Structure, Conformation and Reactivity of Organotransition Metal π-Complexes. part 21. X-Ray Crystallographic Characterization of Two Neutral Half-Sandwich Cr(CO)3 Complexes

Abstract The preferred solid state conformations adopted by two (η6-ligand)Cr(CO)3 (η6-ligand: mesitylene, 1; N- phenyl-2,5-dimethylpyrrole, 2) complexes have been determined via single crystal X-ray crystallographic methods. Iadopts a conformation such that the C 6 ring carbon atoms are eclipsed with respect to the carbonyl ligands. Such a conformation is predictable from both steric and electronic considerations. 2, however, adopts a staggered conformation that must be attributed to the steric requirements of the bulky 2,5-dimethylpyrrole substituent.