496974-67-5Relevant academic research and scientific papers
Synthesis, characterization, and properties of the polyphosphinoboranes [RPH-BH2]n (R = Ph, iBu, p-nBuC6H4, p-dodecylC6H4): Inorganic Polymers with a phosphorus-boron backbone
Dorn, Hendrik,Rodezno, Jose M.,Brunnhoefer, Bjoern,Rivard, Eric,Massey, Jason A.,Manners, Ian
, p. 291 - 297 (2003)
The polyphosphinoboranes [PhPH-BH2]n (1), [iBuPH-BH2]n (2), [(p-nBuCsH4)PH-BH2]nn (3), and [(p-dodecylC6H4)PH-BH2]n (4) were prepared from the corresponding phosphine-borane adducts RPH2·BH3 (R = Ph, iBu.p-nBuC6H4, p-dodecylC6H4) via a rhodium-catalyzed dehydrocoupling procedure at elevated temperatures (ca. 90-130°C). Samples of polymers 1 and 2 and the new materials 3 and 4 were characterized by multinuclear NMR spectroscopy, and the molecular weights were determined by light scattering methods in THF or CH2Cl2 solutions. The absolute weight-average molecular weight of 2 was determined by static light scattering and found to be Mw = 13 100, and values of Mw of ca. 20 000 were estimated for the sample of polymers 1 and the new material 3 using dynamic light scattering (DLS). The molecular weights of polymers 3 and 4 were also analyzed by gel permeation chromatography using polystyrene standards, and values up to Mw = ca. 80 000, Mn = ca. 10 000 were determined for 3 and Mw = ca. 168 000, Mn = ca. 12 000 for 4. The chemical stability of 1 in THF toward HNEt2 or nBu3P was demonstrated using NMR spectroscopy and DLS analysis, which indicated that no significant polymer degradation occurred. WAXS analysis of 1 and 3 showed that the polymers are amorphous. The glass transition temperatures (Tg) of polymers 2, 3, and 4 were analyzed by DSC and were detected at ca. 5, 8, and -1°C, respectively. TGA analysis on 1-3 revealed T5% values (temperature for which 5% or the weight is lost) of 240°C for 1 and ca. 150-160°C for 2 and 3. After heating to 1000°C, ceramic yields in the range of 35-80% were obtained. The high ceramic yield for 1 (75-80%) indicates that this material is of interest as a pyrolytic precursor to boron phosphide-based solid-state materials.
