Oxidative addition of diphenyl disulfide across a tantalum-tantalum double bond. Preparation and characterization of [TaCl3(Me2S)]2(.mu.-SPh)2

1986 ◽  
Vol 25 (3) ◽  
pp. 287-290 ◽  
Author(s):  
Gordon C. Campbell ◽  
Jo Ann M. Canich ◽  
F. Albert Cotton ◽  
Stan A. Duraj ◽  
James F. Haw
Keyword(s):  
Double Bond ◽  
Oxidative Addition ◽  
Diphenyl Disulfide

scholarly journals Channeling of Eukaryotic Diacylglycerol into the Biosynthesis of Plastidial Phosphatidylglycerol

2006 ◽  
Vol 282 (7) ◽  
pp. 4613-4625 ◽  
Author(s):  
Markus Fritz ◽  
Heiko Lokstein ◽  
Dieter Hackenberg ◽  
Ruth Welti ◽  
Mary Roth ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Double Bond ◽  
Transgenic Plants ◽  
Phosphatidic Acid ◽  
Lipid Analysis ◽  
Photosynthetic Apparatus ◽  
Hexadecenoic Acid ◽  
Transgenic Tobacco Plants ◽  
Tobacco Plants

Plastidial glycolipids contain diacylglycerol (DAG) moieties, which are either synthesized in the plastids (prokaryotic lipids) or originate in the extraplastidial compartment (eukaryotic lipids) necessitating their transfer into plastids. In contrast, the only phospholipid in plastids, phosphatidylglycerol (PG), contains exclusively prokaryotic DAG backbones. PG contributes in several ways to the functions of chloroplasts, but it is not known to what extent its prokaryotic nature is required to fulfill these tasks. As a first step toward answering this question, we produced transgenic tobacco plants that contain eukaryotic PG in thylakoids. This was achieved by targeting a bacterial DAG kinase into chloroplasts in which the heterologous enzyme was also incorporated into the envelope fraction. From lipid analysis we conclude that the DAG kinase phosphorylated eukaryotic DAG forming phosphatidic acid, which was converted into PG. This resulted in PG with 2–3 times more eukaryotic than prokaryotic DAG backbones. In the newly formed PG the unique Δ3-trans-double bond, normally confined to 3-trans-hexadecenoic acid, was also found in sn-2-bound cis-unsaturated C18 fatty acids. In addition, a lipidomics technique allowed the characterization of phosphatidic acid, which is assumed to be derived from eukaryotic DAG precursors in the chloroplasts of the transgenic plants. The differences in lipid composition had only minor effects on measured functions of the photosynthetic apparatus, whereas the most obvious phenotype was a significant reduction in growth.

Characterization of the energy surface for the oxidative addition of silanes to manganese complex CpMn(CO)2(heptane)

1992 ◽  
Vol 114 (13) ◽  
pp. 5234-5240 ◽  
Author(s):  
Dennis M. Hester ◽  
Jiemin Sun ◽  
Aaron W. Harper ◽  
Gilbert K. Yang
Keyword(s):  
Energy Surface ◽  
Oxidative Addition ◽  
Manganese Complex

scholarly journals Systematic Syntheses and Characterization of Dodecadien-1-olswith Conjugated Double Bond, Lepidopterous Sex Pheromones

1985 ◽  
Vol 49 (1) ◽  
pp. 141-148 ◽  
Author(s):  
Tetsu Ando ◽  
Yuichi Kurotsu ◽  
Mieko Kaiya ◽  
Masaaki Uchiyama
Keyword(s):  
Double Bond ◽  
Sex Pheromones

C60 Framework Response to Halogen Addition: the Stable Isomers of C60Br2m

1994 ◽  
Vol 47 (1) ◽  
pp. 131 ◽  
Author(s):  
JB Peel ◽  
RG Rothwell
Keyword(s):  
Double Bond ◽  
Molecular Orbital ◽  
High Stability ◽  
Structural Information ◽  
Spectroscopic Characterization ◽  
The Other ◽  
Semiempirical Calculations ◽  
Elementary Model ◽  
Local Distortion

The isolation and spectroscopic characterization of halogenated fullerene-60 compounds has not advanced greatly during the 2 years of effort in this area. While the fully fluorinated C60F60 has been studied in some detail, other halogen addition processes have indicated chlorination up to C60Cl24 and bromination up to C60Br24. However, definitive structural information has to date only been provided for three compounds, namely C60Br6, C60Br6 and C60Br24. Iodine does not appear to form genuine addition compounds. In the work reported here semiempirical calculations using the AM1 approximation with the MOPAC molecular orbital program have been directed to comparing the possible stable isomers of the 1:1 addition compounds C60X2 for X = F, Cl and Br. The favoured isomers can be described as 1,2-additions (to a double bond at a hexagon-hexagon fusion) and 1,4-additions (to the terminal carbons of a butadiene moiety) with higher-energy isomers resulting from 1,6- and 1,8-additions. The other isomers represented by 1,3- 1,5- and 1,7-additions are only stable relative to dissociation in the case of the fluorine addition compounds. By contrast for Br2 addition only the 1,2- and 1,4-isomers are stable toward dissociation. The calculations show that, at and near the addition site carbons, X2 addition is adequately described in terms of local distortion of the C60 sphere. The elementary model of C60 as comprising formal single and double bonds is relevant since C60 behaves as a 'poly- alkene ', with sp3 carbons replacing sp2 carbons at the addition sites. This model offers an explanation for the unique structures observed for C60Br6 and C60Br24 which the AM1calculations show to be very stable toward dissociation. However, the experimental C60Br8 structure is found to be relatively less stable than another isomer. Also high-stability isomers of C60Br4, C60Br10, C60Br12 and C60Br18 are predicted.

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