Poly structural diversities

Stmcturally novel pyrazole derivatives include the propellene 2,3,4,5,6-pentakis(pyrazol-r-yl)pyridine 1 and the corresponding 3 ,5 -dimethylpyrazole derivative 2<96T11075>. Poly(pyrazol-l-ylmethyl)benzenes, such as 3, have been prepared as multidentate ligands <95AJC1587>. Solid phase synthesis of structurally diverse 1-phenylpyrazolones was reported, with application to combinatorial synthesis <96SL667>. 

In summary, our synthetic studies led to the development of interfacial and solution polymerization procedures for the preparation of poly(iminocarbonates) of high molecular weight. These procedures have so far been employed for the synthesis of a small number of structurally diverse poly(iminocarbonates). 

For synthesis of one lead polymer, poly(5-amino-1 -pcntanol-co-1,4-butancdiol diacrylate) (referred to as C32), 5-amino-l-pentanol (Aldrich) and 1,4-butanediol diacrylate (Scientific Polymer Products, Inc.) are required. Additional amine and diacrylate monomers can be purchased and used following the same protocol to create structurally diverse polymers that are useful for gene delivery. These monomers can be purchased from Aldrich (Milwaukee, WI, USA), Scientific Polymer Products, Inc. (Ontario, NY, USA), TCI (Portland, OR, USA), Pfaltz Bauer (Waterbury, CT, USA), Matrix Scientific (Columbia, SC, USA), and Dajac Monomer-Polymer (Feasterville, PA, USA). 

Given the structural diversity of the ligands that can be attached to polyethylene oligomers, it is not surprising that there is a similar diversity in the sorts of catalysts that have been supported on these materials. Selected examples of catalysts prepared using polyethylene ligands are shown in structures 14-26 in Fig. 4 [32-34,38-40,45-49]. While most of these catalysts contain transition metals, non-transition metal catalysts like poly-ethyldibutyltin chloride 14 or phase-transfer onium catalysts like 24 have also been prepared. 

Poly(c -l,4-isoprene) belongs to the family of polyisoprenoids, which are the most structurally diverse and abundant natural products known, with more than 23,000 primary and secondary metabolites. This huge family comprises, for example, sterols which display not only structural functions (control of biological membrane fluidity) but also hormonal functions (steroid hormones). Key phyto-hormones, such as abscisic acid, gibberellins and cytokinins, are isoprenoids too. Moreover, isoprenoids are used in protein prenylation, which is a key step in the activation and the localization of metabolic enzymes in many organisms. The first common step of all isoprenoid biosynthesis pathways is the formation of isopentenyl diphosphate (IPP). ... 

This category of polymers is interesting because of the possible structural diversity for such materials and the mixed-Ugand nature of the excited state. As for the structures, both the diphosphines and diisocyanides can act as assembling ligands for the metal. The mixed-nature of the excited state in the poly-chromophore is easy to predict from EHMO calculations on the luminescent mixed-ligand di-copper and disilver models such as 34-37 [42,43], which can serve as useful polymer models for polymer (38) [44], In complex 34, the atomic contributions for the HOMO are mainly the P-lone pairs and Cu d-orbitals, whereas for the LUMO, these were the CO ... 

Berriaud, N., Milas, M., and Rinaudo M. (1998). Charaeterization and properties of hyaluronie aeid (hyaluronan). In Poly.saccharides Structural Diversity, and Functional Versatility. S. Dumitriu (Ed.). Marcel Decker Inc., New York, pp. 313-334. 

Sato C, Kitajima K, Tazawa I, Inoue Y, Inoue S, Troy FA II (1993) Structural diversity in the o2-8-linked polysialic acid chains in sahnonid fish egg glycoproteins. Occurrence of poly (Neu5 Ac), poly(Neu5Gc), poly(Neu5Ac, Neu5Gc), poly(KDN), and their partially acetylated fimns. J Biol Chem 268 23675—23684... 

Lu, Y., Sun, B., Li, C.H., Schoenfisch, M.H. Structurally diverse nitric oxide-releasing poly(propylene imine) dendrimers. Chem. Mater. 23(18), 4227-4233 (2011)... 

Importantly, for elevated temperature PEM fuel cell operation, the HPAs may be structurally stable to >600°C, although under anhydrous conditions their stability may be limited to 200°C, and they incorporate some water molecules and protons up to >300°C depending on the system [15]. Because of their structural diversity, these materials are particularly suitable for incorporation into a wide variety of membrane materials for which they can be specifically tailored. They have been studied in four composite systems HPAs infused into perfluorinated sulfonic acid (PFSA) polymers such as Nafion [16,17], HPA cast in inert matrices such as poly (vinyl alcohol) (PVA) [18], HPA immobilized in polymer/silicate nanocomposites via sol-gel methods [19], and HPA directly incorporated into polymer films via functionalization to monomers [20]. Here after a discussion of fundamental studies, we review the various HPA-based materials used for fuel cells. 

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