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 a-helical and 3(10) helical conformations. Coordination of rhodium to the i, i + 4 orientated phosphine groups appears to alter the conformational preference.