Halide-induced ligand pairing and sorting processes have been observed in the context of Pd(II) complexes with hemilabile P,S and P,0 ligands. Mixing of the ligands Ph 2PCH 2CH 2SMe (7) and Ph2PCH2CH2SPh (8) with a Pd(H) precursor in CH 2C1 2 results in a mixture of [(7) 2CIPd]CL [(8) 2Cl 2Pd], and [(7)(8)ClPd]Cl complexes at 20 °C. This equilibrium can be driven toward the heteroligated structure [(7)(8)ClPd]Cl by (1) cooling the mixture or (2) precipitation with hexanes, leading to the exclusive formation of semiopen heteroligated complex cis-[K 2-(7)-K 1-(8)ClPd]Cl (9a), as confirmed by a single-crystal X-ray diffraction study and solid state CPMAS 31P 1H} NMR spectroscopy. Dissolution of 9a in CH2C12 leads to the original mixture of complexes, which illustrates the reversible nature of this ligand pairing and sorting process. Similar processes occur when a combination of P,S and P,0 ligands is used. The semiopen heteroligated complexes can be chemically manipulated in a reversible fashion to form closed complexes, allowing for control of the relative position and flexibility between neighboring substituents in these "tweezer"-like structures. Control experiments suggest these ligand sorting and pairing processes occur via a halide-induced ligand rearrangement (HILR) reaction.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry