Structural studies of PdCl2L2 complexes with fluorinated phosphines, phosphites, and phosphinites as precursors of benzyl bromide carbonylation catalysts, and and X-ray crystal structure of cis-PdCl2[PPh2(OEt)](2)

PdCl2L2-type complexes with phosphines (L = PPhx(C6F5)(3-x) (x = 0-3)), pho sphites (L = P(OMe)(3), P(OPh)(3), P(OEt)(3)), and phosphinites (L = PPh2(O C6F5), PPh2(O-3,5-F2C6H3), PPh2(OEt), PPh2(O-n-Bu), PPh2(O-t-Bu)) were synt hesized and characterized by UV-vis and P-31 NMR methods. PdCl2L2 complexes with less sterically demanding phosphines (Theta < 140<degrees>) exist as cis isomers, which is confirmed by the X-ray structure of cis-PdCl2[PPh2(OE t)](2). These complexes react with CO in the presence of NEt3 forming Pd(CO )(x)L-y (x + y = 4) type carbonyls characterized by IR spectra. All PdCl2L2 complexes studied are active as precursors of benzyl bromide carbonylation catalysts at 40 degreesC and 1 atm CO; however, the activity of the cis is omers is higher than that of the trans isomers. The highest yields of the c arbonylation product, phenylacetic acid methyl ester, were obtained using c is-PdCl2[P(OMe)(3)](2) (92%), cis-PdCl2[P(OPh)(3)](2) (89%), and cis-PdCl2[ PPh2(O-n-Bu)](2) (78%) as catalyst precursors.