Answer Happy

1. Phosphine ligands are used extensively in transition metal organometallic chemistry. They are sometimes described as spectator ligands as they usually do not participate directly in a reaction. However, their steric and electronic properties can be altered in an effort to control reactivity at the metal centre. a. Draw the following transition metal complexes that contain phosphorous ligands. Bonding to all ligands and phosphine substituents should be shown clearly for full marks, [1 mark each): i. Fein-cp)(PPh 3)2Me (cp = cyclopentadienyl) ii. [Pt(P'Buz)2(n-C3H6)Cl]* Co(PF3)3EtxH iv. Cr(PPha):(n-C3H5)Me Ni(CO):(PCIPh2) b. How can the steric and electronic properties of phosphines be quantified? Refer to analytical techniques used in each case. [4 marks) V.

C. Using the data provided in the table, predict the IR carbonyl stretching frequency of the following complexes: i. [Ni(CO)3(PCIPh)] ii. [Ni(CO)3(PMe Ph)] [Ni(CO)3(PMF)] Phosphine ligand Carbonyl stretching frequency of PR3 CO in [Ni(CO)=(PR:)] (cm) P'Buz 2056.1 РМез 2064.1 PPh3 2068.9 PC13 2097.0 PF3 2110.8 [3 marks] d. Consider the complex Ru(PF3)a(n?-H2). i. Draw a molecular orbital (MO) energy level diagram to describe the interactions between the metal and the Hz ligand. You must include sketches of the orbital overlaps for full marks. (4 marks) ii. How might the molecule be affected if the PPhz ligands were replaced with PlBuz ligands? [4 marks]