Synthesis and study of phosphines incorporating 2-cyanophenyl groups and the X-ray structure of tris(2-cyanophenyl)phosphine

Both PhP(2-NCC6H4)(2) and P(2-NCC6H4)(3) have been synthesized from the car banions generated from 2-bromobenzonitrile and dimethyl phenylphosphonite o r triphenyl phosphite. The A(1) upsilon(CO) bands for the Ni(CO)(3)L comple xes of these two ligands along with that from the previously reported Ph2P( 2-NCC6H4) have been recorded in dichloromethane solutions. The values (2073 .0, 2076.4 and 2079.7 cm(-1); decreasing number of Ph rings) reflect the el ectron-withdrawing nature of the ortho-positioned cyano groups. P-31 chemic al shifts of the L2PdCl2 complexes of these three ligands have been recorde d, and all provide shifts of delta=24.1+/-1, approximately that for (PPh3)( 2)PdCl2, delta=23.9. The molecular structure of P(2-NCC6H4)(3), from X-ray crystallographic studies, is reported. A prominent feature of the structure is that the cyano groups are pointed in the general direction of the phosp horus lone pair. The average distances from phosphorus to cyano carbon and nitrogen atoms were found to be 3.03 and 3.23 Angstrom, respectively. (C) 1 999 Elsevier Science Ltd. All rights reserved.