
TY  - JOUR
A1  - Colton, R 
A1  - Whyte, T 
T1  - Multinuclear (<sup>13</sup>C, <sup>31</sup>P, <sup>77</sup>Se) Magnetic Resonance Studies on Organophosphorus Selenides and Sulfides. II. Tri- and Tetra-Tertiary Phosphines
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1991
VL  - 44
IS  - 4
SP  - 525
EP  - 535
KW  - 
UR  - https://doi.org/10.1071/CH9910525 
N2  - Selenium and sulfur have been reacted in various stoichiometries with two tritertiary  phosphines Ph2P(CH2)2P(Ph)(CH2)2PPh2(P2P&#8242;) and MeC (CH2PPh2)3 (P3), and two tetratertiary phosphines Ph2P(CH2)2P(Ph)(CH2)2P(Ph)(CH2)2PPh2 (P2P&#8242;2) and P({CH2}2PPh2)3 (P3P&#8242;). The products have been fully characterized in solution by multinuclear (13C, 31P, 77Se) magnetic resonance spectroscopic studies. Reaction of P2P&#8242; with one mole of selenium gives almost exclusively the product with the central phosphorus selenated (P2P&#8242;Se&#8242;) and reaction with greater quantities leads to the identification of P2P&#8242;SeSe&#8242; and P2P&#8242;Se3 by their phosphorus-31 and selenium-77 n.m.r. spectra. The reactions between P2P&#8242;2 and various mole equivalents of selenium are similar to those of P2P&#8242;, leading to the identification of P2P&#8242;2Se&#8242;, P2P2.&#8242;Se&#8242;2, P2P&#8242;2SeSe&#8242;2 and P2P&#8242;2Se4 by both phosphorus-31 and selenium-77 n.m.r. spectroscopies although carbon-13 n.m.r. spectroscopy is required to unambiguously determine their structures. P3 reacts with three moles of selenium to give P3Se3. When P3 is reacted with less than 3 mole equiv. of selenium, phosphorus-31 and selenium-77 n.m.r. spectra cannot distinguish between pure selenides and mixtures of selenides. However, carbon-13 n.m.r. spectra show that reaction of P3 with less than 3 mole equiv. of selenium leads to almost tatistical distributions of P3, P3Se, P3Se2 and P3Se3. The reactions between P3P&#8242; and selenium give a combination of the above behaviours. The central phosphorus is selenated first, but subsequent additions of selenium lead to a distribution of selenium among the terminal phosphorus atoms to give mixtures of P3P&#8242;SeSe&#8242;, P3P&#8242;Se2Se&#8242; and P3P&#8242;Se3Se&#8242; which cannot be distinguished by phosphorus-31 n.m.r. spectroscopy, but can be by selenium-77 n.m.r. spectroscopy. Reaction of P2P&#8242; (and P2P&#8242;2) with sulfur in any proportion is quite different to that with selenium, and gives only P2P&#8242;S3 (and unreacted P2P&#8242;). The reactions between P3 or P3P&#8242; and sulfur are similar to those between these compounds and selenium. Reactions between selenium or sulfur and a series of ditertiary  phosphines have been investigated in an attempt to clarify the different reactions of the elements with P2P&#8242; and P2P&#8242;2. 
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