Rigidity with Flexibility: Porous Triptycene Networks for Enhancing Methane Storage.

In the pursuit of advancing materials for methane storage, a critical consideration arises given the prominence of natural gas (NG) as a clean transportation fuel, which holds substantial potential for alleviating the strain on both energy resources and the environment in the forthcoming decade. In this context, a novel approach is undertaken, employing the rigid triptycene as a foundational building block. This strategy is coupled with the incorporation of dichloromethane and 1,3-dichloropropane, serving as rigid and flexible linkers, respectively. This combination not only enables cost-effective fabrication but also expedites the creation of two distinct triptycene-based hypercrosslinked polymers (HCPs), identified as PTN-70 and PTN-71. Surprisingly, despite PTN-71 manifesting an inferior Brunauer-Emmett-Teller (BET) surface area when compared to the rigidly linked PTN-70, it showcases remarkably enhanced methane adsorption capabilities, particularly under high-pressure conditions. At a temperature of 275 K and a pressure of 95 bars, PTN-71 demonstrates an impressive methane adsorption capacity of 329 cm3 g-1. This exceptional performance is attributed to the unique flexible network structure of PTN-71, which exhibits a pronounced swelling response when subjected to elevated pressure conditions, thus elucidating its superior methane adsorption characteristics. The development of these advanced materials not only signifies a significant stride in the realm of methane storage but also underscores the importance of tailoring the structural attributes of hypercrosslinked polymers for optimized gas adsorption performance.

Diaporaustalides A-L, Austalide Meroterpenoids from a Plant Endophytic Diaporthe sp.

Twelve new austalide meroterpenoids (1-12) were isolated from the endophytic fungus Diaporthe sp. XC1211. Their structures were elucidated by extensive spectroscopic analysis. The absolute configurations of compounds 1, 3, 4, and 6 were established by single-crystal X-ray diffraction, whereas those for the others were established by experimental electronic circular dichroism (ECD) data analysis. Compounds 1-12 represent a rare class of austalides with a 24α-CH3. Compounds 2 and 5 demonstrated potent proliferation inhibitory effects against LPS-induced B cells with IC50 values of 6.7 (SI = 3.6) and 3.8 (SI > 13) µM, respectively. Compounds 2 and 5 decreased the secretion of IL-6 in LPS-induced B cells in a dose-dependent manner.

[11]-Chaetoglobosins from Pseudeurotium bakeri Induce G2/M Cell Cycle Arrest and Apoptosis in Human Cancer Cells.

Twelve new [11]-chaetoglobosins, chaetopseudeurins A-L (1-12), were identified from the fermentation of the endophytic fungus Pseudeurotium bakeri P1-1-1. Their structures with absolute configurations were elucidated by detailed interpretation of NMR spectroscopy, mass spectrometry, and single-crystal X-ray diffraction. Compounds 2 and 5-7 exhibited significant cytotoxicities against seven human cancer cell lines, with IC50 values ranging from 4.7 ± 1.0 to 12.2 ± 0.7 µM, and induced G2/M cell cycle arrest and apoptosis in MCF-7 and A427 cells dose dependently. Western blot analysis showed that compound 2 induced apoptosis of MCF-7 cells via the Bcl-2/caspase-3/PARP pathway.

Hypothemycin-Type Resorcylic Acid Lactones with Immunosuppressive Activities from a Podospora sp.

Twelve new hypothemycin-type resorcylic acid lactones, three 10-membered (1-3) and nine 14-membered (4-12), together with seven known analogues (13-19), were obtained from the solid rice-based culture of Podospora sp. G214. Their structures were elucidated utilizing spectroscopic analysis, and the absolute configurations were determined by modified Mosher's method, Mo2(OAc)4-induced electronic circular dichroism experiments, and single-crystal X-ray diffraction. Compounds 1, 5, 10, and 12-19 exhibited potent immunosuppressive activities against concanavalin A-induced T cell proliferation with IC50 values ranging from 6.0 to 25.1 µM and lipopolysaccharide-induced B cell proliferation with IC50 values ranging from 6.2 to 29.1 µM. Further studies revealed that 1 induced apoptosis in activated T cells through the JNK-mediated mitochondrial pathway.

Structure-based design, synthesis, and biological evaluation of novel piperine-resveratrol hybrids as antiproliferative agents targeting SIRT-2.

A series of novel piperine-resveratrol hybrids 5a-h was designed, synthesized, and structurally elucidated by IR, and 1H, 13C, and 19F NMR. Antiproliferative activities of 5a-h were evaluated by NCI against sixty cancer cell lines. Compound 5b, possessing resveratrol pharmacophoric phenolic moieties, showed a complete cell death against leukemia HL-60 (TB) and Breast cancer MDA-MB-468 with growth inhibition percentage of -0.49 and -2.83, respectively. In addition, 5b recorded significant activity against the other cancer cell lines with growth inhibition percentage between 80 to 95. New 5a-h hybrids were evaluated for their inhibitory activities against Sirt-1 and Sirt-2 as molecular targets for their antiproliferative action. Results showed that compounds 5a-h were more potent inhibitors of Sirt-2 than Sirt-1 at 5 µm and 50 µm. Compound 5b showed the strongest inhibition of Sirt-2 (78 ± 3% and 26 ± 3% inhibition at 50 µM and 5 µM, respectively). Investigation of intermolecular interaction via Hirschfeld surface analysis indicates that these close contacts are mainly ascribed to the O-H⋯O hydrogen bonding. To get insights into the Sirt-2 inhibitory mechanism, a docking study was performed where 5b was found to fit nicely inside both extended C-pocket and selectivity pocket and could compete with the substrate acyl-Lys. Another possible binding pattern showed that 5b could act by partial occlusion of the NAD+ C-pocket. Collectively, these findings would contribute significantly to better understanding the Sirt-2 inhibitory mechanism in order to develop a new generation of refined and selective Sirt-2 inhibitors.

Resorcylic Acid Lactones from an Ilyonectria sp.

Twelve new resorcylic acid lactones (RALs) including three new 16-membered RALs (1a, 1b and 2), eight new 14-membered RALs (3-10), and one new 12-membered RAL (11), along with five known 14-membered RALs (12-16), were identified from the fermentation of the soil-derived fungus Ilyonectria sp. sb65. Their structures were established by detailed analyses of 1D and 2D NMR, HRESIMS, and X-ray diffraction crystallography. All new compounds were evaluated for their cytotoxic effects against three human cancer cell lines, along with their potential as TRAIL sensitizers in TRAIL-resistant A549 human lung adenocarcinoma cells and their in vitro immunosuppressive effects against ConA-induced T-cell and LPS-induced B-cell proliferation.

Alkaloids with Immunosuppressive Activity from the Bark of Pausinystalia yohimbe.

Ten new alkaloids (1-10), including two pairs of enantiomeric mixtures (5a,b and 6a,b), and 15 known analogues (11-25) were obtained from the bark of Pausinystalia yohimbe. The structures of 1-25 were established by spectroscopic methods, and the absolute configurations of compounds 1-10 were resolved by X-ray diffraction and ECD data analyses. The in vitro immunosuppressive activities of selected isolates were tested. Compounds 11 and 16 exhibited moderate inhibition with IC50 values of 16.8 and 27.6 µM against ConA-induced T lymphocyte proliferation and 13.5 and 40.5 µM against LPS-induced B lymphocyte proliferation, respectively.

Neuroprotective Lignans from the Fruits of Schisandra bicolor var. tuberculata.

Nine new lignans (1-9) and ten known analogues (10-19) were isolated from the fruits of Schisandra bicolor var. tuberculata. The structures of compounds 1-9 were established on the basis of spectroscopic data analysis. The absolute configuration of compound 1 was determined by single-crystal X-ray diffraction analysis with Cu Kα irradiation techniques, and the absolute configurations of compounds 2-9 were deduced by comparing their experimental ECD spectra and optical rotations with those of compound 1 or similar compounds. All isolates were evaluated for their neuroprotective activities against CoCl2, H2O2, and Aß25-35-induced SH-SY5Y cell injury, and were found to exhibit different degrees of neuroprotective effects. At a low concentration of 3.2 nM, compounds 3, 8, 9, and 14-19 in CoCl2-induced, compounds 7, 8, 13, 17, and 18 in H2O2-induced, and compounds 2, 6, 7, 9, 10, and 12-19 in Aß25-35-induced SH-SY5Y cell injury models, showed statistically significant neuroprotective activities, when compared with each negative control group.

Conformational Tuning of the Intramolecular Electronic Coupling in Molecular-Wire Biruthenium Complexes Bridged by Biphenyl Derivatives.

The synthesis and characterization of a series of biphenyl-derived binuclear ruthenium complexes with terminal {RuCl(CO)(PMe3)3} moieties and different structural arrangements of the phenyl rings are reported. Electrochemical studies revealed that the two metal centers of the binuclear ruthenium complexes interact with each other through the biphenyl bridge, and the redox splittings ΔE1/2 show a strong linear correlation with cos(2) ϕ, where ϕ is the torsion angle between the two phenyl rings. A combination of electrochemical, UV/Vis/NIR, and in situ IR differential spectroelectrochemical analysis clearly showed that: 1) the intramolecular electronic couplings in the binuclear ruthenium complexes could be modulated by changing ϕ; 2) the electronic ground state of the mixed-valent cations changes from delocalized to localized through the biphenyl bridge with increasing torsion angle ϕ, that is, the redox processes of these complexes change from significant involvement of the bridging ligand to an oxidation behavior with less participation of the bridge.

Two three-dimensional networks in two polymorphs of biphenyl-4,4'-diaminium bis(3-carboxy-4-hydroxybenzenesulfonate) dihydrate.

Two polymorphs of biphenyl-4,4'-diaminium bis(3-carboxy-4-hydroxybenzenesulfonate) dihydrate, C(12)H(14)N(2)(2+)·2C(7)H(5)O(6)S(-)·2H(2)O, have been obtained and crystallographically characterized. Polymorph (I) crystallizes in the space group P2(1)/c with Z' = 2 and polymorph (II) in the space group P-1 with Z' = 0.5. The benzidinium cation in (II) is located on a crystallographic inversion centre. In both (I) and (II), the sulfonic acid H atoms are transferred to the benzidine N atoms, forming dihydrated 1:2 molecular adducts (base-acid). In the crystal packings of (I) and (II), the component ions are linked into three-dimensional networks by combinations of X-H...O (X = O, N and C) hydrogen bonds. In addition, π-π interactions are observed in (I) between inversion-related benzene rings [centroid-centroid distances = 3.632 (2) and 3.627 (2) Å]. In order to simplify the complex three-dimensional networks in (I) and (II), we also give their rationalized topological analyses.

Nanotubular non-covalent macrocycle within non-covalent macrocycle assembly: (MeOH)(12) encapsulated in a molecular clip cyclododecamer.

A noncovalent macrocycle-within-noncovalent macrocycle assembly is formed from twelve molecules of (+/-)-1 and twelve molecules of MeOH in the solid state. The H-bonded (MeOH)(12) cyclododecamer assumes a crown-shaped geometry that has not previously been predicted theoretically or found experimentally.

Formation of unsymmetrical 1,4-enediones via a focusing domino strategy: cross-coupling of 1,3-dicarbonyl compounds and methyl ketones or terminal aryl alkenes.

A highly efficient synthesis of unsymmetrical 1,4-enediones from 1,3-dicarbonyl compounds and methyl ketones or terminal aryl alkenes has been developed via a focusing domino strategy. Simple and readily available starting materials, mild reaction conditions, and a very simple operation are advantages of the reaction, which allow straightforward synthesis of a variety of unsymmetrical 1,4-enediones.

Supramolecular rhombic grids formed from bimolecular building blocks.

A programmed assembly process produces rhombic grid networks from compounds L1-L4 in the crystal by pi-pi stacking interactions that generate a bimolecular grid synthon, which undergoes further NH...N hydrogen-bond-mediated assembly.

Enantioselective Michael reactions of beta, beta-disubstituted nitroalkenes: a new approach to beta(2,2)-amino acids with hetero-quaternary stereocenters.

An atom-economic organocatalytic asymmetric Michael reaction of alpha,beta,beta-trisubstituted olefins has been successfully developed. The reaction exhibits excellent enantioselectivities under low loading of catalysts, and the conjugate addition products are valuable for the synthesis of novel beta(2,2)-amino acids and beta-peptides.

A two-dimensional network in the molecular salt 2-methylimidazolium hydrogen glutarate, and three-dimensional networks in the salts 2-methylimidazolium hydrogen succinate and 2-methylimidazolium hydrogen adipate monohydrate.

All three title compounds, C(4)H(7)N(2)(+).C(4)H(5)O(4)(-), (I), C(4)H(7)N(2)(+).C(5)H(7)O(4)(-), (II), and C(4)H(7)N(2)(+).C(6)H(9)O(4)(-).H(2)O, (III), can be regarded as 1:1 organic salts. The dicarboxylic acids join through short acid bridges into infinite chains. Compound (I) crystallizes in the noncentrosymmetric Cmc2(1) space group and the asymmetric unit consists of a hydrogen succinate anion located on a mirror plane and a 2-methylimidazolium cation disordered across the same mirror. The other two compounds crystallize in the triclinic P1 space group. The carboxylic acid H atom in (II) is disordered over both ends of the anion and sits on inversion centres between adjacent anions, forming symmetric short O...H...O bridges. Two independent anions in (III) sit across inversion centres, again with the carboxylic acid H atom disordered in short O...H...O bridges. The molecules in all three compounds are linked into two-dimensional networks by combinations of imidazolium-carboxylate N(+)-H...O and carboxylate-carboxylate O-H...O hydrogen bonds. The two-dimensional networks are further linked into three-dimensional networks by C-H...O hydrogen bonds in (I) and by O(water)-H...O hydrogen bonds in (III). According to the DeltapK(a) rule, such 1:1 types of organic salts can be expected unambiguously. However, a 2:1 type of organic salt may be more easily obtained in (II) and (III) than in (I).

Three-dimensional networks in the 1:2 organic salts 2,2'-biimidazolium bis(3-carboxy-4-hydroxybenzenesulfonate) and 2,2'-bibenzimidazolium bis(3-carboxy-4-hydroxybenzenesulfonate) trihydrate.

The two title compounds of 2,2'-biimidazole (Bim) with 5-sulfosalicylic acid (5-H(2)SSA) and 2,2'-bibenzimidazole (Bbim) with 5-H(2)SSA are 1:2 organic salts, viz. C(6)H(8)N(4)(2+).2C(7)H(5)O(6)S(-), (I), and C(14)H(12)N(4)(2+).2C(7)H(5)O(6)S(-).3H(2)O, (II). The cation of compound (I) lies on a centre of inversion, whereas that of (II) lies on a twofold axis. Whilst compound (I) is anhydrous, three water molecules are incorporated into the crystal structure of (II). The substitution of imidazole H atoms by other chemical groups may favour the incorporation of water molecules into the crystal structure. In both compounds, the component cations and anions adopt a homogeneous arrangement, forming alternating cation and anion layers which run parallel to the (001) plane in (I) and to the (100) plane in (II). By a combination of N-H...O, O-H...O and C-H...O hydrogen bonds, the ions in both compounds are linked into three-dimensional networks. In addition, pi-pi interactions are observed between symmetry-related benzene rings of Bbim(2+) cations in (II).

Bis(4-amino-benzene-sulfonato-κO)bis-(propane-1,3-diamine-κN,N')copper(II) dihydrate.

In the title compound, [Cu(C(3)H(10)N(2))(2)(C(6)H(6)NO(3)S)(2)]·2H(2)O, the Cu(II) atom lies on an inversion center and is hexa-coordinated by four N atoms from two 1,3-diamino-propane ligands and two O atoms from two 4-amino-benzene-sulfonate ligands in a trans arrangement, displaying a distorted and axially elongated octa-hedral coordination geometry, with the O atoms at the axial positions. A three-dimensional network is formed in the crystal structure through O-H⋯O, N-H⋯O and N-H⋯N hydrogen bonds.

5,11,17,23-Tetra-tert-butyl-25,26,27,28-tetra-propyn-yloxy-2,8,14,20-tetra-thia-calix[4]arene.

THE TITLE COMPOUND [SYSTEMATIC NAME: 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetra-propyn-yloxy-2,8,14,20-tetra-thia-calix[4]arene], C(52)H(56)O(4)S(4), is an alkyl-ated product bearing four propyne groups at the lower rim of a 5,11,17,23-tetra-tert-butyl-tetrathia-calix[4]arene. The mol-ecule is located on a crystallographic twofold rotation axis, running through two S atoms and perpendicular to the long axis of the mol-ecule. The four propyne groups, located in an alternate fashion above and below the mean plane of the four S atoms, are almost parallel to the calixarene long axis. The dihedral angle between the two crystallographically independent benzene rings is 86.77 (14)°. Two tert-butyl groups are disordered over two positions with site occupancies of 0.59 (2) and 0.41 (2).

A new polymorph of 1,4-bis(imidazol-1-ylmethyl)benzene dihydrate and its hydrogen-bonded fivefold interpenetrated CdSO(4) network.

Single crystals of a new polymorph of 1,4-bis(imidazol-1-ylmethyl)benzene dihydrate (bix x 2H(2)O), C(14)H(14)N(4) x 2H(2)O, have been obtained by the hydrothermal method. The asymmetric unit is composed of two independent half-bix molecules, one on an inversion center and one on a twofold axial site, and two water molecules. The disordered water molecules link into discrete tetrameric water units via two O-H...O hydrogen bonds, forming planar R(4)(4)(8) rings. These tetrameric water units and bix molecules are further linked by two O-H...N hydrogen bonds into a three-dimensional network in which an R(20)(20)(106) hydrogen-bonded ring is observed. These large rings lead to the formation of a fivefold interpenetrated network. If both the tetrameric water units and the bix molecules can be regarded as connected nodes, one single three-dimensional net can then be rationalized as a CdSO(4) network. This study indicates that topological methodology can be applied in some cases in order to understand the inherent characteristics of some hydrogen-bonded supramolecular assemblies.

Tetrameric molecular bowl assembled from glycoluril building blocks.

Glycoluril derivative--whose bulky Ph-C[triple bond]C- substituents prevent formation of H-bonded tapes--undergoes solvent dependent assembly in the crystal; a tetrameric molecular bowl is formed by R(24) H-bonding interactions from CH(2)Cl(2) whereas DMF results in H-bond dimerization followed by oligomerization via C-H...pi interactions.