title: Chelating effect as a driving force for the selective formation of heteroligated Pt(II) complexes with bidentate phosphino-chalcoether ligands.
abstract: The halide-induced ligand rearrangement reaction (HILR) has been employed to provide selective and exclusive in situ formation of heteroligated Rh(I), Pd(II), and Pt(II) complexes with bidentate phosphino-chalcoether ligands. To gain insights on the nature of this unique reaction, we explored this process via the stepwise addition of bidentate phosphino-chalcoether (P, X; X = S or Se) and relevant monodentate phosphine ligands with a Pt(II) metal precursor. The corresponding monoligated complexes were obtained in quantitative yields by reacting 1 equiv of a P, X bidentate ligand with Pt(II) and were fully characterized via single crystal X-ray diffraction studies and heteronuclear ((31)P, (77)Se, and (195)Pt) NMR spectroscopy in solution. These species were further reacted with a second equivalent of either a bidentate ligand or the monodentate ethyl diphenylphosphine ligand, resulting in the clean formation of the heteroligated species or, in the case of the monodentate ligand with an electron-withdrawing bidentate ligand, a mixture of products. On the basis of competitive exchange reactions between these heteroligated, homoligated, and monoligated complexes, we conclude that ligand chelation plays a crucial role in the Pt(II) HILR. The in situ preferable formation of the stable monoligated complex allows for ligand sorting to occur in these systems. In all cases where the heteroligated product results, the driving force to these species is ligand chelation.
authors.affiliation: Department of Chemistry and International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: Mari S
authors.initials: MS
authors.lastname: Rosen
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Spokoyny
authors.forename: Charles W
authors.initials: CW
authors.lastname: Machan
authors.forename: Charlotte
authors.initials: C
authors.lastname: Stern
authors.forename: Amy
authors.initials: A
authors.lastname: Sarjeant
authors.forename: Chad A
authors.initials: CA
authors.lastname: Mirkin