Ph2P(CH2)nP(O)Ph2 Ligands


 Ph2P(CH2)nP(O)Ph2 ligands contains both a hard-base site (the oxygen) and a soft-base site (the phosphorus that is three coordinate). We are investigating the ability of these ligands to use both of these sites to form metal complexes.

The major product from reactions of Ln(NO3)3 (Ln = Ce or Tb) with Ph2P(O)CH2CH2PPh2 is (NO3)3Ln(OPPh2CH2CH2PPh2)3.  The phosphine portion of the ligand does not associate with the metal. This result is in contrast with several other phosphine and oxygen donor containing ligands that chelate lanthanide ions through both sites.

Pt and Pd form complexes in which the phosphine coordinates (The structure of a Pd complex with Ph2P(O)CH2PPh2 is shown below)  

 as does Ru2+:


The structure of Cl2Ru(P(Ph)2CH2P(O)PPh2)(PPh3)2 is shown below:



With [Al(OBus)3]2 an equilibrium is established


and the bond strength of the bridging Al-O bond is about 10 kJ/mol stronger than (P)O-Al. We could not detect any coordination of the PPh2 group to Al3+.



Last Modified: 03/19/2013

Chemistry Department
James Madison University
Harrisonburg, VA 22807