CHED 1154 |
| The coordination chemistry of the square-planar palladacycle system (k2-P(OC6H3-2,4-But)2(OC6H2-2,4-But))Pd(L)X (hereafter (P^C)Pd(L)X) where X = Cl or I and L is a neutral P, N, S, or As ligand has been investigated by 31P NMR. The complexes above have been prepared in situ by combining the respective halo dimer with two equivalents of neutral ligand. For most combinations of L and X, mixtures containing significant amounts of both the cis and trans isomers of (P^C)Pd(L)X have been observed. For (P^C)Pd(P(C6H4-p-Z)3)Cl, however, the cis isomers predominated sufficiently such that it has been possible to determine equilibrium constants for cis-(P^C)Pd(P(C6H4-p-Z)3)X + P(C6H4-p-Zx)3 = cis- (P^C)Pd(P(C6H4-p-Zx)3)X + P(C6H4-p-Z)3 to afford a respectable isosteric Hammett-series plot for Z=MeO,Me,H,F,Cl,CF3. The equilibrium experiments have been carried out by recording spectra for solution mixtures of [P^C)Pd(L)X]2 + 2 P(C6H4-p-Z)3 + 2 P(C6H4-p-Zx)3. Equilibrium constants have been calculated using conventional stoichiometry by considering that the dipalladium dimer was completely converted to 2P^C)Pd(P(C6H4-p-Z)3)X, which then interacted with 2 P(C6H4-p-Zx)3. |
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Undergraduate Research Poster Session: Inorganic Chemistry
2:00 PM-4:00 PM, Monday, April 7, 2008 Morial Convention Center -- Hall A, Poster
Division of Chemical Education |