Chemistry of Decaborane-Phosphorus Compounds. III. Decaborane-14-Phosphine Polymers

Synthesis and characterization of a series of alternating copolymers (oligomers) containing organo-.lambda.5-phosphazene backbone moieties

“…Solid-state CP/MAS 31P NMR spectroscopy showed the P=N phosphorus at approximately +5 to -3 (relative to external NH4H2P04) similar to where it appears in monomeric X5-phosphazenes.3,4 In all cases there was an additional small absorption at 24-31, which is where the corresponding oxides would appear,21 and this functionality would of necessity be an end group. The chemical shift of polymer 12 at -2.7 is about 7 ppm upfield from the chemical shifts of the polymethylene polymers [13][14][15][16] and is most likely an electronic effect of the p-phenylene ring between the phosphorus atoms in 12.3,4,21 The same trend is observed in the oxide end groups where the 31P shift of the P=0 group in 12 appears about 6 or 7 ppm upfield of the other systems 13-16. This is the same trend that is observed in the dioxides, 17, where the compound with o 0…”

“…Reaction of 1,4-diazidobenzene (6)12 with l,4-bis(diphenylphosphino)benzene (7), l,2-bis(diphenylphosphino)ethane ( 8), l,3-bis(diphenylphosphino)propane (9), l,4-bis(diphenylphosphino)butane (10), and 1,5-bis-(diphenylphosphino)pentane (11) in benzene gave the alternating copolymers [12][13][14][15][16] respectively (eq 3). These polymers were insoluble in common organic solvents such as tetrahydrofuran, diethyl ether, dimethyl sulfoxide, dimethylformamide, and dimethylacetamide, and so spectroscopic analysis was done on solid samples.…”

“…Weights (Af") of [12][13][14][15][16] polymer Tg,a °C mol wt6 polymer Tg,a °C mol wt6 than one solid-state NMR band because of "solid state effects"; that is, the atoms may appear in crystallographically nonequivalent sites or may show residual dipolar coupling of the spin 3/2 nucleus to an adjacent quadrupolar nucleus such as 14N. 22 CP/MAS 13C NMR spectra of 12-16 showed the aryl carbon atoms in the range of 121-143 (Table I).…”

“…As expected, the polymer with the two p-phenylene units in the backbone, 12, is the most thermally stable. Further, thermal stability appears to increase with increasing chain length in polymers 13-16. In order to obtain glass transition temperatures (Tg) for these polymers (12)(13)(14)(15)(16) duplicate samples were heated in an oven at 280 °C (320 °C for 12) and allowed to equilibrate. One of the duplicate samples of each was cooled autogenously to room temperature (method A) while the other was rapidly cooled in liquid nitrogen (method B).…”

The State of the Art in Boron Polymer Chemistry

“…27,000) by the triethylamine-catalyzed condensation reaction between bis(chlorodiphenylphosphine)decaborane and bis(hydroxydiphenylphosphine)decaborane. 10 The selection of boron as the primary element was based both on bond-strength considerations (after Burg's results) and its ability to form appropriate cluster compounds. Simultaneously, they synthesized a PᎏN ᎏ ᎏ P (phosphonitrile) bonded decaborane polymer by the reaction of two difunctional monomers, a diphosphine and a diazide compound derived from diborane.…”