The stereochemistry of organometallic compounds. XIV. trans-Effects in the 13C n.m.r. spectra of dicarbonyltriphenyl-phosphine- and -arsine-(arene)chromium compounds.

The 13C chemical shifts of some triphenyl-phosphine and -arsine dicarbonyl(arene)chromiums are reported. The shifts are discussed in terms of a deshielding effect on the arene ring carbons trans to the Group 5 atom in the preferred conformations of these molecules.