PHOSPHINES FUNCTIONALIZED WITH CROWN-ETHER GROUPS - SYNTHESIS AND STUDY OF SYSTEMS INCORPORATING 1,3-XYLYL-18-CROWN-5 UNITS

Hybrid phosphine crown ether molecules are obtained from Ph2PCl, PhP(O Me)(2), or P(OPh)(3) and the carbanions generated by a lithium/bormine exchange reaction between n-butyllithium and 5-bromo-1,3-xylyl-18-cro wn-5 or 5-bromo-2-methoxy-1,3-xylyl-18-crown-5. With these phosphine s ystems represented as PhxP(crown)(3-x), the x = 0-2 and 1-2 members ar e reported for the former and latter crown ethers, respectively. The A (1) v(CO) stretching frequencies from the Ni(CO)(3)L (L = PhxP(crown)( 3-x)) complexes are within 0.4 cm(-1) of 2068.9 cm(-1), the frequency for Ni(CO)(3)PPh3. For both series of ligands, H or OMe in the 2-posit ion, the v(CO) stretching frequencies are found to decrease with incre asing substitution by the crown ether groups (deceasing x). The additi on of Na+-Cs+ (SCN- salts) to the Ni complexes causes the Al bands to shift to higher frequencies and to broaden. The largest shifts are obs erved with phosphines substituted with larger numbers of crown ether g roups and added Na+ ions. (PNMR)-P-31 spectral data for the L2PdCl2 co mplexes of these phosphines are reported. For all ligands, the signals from the trans complexes are observed between 22 and 25 ppm, a range considered consistent with cone angles of ca. 145 degrees. The molecul ar structure, from X-ray crystallographic studies, of the oxide of the phosphine with x = 2 and H in the The crown ether ring is based on re gular gauche and anti arrangements of the carbon-carbon and carbon-oxy gen bonds, and the planes defined by the benzene ring and the five oxy gen atoms form an angle of 38.4 degrees.