Highly Reversible Room-Temperature Sulfur/Long-Chain Sodium Polysulfide Batteries

2014 ◽  
Vol 5 (11) ◽  
pp. 1943-1947 ◽  
Author(s):  
Xingwen Yu ◽  
Arumugam Manthiram
Keyword(s):  
Room Temperature ◽  
Sodium Polysulfide ◽  
Long Chain

The Flexibility of Long Chain Substituents Influences Spin-Crossover in Isomorphous Lipid Bilayer Crystals

2021 ◽  
Author(s):  
Iurii Galadzhun ◽  
Rafal Kulmaczewski ◽  
Namrah Shahid ◽  
Oscar Cespedes ◽  
Mark J Howard ◽  
...  
Keyword(s):  
Lipid Bilayer ◽  
High Spin ◽  
Room Temperature ◽  
Spin Crossover ◽  
Pyridine Derivatives ◽  
Long Chain

[Fe(bpp)2][BF4]2 (bpp = 2,6-di{pyrazol-1-yl}pyridine) derivatives bearing a bent geometry of hexadec-1-ynyl or hexadecyl substituents pyrazole are isomorphous, and high-spin at room temperature. However, only the latter compound undergoes an abrupt,...

scholarly journals Phthalocyanine formation using metals in primary alcohols at room temperature

2000 ◽  
Vol 04 (01) ◽  
pp. 103-111 ◽  
Author(s):  
CLIFFORD C. LEZNOFF ◽  
ANNA M. D'ASCANIO ◽  
S. ZEKI YILDIZ
Keyword(s):  
Molecular Weight ◽  
Copper Powder ◽  
Reverse Micelle ◽  
Room Temperature ◽  
Micelle Formation ◽  
Lithium Metal ◽  
Electronic Effects ◽  
Primary Alcohols ◽  
Lower Yield ◽  
Long Chain

Lithium metal added to a solution of 4-neopentoxyphthalonitrile in 1-octanol or other long-chain primary alcohols at room temperature resulted in phthalocyanine formation at a reasonable rate in good yield, while preformed lithium 1-octanolate under the same conditions gave 2,9,16,23-tetraneopentoxyphthalocyanine, but in lower yield at a slower rate. The use of lower-molecular-weight alcohols slowly gave a phthalocyanine in lower yields. Reverse micelle formation when using long-chain alcohols is proposed as a possibility for enhanced phthalocyanine formation at room temperature. 2,9,16,23-Tetrasubstituted phthalocyanines and metallated phthalocyanines were prepared at room temperature from 4-neopentoxyphthalonitrile, 4-bis(4-methoxyphenyl)methoxyphthalonitrile, 4-[1-(4-ethoxy-3-methoxyphenyl)-1-phenyl]methoxyphthalonitrile and phthalonitrile using lithium 1-octanolate in 1-octanol or by the addition, to a solution of the phthalonitrile in ethanol, of calcium turnings or, to a solution of the phthalonitrile in methanol, of magnesium, zinc, iron or copper powder. The tetrasubstituted phthalocyanines produced exhibited a non-statistical distribution of regioisomers, indicating that electronic effects become important in room-temperature cyclotetramerization of phthalonitriles to phthalocyanines.

Discotic Liquid Crystals of Transition metal Complexes 23: Synthesis and Mesomorphism of Tetrakis(3,4-di-n-alkylphenyl)porphyrin Derivatives and Their Metal Complexes

1999 ◽  
Vol 03 (04) ◽  
pp. 249-258 ◽  
Author(s):  
KAZUCHIKA OHTA ◽  
MASAHIRO ANDO ◽  
IWAO YAMAMOTO
Keyword(s):  
Liquid Crystal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Room Temperature ◽  
Discotic Liquid Crystals ◽  
X Ray ◽  
Alkyl Chains ◽  
Porphyrin Derivatives ◽  
Crystal Phases ◽  
Long Chain

Five novel long-chain-substituted porphyrin derivatives, tetrakis(3,4-dialkylphenyl)porphyrins (abbreviated as (Cn)8 TPPH 2 (n = 8, 12, 18), ( C 18)8 TPPCu and ( C 18)8 TPPNi ), were synthesized and their mesomorphism was investigated. It was found that the (Cn)8 TPPH 2 (n = 8, 12), derivatives are isotropic liquids at room temperature and that each of the ( C 18)8 TPPM ( M ≡ H 2, Cu , Ni ) derivatives has two liquid crystal phases M1 and M2 and two unidentified phases X1 and X2. It was revealed by X-ray studies that the M2 phase is a discotic lamellar (DL) phase. Interestingly, these porphyrin derivatives exhibit not a columnar but a lamellar mesophase, even though they have a disk-like central core with eight alkyl chains in the surroundings.

Phase Changes in Fe(III)OCl–RNH2-Intercalation Complexes

1984 ◽  
Vol 39 (9) ◽  
pp. 1193-1198 ◽  
Author(s):  
Armin Weiss ◽  
Jin Ho Choy
Keyword(s):  
Room Temperature ◽  
Host Lattice ◽  
Phase Changes ◽  
Temperature Dependent ◽  
Chain Molecules ◽  
Intercalation Complexes ◽  
Long Chain

Iron(III)oxide chloride is capable of intercalating ammonia and amines into its layer lattice. Long chain molecules form bilayers with extended chains almost perpendicular to the host lattice layers at room temperature (intercalate composition): FeOCl · (0.54 ±0.03)n -CxH2x+1NH2 with x ≥ 12) and tilted by 57° at about 100-110 °C (intercalate composition: FeOCl · (0.45 ±0.02)n-CxH2x+1NH2 with ≥12). The temperature-dependent changes in basal spacings between 20 and 110 °C are complex. Above 120 °C the layers of the host lattice are altered irreversibly by substitution and HCl-release to FeOCl1-y(-NHCxH2x+1)y with y ≤ ca. 0.4.

Synthesis and Magnetic Properties of Co Nanorod Superlattices

2006 ◽  
Vol 962 ◽  
Author(s):  
Fabienne Wetz ◽  
Katerina Soulantica ◽  
Marc Respaud ◽  
Andrea Falqui ◽  
Bruno Chaudret
Keyword(s):  
Thermal Decomposition ◽  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Magnetic Recording ◽  
Coercive Field ◽  
Shape Control ◽  
Room Temperature ◽  
High Density ◽  
High Density Magnetic Recording ◽  
Long Chain

ABSTRACTWe present the synthesis and magnetic properties of Co nanorods spontaneously organized in superlattices over a surface of several microns. This material results from the thermal decomposition of a cobalt precursor under hydrogen, in the presence of a long-chain amine and a long-chain acid as shape control agents. These nanorod superlattices are ferromagnetic at room temperature and they are characterized by a strong coercive field as a consequence of their large magnetic anisotropy. This system can be considered as a good candidate for high density magnetic recording.

Permanent Set in Vulcanized Rubber

1949 ◽  
Vol 22 (4) ◽  
pp. 1036-1044 ◽  
Author(s):  
L. Mullins
Keyword(s):  
Plastic Flow ◽  
Room Temperature ◽  
Elastic Recovery ◽  
The Other ◽  
Initial Length ◽  
Chain Molecules ◽  
Permanent Set ◽  
Vulcanized Rubber ◽  
Rate Of Recovery ◽  
Long Chain

Abstract The residual extension which remains after a sample of rubber has been stretched for some period, then released and allowed to recover, is popularly called permanent set. This set, however, is far from being permanent since it continuously decreases with the period of recovery; furthermore, after the rate of recovery has become exceedingly slow and is no longer readily observable, an increase in temperature will usually result in a sharp increase in the rate of recovery. It has been usual to identify this set with irreversible plastic flow, but it will be immediately evident that this can rarely be justified for, owing to incomplete high-elastic recovery, the measured value of set is a combination of both plastic flow and high-elastic deformation which has not completely recovered. Thus before any attempt is made to discuss the interpretation of the results of set tests, a study must be made of the significance of set. Treloar has investigated this phenomenon in raw natural rubber and has shown that entanglements or cohesional linkages may form while the rubber is stretched, and these oppose recovery; further, although van der Waals forces between the long-chain molecules largely control the rate and the amount of recovery, the crystallization of rubber produced by stretching may profoundly influence the set. On the other hand Tobolsky has studied the set which results from stretching rubber vulcanizates at high temperatures ; in such cases the amount of set is controlled by two processes which take place while the rubber is stretched; one of these involves the oxidative breaking of network chains, the other the oxidative cross-linking of network chains. Although these ideas are well founded, they do not provide a completely satisfactory basis for the understanding of set, and the purpose of this work is to extend these ideas and to explain the significance of the results of normal set tests ; in these tests rubber samples were extended at room temperatures to moderate elongations for relatively short periods of time. Most of the tests performed in this investigation were made on dumbbell shaped samples, which were extended by 200 per cent of their initial length for fifteen minutes at room temperature and then allowed to recover for one hour at room temperature; the residual extension was then noted and expressed as a percentage of the initial length. These tests will be referred to as normal set tests. In some tests various periods and temperatures of extension and recovery were used.

The Dielectric Properties of Symmetrical Long-Chain Secondary Alcohols in the Solid State

1951 ◽  
Vol 4 (2) ◽  
pp. 213 ◽  
Author(s):  
RL Meakins ◽  
RA Sack
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Dielectric Loss ◽  
Low Temperatures ◽  
Room Temperature ◽  
Molecular Chain ◽  
Hydroxyl Groups ◽  
Crystal Formation ◽  
Secondary Alcohols ◽  
Long Chain

Symmetrical long-chain secondary alcohols in the solid state show very high dielectric loss at audio and radio frequencies. This can be explained by the presence of chains of hydroxyl groups linked by hydrogen bonding and capable of reversing their direction. Further evidence of hydrogen bonding is provided by a study of the melting points of the secondary alcohols and related compounds. The amount of dielectric loss depends markedly on the manner of formation of the solid, being smallest for samples formed by recrystallization from solvents at low temperatures and largest for specimens obtained by slow cooling from the melt. The alcohols of molecular chain-lengths of 13, 15,17, and 19 carbon atoms show a considerable decrease of absorption on storing at room temperature. For alcohols of between 23 and 43 carbon atoms the loss is rather smaller with a peak at higher frequencies, but remains more constant in time. These results are interpreted in terms of competing influences of van der Waals forces and hydrogen bonds during crystal formation ; the former, which lead to a structure unsuitable for the formation of hydrogen-bond chains, are predominant at low temperatures, but become more rapidly neutralized by thermal motion, especially for the shorter molecules. The high temperature modification of the lower homologues is unstable at room temperature, and a molecular diffusion process causes the bond chains to break. Dilute systems of secondary alcohols with hydrocarbons or paraffin wax of similar molecular chain-length show very small dielectric loss suggesting a solid solution in which bond chains cannot be formed ; if the paraffin molecules are appreciably longer, the absorption is large and decreases on storing, presumably owing to the presence of a pure alcohol phase. I.

scholarly journals The torsional flexibility of aliphatic chain molecules

1940 ◽  
Vol 174 (956) ◽  
pp. 137-144 ◽  
Keyword(s):  
Room Temperature ◽  
Threshold Energy ◽  
Chain Molecule ◽  
Aliphatic Chain ◽  
Chain Molecules ◽  
Distortion Effect ◽  
A Chain ◽  
Single Bonds ◽  
Long Chain ◽  
Made In

The rotation of the CH 3 groups round the single C—C bond in ethane is associated with a threshold energy of about 3000 gcal./gmol. or 2 x 10 -13 erg/mol. (Schäfer 1938; Kistiakowsky, Lacher and Strutt 1939). In an aliphatic CH 2 chain where the carbon atoms are linked together by single bonds the corresponding energy must be of the same order and is most likely rather smaller. Supposing we consider any particular C—C bond in the chain and treat the two parts at each side of this bond as rigid rotators, then their kinetic energy would be 2 x 1/2 kT which at room temperature amounts to about one-fifth of the threshold energy. It seems very likely under these circumstances that a chain molecule of say ten to twenty carbon atoms should already at room temperature show signs of distortion due to internal rotation. If this is true, then the previously observed increase of the crystal symmetry at the melting-point of paraffins (Müller 1930, 1932) and the corresponding changes of the polarization of long-chain ketones (Müller 1937, 1938) can no longer be ascribed entirely to a rotation of the molecule in the field of the surrounding molecules but must at least partly be due to this internal distortion. It is clear that a distortion of this type tends to destroy the anisotropy of the molecule and to give an apparent isotropy to the crystal. The present experiments were made in order to obtain an estimate of the magnitude of the distortion effect. It is found to be surprisingly large.

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