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

Abstract

Both PhP(2-NCC 6H 4) 2 and P(2-NCC 6H 4) 3 have been synthesized from the carbanions generated from 2-bromobenzonitrile and dimethyl phenylphosphonite or triphenyl phosphite. The A 1 υ(CO) bands for the Ni(CO) 3L complexes of these two ligands along with that from the previously reported Ph 2P(2-NCC 6H 4) have been recorded in dichloromethane solutions. The values (2073.0, 2076.4 and 2079.7 cm −1; decreasing number of Ph rings) reflect the electron-withdrawing nature of the ortho-positioned cyano groups. 31P chemical shifts of the L 2PdCl 2 complexes of these three ligands have been recorded, and all provide shifts of δ=24.1±1, approximately that for (PPh 3) 2PdCl 2, δ=23.9. The molecular structure of P(2-NCC 6H 4) 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 phosphorus lone pair. The average distances from phosphorus to cyano carbon and nitrogen atoms were found to be 3.03 and 3.23 Å, respectively.