Complexation with diol host compounds. Part 1. Structures of the 1:2 molecular complexes oftrans-9, 10-dihydroxy-9,10-diphenyl-9,10-dihydroanthracene with acetophenone and with 3-methylcyclopentanone

The structures of the 1:2 molecular complexes of trans -9,10-dihydroxy-9,10-diphenyl-9,10-dihydroanthracene with acetophenone (1), (C₂₆H₂₀O₂·2 C₈H₈O) and with 3-methylcyclopentanone (2), (C₂₆H₂₀O₂·2C₆H₁₀O) have been determined by X-ray crystallography. The crystal data are as follows: Compound (1):P ,a =8.979(5) Å,b =9.316(3) Å,c = 11.12(1) Å, =94.40(6)°, = 106.53(6)°, = 109.92(5)°,V = 822.94 ų,Z = 1,R = 0.097 for 2549 unique reflections. Compound (2):P ,a = 8.958(7) Å,b =9.815(4) Å,c = 9.807(4) Å, = 96.88(3)°, = 109.21(8)°, = 103.33(7)°,V = 774.10 ų,Z = 1,R = 0.059 for 2494 unique reflections. The intermolecular arrangements in both structures are characterised by host-to-guest hydrogen bonding interactions. The thermal properties of compound (2) have been characterised by DTA and TGA thermograms.     

Crystal structure of [Pb(cis-anti-cis-dicyclohexyl-18-crown-6)(OH2)2][ClO4]2

[Pb(cis-anti-cis-dicyclohexyl-18-crown-6)(OH₂)₂][ClO₄]₂ was crystallized using a slightly modified literature method for the separation of dicyclohexyl-18-crown-6 isomers. It crystallizes in the monoclinic space groupP2₁/n witha=8.415(5),b=20.993(9),c=8.973(5) Å, β=111.56(6)^o, andD _calc=1.84 g/cm³ for Z=2. The Pb²⁺ ion resides on a crystallographic center of inversion and is coordinated to the six crown ether donors and two axial water molecules in a hexagonal bipyramidal geometry. The Pb-O(etheric) distances range from 2.694(4) to 2.743(4) Å while the Pb?OH₂ distance is 2.522(6) Å.     

Complexation with diol host compounds. Part 2. Structures of 1,1,2,2-tetraphenylethane-1,2-diol and its 1∶2 molecular inclusion complex with dimethylsulphoxide

The structures of 1,1,2,2-tetraphenylethane-1,2-diol and its 12 molecular inclusion complex with dmso have been elucidated by X-ray crystallography from single crystal diffraction data. Crystals of the host, compound I, are monoclinic, space groupP2₁/n, witha=17.669(6) Å,b=6.144(6) Å,c=17.873(6) Å,=92.67(3)°,z=4. Crystals of the clathrate, compound II, are triclinic,P¯1, witha=9.138(5) Å,b=18.384(6) Å,c=18.496(3) Å,=61.16(2)°,=83.22(3)°, =88.06(3)°,Z=4. Both structures were solved by direct methods and refined to finalR values of 0.072 and 0.107, respectively. Compound I is partially disordered and its packing is governed by strong intermolecular hydrogen bonds. Compound II is characterized by crossing channels which accommodate the guest dmso molecules. The thermal properties of the latter compound have been characterized by DTA and TGA thermograms.     

Synthesis and X-ray crystallographic characterization of [Cd(NO3)2(15-Crown-5)] and [Cd(NO3)2(18-Crown-6)]

Reaction of 15-crown-5 or 18-crown-6 in 3:1 (v/v) CH₃CN:CH₃OH with Cd(NO₃)₂·4H₂O followed by slow evaporation produces [Cd(NO₃)₂(15-crown-5)] or [Cd(NO₃)₂(18-crown-6)]. Crystals of [Cd(NO₃)₂(15-crown-5)] are orthorhombic with space group Pbca and cell parameters a = 13.562(5), b = 15.941(9), and c = 15.011(7) Å at 295 K. [Cd(NO₃)₂(18-crown-6)] crystallizes in the monoclinic space group C2/c with a = 11.235(2), b = 11.196(5), c = 15.385(3) Å, and = 99.89(2)° at 295 K. The metal center in [Cd(NO₃)₂(15-crown-5)] rests atop the macrocyclic donor array with two cis-bound nitrate anions and adopts a distorted tricapped trigonal prismatic geometry. [Cd(NO₃)₂(18-crown-6)] resides on an equatorial two-fold rotation axis with Cd²⁺ coordinated in the 18-crown-6 cavity and the nitrate anions oriented in twisted trans positions.     

Heat capacities of perfluoropolyethers

The heat capacities at constant pressure of liquid perfluoropolyethers with different chain structures were determined above the glass transition temperature up to 480 K by means of differential scanning calorimetry (DSC). The group contributions of the  O , CF₂ , and  CF(CF₃) were calculated as a function of the temperature. Anomalous behavior of ethereal oxygen in a perfluorinated chain, as previously found for group contributions to the glass transition and to the vaporization energy, was observed also for heat capacity where the oxygen contribution is consistently lower for perfluorinated polyoxides in comparison to the hydrogenated homologous. The jump in c_p at the glass transition follows a regular behavior in the sense that ΔC_p/beadmole is within the average range found by Wunderlich for the majority of polymers. Moreover, data obtained in the present work allow the prediction of c_p of perfluoropolyethers of whatever structure between T_g and 480 K. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2073–2082, 1997     

Amphiphiles as novel solvents for photochromics: stability and photophysical properties

Abstract

The photochromic compound 2,6-bis(2-hydroxybenzilidene)cyclohexanone (PC) has been dissolved in some selected liquid amphiphiles: dibutyl, tributyl, bis-2-ethylhexyl, tris-2-ethylhexyl phosphate and bis-2-ethylhexyl amine. The aim was to explore its photophysical properties when embedded in the novel chemical environment provided by the amphiphilic solvents. UV-Vis spectra revealed different features depending on the solvent thus highlighting specific solvent-solute interactions and different chemical environments. All the alkylphosphate-based systems were found to be unstable; slow (days) changes in the absorption features due to the slow change in populations of the various species present in solution. Interestingly, the dissolution of PC into bis-2-ethylhexyl amine leads to stable solutions most probably due to the basic character of the solvent stabilising as major specie chalcone forms. Fluorescence spectra suggested the equilibrium between two species with different absorption and fluorescence properties.     

Longitudinal Bottom-Up Proteomics of Serum,Serum Extracellular Vesicles,and Cerebrospinal Fluid Reveals Candidate Biomarkers for Early Detection of Glioblastoma in a Murine Model

Glioblastoma Multiforme (GBM) is a brain tumor with a poor prognosis and low survival rates. GBM is diagnosed at an advanced stage, so little information is available on the early stage of the disease and few improvements have been made for earlier diagnosis. Longitudinal murine models are a promising platform for biomarker discovery as they allow access to the early stages of the disease. Nevertheless, their use in proteomics has been limited owing to the low sample amount that can be collected at each longitudinal time point. Here we used optimized microproteomics workflows to investigate longitudinal changes in the protein profile of serum, serum small extracellular vesicles (sEVs), and cerebrospinal fluid (CSF) in a GBM murine model. Baseline, pre-symptomatic, and symptomatic tumor stages were determined using non-invasive motor tests. Forty-four proteins displayed significant differences in signal intensities during GBM progression. Dysregulated proteins are involved in cell motility, cell growth, and angiogenesis. Most of the dysregulated proteins already exhibited a difference from baseline at the pre-symptomatic stage of the disease, suggesting that early effects of GBM might be detectable before symptom onset.     

Fiber spinning behavior of a 3-hydroxybutyrate/3-hydroxyhexanoate copolymer

The fiber spinning behavior of a poly(3-hydroxyalkanoate) (PHA) copolymer resin containing 11.3 mol% hexanoate copolymer (H11) was studied to determine its usefulness in fiber based applications, such as nonwovens. Monocomponent fibers were spun initially, but it was found they would not solidify in the spinline. Bicomponent (sheath/core) fibers were melt spun using a H11 core and a polylactic acid (PLA), as well as a polyethylene succinate (PES) sheath. The spinning results showed that H11 levels up to 30wt% could be incorporated with stable spinning. The incorporation of H11 was found to be limited due to the slow crystallization kinetics of the H11 in the spinline. The neat and bicomoponent fibers were found to have tensile strengths similar to polypropylene. The PES based fiber compositions were found to have elongation-at-break values similar to PP. Neat H11 copolymer fibers were found to be readily biodegradable at 25°C under aerobic conditions.     

Cyclophosphazenes as polymer modifiers

The utilization of Cyclophosphazenes as polymer modifiers is reviewed, with particular concern to their exploitation as versatile chain extenders, possibly for recycle problems, crosslinkers, to enhance mechanical properties of polymeric materials, branchers, to selectively introduce ramifications in linear polymers, and compatibilizers, to favor the formation of blends between originally incompatible organic macromolecules. The great versatility of the synthetic methods put forward for these substrates, together with the ease of controlling their modification, functionalization and reactivity are important parameters for the evaluation of which type of use is more feasible for these trimers. The importance of cyclophosphazenes bearing organic polymeric chains, azide groups, 2-oxazoline derivatives and oxirane rings in connection with organic conventional macromolecules is critically highlighted.