis and characterization of borohydride rare-earth complexes supported by 2-pyridinemethanamido ligands and their application in the ring-opening polymerization of cyclic esters.

The synthesis of 2-pyridinemethanamido borohydride complexes of yttrium and neodymium was achieved through the deprotonation of the protio-ligand 2-pyridinemethanamine CHRN-C(CH)R-NH(2,6-PrCH), denoted as PyAH (with PyAH1: R = R = H; PyAH2: R = CH, R = H; PyAH3: R = C(CH)N-(2,6-PrCH), R = CH), in the presence of trisborohydride RE(BH)(THF) (RE = Y and Nd) as a precursor and a base. The isolation of various molecular structures, nine of which were structurally characterized by X-ray diffraction analysis, was achieved and revealed to depend not only on (i) the nature of the 2-pyridinemethanamido ligand and (ii) the rare-earth element but also on (iii) the reaction conditions, notably the type of base used. These include seven mono-substituted species, eventually also comprising the cation derived from the base reagent, such as [(PyA1)Y(BH)][Mg(THF)] (1Y), [(PyA1)Nd(BH)Mg(PyA1)](THF) (1Nd), (PyA1)Nd(BH)(THF) (1'Nd), [(PyA1)Nd(THF)(BH)(μ-BH)] (1''Nd), [(PyA2)Nd(BH)][Mg(THF)] (3Nd), (PyA2)Nd(BH)(THF) (3'Nd) and (PyA3)Nd(BH) (4Nd), as well as two bis-substituted complexes (PyA1)Y(BH) (2Y) and (PyA1)Nd(BH) (2Nd).

Antipolar 2D Metallicity with Tunable Valence W (5 ≤ ≤ 5.6) in the Layered Monophosphate Tungsten Bronzes [Ba(PO)]WO.

The newly discovered series of layered monophosphate tungsten bronzes (L-MPTB) [Ba(PO)]WO consist of -layer-thick slabs of WO6 octahedra separated by barium-phosphate spacers. They display a 2D metallic behavior confined in the central part of the perovskite slabs. Here, we report the missing = 2 member of this series, containing the rather uncommon W5+ oxidation state.

Crystal structure, Hirshfeld surface analysis, inter-action energy and energy framework calculations, as well as density functional theory (DFT) com-putation, of methyl 2-oxo-1-(prop-2-yn-yl)-1,2-di-hydro-quinoline-4-carboxyl-ate.

In the title mol-ecule, CHNO, the di-hydro-quinoline core deviates slightly from planarity, indicated by the dihedral angle of 1.07 (3)° between the two six-membered rings. In the crystal, layers of mol-ecules almost parallel to the plane are formed by C-H⋯O hydro-gen bonds.

Rapid and Efficient Access to Novel Bio-Inspired 3-Dimensional Tricyclic SpiroLactams as Privileged Structures via Meyers' Lactamization.

The concept of privileged structure has been used as a fruitful approach for the discovery of novel biologically active molecules. A privileged structure is defined as a semi-rigid scaffold able to display substituents in multiple spatial directions and capable of providing potent and selective ligands for different biological targets through the modification of those substituents. On average, these backbones tend to exhibit improved drug-like properties and therefore represent attractive starting points for hit-to-lead optimization programs.

Fast Protein Modification in the Nanomolar Concentration Range Using an Oxalyl Amide as Latent Thioester.

We show that latent oxalyl thioester surrogates are a powerful means to modify peptides and proteins in highly dilute conditions in purified aqueous media or in mixtures as complex as cell lysates. Designed to be shelf-stable reagents, they can be activated on demand to enable ligation reactions with peptide concentrations as low as a few hundred nM at rates approaching 30 M  s .

Synthesis and crystal structure of a new chiral α-amino-oxime nickel(II) complex.

A dinuclear nickel complex with ()-limonene based amino-oxime ligand has been isolated and its crystal structure determined. The resolved structure of dichloridobis-{(2,5)-2-methyl-5-(prop-1-en-2-yl)-2-[(pyridin-2-yl)methyl-amino]-cyclo-hexan-1-one oxime}dinickel(II), [NiCl(CHClNO)], at 100 K has monoclinic (2) symmetry. The two Ni ions in the dinuclear complex are each coordinated in a distorted octa-hedral environment by three nitro-gen atoms, a terminal chloride and two μ bridging chlorides.

Isonitrile ruthenium and iron PNP complexes: synthesis, characterization and catalytic assessment for base-free dehydrogenative coupling of alcohols.

Neutral and ionic ruthenium and iron aliphatic PNHP-type pincer complexes (PNHP = NH(CH2CH2PiPr2)2) bearing benzyl, n-butyl or tert-butyl isocyanide ancillary ligands have been prepared and characterized. Reaction of [RuCl2(PNHP)]2 with one equivalent CN-R per ruthenium center affords complexes [RuCl2(PNHP)(CNR)] (R = benzyl, 1a, R = n-butyl, 1b, R = t-butyl, 1c), with cationic [RuCl(PNHP)(CNR)2]Cl 2a-c as side-products. Dichloride species 1a-c react with excess NaBH4 to afford [RuH(PNHP)(BH4)(CN-R)] 3a-c, analogues to benchmark Takasago catalyst [RuH(PNHP)(BH4)(CO)].

Crystal structure, Hirshfeld surface analysis and DFT studies of 5-bromo-1-{2-[2-(2-chloro-eth-oxy)eth-oxy]eth-yl}indoline-2,3-dione.

The title compound, CHBrClNO, consists of a 5-bromo-indoline-2,3-dione unit linked to a 1-{2-[2-(2-chloro-eth-oxy)eth-oxy]eth-yl} moiety. In the crystal, a series of C-H⋯O hydrogen bonds link the molecules to form a supramolecular three-dimensional structure, enclosing (8), (12), (18) and (22) ring motifs. π-π contacts between the five-membered dione rings may further stabilize the structure, with a centroid-centroid distance of 3.

Crystal structure, Hirshfeld surface analysis and inter-action energy and DFT studies of 5,5-diphenyl-1,3-bis-(prop-2-yn-1-yl)imidazolidine-2,4-dione.

The title compound, CHNO, consists of an imidazolidine unit linked to two phenyl rings and two prop-2-yn-1-yl moieties. The imidazolidine ring is oriented at dihedral angles of 79.10 (5) and 82.

Grafting of a new bis-silylamido aluminum species on silica: insight from solid-state NMR into interactions with the surface.

The new bisamido aluminum species [AlCl{N(SiMe3)2}2(THF)] (1) was prepared and fully characterized by 27Al and 35Cl solid-state NMR, along with X-ray diffraction studies. 1 was grafted on silica partially dehydroxylated at 700 °C, affording silica-supported Al species. The resulting material (2) was characterized by IR, elemental analysis and 1H, 13C and 27Al solid-state MAS NMR.

Crystal structure and Hirshfeld surface analysis of 4-allyl-6-bromo-2-(4-chloro-phen-yl)-4-imidazo[4,5-]pyridine.

The title compound, CHBrClN, is built up from a planar imidazo[4,5-]pyridine unit linked to phenyl and allyl substituents. The allyl substituent is rotated significantly out of the imidazo[4,5-]pyridine plane, while the benzene ring is inclined by 3.84 (6)° to the ring system.

Diastereoselective auxiliary- and catalyst-controlled intramolecular aza-Michael reaction for the elaboration of enantioenriched 3-substituted isoindolinones. Application to the synthesis of a new pazinaclone analogue.

A new asymmetric organocatalyzed intramolecular aza-Michael reaction by means of both a chiral auxiliary and a catalyst for stereocontrol is reported for the synthesis of optically active isoindolinones. A selected cinchoninium salt was used as phase-transfer catalyst in combination with a chiral nucleophile, a Michael acceptor and a base to provide 3-substituted isoindolinones in good yields and diastereomeric excesses. This methodology was applied to the asymmetric synthesis of a new pazinaclone analogue which is of interest in the field of benzodiazepine-receptor agonists.

Mixed Allyl Rare-Earth Borohydride Complexes: Synthesis, Structure, and Application in (Co-)Polymerization Catalysis of Cyclic Esters.

A series of new trivalent rare-earth allyl-borohydride complexes with the formula [RE(BH ) (C H )(thf) ] (RE=Sc (1), x=2; RE=Y (2) and La (3), x=3) were synthesized by reaction of the corresponding rare-earth trisborohydrides [RE(BH ) (thf) ] with half an equivalent of bis(allyl)magnesium. The complexes were fully characterized by determining their X-ray structure. Similar to their previously described Nd (4) and Sm (5) analogues, these complexes display a monomeric structure with two terminal trihapto BH groups, one π-η allyl ligand, three THF molecules for complexes 2 and 3, and two THF molecules for complex 1.

Gold(I)-Catalysed Asymmetric Hydroamination of Alkenes: A Silver- and Solvent-Dependent Enantiodivergent Reaction.

In the present study, we report the first silver-dependent enantiodivergent gold-catalysed reaction. The asymmetric intramolecular hydroamination of alkenes catalysed by the combination of a single chiral binuclear gold(I) chloride complex and silver perchlorate can afford both enantiomers of the products by a simple solvent change from toluene to methanol. Such an enantiodivergent reaction is strictly independent of the reaction temperature or of the nature of the catalyst anion and displays the same first-order kinetic rate law with respect to substrate concentration in both solvents.

Selective Hydrosilylation of Esters to Aldehydes Catalysed by Iridium(III) Metallacycles through Trapping of Transient Silyl Cations.

The combination of an iridium(III) metallacycle and 1,3,5-trimethoxybenzene catalyses rapidly and selectively the reduction of esters to aldehydes at room temperature with high yields through hydrosilylation followed by hydrolysis. The ester reduction involves the trapping of transient silyl cations by the 1,3,5-trimethoxybenzene co-catalyst, supposedly by formation of an arenium intermediate whose role was addressed by DFT calculations.

Catalytic Conversion of Alcohols into Carboxylic Acid Salts in Water: Scope, Recycling, and Mechanistic Insights.

The catalytic conversion of alcohols into carboxylic acid salts in water was performed in the presence of ruthenium complexes supported by aliphatic PNP pincer ligands preformed or formed in situ. High activity toward a wide substrate scope was achieved with turnover number values of up to 4000. The air-stable catalytic system can be recycled by using toluene as a catalyst-immobilizing phase; the activity is maintained after five consecutive runs.

Crystal structure of 5-bromo-1-ethyl-indoline-2,3-dione.

The title compound, C10H8BrNO2, crystallizes with two independent molcules (A and B) in the asymmetric unit. In each mol-ecule, the indoline ring system is almost planar, with the largest deviation from the mean plane being 0.016 (2) Å in mol-ecule A and 0.

Crystal structure of tris-[4-(di-methyl-amino)-pyridinium] tris-(oxalato-κ(2) O,O')chromate(III) tetra-hydrate.

In the title hybrid salt, (C7H11N2)3[Cr(C2O4)3]·4H2O, the central Cr(III) ion of the complex anion (point group symmetry 2) is coordinated by six O atoms from three chelating oxalate(2-) ligands in a slightly distorted octa-hedral coordination sphere. The Cr-O bond lengths vary from 1.9577 (11) to 1.

Crystal structure of 4-(di-methyl-amino)-pyridinium cis-di-aqua-bis-(oxalato-κ(2) O,O')ferrate(III) hemihydrate.

The Fe(III) ions in the hybrid title salt, (C7H11N2)[Fe(C2O4)2(H2O)2]·0.5H2O, show a distorted octa-hedral coordination environment, with four O atoms from two chelating oxalate dianions and two O atoms from two cis aqua ligands. The average Fe-O(oxalate) bond length [2.

Novel La3Fe(MoO4)6 phase: magnetic properties and ethanol reactivity.

Single crystals of a new oxide, La3Fe(MoO4)6, were grown from fluxes of oxide precursors, and a polycrystalline sample was also prepared by a standard solid state reaction. La3Fe(MoO4)6 crystallizes in the orthorhombic space group Pbca with unit cell parameters a = 19.3164(11), b = 10.

Evaluation and comparison of three different separation techniques for analysis of retroamide enantiomers and their biological evaluation against h-P2X7 receptor.

The P2X receptors are seven-transmembrane domain G protein-coupled receptors and the 7 subtypes of P2X receptors identified in humans, and named P2X1 to P2X7, are channel receptors whose endogenous ligand is ATP. New antagonists of the P2X7 receptor were developed, since this purinergic receptor was highlighted to be involved in many diseases such as different types of pain, cancer, ischemia, neurodegenerative diseases (including Parkinson's and Alzheimer's diseases) characterized by inflammatory processes. With the aim of evaluate the impact of chirality on the pharmacological activity of a new P2X7R antagonist, a semi-preparative method was developed in supercritical fluid chromatography (SFC).