Bridging polymers structure

The polymerization applied produces spherical polymer particles (1-10 pm diameter) connected by polymer bridges [3]. Thus, a one-piece polymer phase is obtained. The interstices between the particles have a characteristic length of a few micrometers. Overall, the polymer structure can be ascribed as lose. 

The diisocyanatoargenate(I) ion, Ag(NCO)j, was found to give a chemical shift value, 5(NCO), of —l-42p.p.m.13S Based on this and IR data136,137 it was proposed that N bonding was present as was found in the crystal structure of the N-bridged polymer AgNCO.138... 

The complex 613 is not structurally characterized, so it is not clear whether a metal-cycle exists in this compound. An analogous situation with Mn(OAc)2 leads to a polymer structure with chelate-bridge MnN2S2 fragments (x-ray diffraction data [61]). 

Although critical concentrations of a polysaccharide may enhance the emulsifying and stabilizing ability of a protein, small additions may have the opposite effect (Cao et al., 1990). The discovery of destabilization by 0.05% xanthan on caseinate led Dickinson and Euston (1991a) to remark that small changes in polymer structure or solvent conditions can easily tip the balance in favor of depletion or bridging flocculation. 

If instead of a mild Lewis base such as THF a strong Lewis base such as pyridine is used in the reaction between copper acetate and dtbp-H, one obtains yet another type of one-dimensional polymeric phosphate (Chart 16).36c Recrystallization of this water-bridged polymer in a DMSO/ THF/CH3OH mixture results in the transformation of the polymer to a more stable tetranuclear copper cluster [Cu4-(u3-OH)2(dtbp)e(py)2] in about 60% yield (Figure 3). This observation demonstrates that even simple recrystallization can bring about an interesting structural transformation at room temperature in such materials. 

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