Molecular hydrogen-bonding interactions

Many amino acids are condensed together in a sequential manner to form a protein or a polypeptide chain. It may be noted that proteins are not simply linear chains as written above. Such a linear representation showing the sequence of amino acid units is known as the primary structure of a protein. A protein possesses complieated secondary, tertiary and quaternary structures. The secondary and tertiary struetures involve intra- and inter molecular hydrogen bonding interactions. The quaternary structure includes ionic interactions as well. The overall result is that proteins have complex three-dimensional structures. 

RNA is found in a repertoire of intra- and inter-molecular hydrogen bonding interactions. One famiUar structural element in an RNA molecule is the stem-loop, in which a noncomplementary segment separates two complementary stretches of nucleotides. 

The basic requirement for cellulose dissolution is that the solvent is capable of interacting with the hydroxyl groups of the AGU, so as to eliminate, at least partially, the strong inter-molecular hydrogen-bonding between the polymer chains. There are two basic schemes for cellulose dissolution (i) Where it results from physical interactions between cellulose and the solvent (ii) where it is achieved via a chemical reaction, leading to covalent bond formation derivatizing solvents . Both routes are addressed in details below. 

In the transmission electron microscopy (TEM) images, the starch nanoplatelets (SNPs) are believed to aggregate as a result of hydrogen bond interactions due to the surface hydroxyl groups [13] (Fig. lA). Blocking these interactions by relatively large molecular weight molecules obviously improves the individualization of the nanoparticles. The acetylated starch and cellulose nanoparticles (SAcNPs and CelAcNPs) appeared more individualized and monodispersed than their unmodified counterparts with a size of about 50 nm (Fig. IB C). 

Braga D, Maini L, Polito M, Grepioni F (2004) Hydrogen Bonding Interactions Between Ions A Powerful Tool in Molecular Crystal Engineering 111 1-32 Brechin EK, see Aromf G (2006) 122 1-67... 

The hydrogen-bonding interactions within the complexes W2CI4-(y-OR)2(OR)2(ROH)2 and V Cli y-OR)2(ORT)2(Rf0H)2 may provide the molecular analogues with which to model the structure and reactivities of transition metal oxide catalysts that possess surface hydroxyl groups. The thermal treatment which is often carried out in the pretreatment of metal oxides (leading to the loss of -OH... 

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