Geometrical and rotational isomerism in boron-phosphorus compounds. Low temperature 19F NMR investigation of B4H8PF2N(CH3)2

1978 ◽  
Vol 14 (1) ◽  
pp. 45-48 ◽  
Author(s):  
T.F. Moore ◽  
A.R. Garber ◽  
J.D. Odom
Keyword(s):  
Low Temperature ◽  
Rotational Isomerism ◽  
19F Nmr ◽  
Phosphorus Compounds

scholarly journals The dynamics of acid-soluble phosphorus compounds in the course of winter and spring wheat germination under various thermic conditions. Part II. Labile phosphorus after hydrolysis of the acid-soluble fraction

2015 ◽  
Vol 24 (2) ◽  
pp. 297-308
Author(s):  
A. Barbaro
Keyword(s):  
Low Temperature ◽  
Phosphorus Content ◽  
Soluble Fraction ◽  
Phosphorus Compounds ◽  
Labile Phosphorus ◽  
Soluble Phosphorus ◽  
Germination Temperature ◽  
Wheat Germination ◽  
Labile P ◽  
Hydrolysis Of

The changes in labile phosphorus compounds content during germination of wheat were investigated. These compounds were determined in acid-soluble germ extracts separated into fractions according to the solubility of their barium salts. Low germination temperature was found to raise the labile phosphorus content in the fraction of insoluble barium salts. If we assume that labile P of this fraction consisted mainly of adenosinedi- and triphosphates, it would seem that the rise, in the ATP and ADP level under the influence of low temperature may be essential for initiating flowering in winter varieties.

Low-temperature 19F NMR spectroscopy of 1-fluoro-1-lithioethenes

2002 ◽  
Vol 113 (2) ◽  
pp. 211-218 ◽  
Author(s):  
Jaroslav Kvı́čala ◽  
Richard Hrabal ◽  
Jiřı́ Czernek ◽  
Ivana Bartošová ◽  
Oldřich Paleta ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Low Temperature ◽  
19F Nmr ◽  
19F Nmr Spectroscopy

Rotational isomerism in polyarylates obtained by low temperature polyesterification

1974 ◽  
Vol 16 (2) ◽  
pp. 336-347 ◽  
Author(s):  
V.V Korshak ◽  
S.V Vinogradova ◽  
V.A Basnev ◽  
V.A Vasil'ev ◽  
A.A Askadskii ◽  
...  
Keyword(s):  
Low Temperature ◽  
Rotational Isomerism

Rotational isomerism in fluorene derivatives. XX. Conformational equilibria of 9-substituted 9-(o-methylthiomethylphenyl)- and 9-substituted 9-(o-methylsulfinylmethylphenyl)fluorenes

1991 ◽  
Vol 69 (4) ◽  
pp. 615-619 ◽  
Author(s):  
Akiko Nishida ◽  
Yoshifumi Akagawa ◽  
Shinsuke Shirakawa ◽  
Shizuo Fujisaki ◽  
Shoji Kajigaeshi
Keyword(s):  
Low Temperature ◽  
Key Words ◽  
Equilibrium Constant ◽  
Internal Rotation ◽  
Kinetic Data ◽  
Room Temperature ◽  
Rotational Isomerism ◽  
Oxidation Products ◽  
Conformational Isomerism ◽  
Conformational Equilibria

Several 9-substituted 9-(o-methylthiomethylphenyl)fluorenes and their oxidation products, 9-substituted 9-(o-methylsulfinylmethylphenyl)fluorenes, were prepared. Each equilibrium constant at room temperature or at low temperature was investigated and the conformational equilibria [Formula: see text] of these compounds are discussed by comparing them with those of the corresponding 9-substituted 9-(o-methylthiophenyl)fluorenes and 9-substituted 9-(o-methylsulfinylphenyl)fluorenes in which the o-substituents were one CH2 unit shorter than those of the title compounds. Kinetic data for the internal rotation of several compounds are also given. Key words: conformational isomerism, restricted rotation, 9-arylfluorenes.

(9H-Fluoren-9-ylidene)fluoromethyllithium, a Stabilized Fluoroalkenyl Carbanion. Preparation, Reactions, 13C and 19F NMR Spectra

2001 ◽  
Vol 66 (10) ◽  
pp. 1508-1520 ◽  
Author(s):  
Jaroslav Kvíčala ◽  
Andrew Pelter
Keyword(s):  
Nmr Spectroscopy ◽  
Low Temperature ◽  
Methyl Iodide ◽  
Nmr Spectra ◽  
19F Nmr ◽  
19F Nmr Spectra ◽  
13C And 19F Nmr ◽  
C Nmr

(9H-Fluoren-9-ylidene)fluoromethyllithium (1) was prepared by a low-temperature transmetallation of bromo(9H-fluoren-9-ylidene)fluoromethane (2). Whereas the synthesis of unlabeled bromofluoroalkene 2a was based on Wittig-Horner reaction of fluorenone (3) with ethyl (diethoxyphosphoryl)fluoroacetate (4), (1-13C)-labeled compound 2b was obtained via an addition of labeled lithium 1-ethoxy-2-fluoro(2-13C)ethen-1-olate (5) to ketone 3. Fluoroethenyllithium 1 was found by a low-temperature 19F NMR spectroscopy to be stable up to -40 °C; it was reacted with the series of electrophiles, e.g. benzaldehyde (6), methyl iodide (7) or chloro(trimethyl)silane (8). 13C NMR experiments with (1-13C)-labeled 1a proved that fluorocarbenoid 1 is probably monomeric in THF solution in analogy to other halocarbenoids.

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