Two new uranyl sulfates, (C4H14N2)(UO2)2(SO4)3(H2O)·2H2O (NDUS2) and (C4H14N2)(UO2)(SO4)2(H2O)·2H2O (NDUS3), were synthesized and their crystal structures determined. NDUS2 was obtained in highly ...acidic media heat-treated at 373K and subsequently maintained at 278K until crystals formed after two months. NDUS3 results from the degradation of NDUS2 over the course of a few days. NDUS2 and NDUS3 crystallize in the monoclinic space group P21/n, a=10.9075(4)Å, b=10.4513(4)Å, c=17.7881(7)Å, β=97.908(2)°, V=2008.52(13)Å3, Z=4, at 140K and a=8.8570(4)Å, b=7.3299(3)Å, c=20.4260(9)Å, β=95.140(2)°, V=1320.74(10)Å3, Z=4, at 140K, respectively. The compounds contain interlayer 1,4-n-butyldiammonium cations that charge-balance the anionic structural units.
Amine templating effect absent in uranyl sulfates synthesized with 1,4-diaminobutane, as shown by the synthesis of two new uranyl sulfates, (C4H14N2)(UO2)2(SO4)3(H2O)·2H2O (NDUS2) and (C4H14N2)(UO2)(SO4)2(H2O)·2H2O (NDUS3) Display omitted .
► Two layered uranyl sulfates were synthesized. ► Amine molecules are located in the interlayers of the compounds. ► No templating effect of the amine was observed. ► Amine molecules are only charge balancing cations in the structures.
Three new uranium arsonate compounds, UO2(C6H5)2As2O5(H2O) (UPhAs-1), UO2(HO3AsC6H4AsO3H)(H2O)·H2O (UPhAs-2), and UO2(HO3AsC6H4NH2)2·H2O (UPhAs-3) have been synthesized under mild hydrothermal ...conditions. UPhAs-1 is constructed from UO7 pentagonal bipyramids that are chelated by the pyroarsonate moiety, PhAs(O2)OAs(O2)Ph2–, 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. The structure of UPhAs-2 consists of UO7 pentagonal bipyramids that are chelated by phenylenediarsonate ligands, forming one-dimensional chains of uranyl polyhedra. UPhAs-3 consists of a rare UO6 tetragonally distorted octahedron (D 4h ) that is on a center of symmetry and linked to two pairs of adjacent 4-aminophenylarsonate ligands. This linear chain structure is networked through hydrogen bonds between the lattice water molecules and the −NH2 moiety. All three of these compounds fluoresce at room temperature, showing characteristic vibronically coupled charge-transfer based emission.
The access to cupola-like or tube-like structures from
ortho
- and
meta
-arylopeptoid macrocycles was explored through CuAAC reaction using a partially flexible bis(azide) and Cu
I
-N-heterocyclic ...carbene as catalyst. NMR studies showed that a bis-triazolium bicylic compound in the
ortho
-series adopts well-defined structure in polar aprotic and protic solvents. Besides, preliminary study revealed its potential for oxoanion recognition.
Selective access to cupola-like bis-triazolium architectures thanks to copper(
i
) N-heterocyclic carbene led to well-structured cage with potential for oxoanion recognition.
Single crystals of γ‐K(UO2)(NO3)3 were prepared from aqueous solutions by evaporation. The crystal structure orthorhombic, Pbca (61), a = 9.2559(3) Å, b = 12.1753(3) Å, c = 15.8076(5) Å, V = ...1781.41(9) Å3, Z = 8 was determined by direct methods and refined to R1 = 0.0267 on the basis of 3657 unique observed reflections. The structure is composed of isolated anionic uranyl trinitrate units, (UO2)(NO3)3–, that are linked through eleven‐coordinated K+ cations. Both known polymorphs of K(UO2)(NO3)3 (α‐ and γ‐phases) can be considered as based upon sheets of isolated complex (UO2)(NO3)3– ions separated by K+ cations. The existence of polymorphism in the two KUO2(NO3)3 polymorphs is due to the different packing modes of uranyl trinitrate clusters that adopt the same two‐dimensional but different three‐dimensional arrangements.
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. We have explored for the first time the possibility to achieve similar performances with a sterically hindered α-chiral aliphatic side chain. Herein, we report on the synthesis and detailed conformational analysis of a series of (S)-N-(1-tert-butylethyl)glycine (Ns1tbe) peptoid homo-oligomers. The X-ray crystal structure of an Ns1tbe pentamer revealed an all-cis PPI helix, and the CD curves of the Ns1tbe oligomers also resemble those of PPI peptide helices. Interestingly, the CD data reported here are the first for any conformationally homogeneous helical peptoids containing only α-chiral aliphatic side chains. Finally we also synthesized and analyzed two mixed oligomers composed of NtBu and Ns1tbe monomers. Strikingly, the solid state structure of the mixed oligomer Ac-(tBu)2-(s1tbe)4-(tBu)2-COOtBu, the longest to be solved for any linear peptoid, revealed a PPI helix of great regularity despite the presence of only 50% of chiral side chain in the sequence.
View of the intermolecular interactions N–H⋯O and O–H⋯O forming polymeric dihydrogendecavanadate(V)–decavanadate(V) chains running along the
1
1
¯
1
axis in NH
2(CH
2)
4
5V
10O
28H
2
0.5V
10O
28
...0.5.
A new polymeric compound, NH
2(CH
2)
4
5V
10O
28H
2
0.5V
10O
28
0.5, was obtained by
in situ synthesis of the organic cation from an aqueous solution of V
2O
5–HCl–NH
2(CH
2)
4NH
2. The crystal structure was solved by single-crystal X-ray diffraction. NH
2(CH
2)
4
5V
10O
28H
2
0.5V
10O
28
0.5 consists of dihydrogendecavanadate(V), H
2V
10O
28
4−, and decavanadate(V), V
10O
28
6−, units assembled in one-dimensional arrays by interanionic hydrogen bonds O–H⋯O and cation-anion N–H⋯O interactions. The latter involve pyrrolidinium cations, which were obtained in the compound instead of the starting butane-1,4-diamine. Pyrrolidinium cations further connect the polymeric chains into a three-dimensional network. The presence of the two types of units, H
n
V
10O
28
(6−
n
)− with
n
=
0 and
n
=
2, in one compound was not yet observed and is herein reported for the first time.
Here, we report on synthesis and characterization of single crystals of the hexagonal Ga-containing κ-carbide phase Mo3(2+y)Ga3(1-x)Fe1+3(1-y+x)C4 with x = 0.15, y = 0.35 and mixed occupation of two ...6 h sites. We refined its crystal structure as hexagonal with P63/mmc symmetry. We combined polarized Raman spectroscopy, X-ray absorption near edge structure, X-ray magnetic circular dichroism and electrical resistivity measurements with density functional theory in order to give a first consistent description of the structural, electronic and magnetic properties of this new compound. The phase exhibits metallic conductivity, has a high thermal stability in inert atmosphere and surprisingly has a non-magnetic ground state. Our study provides further impetus for the rediscovery of the κ-phase family, which, due to its chemical diversity, should have many physical properties to be easily tailored.
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•3-Pyrazolyl-pyran-2-one was synthesized using two conditions.•Crystal structure and DFT are discussed in comparative study.•Hirshfeld surface analysis and energy frameworks calculations were ...described..•Mulliken and QTAIM atomic charges, NBO, MEP, HOMO-LUMO were computed.•In silico ADME parameters have been studied.
Synthesis, crystal structure, Hirshfeld surface analysis, DFT and in-silico studies were carried out for the 4‑hydroxy-6-methyl-3-(1-phenyl-1H-pyrazol-3-yl)-2H-pyran-2-one 2. The reaction efficiency was evaluated performing two conditions to prepare the Vilsmeir-Haack reagent: phosphoryl trichloride in DMF and phosphorus pentachloride in DMF. The molecular structure was confirmed by 1H and 13C NMR, IR spectroscopy and X-ray diffraction analysis. The pyrazole and pyran rings are nearly coplanar. The molecules are connected through C—H···O hydrogen bonds, C—H⋯π and π⋯π stacking interactions, forming layers in the crystal lattice. Hirshfeld surface analysis for crystal packing indicates that the most important contributions are H⋯H (41.6 %), C⋯H/H⋯C (22.6 %), O…H/H…O (20.9 %) interactions. The frontier molecular orbital, Mulliken and QTAIM atomic charge, Molecular Electrostatic Potential, Natural Bond Orbitals were produced using the optimized structure by B3LYP/6–311G(d,p) level of theory. The calculated LUMOHOMO gap (4.261 eV) indicated that the eventual charge transfer and showed chemical reactivity. Intrinsic reaction coordinate (IRC) calculation confirm that the transition state connects the reactants to the products. The experimental geometry parameters of the title compound are compared with the geometry of the optimized molecule in the gas phase and found in good agreement. The crystal structure was further explored to define the interaction energy between the molecular pairs. The ADME profile that pyrazolyl-pyran-2-one 2 is an inhibitor of CYP1A2 one of the five key cytochrome isoforms enzymes involved in drug metabolism.
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Starting from imidazolium chlorides bearing bulky nitrogen donors, a series of four complexes, mainly Cu(C^N)Cl
n
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
3
−
) 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. Samples of all polymeric complexes displayed remarkable stability towards air oxidation remaining unchanged upon storage for several months and partially retaining their photoluminescence properties even after a thermal treatment at 100 °C for 24 h.
Aqueous phase syntheses of copper(
i
) coordination polymers yielded bulk samples of luminescent powders with moderate to excellent photoluminescence quantum yields.
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, cis–trans isomerization of the backbone tertiary amides may impair the peptoid’s adoption of stable secondary structures, notably the all-cis polyproline I-like helical conformation. Here, we show that cis-inducing NtBu achiral monomers strategically positioned within chiral sequences may reinforce the degree of peptoid helicity, although with a reduced content of chiral side chains. The design principles presented here will undoubtedly help achieve more conformationally stable helical peptoids with desired functions.
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