Vol 489, No 2 (2019)

N-Heterocyclic phospholes based on N,N '-disubstituted 9,10-phenanthrenediimines have been synthesized for the first time. Dimeric 1,3,2-diazaphospholes have been obtained by the reduction of 2-bromodiazaphospholes. In the case of the most sterically hindered phenanthrenediimine, diphosphole can dissociate into phosphorus-centered radicals at extremely low temperatures (220 K) for this class of compounds, which makes it possible to synthesize new organophosphorus and coordination compounds under mild conditions.

Oligomers of cholesterol vinyl ether with methyl vinyl sulfide were synthesized in up to 81% yield (M_n up to 5700) by cationic copolymerization of the indicated monomers in the presence of BF₃ ‧ OEt₂. The oligomers demonstrate optical activity exceeding that of cholesterol vinyl ether homopolymer.

The monazite–SiO₂–NaF–Nb₂O₅–Fe₂O₃ system in the isotherm at 1200°C is characterized by a wide region of two immiscible melts: a silicate melt and a phosphate–fluoride (salt) melt. The system is reciprocal; in the salt melt, new rare-earth metal (REM) phases form: binary phosphates and fluoride phosphates of REM and Na, which contain neither Fe, nor Nb. Iron has a strong effect on the immiscibility of the melts: in the absence of iron, the segregation region occupies 50% of the area of the diagram; at 5% Fe₂O₃, 57%; and at 10% Fe₂O₃, 70%. REM, P, and Nb oxides are contrastingly distributed between the immiscible melts. Most (95%) of REM and P are concentrated in the phosphate–salt melt, and Nb is concentrated in the iron–silicate melt. If the silicate melt contains no Fe₂O₃, then the Nb₂O₅ content is 4.91%; and at a Fe₂O₃ content of 15.33%, the Nb₂O₅ content is 6.89%, i.e. is 40% higher.