Studies in the Stereochemistry of Zinc(II). I. Derivatives of Bis(acetyl-acetonato)zinc(II)

1963 ◽  
Vol 16 (6) ◽  
pp. 980 ◽  
Author(s):  
DP Graddon ◽  
DG Weeden
Keyword(s):  
Molecular Weight ◽  
Crystal Field ◽  
Predominant Species ◽  
Anhydrous Compound ◽  
Derivatives Of

The compound melting at 138� and for long supposed to be anhydrous bis(acetylacetonato)zinc(II) is shown to be the monohydrate. The anhydrous compound has also been obtained, melting at 152�; and adducts are described with one and two molecules of pyridine or 4-methylpyridine, one molecule of 2-methylpyridine, and two molecules of ammonia. Molecular weight determinations in benzene and triphenylmethane show that with the exception of the anhydrous compound which is monomeric, the predominant species in solution are five-coordinate. Differences in the stereochemical behaviour of zinc in these compounds from the behaviour of cobalt(II) and nickel(II) in corresponding compounds are interpreted in terms of crystal-field stabilization of octahedral complexes of the latter ions.

scholarly journals Complex Formation of Covalently Crosslinked Fibrin Oligomers with Agarose Coupled Fibrinogen and Fibrin

1977 ◽  
Author(s):  
R. von Hugo ◽  
R. Hafter ◽  
A. Stemberger ◽  
H. Graeff
Keyword(s):  
Molecular Weight ◽  
Complex Formation ◽  
Affinity Chromatography ◽  
High Molecular Weight ◽  
Calcium Chloride ◽  
Gel Filtration ◽  
Void Volume ◽  
Soluble Fibrin ◽  
Derivatives Of

Crosslinked high molecular weight derivatives of fibrin (fibrinoligomers) were observed during intravascular coagulation. It was the purpose of this study to investigate the complex formation of fibrin oligomers with fibrinogen and fibrinmonomer. Fibrinogen coupled to agarose (Fg-ag) as well as fi-brinmonomer coupled to agarose (Fm-ag) was used as substrate. Soluble oligomers of fibrin were produced by incubating fibrinogen with thrombin, calcium-chloride, cystein and F XIII. They were separated from fibrinogen by gel filtration. Γ-dimers were demonstrated in fractions from the void volume and the shoulder prior to the fibrinogen peak. These fractions were subjected to affinity chromatography. Crosslinked oligomers of fibrin were not adsorbed on Fg-ag, yet adsorption occured on Fm-ag. This indicates that fibrin oligomers have no affinity to fibrinogen, yet readily form complexes with fibrin. This could mean that in vivo they compete with fibrinogen for the fibrinmonomer part of soluble fibrin monomer complexes, and hence have a tendency to increase in size.

Catabolism of streptokinase and polyethylene glycol-streptokinase: evidence for transport of intact forms through the biliary system in the mouse

Blood ◽  
1990 ◽  
Vol 76 (1) ◽  
pp. 73-79 ◽  
Author(s):  
FH Brucato ◽  
SV Pizzo
Keyword(s):  
Molecular Weight ◽  
Polyethylene Glycol ◽  
Gel Electrophoresis ◽  
Proteinase Inhibitors ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gi Tract ◽  
Substantial Fraction ◽  
Sds Page ◽  
Derivatives Of

Abstract The catabolism of streptokinase (SK) and polyethylene glycol derivatives of SK (PEG-SK) were studied in mice. The clearance and catabolism of SK:plasmin (SK:Pm) and PEG-SK:Pm activator complexes were also investigated. Native 125I-SK cleared rapidly (t1/2 = 15 minutes) from the circulation, with the majority of the ligand accumulating in the liver and gastrointestinal (GI) tract and a substantial fraction also localizing in the kidneys. SK, which was removed from the plasma by the liver, was secreted into bile and then the GI tract. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that 125I-SK recovered from liver and bile was homogeneous and of the same molecular weight (mol wt approximately 50,200) as native SK. PEG-125I-SK cleared slowly (t1/2 greater than 200 minutes), with more than 80% of the preparation localizing in liver and GI tract. The PEG-125I-SK secreted into the bile was also intact. The bile containing 125I-SK was incubated with stoichiometric amounts of plasminogen and electrophoresed under nondenaturing conditions. This study demonstrated that the secreted SK was able to form SK:Pg complexes. SDS-PAGE also showed activation of 125I-Pg that was incubated with recovered bile containing the SK. 125I-SK:Pm catabolism was also studied. In these experiments, the mol wt approximately 42,000 fragment obtained when SK is cleaved by plasmin was found in the bile. This fragment of 125I-SK was not recovered as part of a complex with plasmin, consistent with our previous observations that catabolism of SK:Pm involves transfer of the plasmin to plasma proteinase inhibitors while SK is catabolized independently. By contrast, when PEG-125I-SK:Pm was injected into mice, only intact PEG-125I-SK was found in the bile, consistent with our previous observations that the PEG derivatization blocks its degradation by plasmin.

Preparation and Spectroscopic Characterisation of a Series of Heterobimetallic N-phenyldiethanolaminate-alkoxide Derivatives of Oxovanadium(V)

2005 ◽  
Vol 2005 (6) ◽  
pp. 352-355 ◽  
Author(s):  
Rajendra Singh Ghadwal ◽  
Ram C. Mehrotra ◽  
Anirudh Singh
Keyword(s):  
Molecular Weight ◽  
Spectral Studies ◽  
Metal Alkoxides ◽  
Nmr Studies ◽  
Mass Spectral ◽  
Elemental Analyses ◽  
Derivatives Of ◽  
Spectroscopic Characterisation

Reaction of VO(OPri)3 with two equivalents of N-phenyldiethanolamine (PhDEAH2) yields a homometallic complex [VO(PhDEA)(PhDEAH)] 1, which reacts with a number of metal alkoxides to afford heterobimetallic oxovanadium(V) complexes of the types [VO(PhDEA)2{M(OR)n-1}] [where PhDEA = C6H5N(CH2CH2O–)2], [M =: Al (n = 3, R = Pri) 2; Al (n = 3, R = But) 3; Ti (n = 4, R = Pri) 4; Zr (n = 4, R = Pri) 5; Nb (n = 5, R = Pri) 6; Ta (n = 5, R = Pri) 7. The derivative [VO(PhDEA)(OSiPh3)] 8 has been prepared by the equimolar interaction of [VO(PhDEA)(OPri)] with Ph3SiOH. All of these complexes have been characterised by spectroscopic (IR; 1H, 13C, 27Al and 51V NMR) studies, elemental analyses, and molecular weight measurements. The derivative 2 has also been characterised by FAB mass spectral studies, which supports for its monomeric nature.

Isoprene and Rubber. Part 29. High Molecular Hydrorubbers

1932 ◽  
Vol 5 (2) ◽  
pp. 136-140
Author(s):  
H. Staudinger ◽  
W. Feisst
Keyword(s):  
Molecular Weight ◽  
Catalytic Reduction ◽  
Molecular Form ◽  
Average Molecular Weight ◽  
Molecular Size ◽  
Decomposition Products ◽  
Molecular Weights ◽  
Rubber Part ◽  
Derivatives Of ◽  
Suitable Process

Abstract The molecular concept in organic chemistry is based upon the fact that the molecules, whose existence is proved by vapor density determinations, enter into chemical reactions as the smallest particles. If now it is assumed that organic molecular colloids like rubber are dissolved in dilute solution in molecular form then it must be proved that in the chemical transposition of macromolecules as well no change in the size of the macromolecules occurs. In the case of hemicolloids, therefore for molecular colloids with an average molecular weight of 1000 to 10,000, this has been proved by the reduction of polyindenes, especially of polysterenes, to hydroproducts with the same average molecular weight, and also by the fact that cyclorubbers do not change their molecular weight upon autoöxidation. The molecular weights of hemi-colloidal hydrocarbons are therefore invariable. This is much more difficult to prove in the case of rubber, although there are many more ways in which unsaturated rubber can be transposed than the stable polysterenes, polyindenes, and poly cyclorubbers. In most of the reactions with rubber, as in its action with nitrosobenzene, oxidizing agents, hydrogen halides, and halogens, an extensive decomposition takes place as a result of the instability of the molecule, which is referred to in another work. Therefore derivatives of rubber are not formed, but derivatives of hemi-colloidal decomposition products. The catalytic reduction of rubber in the cold appears to be the most suitable process of making it react without changing its molecular size in order to prove that in a chemical transposition its molecular weight remains the same.

Chemical Reactions of Rubber

1943 ◽  
Vol 16 (1) ◽  
pp. 111-123
Author(s):  
R. L. Sibley
Keyword(s):  
Molecular Weight ◽  
Atmospheric Pressure ◽  
Rapid Heating ◽  
Slow Heating ◽  
Gutta Percha ◽  
Volatile Products ◽  
Almost All ◽  
Isomeric Product ◽  
Derivatives Of ◽  
Complete Investigation

Abstract Most of the literature descriptive of the various known derivatives of rubber is found published as patents rather than as technical papers, thus indicating the commercial possibilities that may be expected from these developments. Fisher, Schidrowitz and, more recently, Jones have summarized and discussed the chemistry of rubber and its commercial derivatives. The decomposition of rubber by heat has been studied by several investigators. Williams showed that isoprene is one of the main products formed by the destructive distillation of either caoutchouc or gutta percha. Later investigators have shown that slow heating in vacuo at 300° C converts somewhat more than one-half of rubber hydrocarbon into a solid, thermoplastic, isomeric product, which has a high molecular weight and less unsaturation than that of the original hydrocarbon. Rapid heating, especially in vacuo, converts almost all the rubber into volatile products. The most complete investigation of the products obtained by the heat decomposition of rubber apparently was carried out by Midgley and Henne. These investigators destructively distilled 200 pounds of pale crepe rubber in 16-pound batches by raising the temperature as rapidly as possible to 700° C at atmospheric pressure in an iron kettle. The condensate was fractionally distilled, and cuts were made every degree between 50 to 176° C. Each cut was then separately examined. Twenty-three different hydrocarbons were identified in the distillate.

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