Thermostable sites of palladium phthalocyanine in Shpol'skii matrices of mixed solvents

1984 ◽  
Vol 62 (11) ◽  
pp. 2264-2272 ◽  
Author(s):  
Wen-Hsiung Chen ◽  
Klaus E. Rieckhoff ◽  
Eva-Maria Voigt
Keyword(s):  
Excited States ◽  
Mixed Solvent ◽  
Mixed Solvents ◽  
Dipolar Interaction ◽  
Site Formation ◽  
Effective Mechanism ◽  
Large Molecules ◽  
Clear Guideline ◽  
Vibrational Features ◽  
Insight Into

A study was made of the effects of three different mixed solvent Shpol'skii matrices at 4.2 K on site formation and on vibronic progressions of palladium phthalocyanine. It is found that only a limited number of thermostable sites are formed and these sites are common to all three matrices, but vary in their statistical weights. However, in all solvents the statistical weights of the first few most important sites are similar, with the predominant site at least eight or nine times stronger than the next. As well, the vibrational features of both the ground state and the first excited states of a few of the most populated sites examined are practically the same for the different mixed solvents. The absence of any significant differences in site splitting implies the absence of any dipolar interaction effects on these splittings.The above findings provide a better insight into the interaction between phthalocyanine, intermediate solvent, and basic solvent (n-octane) in the three-component solutions and give a clear guideline for choosing convenient solvents and for using Shpol'skii matrices as a simple effective mechanism for producing quasi-line vibronic spectra of phthalocyanines and other related large molecules insoluble in the alkanes.

PubChem and ChEMBL Beyond Lipinski

2019 ◽  
Author(s):  
Jean-Louis Reymond ◽  
Mahendra Awale ◽  
Daniel Probst ◽  
Alice Capecchi
Keyword(s):  
Nearest Neighbor ◽  
Molecular Shape ◽  
Biological Properties ◽  
Web Based ◽  
Large Molecules ◽  
Interactive Tools ◽  
Small Molecule Drugs ◽  
Pubchem Database ◽  
Nearest Neighbor Searches ◽  
Insight Into

<p>Seven million of the currently 94 million entries in the PubChem database break at least one of the four Lipinski constraints for oral bioavailability, 183,185 of which are also found in the ChEMBL database. These non-Lipinski PubChem (NLP) and ChEMBL (NLC) subsets are interesting because they contain new modalities that can display biological properties not accessible to small molecule drugs. Unfortunately, the current search tools in PubChem and ChEMBL are designed for small molecules and are not well suited to explore these subsets, which therefore remain poorly appreciated. Herein we report MXFP (macromolecule extended atom-pair fingerprint), a 217-D fingerprint tailored to analyze large molecules in terms of molecular shape and pharmacophores. We implement MXFP in two web-based applications, the first one to visualize NLP and NLC interactively using Faerun (http://faerun.gdb.tools/), the second one to perform MXFP nearest neighbor searches in NLP (http://similaritysearch.gdb.tools/). We show that these tools provide a meaningful insight into the diversity of large molecules in NLP and NLC. The interactive tools presented here are publicly available at http://gdb.unibe.ch and can be used freely to explore and better understand the diversity of non-Lipinski molecules in PubChem and ChEMBL.</p>

scholarly journals Natural product mixture analysis by matrix-assisted DOSY using Brij surfactants in mixed solvents

RSC Advances ◽  
2014 ◽  
Vol 4 (79) ◽  
pp. 42029-42034 ◽  
Author(s):  
Mariano G. S. Vieira ◽  
Nilce V. Gramosa ◽  
Nágila M. P. S. Ricardo ◽  
Gareth A. Morris ◽  
Ralph W. Adams ◽  
...  
Keyword(s):  
Natural Product ◽  
Mixed Solvent ◽  
Mixed Solvents ◽  
Mixture Analysis ◽  
Surfactant Micelles ◽  
Product Mixture ◽  
Solvent Systems ◽  
Nmr Signals

Brij surfactant micelles in mixed solvent systems aid resolution of natural product NMR signals in diffusion-ordered spectroscopy.

scholarly journals A review on conductometric studies of electrolytes in mixed solvent systems to understand ion-ion and ion-solvent interactions

2020 ◽  
Vol 10 (3) ◽  
pp. 5355-5360
Keyword(s):  
Mixed Solvent ◽  
Mixed Solvents ◽  
Chemical Properties ◽  
Electrolyte Solutions ◽  
Molar Conductance ◽  
Extensive Literature ◽  
Solvent Interactions ◽  
Physico Chemical ◽  
Wide Range ◽  
Solvent Systems

The study of ion- solvent interaction is of much importance to investigate the nature of different solutions. Measurement of electrical conductivity and evaluation of physico-chemical properties, such as molar conductance, limiting molar conductance, ion-pair association, Walden product etc. shade light on different intermolecular interactions present in electrolyte solutions. Solvation properties can be varied by mixing two or more solvents. An extensive literature survey on conductometric studies has been carried out on different electrolytes dissolved in a wide range of mixed solvent systems. The reported results show that strong solute-solute, solute-solvent and solvent-solvent interactions are responsible for the physico- chemical behavior of a solution in mixed solvents.

scholarly journals Mixed Solvents in Multi-Layer Ceramic Capacitors (MLCC) Elec-Tronic Paste and Their Effects on the Properties of Organic Vehicle

2021 ◽  
Author(s):  
Ruolong Gan ◽  
Junrong Li ◽  
Xiuhua Cao ◽  
Jun Huang ◽  
Liying Qian
Keyword(s):  
Mixed Solvent ◽  
Mixed Solvents ◽  
Nitrogen Atmosphere ◽  
Carbon Residue ◽  
Solubility Parameters ◽  
Multilayer Ceramic Capacitors ◽  
Organic Vehicle ◽  
Thermogravimetric Analyzer ◽  
Ceramic Capacitors ◽  
Multilayer Ceramic

The copper end paste used in multilayer ceramic capacitors sintered in nitrogen atmosphere will lead to carbon residue of organic vehicle, which will lead to the reduction of electrode conduc-tivity and high scrap rate. With an attempt to leave no residue in the sintering, the compatibility of solvents and thickeners should be improved because it has an important influence on the hi-erarchical volatilization and carbon residue of organic vehicles. In this work, the volatility of different solvents was compared and several solvents were mixed in a definite proportion to prepare an organic vehicle with polyacrylate resins. The hierarchical volatility and solubility parameters of mixed solvents were adjusted effectively by changing proportions of different components, the thermogravimetric curves of resins and organic vehicles were measured by thermogravimetric analyzer, the effect of solubility parameter on the dissolvability of resins in the solvent and the residual of organic vehicles were studied. Results showed that the hierar-chical volatilization of solvents can be obtained by mixing different solvents; the intrinsic vis-cosity of the organic vehicle is higher and the thermal decomposition residue of polyacrylate resins is lower when the solubility parameters of mixed solvents and polyacrylate resins are closer. The low residual sintering of organic vehicles can be achieved by using the mixed solvent with hierarchical volatility and approximate solubility parameters as resins.

Single-Reference ab Initio Methods for the Calculation of Excited States of Large Molecules

2005 ◽  
Vol 105 (11) ◽  
pp. 4009-4037 ◽  
Author(s):  
Andreas Dreuw ◽  
Martin Head-Gordon
Keyword(s):  
Ab Initio ◽  
Excited States ◽  
Ab Initio Methods ◽  
Large Molecules

scholarly journals The behaviour of electrolytes in mixed solvents. Part. III.–The molecular refractivities and partial molar volumes of lithium chloride in water-ethyl alcohol solutions

1931 ◽  
Vol 131 (817) ◽  
pp. 382-390 ◽  
Keyword(s):  
Lithium Chloride ◽  
Ethyl Alcohol ◽  
Mixed Solvent ◽  
Mixed Solvents ◽  
Partial Molar Volumes ◽  
Ammonium Iodide ◽  
Dilute Aqueous Solutions ◽  
The Difference ◽  
Value Of It ◽  
Water Alcohol

It is well known that the molecular refractivity of most salts, as calculated by the Lorentz-Lorenz formula, is nearly independent of the concentration in moderately dilute aqueous solutions. Walden determined the refractivities of tetra-ethyl-ammonium iodide and other similar salts in a variety of solvents and found that, while the molecular refractivity was approximately independent of the concentration in each solvent, it varied from one solvent to another, the greatest variation from the value in water, amounting to about 2 per cent., being obtained in nitro-methane, Schreiner has recently determined the molecular refractivity of hydrogen chloride and lithium chloride in methyl and ethyl alcohols, and found that in the case of lithium chloride the value is independent of the concentration up to a concentration of about 3 M. His values for R 18 D for lithium chloride are: 8.73 in water, 8.55 in methyl alcohol and 8.38 in ethyl alcohol. The difference between the values in water and ethyl alcohol appeared to make it just possible to determine the variation of the refractivity with the composition of the solvent in mixtures of water and the alcohol. It is possible that a solvent might he found, miscible in water in all proportions, in which the value of It is further removed from that in water. Such a substance would he more suitable than alcohol for the investigation of this effect, but in order to correlate the results with the measurements recorded in Part II of the activities of alcohol and water in water-alcohol-lithium chloride solutions, it seemed desirable to investigate this case in the first instance. The variation of the refractivity of a salt with the composition of a mixed solvent may be expected to give some indication of the composition of the solvent in the immediate vicinity of the ions. For the refractivity of a salt is determined by (1) the polarisability of the ions themselves and (2) the change in the polarisability of the solvent produced by their presence. The molecular refractivity of a salt in a solution containing m grams of a salt in w grams of the solvent is taken as R = M/ m ( n 2 -1/ n 2 + 2 . w + m / d - n 2 0 -1/ n 2 0 + 2 . w / d 0 (1) where n , and d and n 0 , d 0 are the refractive index and density of the solution and of the solvent, respectively, and M the molecular weight of the salt.

Lithic technology and discard at Marki, Cyprus: consumer behaviour and site formation in the prehistoric Bronze Age

Antiquity ◽  
1998 ◽  
Vol 72 (278) ◽  
pp. 796-805 ◽  
Author(s):  
Jennifer M. Webb
Keyword(s):  
Bronze Age ◽  
Consumer Behaviour ◽  
Lithic Technology ◽  
Site Formation ◽  
Lithic Studies ◽  
Insight Into

Lithic studies all too often ignore the material of later prehistory. Here an exploration of ideas of curation and expediency offers a new insight into material from Bronze Age Cyprus.

scholarly journals Micro-FTIR and EPMA Characterisation of Charoite from Murun Massif (Russia)

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Maria Lacalamita
Keyword(s):  
Single Crystal ◽  
Complex Structure ◽  
Structural Complexity ◽  
Adsorbed Water ◽  
Bending Vibration ◽  
Structural Water ◽  
Stretching Vibration ◽  
Vibrational Features ◽  
Polytype Structure ◽  
Insight Into

Combined micro-Fourier transform infrared (micro-FTIR) and electron probe microanalyses (EPMA) were performed on a single crystal of charoite from Murun Massif (Russia) in order to get a deeper insight into the vibrational features of crystals with complex structure and chemistry. The micro-FTIR study of a single crystal of charoite was collected in the 6000–400 cm−1 at room temperature and after heating at 100°C. The structural complexity of this mineral is reflected by its infrared spectrum. The analysis revealed a prominent absorption in the OH stretching region as a consequence of band overlapping due to a combination of H2O and OH stretching vibrations. Several overtones of the O-H and Si-O stretching vibration bands were observed at about 4440 and 4080 cm−1 such as absorption possibly due to the organic matter at about 3000–2800 cm−1. No significant change due to the loss of adsorbed water was observed in the spectrum obtained after heating. The occurrence of well-resolved water bending vibration bands at about 1595 and 1667 cm−1 accounts for more than one structural water molecule as expected by charoite-90 polytype structure model from literature. The chemical composition of the studied crystal is close to the literature one.

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