89299-24-1Relevant academic research and scientific papers
Ligation of phosphorus ligands to silver(I). 2. Electronic and steric effects in the coordination of one to four P(OR)3 and PR3 ligands
Socol,Verkade
, p. 3487 - 3493 (2008/10/08)
Syntheses for the isolable complexes {Ag[P(OPh)3]3}BF4, {Ag[P(O-i-Pr)3]3}BPh4, {Ag[P(O-i-Pr)3]4}X (X = BF4, BPh4), {Ag[P(O-t-Bu)3]2}BF4, {Ag[P(O-t-Bu)3]X} (X = Cl, I, CN), {Ag[P(O-t-Bu)3]2NO3} and {Ag[P(O-2,6-Me2C6H3)3]BF 4} are described. 31P NMR chemical shift and 1J(107Ag31P) coupling constant data are reported for these and additional solution species of the type AgLn+ where n may vary from 1 to 4 for L = PEt3, PPhMe2, PPhMe, PPh3, P(OMe)3, P(OEt)3, P(O-t-Bu)3, P(OCH2CH2Cl)3, P(OCH2CCl3)3, P(OCH2)3CEt, P(OCH2)2CHO, P(OPh)3, P(O-o-tol)3 and P(O-2,6-Me2C6H3)3. What appear to be linear correlations are observed for 1J(AgP) vs. electronegativity of the atom bound to phosphorus in AgLn+ species for n = 1-4. It is concluded from the 31P NMR data, the ligand-exchange characteristics of some of the complexes, and the results of ligand competition experiments that ligand electronic effects in addition to steric influences determine the coordination behavior of phosphorus ligands in these complexes. Comparison of the Ag(I) ligating properties of the very bulky ligands P(O-t-Bu)3, P(t-Bu)3, and P(2,4,6-Me3C6H2)3 reveals that steric effects appear to dominate. In contrast to P(2,4,6-Me3C6H2)3, which is expected to possess a larger cone angle than P(O-2,6-Me2C6H3)3, the former ligand allows isolation of an AgL2+ complex, which in the case of the latter ligand is observed only in solution and is in equilibrium with the monoligated species.
