ISSN:
0009-2940
Keywords:
Trisphosphanes
;
Phosphane - boranes
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The structure of tris(diphenylphosphino)methane, HC(PPh2)3 (1), has been determined by X-ray diffraction. The molecules have approximate C3 symmetry with the lone pairs at the three phosphorus atoms in an “all-trans” orientation. Variable-temperature NMR experiments (+ 35 to - 90°C in CH2Cl2) show free intramolecular motion in solution. The partially or fully borylated adducts HC(PPh2)2[PPh2(BH3)] (2), HC(PPh2)[PPh2;-(BH3)]2 (3), and HC[PPh2(BH3)]3 (4) have been prepared from 1 and THF · BH3 or Me2S · BH3. For 2 and 3 the internal rotation about the phosphorus-methine carbon bonds is also essentially unhindered, but has been shown to be restricted in 4 (Ea=31.2 kJ/mol). The chemical shifts of the methine protons in these compounds can be calculated on the basis of a BH3 substituent constant.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19911240517
