Preparation and characterization of polyvinyl alcohol (PVA)-glycerol composite films incorporating nanosilica from municipal solid waste incinerator bottom ash.

This study investigates the fabrication of a composite film composed of polyvinyl alcohol (PVA) and glycerol, incorporating nanosilica derived from municipal solid waste incinerator bottom ash (BA). The nanosilica is blended with a PVA film-forming solution containing glycerol as a plasticizer. The composite films are characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Additionally, thermogravimetric analysis (TGA) is conducted to evaluate the thermal properties, while the mechanical properties are assessed in terms of tensile strength (TS) and elongation at break (EAB). The results indicate that the presence of silica nanoparticles reduces transparency and increases film thickness in the presence of glycerol. Notably, the film containing 1% silica demonstrates a significant enhancement in tensile strength, exhibiting a 50% increase compared to the film without silica. However, higher silica loadings lead to a deterioration in mechanical properties due to silica agglomeration within the polymer matrix. As expected, the presence of silica in the films slightly elevates the degradation temperature.

Modified tetra-oxygenated xanthones analogues as anti-MRSA and P. aeruginosa agent and their synergism with vancomycin.

Five isolated xanthones from the C. cochinchinense and G. mangostana were evaluated and tested for antibacterial activities. Isolated 4 and 5 exhibited potent anti-MRSA and P. aeruginosa activity, but showed poor pharmacokinetic properties via ADMET prediction. It led us to improve pharmacokinetic properties of 4 and 5 by partially modifying them in acidic condition yielding fourteen analogues. It was found that analogues 4b, 4d and 5b possessed proper pharmacokinetic properties, while only 4b exhibited the best anti-MRSA and P. aeruginosa activity. The SEM results indicated that 4b may interact with or damage the cell wall of MRSA and P. aeruginosa. Moreover, a combination of 4b and vancomycin exhibits synergistic effect against both MRSA and P. aeruginosa at MIC value of 4.98 (MIC = 18.75 µg/mL for 4b) and 9.52 µg/mL (MIC = 75 µg/mL for 4b), respectively.

Crystal structure of (E)-N'-(3,4-di-hydroxy-benzyl-idene)-4-hy-droxy-benzohydrazide.

In the title benzohydrazide derivative, C14H12N2O4, the azomethine C=N double bond has an E configuration. The hydrazide connecting bridge, (C=O)-(NH)-N=(CH), is nearly planar with C-C-N-N and C-N-N=C torsion angles of -177.33 (10) and -174.98 (12)°, respectively. The 4-hy-droxy-phenyl and 3,4-di-hydroxy-phenyl rings are slightly twisted, making a dihedral angle of 9.18 (6)°. In the crystal, mol-ecules are connected by N-H⋯O and O-H⋯O hydrogen bonds into a three-dimensional network, while further consolidated via π-π inter-actions [centroid-centroid distances = 3.6480 (8) and 3.7607 (8) Å]. The conformation is compared to those of related benzyl-idene-4-hy-droxy-benzohydrazide derivatives.

Synthesis, spectroscopic and Hirshfeld surface analysis and fluorescence studies of (2E,2'E)-3,3'-(1,4-phenyl-ene)bis-[1-(4-hy-droxy-phen-yl)prop-2-en-1-one] N,N-di-methyl-formamide disolvate.

In the bis-chalcone mol-ecule of the title compound, C24H18O4·2C3H7NO, the central benzene and terminal hy-droxy-phenyl rings form a dihedral angle of 14.28 (11)° and the central C=C double bond adopts a trans configuration. In the crystal, the bis-chalcone and solvate mol-ecules are inter-connected via O-H⋯O hydrogen bonds, which were investigated by Hirshfeld surface analysis. Solid-state fluorescence was measured at λex = 4400 Å. The emission wavelength appeared at 5510 Å, which corresponds to yellow light and the solid-state fluorescence quantum yield (Ff) is 0.18.

Crystal structure of (E)-4-hy-droxy-N'-(3-meth-oxy-benzyl-idene)benzohydrazide.

The title compound, C15H14N2O3, crystallizes with two independent mol-ecules (A and B) in the asymmetric unit that differ in the orientation of the 3-meth-oxy-phenyl group with respect to the methyl-idenebenzohydrazide unit. The dihedral angles between the two benzene rings are 24.02 (10) and 29.30 (9)° in mol-ecules A and B, respectively. In mol-ecule A, the meth-oxy group is twisted slightly relative to its bound benzene ring, with a Cmeth-yl-O-C-C torsion angle of 14.2 (3)°, whereas it is almost co-planar in mol-ecule B, where the corresponding angle is -2.4 (3)°. In the crystal, the mol-ecules are linked by N-H⋯O, O-H⋯N and O-H⋯O hydrogen bonds, as well as by weak C-H⋯O inter-actions, forming sheets parallel to the bc plane. The N-H⋯O hydrogen bond and weak C-H⋯O inter-action link different mol-ecules (A⋯B) whereas both O-H⋯N and O-H⋯O hydrogen bonds link like mol-ecules (A⋯A) and (B⋯B). Pairs of inversion-related B mol-ecules are stacked approximately along the a axis by π-π inter-actions in which the distance between the centroids of the 3-meth-oxy-phenyl rings is 3.5388 (12) Å. The B mol-ecules also participate in weak C-H⋯π inter-actions between the 4-hy-droxy-phenyl and the 3-meth-oxy-phenyl rings.

Crystal structure of bis-(2-{1-[(E)-(4-fluoro-benz-yl)imino]-eth-yl}phenolato-κ(2) N,O)palladium(II).

The asymmetric unit of the title complex, [Pd(C15H13FNO)2], contains one half of the mol-ecule with the Pd(II) cation lying on an inversion centre and is coordinated by the bidentate Schiff base anion. The geometry around the cationic Pd(II) centre is distorted square planar, chelated by the imine N- and phenolate O-donor atoms of the two Schiff base ligands. The N- and O-donor atoms of the two ligands are mutually trans, with Pd-N and Pd-O bond lengths of 2.028 (2) and 1.9770 (18) Å, respectively. The fluoro-phenyl ring is tilted away from the coordination plane and makes a dihedral angle of 66.2 (2)° with the phenolate ring. In the crystal, mol-ecules are linked into chains along the [101] direction by weak C-H⋯O hydrogen bonds. Weak π-π inter-actions with centroid-centroid distances of 4.079 (2) Šstack the mol-ecules along c.

Crystal structure of (E)-2-hy-droxy-4'-meth-oxy-aza-stilbene.

The title aza-stilbene derivative, C14H13NO2 {systematic name: (E)-2-[(4-meth-oxy-benzyl-idene)amino]-phenol}, is a product of the condensation reaction between 4-meth-oxy-benzaldehyde and 2-amino-phenol. The mol-ecule adopts an E conformation with respect to the azomethine C=N bond and is almost planar, the dihedral angle between the two substituted benzene rings being 3.29 (4)°. The meth-oxy group is coplanar with the benzene ring to which it is attached, the Cmeth-yl-O-C-C torsion angle being -1.14 (12)°. There is an intra-molecular O-H⋯N hydrogen bond generating an S(5) ring motif. In the crystal, mol-ecules are linked via C-H⋯O hydrogen bonds, forming zigzag chains along [10-1]. The chains are linked via C-H⋯π inter-actions, forming a three-dimensional structure.

Crystal structure of bis-{2-[(E)-(4-fluoro-benz-yl)imino-meth-yl]phenolato-κ(2) N,O}nickel(II).

The asymmetric unit of the title complex, [Ni(C14H11FNO)2], contains one-half of the mol-ecule with the Ni(II) cation lying on an inversion centre coordinated by a bidentate Schiff base anion. The cationic Ni(II) center is in a distorted square-planar coordination environment chelated by the imine N and phenolate O donor atoms of the two Schiff base ligands. The N and O donor atoms of the two ligands are mutually trans with Ni-N and Ni-O bond lengths of 1.9242 (10) and 1.8336 (9) Å, respectively. The fluoro-phenyl ring is almost orthogonal to the coordination plane and makes a dihedral angle of 82.98 (7)° with the phenolate ring. In the crystal, mol-ecules are linked into screw chains by weak C-H⋯F hydrogen bonds. Additional C-H⋯π contacts arrange the mol-ecules into sheets parallel to the ac plane.

Crystal structure of bis-{2-[(E)-(4-meth-oxy-lbenz-yl)imino-meth-yl]phenolato-κ(2) N,O (1)}nickel(II).

The asymmetric unit of the title compound, [Ni(C15H14NO2)2], comprises an Ni(II) cation, lying on an inversion centre, and a Schiff base anion that acts as a bidentate ligand. The Ni(II) cation is in a square-planar coordination environment binding to the imine N and phenolate O atoms of the two Schiff base ligands. The N- and O-donor atoms of the two ligands are mutually trans, with Ni-N and Ni-O bond lengths of 1.9191 (11) and 1.8407 (9) Å, respectively. The plane of the meth-oxy-benzene ring makes a dihedral angle of 84.92 (6)° with that of the phenolate ring. In the crystal, mol-ecules are linked into screw chains by weak C-H⋯O hydrogen bonds. Additional C-H⋯O hydrogen bonds, together with C-H⋯π contacts, arrange the mol-ecules into sheets parallel to the ac plane.

Bis{2-meth-oxy-6-[(E)-(4-methyl-benz-yl)imino-meth-yl]phenolato}palladium(II) chloro-form monosolvate.

In the title complex, [Pd(C16H16NO2)2]·CHCl3, the Pd(II) cation lies on an inversion center. One Cl atom of the CHCl3 solvent mol-ecule lies on a twofold axis and the C-H group is disordered with equal occupancies about this axis with the other Cl atom in a general position with full occupancy. The Pd(II) cation is four-coordinate and adopts a square-planar geometry via coordination of the imine N and phenolic O atoms of the two bidentate Schiff base anions. The N and O atoms of these ligands are mutually trans. The plane of the benzene ring makes a dihedral angle of 73.52 (10)° with that of the meth-oxy-phenolate ring. In the crystal, mol-ecules of the Pd(II) complex are arranged into sheets parallel to the ac plane, and the chloro-form solvent mol-ecules are located in the inter-stitial areas between the complex mol-ecules. Weak inter-molecular C-H⋯O and C-H⋯π inter-actions stabilize the packing.

First order temperature dependent phase transition in a monoclinic polymorph crystal of 1,6-hexanedioic Acid: an interpretation based on the landau theory approach.

Crystals of 1,6-hexanedioic acid (I) undergo a temperature-dependent reversible phase transition from monoclinic P21/c at a temperature higher than the critical temperature (Tc) 130 K to another monoclinic P21/c at temperature lower than Tc. The phase transition is of first order, involving a discontinuity and a tripling of the b-axis at Tc whereas the other unit cell parameters vary continuously. The transition is described by the phenomenological Landau theory. The crystal structure analyses for data collected at 297(2) K and 120.0(1) K show that there is half of a molecule of (I) in the asymmetric unit at 297(2) K whereas there are one and a half molecules of (I) in the asymmetric unit at 120.0(1) K. At both temperatures, 297(2) and 120.0(1) K, intermolecular O-H···O hydrogen bonds link the molecules of I into infinite 1D chains along [101] direction. However there are significantly more O-H···O hydrogen bonds presented in the 120.0(1) K polymorph, thereby indicating this phase transition is negotiated via hydrogen bonds. The relationship of the conformational changes and hydrogen bonding for these two polymorphs are explained in detail.

Three types of cytotoxic natural caged-scaffolds: pure enantiomers or partial racemates.

Two rare new natural products, the neocaged-xanthone pruniflorone T (1) and the rearranged caged-xanthone pruniflorone U (3), and the known caged-xanthone cochinchinone C (2) were isolated from the roots of Cratoxylum formosum ssp. pruniflorum. The unique structures of 1-3 were determined by analysis of NMR and X-ray diffraction data. The X-ray data of 1-3 revealed that they all exist with both enantiomers in their crystal packing. Separation of 1-3 by chiral HPLC led to the isolation of three pairs of enantiomers, (-)-1/(+)-1, (-)-2/(+)-2, and (-)-3/(+)-3, and their absolute configurations were determined by analysis of single-crystal X-ray diffraction and ECD spectroscopic data. A 1:1 mixture of 1 and 3 showed potent in vitro cytotoxicity against an MCF-7 human breast cancer cell line with an IC50 value of 0.11 µg/mL.

2,2'-[2,4-Bis(naphthalen-1-yl)cyclo-butane-1,3-di-yl]bis-(1-methyl-pyridinium) bis-(4-chloro-benzene-sulfonate): thermal-induced [2 + 2] cyclo-addition reaction of a heterostilbene.

The asymmetric unit of the title salt, C36H32N2 (2+)·2C6H4ClO3S(-), consists of one anion and one half-cation, the other half being generated by inversion symmetry. The dihedral angle between the pyridinium ring and the napthalene ring system in the asymmetric unit is 42.86 (6)°. In the crystal, cations and anions are linked by weak C-H⋯O inter-actions into chains along [010]. Adjacent chains are further arranged in an anti-parallel manner into sheets parallel to the bc plane. π-π inter-actions are observed involving the cations, with centroid-centroid distances of 3.7664 (8) and 3.8553 (8) Å.

(1E,4E)-1,5-Bis[4-(di-ethyl-amino)-phen-yl]penta-1,4-dien-3-one.

There are two crystallograpically independent mol-ecules in the asymmetric unit of the title bis-chalcone derivative, C25H32N2O. Both mol-ecules are twisted with a dihedral angle between the two substituted benzene rings of 11.19 (16)° in one mol-ecule and 14.40 (15)° in the other. The central penta-1,4-dien-3-one fragments make dihedral angles of 8.49 (17) and 4.26 (17)° with the two adjacent benzene rings in one mol-ecule, whereas the corresponding values are 8.42 (16) and 6.18 (16)° in the other. In the crystal, mol-ecules are arranged into chains along the c-axis direction. Adjacent chains are inter-linked by weak inter-molecular C-H⋯O inter-actions. The crystal is further stabilized by C-H⋯π inter-actions.

(E)-2-[4-(Di-ethyl-amino)-styr-yl]-1-methyl-quinolin-1-ium 4-chloro-benzene-sulfonate monohydrate.

The asymmetric unit of the title hydrated salt, C22H25N2 (+)·C6H4ClO3S(-)·H2O, comprises two 2-[4-(di-ethyl-amino)-styr-yl]-1-methyl-quinolin-1-ium cations, two 4-chloro-benzene-sul-fon-ate anions and two solvent water mol-ecules. One ethyl group of both cations displays disorder over two positions in a 0.659 (2):0.341 (2) ratio in one mol-ecule and in a 0.501 (2):0.499 (2) ratio in the other. The sulfonate group of one anion is also disordered over two positions in a 0.893 (7):0.107 (7) ratio. The dihedral angle between the mean plane of the quinolinium ring system and that of benzene ring is 10.57 (18)° in one cation and 14.4 (2)° in the other. In the crystal, cations, anions and water mol-ecules are linked into chains along the [010] direction by O-H⋯Osulfonate hydrogen bonds, together with weak C-H⋯Osulfonate and C-H⋯Cl inter-actions. The cations are stacked by π-π inter-actions, with centroid-centroid distances in the range 3.675 (2)-4.162 (3) Å.

Trichodermaerin: a diterpene lactone from Trichoderma asperellum.

The title compound, C20H28O3, known as 'trichodermaerin' [systematic name: (4E)-4,9,15,16,16-penta-methyl-6-oxa-tetra-cyclo-[10.3.1.0(1,10).0(5,9)]hexa-dec-4-ene-7,13-dione], is a diterpene lactone which was isolated from Trichoderma asperellum. The structure has a tetra-cycic 6-5-7-5 ring system, with the cyclo-hexa-none ring adopting a twisted half-chair conformation and the cyclo-pentane ring adopting a half-chair conformation, whereas the cyclo-heptene and tetra-hydro-furan-anone rings are in chair and envelope (with the methyl-substituted C atom as the flap) conformations, respectively. The three-dimensional architecture is stabilized by C-H⋯O inter-actions.

(E)-4-Meth-oxy-N'-(2,4,5-tri-meth-oxy-benzyl-idene)benzohydrazide hemihydrate.

The title compound crystallizes as a hemihydrate, C18H20N2O5·0.5H2O. The mol-ecule exists in an E conformation with respect to the C=N imine bond. The 4-meth-oxy-phenyl unit is disordered over two sets of sites with a refined occupancy ratio of 0.54 (2):0.46 (2). The dihedral angles between the benzene rings are 29.20 (9) and 26.59 (9)°, respectively, for the major and minor components of the 4-meth-oxy-substituted ring. All meth-oxy substituents lie close to the plane of the attached benzene rings [the Cmeth-yl-O-C-C torsion angles range from -4.0 (12) to 3.9 (2)°]. In the crystal, the components are linked into chains propagating along [001] via N-H⋯O and O-H⋯O hydrogen bonds and weak C-H⋯O inter-actions.

1-(2,4-Di-nitro-phen-yl)-2-[(E)-(3,4,5-tri-meth-oxy-benzyl-idene)]hydrazine.

Mol-ecules of the title compound, C16H16N4O7, are not planar with a dihedral angle of 5.50 (11)° between the substituted benzene rings. The two meta-meth-oxy groups of the 3,4,5-tri-meth-oxy-benzene moiety lie in the plane of the attached ring [Cmeth-yl-O-C-C torsion angles -0.1 (4)° and -3.7 (3)°] while the para-meth-oxy substituent lies out of the plane [Cmeth-yl-O-C-C, -86.0 (3)°]. An intra-molecular N-H⋯O hydrogen bond involving the 2-nitro substituent generates an S(6) ring motif. In the crystal structure, mol-ecules are linked by weak C-H⋯O inter-actions into screw chains, that are arranged into a sheet parallel to the bc plane. These sheets are connected by π-π stacking inter-actions between the nitro and meth-oxy substituted aromatic rings with a centroid-centroid separation of 3.9420 (13) Å. C-H⋯π contacts further stabilize the two-dimensional network.

2-[(E)-2-(4-Eth-oxy-phen-yl)ethen-yl]-1-methyl-quinolinium 4-fluoro-benzene-sulfonate.

In the structure of the title salt, C20H20NO(+)·C6H4FO3S(-), the 4-(eth-oxy-phen-yl)ethenyl unit is disordered over two positions with a refined site-occupancy ratio of 0.610 (6):0.390 (6). The cation is nearly planar, the dihedral angle between the quinolinium and benzene rings being 6.7 (4) and 1.7 (7)° for the major and minor components, respectively. The eth-oxy group is essentially coplanar with the benzene ring [C-O-C-Cmethy = 177.1 (8) and 177.8 (12)° for the major and minor components, respectively]. In the crystal, cations and anions are linked into chains along the b-axis direction by C-H⋯Osulfon-yl weak inter-actions. These chains are further connected into sheets parallel to (001) by C-H⋯Osulfon-yl weak inter-actions. The chains are also stacked along the a axis through π-π inter-actions involving the quinolinium and benzene rings [centroid-centroid distances = 3.636 (5) Šfor the major component and 3.800 (9) Šfor the minor component]. C-H⋯π inter-actions are also present.

(E)-2-[(2,4,6-Tri-meth-oxy-benzyl-idene)amino]-phenol.

There are two independent mol-ecules in the asymmetric unit of the title compound, C16H17NO4, with similar conformations but some differences in their bond angles. Each mol-ecule adopts a trans configuration with respect to the methyl-idene C=N bond and is twisted with a dihedral angle between the two substituted benzene rings of 80.52 (7)° in one mol-ecule and 83.53 (7)° in the other. All meth-oxy groups are approximately coplanar with the attached benzene rings, with Cmeth-yl-O-C-C torsion angles ranging from -6.7 (2) to 5.07 (19)°. In the crystal, independent mol-ecules are linked together by O-H⋯N and O-H⋯O hydrogen bonds and a π-π inter-action [centroid-centroid distance of 3.6030 (9) Å], forming a dimer. The dimers are further linked by weak C-H⋯O inter-actions and another π-π inter-action [centroid-centroid distance of 3.9452 (9) Å] into layers lying parallel to the ab plane.