The Synthesis and Structural Characterization of Mesitydiphenylphosphine, Dimesitylphenylphosphine and Trimesityphosphine

Abstract

The synthesis and structural characterization of the tertiary phosphines mesityldiphenylphosphine [PPh2( mes )], dimesitylphenylphosphine [ PPh ( mes )2] and a new phase of trimesitylphosphine [P( mes )3] have been carried out. Crystals of PPh2( mes ) are monoclinic, space group P21/c, with a 10.252(10), b 9.847(11), c 17.444(7) ?, ߠ99.78(6)ଠZ 4; R 0.059 for 2102 'observed' reflections. Crystals of PPh ( mes )2 are also monoclinic, space group P 21/c, with a 8.964(9), b 22.99(1), c 10.228(4) ?, ߠ107.98(5)ଠZ 4; R 0.058 for 2350 'observed' reflections. The new phase of P( mes )3 is monoclinic, Cc, a 11.390(5), b 12.034(4), c 17.564(9) ?, ߠ104.22(4)ଠZ 4 (R 0.060 for 1046 'observed' reflections), in which the molecule is disordered. A full report is given for the phase previously studied (triclinic), Pi , a 8.191(3), b 16.447(5), c 18.667(6) ?, a 104.82(3), ߠ97.74(3), ? 100.07(3)ଠZ 4; R 0.065 for 4964 'observed' reflections. The P-C bond distances are similar for the whole series of compounds with an average value of 1.833(1)?. Introduction if the mesityl groups results in an increase of the C-P-C angles from c. 103 to c. 110࠷ith a concomitant flattening of the PC3 pyramid.