Design of Triazolium-Grafted Peptidomimetic Macrocycles with Facial Amphipathicity to Target Pathogenic Bacteria.

Access to 1,2,3-triazolium-grafted peptoid macrocycles was developed by macrocyclization and multivalent postmodification of linear peptoid oligomers carrying an alternance of benzylic and propargyl groups as side chains. X-ray analysis and NMR studies revealed a conformational preference for constrained hairpin-shaped structures leading to the facial amphipathic character of these macrocycles. A preliminary evaluation showed the antimicrobial activities of these new cationic amphipathic architectures.

Polymeric copper(I)-NHC complexes with bulky bidentate (N^C) ligands: synthesis and solid-state luminescence.

Starting from imidazolium chlorides bearing bulky nitrogen donors, a series of four complexes, mainly [Cu(C^N)Cl] coordination polymers were obtained directly as luminescent species by simple filtration from the aqueous reaction medium, highlighting a simple, eco-friendly, robust and reproducible synthetic procedure. Additionally, we have shown on the most efficient example that chloride could be exchanged very easily by other halides/pseudohalides (Br, I, NCS, N) allowing to slightly modulate the emitted colour while conserving the polymeric structure, except for azide for which a dimer was obtained. The combination of chemical analyses, of photoluminescence studies in the solid state including quantum yield measurement and X-ray diffraction on single crystals and as-synthesized microcrystalline powders highlighted that the polymeric luminescent species was indeed obtained directly by simple filtration and that no major alteration of the structure was observed upon recrystallisation.

Cage-like structures based on constrained cyclic arylopeptoids.

The access to cupola-like or tube-like structures from - and -arylopeptoid macrocycles was explored through CuAAC reaction using a partially flexible bis(azide) and Cu-N-heterocyclic carbene as catalyst. NMR studies showed that a bis-triazolium bicylic compound in the -series adopts well-defined structure in polar aprotic and protic solvents. Besides, preliminary study revealed its potential for oxoanion recognition.

Unveiling the conformational landscape of achiral all--butyl β-peptoids.

The synthesis and conformational study of -substituted β-alanines with -butyl side chains is described. The oligomers prepared by submonomer synthesis and block coupling methods are up to 15 residues long and are characterised by amide bonds in the -conformation. A conformational study comprising experimental solution NMR spectroscopy, X-ray crystallography and molecular modeling shows that despite their intrinsic higher conformational flexibility compared to their α-peptoid counterparts, this family of achiral oligomers adopt preferred secondary structures including a helical conformation close to that described with (1-naphthyl)ethyl side chains but also a novel ribbon-like conformation.

First series of -alkylamino peptoid homooligomers: solution phase synthesis and conformational investigation.

The synthesis and conformational analysis of the first series of peptoid oligomers composed of consecutive -(alkylamino)glycine units is investigated. We demonstrate that -(methylamino)glycine homooligomers can be readily synthesized in solution using -Boc--methylhydrazine as a peptoid submonomer and stepwise or segment coupling methodologies. Their structures were analyzed in solution by 1D and 2D NMR, in the solid state by X-ray crystallography (dimer ), and implicit solvent QM geometry optimizations.

Strengthening Peptoid Helicity through Sequence Site-Specific Positioning of Amide -Inducing Bu Monomers.

The synthesis of biomimetic helical secondary structures is sought after for the construction of innovative nanomaterials and applications in medicinal chemistry such as the development of protein-protein interaction modulators. Peptoids, a sequence-defined family of oligomers, enable a peptidomimetic strategy, especially considering the easily accessible monomer diversity and peptoid helical folding propensity. However, - isomerization of the backbone tertiary amides may impair the peptoid's adoption of stable secondary structures, notably the all- polyproline I-like helical conformation.

Exploring the Conformation of Mixed Cis- Trans α,β-Oligopeptoids: A Joint Experimental and Computational Study.

The synthesis and conformational preferences of a set of new synthetic foldamers that combine both the α,β-peptoid backbone and side chains that alternately promote cis- and trans-amide bond geometries have been achieved and addressed jointly by experiment and molecular modeling. Four sequence patterns were thus designed and referred to as cis-β- trans-α, cis-α- trans-β, trans-β- cis-α, and trans-α- cis-β. α- and β NtBu monomers were used to enforce cis-amide bond geometries and α- and β NPh monomers to promote trans-amides.

Topologically Diverse Shapes Accessible by Modular Design of Arylopeptoid Macrocycles.

N-Substituted aromatic cyclooligoamides composed of different combinations of ortho-, meta-, and/or para-arylopeptoid residues carrying methoxyethyl side chains have been efficiently synthesized by macrocyclization of the corresponding linear oligomers. The study of the architectures of these macrocycles in solution and solid state has revealed that tetracyclic arylopeptoids adopt sequence-dependent shapes with different backbone amide conformations and side-chain orientations. Remarkably, despite the absence of intramolecular H-bonding ability, some of these arylopeptoid macrocycles show well-defined architectures in solution.

Homogeneous and Robust Polyproline Type I Helices from Peptoids with Nonaromatic α-Chiral Side Chains.

Peptoids that are oligomers of N-substituted glycines represent a class of peptide mimics with great potential in areas ranging from medicinal chemistry to biomaterial science. Controlling the equilibria between the cis and trans conformations of their backbone amides is the major hurdle to overcome for the construction of discrete folded structures, particularly for the development of all-cis polyproline type I (PPI) helices, as tools for modulating biological functions. The prominent role of backbone to side chain electronic interactions (n → π*) and side chains bulkiness in promoting cis-amides was essentially investigated with peptoid aromatic side chains, among which the chiral 1-naphthylethyl (1npe) group yielded the best results.

A catalytic intramolecular nitrene insertion into a copper(i)-N-heterocyclic carbene bond yielding fused nitrogen heterocycles.

N-(2-Azidophenyl)azolium salts were easily prepared and reacted with copper(i) under conditions allowing the formation of NHC complexes. Under these conditions, the formation of benzimidazo-fused heterocycles occurred under catalytic, efficient and very mild conditions. This reaction is proposed to proceed via dinitrogen elimination and imido/nitrene-NHC cyclization.

Insight into the Uranyl Oxyfluoride Topologies through the Synthesis, Crystal Structure, and Evidence of a New Oxyfluoride Layer in [(UO)F][Sr(HO)](NO)·HO.

A new strontium uranyl oxyfluoride, [(UO)F][Sr(HO)](NO)·HO, was synthesized under hydrothermal conditions. The single-crystal X-ray structure was determined. This compound crystallizes in the triclinic space group P1̅ (No.

Cation templating and electronic structure effects in uranyl cage clusters probed by the isolation of peroxide-bridged uranyl dimers.

The self-assembly of uranyl peroxide polyhedra into a rich family of nanoscale cage clusters is thought to be favored by cation templating effects and the pliability of the intrinsically bent U-O2-U dihedral angle. Herein, the importance of ligand and cationic effects on the U-O2-U dihedral angle were explored by studying a family of peroxide-bridged dimers of uranyl polyhedra. Four chemically distinct peroxide-bridged uranyl dimers were isolated that contain combinations of pyridine-2,6-dicarboxylate, picolinate, acetate, and oxalate as coordinating ligands.

(H3O)2NaAl3F12, isostructural with A2NaAl3F12 (A = K(+), Rb(+), Cs(+)) fluorides having HTB-type sheets.

The title compound, (H3O)2NaAl3F12 [dihydronium sodium trialuminum(III) dodecafluoride], was obtained by solvothermal synthesis from the reaction of aluminium hydroxide, sodium hydroxide, 1,2,4-triazole and aqueous HF in ethanol at 463 K for 48 h. The structure consists of AlF6 octahedra organized in [AlF4(-)]n HTB-type sheets (HTB is hexagonal tungsten bronze) separated by H3O(+) and Na(+) cations.

Raman spectroscopic and ESI-MS characterization of uranyl peroxide cage clusters.

Strategies for interpreting mass spectrometric and Raman spectroscopic data have been developed to study the structure and reactivity of uranyl peroxide cage clusters in aqueous solution. We demonstrate the efficacy of these methods using the three best-characterized uranyl peroxide clusters, {U24}, {U28}, and {U60}. Specifically, we show a correlation between uranyl-peroxo-uranyl dihedral bond angles and the position of the Raman band of the symmetric stretching mode of the peroxo ligand, develop methods for the assignment of the ESI mass spectra of uranyl peroxide cage clusters, and show that these methods are generally applicable for detecting these clusters in the solid state and solution and for extracting information about their bonding and composition without crystallization.

New series of hybrid fluoroferrates synthesized with triazoles: various dimensionalities and Mössbauer studies.

The solvothermal reactions of an equimolar mixture of FeF2 and FeF3 with Htaz (1,2,4-triazole), aqueous HF and DMF (dimethylformamide) at 120 °C yielded a series of new hybrid fluoroferrates (1-5). Their structures were characterized by either single crystal or powder X-ray diffraction data analysis. Both classes of hybrid networks were observed according to the Fe(n+)/Htaz/HF starting ratio: class I for 1 and 2 and class II for 3, 4 and 5.

Series of uranyl-4,4'-biphenyldicarboxylates and an occurrence of a cation-cation interaction: hydrothermal synthesis and in situ Raman studies.

Three uranium(VI)-bearing materials were synthesized hydrothermally using the organic ligand 4,4'-biphenyldicarboxylic acid: (UO2)(C14O4H8) (1); [(UO2)2(C14O4H8)2(OH)]·(NH4)(H2O) (2); (UO2)2(C14O4H8)(OH)2 (3). Compound 1 was formed after 1 day at 180 °C in an acidic environment (pH(i) = 4.03), and compounds 2 and 3 coformed after 3 days under basic conditions (pH(i) = 7.

Synthesis, structure, and spectroscopy of two ternary uranium(IV) thiophosphates: UP2S9 and UP2S7 containing P2S9(2-) and P2S7(2-) ligands.

The two ternary uranium thiophosphate compounds were isolated from polychalcogenide flux reactions. UP2S9 crystallizes in the tetragonal space group P42/mcm with two formula units per unit cell, where a = 7.762(1) and c = 9.

Time-resolved assembly of chiral uranyl peroxo cage clusters containing belts of polyhedra.

Two chiral cage clusters built from uranyl polyhedra and (HPO(3))(2-) groups have been synthesized in pure yield and characterized structurally and spectroscopically in the solid state and aqueous solution. Synthesis reactions under ambient conditions in mildly acidic aqueous solutions gave clusters U(22)PO(3) and U(28)PO(3) that contain belts of four uranyl peroxide pentagonal and hexagonal bipyramids, in contrast to earlier reported uranyl peroxide cage clusters that are built from four-, five-, and six-membered rings of uranyl hexagonal bipyramids. U(22)PO(3) and U(28)PO(3) are also the first chiral uranyl-based cage clusters, the first that contain uranyl pentagonal bipyramids that contain no peroxide ligands, and the first that incorporate (HPO(3))(2-) bridges between uranyl ions.

Correlations and differences between uranium(VI) arsonates and phosphonates.

Three new uranium arsonate compounds, UO(2)(C(6)H(5))(2)As(2)O(5)(H(2)O) (UPhAs-1), UO(2)(HO(3)AsC(6)H(4)AsO(3)H)(H(2)O)·H(2)O (UPhAs-2), and UO(2)(HO(3)AsC(6)H(4)NH(2))(2)·H(2)O (UPhAs-3) have been synthesized under mild hydrothermal conditions. UPhAs-1 is constructed from UO(7) pentagonal bipyramids that are chelated by the pyroarsonate moiety, [PhAs(O(2))OAs(O(2))Ph](2-), forming chains of layered uranyl polyhedra. Two of the phenylarsonic acids are condensed in situ to form the fused tetrahedra of the pyroarsonate moiety through a metal-mediated, thermally induced condensation process.

Synthesis of a uranyl persulfide complex and quantum chemical studies of formation and topologies of hypothetical uranyl persulfide cage clusters.

The compound Na(4)[(UO(2))(S(2))(3)](CH(3)OH)(8) was synthesized at room temperature in an oxygen-free environment. It contains a rare example of the [(UO(2))(S(2))(3)](4-) complex in which a uranyl ion is coordinated by three bidentate persulfide groups. We examined the possible linkage of these units to form nanoscale cage clusters analogous to those formed from uranyl peroxide polyhedra.

Cation-cation interactions between neptunyl(VI) units.

The boric acid flux reaction of NpO(2)(ClO(4))(2) with NaClO(4) affords Na[(NpO(2))(4)B(15)O(24)(OH)(5)(H(2)O)](ClO(4))·0.75H(2)O (NaNpBO-1). NaNpBO-1 possesses a layered structure consisting of double neptunyl(VI) borate sheets bridged by another Np(VI) site through cation-cation interactions.

Systematic evolution from uranyl(VI) phosphites to uranium(IV) phosphates.

Six new uranium phosphites, phosphates, and mixed phosphate-phosphite compounds were hydrothermally synthesized, with an additional uranyl phosphite synthesized at room temperature. These compounds can contain U(VI) or U(IV), and two are mixed-valent U(VI)/U(IV) compounds. There appears to be a strong correlation between the starting pH and reaction duration and the products that form.

Linear alkyl diamine-uranium-phosphate systems: U(VI) to U(IV) reduction with ethylenediamine.

Mild-hydrothermal reactions in acidic medium using 1,3-diaminopropane, 1,4-diaminobutane, and 1,5-diaminopentane as structure directing agents led to three-dimensional (3D) uranyl phosphates (CH₂)₃(NH₃)₂{[(UO₂)(H₂O)][(UO₂)(PO₄)]₄} (C3U5P4), (CH₂)₄(NH₃)₂{[(UO₂)(H₂O)][(UO₂)(PO₄)]₄} (C4U5P4) and (CH₂)5(NH₃)₂{[(UO₂)(H₂O)][(UO₂)(PO₄)]₄} (C5U5P4). The structures of (C4U5P4) and (C5U5P4) were solved in the space group Cmc2₁ using single-crystal X-ray diffraction data. The compounds are isostructural to the corresponding uranyl vanadates and contain the same 3D inorganic framework built from uranyl-phosphate layers of uranophane-type anion topology pillared by [UO₆(H₂O)] pentagonal bipyramids.