Chemistry Colloquium
"A new twist on an old ligand: Recent developments in the coordination chemistry and reactivity of PTA"
Presented by Prof. Brian Frost, University of Nevada
Our group has been interested in the coordination chemistry and reactivity of metal complexes of the air-stable and water-soluble heterocyclic phosphine 1,3,5-triaza-7-phosphaadamantane (PTA). The synthesis, characterization, and reactivity of a series of water-soluble complexes with the general formula Cp'Ru(PTA)(PR3)X (where PR3 = PTA or PPh3; X = Cl, H; and Cp' = Cp, Dp, Ind, or Tp) will be discussed along with their ability to catalyze atom transfer radical addition reactions and the hydrogenation of unsaturated carbonyls. The coordination chemistry of PTA and derivatives including N vs P coordination to metals will be discussed along with recent advances toward the modifications of the "upper" or "lower" rim of the ligand. Lower rim derivatives, modification of the triazacyclohexane ring, of PTA have been synthesized by condensation of P(CH2NH2)3 with a variety of aldehydes. Depending on reaction conditions triiminomethylphosphines, P(CH2N=CHR)3, or the closed cage 1,3,5-triaza-7-phosphaadamantane structures trisubstituted at the "lower-rim" are obtained. Chiral upper rim derivatives have been synthesized from the convenient synthon 1,3,5-triaza-7-phosphaadamantan-6-yllithium (PTA-Li). The insertion of electrophiles such as CO2, ketones, aldehydes, and imines into the C-Li bond of PTA-Li has allowed for the isolation of a series of water-soluble β-phosphino alcohols, amines, and carboxylates. The coordination chemistry and water solubility of these phosphine ligands will be discussed.
Hosted by Prof. Jack Norton
Thursday, October 28, 2010
Meet the speaker at 1:30 in Room, 328
Havemeyer
Tea & cookies at 4:00pm in Room, 328 Havemeyer
Seminar at 4:30 in Room 209 Havemeyer
