A Comprehensive Experimental and Theoretical Study on the [{(η5-C5H5)2Zr[P(µ-PNEt2)2P(NEt2)2P]}2O Crystalline System

The structure of tetraphosphetane zirconium complex C52H100N8OP10Zr2 1 was determined by single crystal X-ray diffraction analysis. The crystal belongs to the monoclinic system, space group P21/c, with a = 19.6452(14), b = 17.8701(12), c = 20.7963(14)Å, α = γ = 90°, β = 112.953(7)°, V = 6722.7(8)Å3, Z = 4. The electronic structure of the organometallic complex has been characterized within the framework of Quantum Chemical Topology. The topology of the Electron Localization Function (ELF) and the electron density according to the Quantum Theory of Atoms in Molecules (QTAIM) show no covalent bonds involving the Zr atom, but rather dative, coordinate interactions between the metal and the ligands. This is the first reported case of a Zr complex stabilized by an oxide anion, anionic cyclopentadienyl ligands and rare tetraphosphetane anions.

Femtosecond control of phonon dynamics near a magnetic order critical point

The spin-phonon interaction in spin density wave (SDW) systems often determines the free energy landscape that drives the evolution of the system. When a passing energy flux, such as photoexcitation, drives a crystalline system far from equilibrium, the resulting lattice displacement generates transient vibrational states. Manipulating intermediate vibrational states in the vicinity of the critical point, where the SDW order parameter changes dramatically, would then allow dynamical control over functional properties. Here we combine double photoexcitation with an X-ray free-electron laser (XFEL) probe to control and detect the lifetime and magnitude of the intermediate vibrational state near the critical point of the SDW in chromium. We apply Landau theory to identify the mechanism of control as a repeated partial quench and sub picosecond recovery of the SDW. Our results showcase the capabilities to influence and monitor quantum states by combining multiple optical photoexcitations with an XFEL probe. They open new avenues for manipulating and researching the behaviour of photoexcited states in charge and spin order systems near the critical point.

Growth and characterization of 4-(((4-aminophenyl)sulfonyl)oxy)-2,3-dihydroxy-4-oxobutanoic acid with Ce3+: for semiorganic nonlinear optical application

This work aims at the growth and characterization of novel semi-organometallic nonlinear optical (NLO) crystal 4-(((4-aminophenyl) sulfonyl) oxy)-2,3-dihydroxy-4-oxobutanoic acid (ASODA) with ammonium ceric (II) sulfate dehydrate (ACS). The crystal 4-(((4-aminophenyl) sulfonyl) oxy)-2,3-dihydroxy-4-oxobutanoic acid with Ce3+ (STA) was grown by slow evaporation solution growth technique using deionized water as a solvent. Crystalline system of the grown STA crystal was identified by a single crystal X-ray diffraction study and confirmed as monoclinic crystalline system with non-centrosymmetric space group P21/C. The powder X-ray diffraction study confirmed the purity and crystallinity of the crystal. The presence of functional groups and hydrogen bonds (–O–H–O–) was confirmed by FT-IR spectroscopy. UV-Vis spectra showed that the grown crystal had a low cutoff wavelength at 219 nm. The position of protons and carbons were determined by structural studies based on NMR technique. The grown crystal was thermally stable up to 130 °C and its melting point was 163 °C. The SHG studies were performed by Quanta Ray Model laser source using Kurtz powder technique. The NLO efficiency of the STA crystal was 0.5 times greater than that of standard KDP. The dielectric constant and dielectric loss of the grown crystal were studied at different temperatures. The surface morphology and the particle size of the crystal were determined by FE-SEM technique. From the mechanical studies, it was found that the grown crystal is a soft material.

Polar and Helical Isomorphous Crystals of Proline Derivatives: Influence of a Fluorine Atom on the Electric Susceptibility

Two novel nonlinear optical isomorphous crystals of proline derivatives with alkyne functionality have been obtained (Boc-L-ProNH(CH2)2CCH and Boc-cis-4-fluoro-L-ProNH(CH2)2CCH). Both derivatives, which differ only by the substitution of a H atom to a F atom, adopt the same polar and columnar right-handed helix arrangement in the crystalline state. In addition, adjacent polar helical columns all point in the same direction, thus generating a macrodipole and a crystalline system conducive for second harmonic generation (SHG) properties. This isomorphous crystal system constitutes an interesting tool to study the effect of the fluorine atom on the dipole moment and on the first hyperpolarizability. Starting from the PBC optimized geometries of the crystals, the macroscopic second-order nonlinearity, χ(2), of the newly synthesized crystals has been estimated by quantum chemical calculations. These χ(2) responses are of the same order of magnitude as those of inorganic proline derivatives while smaller than those observed in crystals of push–pull π-conjugated molecules. Graphic Abstract

Innovative Mucoadhesive Precursor of Liquid Crystalline System Loading Anti-Gellatinolytic Peptide for Topical Treatment of Oral Cancer

Current researches report an actual benefit of a treatment for oral cancer via inhibition of proteolytic matrix metallopro-teinases (MPP) with a peptide drug, called CTT1. However, peptides present poor oral bioavailability. Topical administration on oral mucosa avoids its passage through the gastrointestinal tract and the first-pass liver metabolism, but the barrier function of the oral mucosa can impair the permeation and retention of CTT1. The objective of this study is to incorporate CTT1 into a mucoadhesive precursor of liquid crystalline system (PLCS) as an interesting strategy for the topical treatment of oral cancer. PLCS consisting of oleic acid, ethoxylated 20 and propoxylated cetyl alcohol 5, polyethyleneimine (P)-associated chitosan (C) dispersion and CTT1 (FPC-CTT1) was developed and characterized by polarized light microscopy (PLM) and small-angle X-ray scattering (SAXS). In vitro permeation and retention across esophageal mucosa, In vitro cytotoxicity towards tongue squamous cell carcinoma cells, and in vivo evaluation of vascular changes using the chick embryo chorioallantoic membrane (CAM) model were performed. PLM and SAXS showed that FPC-CTT1acted as PLCS, because it formed a lamellar liquid crystalline system after the addition of artificial saliva. FPC-CTT1increased approximately 2-fold the flux of permeation and 3-fold the retention of CTT1 on the porcine esophageal mucosa. CTT1 does not affect cell viability. CAM tests showed that FPC preserved the blood vessels and it can be a safe formulation. These findings encourage the use of the FPC-CTT1 for topical treatment of oral cancer.

Pengaruh Penambahan Poli Vinil Alkohol (PVA) terhadap Karakteristik Nanopartikel Perak Hasil Sintesis Menggunakan Bioreduktor Ekstrak Daun Kelor (Moringa oleifera)

Telah dilakukan penelitian tentang sintesis nanopartikel perak menggunakan bioreduktor ekstrak daun kelor (Moringa oleifera) yang berperan sebagai agen pereduksi. Penelitian ini bertujuan untuk menentukan pengaruh penambahan PVA terhadap karakteristik nanopartikel perak yang terbentuk dengan menggunakan ekstrak daun kelor (Moringa oleifera). Nanopartikel perak disintesis dengan variasi konsentrasi PVA yang berbeda-beda yaitu 0%, 1%, 3% dan 5%. Proses pembentukan nanopartikel perak dimonitoring dengan menggunakan spektrofotometer UV-Vis. Hasil penelitian menunjukkan bahwa nilai absorbansi meningkat dengan bertambahnya waktu reaksi dimana PVA digunakan untuk menstabilkan ukuran nanopartikel perak sehingga mencegah aglomerasi pada pembentukan nanopartikel perak. Serapan maksimum UV-Vis dari sampel hasil sintesis dengan variasi konsentrasi PVA yaitu 0%, 1%, 3% dan 5% masing-masing pada panjang gelombang 432,1 nm, 431,0 nm, 502,0 nm, dan 409,0 nm selama penyimpanan 2 hari. Ukuran nanopartikel perak ditentukan menggunakan instrumen X-Ray Diffraction (XRD) dengan persamaan Debye Scherrer. Distribusi rata-rata ukuran sintesis nanopartikel perak tanpa penambahan PVA yaitu 13,24 - 22,53 nm sedangkan dengan penambahan PVA ukuran terkecil nanopartikel perak mencapai 11,61 - 15,40 nm pada konsentrasi PVA 5%. Berdasarkan database ICDD, hasil analisis XRD menunjukkan adanya kesesuaian pola difraksi dengan referensi sehingga dapat disimpulkan pada penelitian ini terbentuk nanopartikel perak dengan sistem kristal kubik fcc (Face Centered Cubic) dengan indeks Miller (111), (200), (220), dan (311). Morfologi nanopartikel perak diamati dengan Scanning Electron Microscopy (SEM), terlihat partikel tidak memiliki pori dan bentuk partikel yang tidak seragam. Kata kunci: Ekstrak daun kelor, nanopartikel perak, bioreduksi, dan Poli Vinil Alkohol ABSTRACT The research was conducted to synthesize of silver nanoparticle using bioreductor of Moringa Oleifera leave extract (Moringa oleifera) as a reducing agent. This study aims to determine the effect of addition of PVA to the characteristics of silver nanoparticles formed using Moringa Oleifera leave extract (Moringa oleifera). Silver nanoparticles was synthesized with varying concentrations of PVA namely 0%, 1%, 3% and 5%. The process of forming silver nanoparticles was monitored by using a UV-Vis spectrophotometer. The results showed that the absorbance value increased with increasing reaction time where PVA was used to stabilize the size of silver nanoparticles so as to preventing agglomeration in the formation of silver nanoparticles. The maximum UV-Vis uptake of the synthesize samples with variation PVA is 0%, 1%, 3% and 5% respectly at wavelengths of 432.1 nm, 431.0 nm, 502.0 nm, and 409.0 nm for 2 days of storage. The size of silver nanoparticles was determined using X-Ray Diffraction (XRD) with the Debye Scherrer equation. The average distribution of the size of silver nanoparticles synthesis without the addition of PVA is 13,24 – 22,53 nm while with the addition of PVA the smallest size of silver nanoparticles reaches 11,61 – 15,40 nm at a 5% PVA concentration. Based on the ICDD database, the results of the XRD analysis indicate that there is a suitability of the diffraction pattern with reference so that it can be concluded that this study formed silver nanoparticles with a fcc (Face Centered Cubic) crystalline system with the Miller index (111), (200), (220), and (311). The morphology of silver nanoparticles was observed by Scanning Electron Microscope (SEM). It was seen that the particles did not have pores and the shape of the particles was not uniform. Keywords: Moringa leaves extract, silver nanoparticles, bioreduction, and Poly Vinyl Alcohol

Anisotropic thermal expansion of the acetylene–ammonia co-crystal under Titan's conditions

Acetylene and ammonia are known to form a stable orthorhombic co-crystal under the surface conditions of Saturn's moon Titan (1.5 bar = 150 kPa, 94 K). Such a material represents a potential new class of organic minerals that could play an important role in Titan's geology. In this work, the thermal expansion of this co-crystalline system has been derived from in situ powder X-ray diffraction data obtained between 85 and 120 K. The results indicate significant anisotropy, with the majority of the expansion occurring along the c axis (∼2% over the temperature range of interest). Rietveld refinements reveal little change to the structure compared with that previously reported by Boese, Bläser & Jansen [J. Am. Chem. Soc. (2009), 131, 2104–2106]. The expansion is consistent with the alignment of C—H...N interactions along the chains in the a and b axes, and weak intermolecular bonding in the structural layers along the c axis.

Entropy Multiparticle Correlation Expansion for a Crystal

As first shown by H. S. Green in 1952, the entropy of a classical fluid of identical particles can be written as a sum of many-particle contributions, each of them being a distinctive functional of all spatial distribution functions up to a given order. By revisiting the combinatorial derivation of the entropy formula, we argue that a similar correlation expansion holds for the entropy of a crystalline system. We discuss how one- and two-body entropies scale with the size of the crystal, and provide fresh numerical data to check the expectation, grounded in theoretical arguments, that both entropies are extensive quantities.