Cellulose-diaminopropane complexes unit cells

Unit cells of pure cellulose fall into five different classes, I—IV and x. This organization, with recent subclasses, is used here, but Cellulose x is not discussed because there has been no recent work on it. Crystalline complexes with alkaU (50), water (51), or amines (ethylenediamine, diaminopropane, and hydrazine) (52), and crystalline cellulose derivatives also exist. Those stmctures provide models for the interactions of various agents with cellulose, as well as additional information on the cellulose backbone itself. Usually, as shown in Eigure la, there are two residues in the repeated distance. However, in one of the alkah complexes (53), the backbone takes a three-fold hehcal shape. Nitrocellulose [9004-70-0] heUces have 2.5 residues per turn, with the repeat observed after two turns (54). 

The unit cells determined in this and other laboratories for cellulose I and II complexes with ehtylenediamine and hydrazine are listed in tables 1 and 2. Table 3 shows our unit cells for the 1,2- and 1,3- diaminopropane complexes for which there have been no previous proposals. 

The ramie cellulose I-l,3-diaminopropane complex structure is the most crystalline of the diaminopropane complexes so far examined, and has a (metrically) orthorhombic unit cell that can contain only one chain which dictates a parallel chain structure. Elemental analysis and density measurements point to one molecule of 1,3-diamlnopropane per glucose residue. Refinement proceeded in a manner similar to that described above for the ethylenedlamlne complex, based on Intensity data for 24 observed and 12 unobserved reflections. 

The one-chain unit cell prescribes an unstaggered array of parallel chains and thus the rearrangement from the original cellulose I structure that has occurred is very similar to that which occurs on formation of the ethylenediamine complex. A one chain unit cell is also seen for the 1,2-diaminopropane complex, and this structure appears to be similar, except for minor modifications of the a and b dimensions. 

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See also in sourсe #XX -- [ ]

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