Ring-Borylated 15-Electron and 17-Electronansa-Chromocene Complexes, their Physical Properties and Molecular Structures

2007 ◽  
Vol 13 (21) ◽  
pp. 6212-6222 ◽  
Author(s):  
Pamela J. Shapiro ◽  
Piet-Jan Sinnema ◽  
Philippe Perrotin ◽  
Peter H. M. Budzelaar ◽  
Høgni Weihe ◽  
...  
Keyword(s):  
Physical Properties ◽  
Molecular Structures

scholarly journals Rapidly solidified materials

1987 ◽  
Vol 322 (1567) ◽  
pp. 425-438 ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Liquid State ◽  
Molecular Structures ◽  
Electric Response ◽  
Grain Sizes ◽  
Ceramic Compounds ◽  
Rapidly Solidified ◽  
Magnetic Hardness ◽  
Made In

Although rapid solidification has been used for generations to refine the grain sizes of materials, its effects are most significant when it succeeds in converting the liquid state into a glass. This is because homogeneous materials can be made in this way that have distinctly different compositions, as well as different molecular structures, from traditional materials. The liquids of interest are alloys, in the widest sense. These may consist of two or more metals, two or more polymers, two or more ceramic compounds, or other combinations. When they have been converted into glasses they may be useful in that form, or the glass may be the precursor to devitrified forms that cannot be created in any other way. Such materials often have unusual combinations of chemical and physical properties including strength, magnetic hardness or softness, electric response, catalytic ability and corrosion resistance.

Structural studies of organoboron compounds. XXXIII. 4,4-Dimethyl-2,2-diphenyl-1,3-dioxa-4-azonia-2-boratacyclohexaneand 3,3-dimethyl-2-phenoxy-2-phenyl-1-oxa-3-azonia-2-boratacyclopentane

1989 ◽  
Vol 67 (5) ◽  
pp. 933-940 ◽  
Author(s):  
Eckardt Ebeling ◽  
Wolfgang Kliegel ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Physical Properties ◽  
Crystal Structures ◽  
Direct Methods ◽  
Molecular Structures ◽  
Structural Studies ◽  
Boron Compounds ◽  
Organoboron Compounds ◽  
Thermally Induced ◽  
Full Matrix ◽  
Space Group

Details of the syntheses, physical properties, and crystal structures of the title compounds are reported. Crystals of 4,4-dimethyl-2,2-diphenyl-1,3-dioxa-4-azonia-2-boratacyclohexane, 3, are monoclinic, a = 6.512(1), b = 15.765(2), c = 14.342(4) Å, β = 93.170(7)°, Z = 4, space group Pn, and those of 3,3-dimethyl-2-phenoxy-2-phenyl-1-oxa-3-azonia-2-boratacyclopentane, 4, are orthorhombic, a = 13.5829(8), b = 16.940(1), c = 6.3181(4) Å, Z = 4, space group P21212. Both structures were solved by direct methods and were refined by full-matrix least-squares procedures to R = 0.034 and 0.034 for 1974 and 1478 reflections with I ≥ 3σ(I), respectively. The molecular structures are discussed in terms of the thermally-induced 1,2-migration of B-substituents by which 3 is converted to 4. Keywords: crystal structures, boron compounds, organoboron compounds.

Annealing effects on molecular structures and physical properties of side-by-side conjugate fibers

2011 ◽  
Vol 81 (19) ◽  
pp. 2065-2071
Author(s):  
Tae Hwan Oh ◽  
Sung Soo Han ◽  
Won Seok Lyoo ◽  
Myung Seob Khil
Keyword(s):  
Physical Properties ◽  
Ethylene Terephthalate ◽  
Annealing Temperature ◽  
Molecular Structures ◽  
Thermal Shrinkage ◽  
X Ray ◽  
Poly Ethylene Terephthalate ◽  
Heat Treated ◽  
Annealing Effects ◽  
Poly Ethylene

Poly(trimethylene terephthalate) (PTT)/poly(ethylene terephthalate) (PET) side-by-side conjugate fibers were heat-treated to investigate the effects of annealing on structure development and physical properties. The effects of annealing temperature and time were observed. Even though the drawn conjugate fibers were sufficiently drawn, X-ray profiles showed that the molecular orientation was insufficient. After annealing for more than 1 hour at 180°C, PET and PTT crystal structures developed sufficiently. Crimp contraction decreased from 29% to 22.6% by annealing due to the development of the crystalline structure of the annealed PTT part. Decrease in a shrinkage difference between PET and PTT leads to a decrease in crimp contraction. Thermal shrinkage was also reduced from 11.0% to 1.8% by annealing.

Structural studies of organoboron compounds. XVI. Preparation and crystal and molecular structures of 4,4-dimethyl-2,5,5-triphenyl-1,3-dioxa-4-azonia-2-bora-5-boratacyclopentane and 4,4,5,5-tetramethyl-2,2-diphenyl-1,3-dioxa-4-azonia-2-boratacyclopentane

1984 ◽  
Vol 62 (5) ◽  
pp. 838-844 ◽  
Author(s):  
W. Kliegel ◽  
H.-W. Motzkus ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Physical Properties ◽  
Least Squares ◽  
Steric Hindrance ◽  
Direct Methods ◽  
Structural Features ◽  
Molecular Structures ◽  
Structural Studies ◽  
Full Matrix ◽  
Space Group ◽  
Crystal And Molecular Structures

Details of the synthesis, physical properties, and molecular structures of 4,4-dimethyl-2,5,5-triphenyl-1,3-dioxa-4-azonia-2-bora-5-boratacyclopentane, 4, and 4,4,5,5-tetramethyl-2,2-diphenyl-1,3-dioxa-4-azonia-2-boratacyclopentane, 5, are reported. Crystals of 4 are triclinic, a = 9.841(2), b = 14.722(3), c = 6.6701(12) Å, α = 86.79(1), β = 102.95(1), γ = 93.89(1)°, Z = 2, space group [Formula: see text]; and those of 5 are monoclinic, a = 14.9164(12), b = 6.4732(3), c = 18.2248(15) Å, β = 117.263(3)°, Z = 4, space group Cc. Both structures were solved by direct methods and were refined by full-matrix least-squares procedures to final R values of 0.032 and 0.035 for 1456 and 1649 observed reflections, respectively. Molecules of 4 contain non-planar BOBON rings with an unusually long N(sp3)—B(sp3) distance of 1.728(3) Å and in 5 there is a long N(sp3)—C(sp3) bond of 1.591(3) Å. These structural features are ascribed to steric hindrance.

Infrared Evaluation of Enantiometric Amount and Application to Racemization at the Interface Between L- and D-Alanine

2018 ◽  
Vol 72 (7) ◽  
pp. 1074-1079
Author(s):  
Shun Kamei ◽  
Jigen Hibi ◽  
Yoshiyuki Ohtsubo ◽  
Hiroshi Watanabe ◽  
Shin-ichi Kimura
Keyword(s):  
Thin Films ◽  
Amino Acids ◽  
Spatial Distribution ◽  
Amino Acid ◽  
Synchrotron Radiation ◽  
Physical Properties ◽  
Volume Fraction ◽  
Molecular Structures ◽  
Conventional Methods

Amino acids, except for glycine, have two types of molecular structures, L- and D-forms, which are enantiomers. As the L- and D-form molecules have identical chemical and physical properties, they cannot be easily identified by conventional methods. In this study, we found that the amount and the spatial distribution of D-enantiomers in an L-alanine (CH3CH(COOH)NH2) matrix in evaporated thin films, which is one of amino acid molecules, can be evaluated quantitatively using an infrared micro spectroscopy with synchrotron radiation. This method was applied to the evaluation of the volume fraction of a racemic component appearing at the interface between L- and D-alanine thin films.

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