Novel structures

Hollow carbon nanostructures are exciting new systems for research and for the design of potential nano-electronic devices. Their atomic structures are closely related to their outer shapes and are described by hex-agonal/pentagonal network configttrations. The surfaces of such structures are atomically smooth and perfect. The most prominent of these objects are ftil-lerenes and nanotubesjl]. Other such novel structures are carbon onions[2] and nanocones[3]. 

With the discovery of the crowns and related species, it was inevitable that a search would begin for simpler and simpler relatives which might be useful in similar applications. Perhaps these compounds would be easier and more economical to prepare and ultimately, of course, better in one respect or another than the molecules which inspired the research. In particular, the collateral developments of crown ether chemistry and phase transfer catalysis fostered an interest in utilizing the readily available polyethylene glycol mono- or dimethyl ethers as catalysts for such reactions. Although there is considerable literature in this area, much of it relates to the use of simple polyethylene glycols in phase transfer processes. Since our main concern in this monograph is with novel structures, we will discuss these simple examples further only briefly, below. 

Novel structure and bondmg such as Xe(CF3)2, with the first repotted Xe-C bond Although this compound is unstable, its stmcture is supported by ample NMR evidence [119]... 

Beginning in the 1980s, research directed toward the isolation of new drugs derived from natural sources identified a family of tumor-inhibitory antibiotic substances characterized by novel structures containing a C=C—C=C—C=C unit as part of a nine- orten-membered ring. With one double bond and two triple bonds (-ene + di- + -yne), these compounds soon became known as enediyne antibiotics. The simplest member of the class is dynemicin A most of the other enediynes have even more complicated structures. 

Some of the more imaginative analog programs were sometimes rewarded by the finding of novel structures with unanticipated biologic activities. 

At r = 0.5 (Fig. 9b), the most interesting and novel morphology can be observed. This morphology can be described as follows. The P4VP cores of the microspheres form a regular structure, and a P4VP bilayer surrounds each microsphere with a honeycomb-like structure, similar to a cell wall, as the number of the microsphere surrounded by the P4VP wall ( T) was 1.08. Similar structures have been observed for ABC triblock copolymers [39]. Our honeycomb-like novel structure, however, is different from that of the ABC triblock co-... 

Our ultimate objective is to produce automatically with laboratory-scale reactors polymers with pre-defined molecular characteristics in reasonable amounts for test purposes. Whatever control is exercised over the chemistry of a polymerization to introduce novel structural features into polymer chains, the final molecular weight distribution (MWD) of the product is always of importance hence attention has been given to... 

Many peptide antibiotics have novel structural motifs, such as cyclic structures and are often further modified, (such as in jS-lactamic antibiotics) and conjugated with sugars, lipids, and other molecules. 

A variety of complexes with numerous novel structural features have also been unearthed in the study of phosphorus ligands with group 13 halides which will not be described in this review [38, 39]. 

Xavier AV, Moura JJG, Moura I (1981) Novel Structures in Iron-Sulfur Proteins. 43 187-213 Xavier AV, see Pereira lAC (1998) 91 65-90... 

A promising novel structure for highly exothermic reactions is shown in Figure 9.8. The void fraction of this structure exceeds 90% and the geometric... 

Lee, PC. et al., Directed evolution of Esherichia coli famesyl diphosphate synthase (IspA) reveals novel structural determinants of chain length specihcity, Metab. Eng. 7, 18, 2005. 

Koenig K, JR Andreesen (1990) Xanthine dehydrogenase and 2-furoyl-coenzyme A dehydrogenase from Pseudomonasputida Ful two molybdenum-containing dehydrogenases of novel structural composition. J Bacterial 172 5999-6009. 

Size Controlled Pd Nanoparticles Anchored to Carbon Fiber Fabrics Novel Structured Catalyst Effective for Selective Hydrogenation... 

Xavier, A. V., Moura, J. J. G., Mowa, I. Novel Structures in Iron-Sulfur Proteins. Vol. 43,... 

L-type calcium channels (voltage-gated calcium channels L-subtype) Similarity to Diltiazem and a second ligand. ZINC db ( 50 K commercially available subset screened but most filtered to achieve desired PK profile using VolSurf). SHOP similarity, and feature-presence filtering down to 36 compounds 7 hits 18 tested, active in a vasorelaxant assay and some had novel structures. [67]... 

---