Promoting effect of ionic liquids on ligand substitution reactions

Palladium-catalyzed hydroesterification of styrene derivatives in the presence of ionic liquids

“…Ionic liquids are expected to be able to stabilize charge separated species because of their polarity and good hydrogen bond donor character. ILs have been shown to promote the ligand displacement of anionic ligands by neutral ligands in d 8 square planar metal complexes [37]. In this study, we saw a stronger than expected preference for formation of the linear ester that was largely unaffected by reaction conditions.…”

Sterically Demanding, Sulfonated, Triarylphosphines: Application to Palladium-Catalyzed Cross-Coupling, Steric and Electronic Properties, and Coordination Chemistry

“…Given the large counterion effects seen in the computation results, it is possible that ion-pairing effects in the trans -Rh(L·TBA 3 ) 2 (CO)Cl complexes have a strong affect on the CO stretching frequency. We have previously seen that the TBA counterions in trans -Rh(TPPTS·TBA 3 ) 2 (CO)(NO 3 ) cluster tightly around the metal center in CH 2 Cl 2 , preventing displacement of the nitrate anion . A similar tight clustering in this CO study may have had a dominating effect on the CO stretching frequency, making the electronic contribution of the phosphine inconsequential.…”

Room-Temperature Ionic Liquids: Solvents for Synthesis and Catalysis. 2

“…The ligand substitution reactions of [Rh(CO)(PPh 3 ) 2 (NO 3 )] with substituted pyridines have been investigated in [C 6 pyr][NTf 2 ] and [C 4 C 1 im][PF 6 ] and compared to those in dichloromethane . It was found that conversions to the product [Rh(CO)(PPh 3 ) 2 py][NO 3 ] were poor in CH 2 Cl 2 for all but the most basic substituted pyridines used, whereas in the ionic liquids complete conversions were achieved in all cases studied.…”