Conditioning, xiii, xviii

Scheme 55. Reaction conditions i, MeS03p ii, LDA-THF iii, EtSLi-DMF iv, CF3CO3H-CF3CO2H V, Li-ethylenediamine vi, CrOs vii, Ph3l CH2 viii, p-TsOH, xylene, reflux ix, H2-Pd/C X, BH3-M62S xi, HjOz-NaOH xii, CrOa xiii, MeOCH(NMe2)2 xiv, BuSH-p-TsOH xv, LiAlH4 xvi, H3O + xvii, Li-NFl3 xviii, MsCl-Et3N xix, LiBHEts xx, m-CPBA.

Compounds XV and XVI are unstable in solution and tend to lose H2 to form 11-vertex c/oso-clusters. Indeed and the latter species are often formed during attempts to isolate XV and XVI. However the situation is more complex. When a dilute solution of XV is heated at reflux temperature, in CH2C1j for one day, the resultant solution contains a mixture of the parent rhodathiaborane, XII, and free phosphine, dppe, as major components, together with a new species, XVII, as minor component. Under the same conditions, compound XVI affords a mixture of only the parent XIQ and free phosphine, dppp. By contrast, when a concentrated solution of XV in CDC1, is heated at 40° degrees in an NMR tube, the new species XVII is obtained almost quantitatively. Under the same conditions, XVI, gives a mixture of XIII and free dppp, this time as minor products, and two new compounds, XVIII and XIX. 

Polymer Properties. Preliminary studies are being carried out with the various cross-linked polymers using 13C NMR spectroscopy to determine the changes in structure that occur with different pH changes and with different metal ions present. Of particular interest have been samples of cross-linked resins XIII and XIV that have been hydrolyzed to the amino acid polypyrrolidines XVII and XVIII, respectively. In these cases there are extensive changes in the 13C NMR spectra of the water-swollen polymers depending on whether the conditions are acidic, basic, or neutral (Figure 5). 

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