Higher oligomerization

Eor production use, once an accurate determination of monomeric, dimeric, and higher oligomeric dimer acids has been estabHshed for a specific process and feedstock s oligomerization, subsequent reaction extent can be estimated rapidly by a viscometric method (80). 

In addition to the dimer bands higher oligomeric complexes were obtained by cross-linking chromatin. 

Some flavonoids, such as dicoumerol, can also serve as herbivore deterrents for mammals. Higher oligomeric forms of proanthocyanidins are feeding deterrents, or else they impair digestion due to their ability to precipitate proteins. This has been reviewed previously. 

There is no commonly accepted trivial nomenclature for the bi- and triflavonoids and higher oligomeric forms. Their full systematic names, not to mention their often complex common names, are extremely cumbersome. Geiger and Quinn have proposed a system that requires frequent reference for understanding and has become increasingly difficult to implement as the number of new compounds has grown. No doubt, the nomenclature of this class of compounds is in disarray and it depends on active researchers in the field to select a simple but logical system and then to use it consistently. 

When the synthetic procedure to prepare Pt2(P20sH2)4- (equation 441) is carried out at higher temperature, a higher oligomeric complex with platinum(U) centers coupled by an oligomeric condensed phosphorous acid ligand is formed. Little information is known about the complex except that the intense absorption chromophore is now at 580 nm and the emission in the red at 650 nm.1501... 

C1-reduction products and certainly to higher oligomerized reduced products. Also, reduction of C02 in an aqueous medium is anticipated to be accompanied by the competitive reduction of water (H2 evolution), see Eq. (25). Thus, the intermediary redox species generated in an ET process could yield a mixture of products. Catalysts could play a central role in inducing selectivity and in controlling a desired specific route that utilizes the ET products. Thus, one can define three complementary functions of catalysts in artificial photosynthetic devices ... 

A 16 membered ring carbodiimide is obtained in the reaction of Me2SiCl2 with cyanamide." In addition to the tetramer, oligomers with n = 2 to 7 are detected. Also, higher oligomeric carbodiimides are formed in the reaction of alkyl- and dialkyl silicon chlorides with cyanamide in the presence of pyridine." Also, from bis(trimethylsilyl)carbodiimide and silicon tetrachloride in the presence of pyridine, the silicon polycarbodiimide 34 is obtained." ... 

The theoretical studies confirm intermediacy of tantalacy-cloheptane in the trimerization process. The conversion of tantalacycloheptane to the Ta-(l-hexene) complex follows. The dimerization is disfavored by the nonexistence of such concerted reductive elimination process for the tantalacy-clopentane. The bimolecular process of tetramerization and possible higher oligomerization cannot compete with the facile reductive elimination (see Reductive Elimination) ... 

X-Ray Structures of Organolithium Compounds D. Higher Oligomeric Organolithium Compounds... 

It is well known that D3 cyclic has a Si NMR signal at — 9 ppm, (5) and that higher oligomeric cyclic compounds (D4 to DJ and linear dimethylsiloxy units appear between —19 and —22 ppm. When samples of T2D3 and T2D4 were examined by the Jancke group their results unequivocally identified structures [25] and [27] (chemical shifts in Table XIII). 

Owing to the enormous range of what can now be described as supramolecular chemistry, the present work will chiefly focus on discrete molecular assemblies. In particular, no attempt has been made to discuss the burgeoning field d of crystal engineering . Similarly, unless of particular relevance to the topic under discussion, higher oligomeric and polymeric systems, including most metal cluster and related compounds, have also been excluded from the discussion. 

Large variations in E° (Cclv/Ceni) are observed in different acids ranging from + 1.87 V (8M HC104) to +1.42V (6MH2S04) (vs. nhe). The first pAa has been determined as 1.1 (I = 3.0M C104 ) and 50% is therefore hydrolyzed in 1.0 MH+. The formation of dimeric and higher oligomeric forms has been proposed. The PrIV and TbIV oxidation states have also been obtained under alkaline conditions. 

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