Structure of Phosphorus-Containing Peptide Ligands. X-ray and NMR Structural Study of Free Ligand and Rhodium Complex

The structure of a series of phosphorus-containing peptides was studied. The X-ray structure of a phosphorus-containing dodecapeptide is reported. Analysis of the solution structure of similar phosphorus-containing peptides before and after coordination of rhodium is also reported. In both the solid state and in solution, the peptides were found to exist in a mixture of α-helical and 3 10 helical conformations. Coordination of rhodium to the i, i + 4 orientated phosphine groups appears to alter the conformational preference.