New Pd‐phosphorus ylide complexes based on FC₆₀ as heterogeneous nano‐catalyst for H/D exchange reaction

Abstract

In this account, new Pd(0) complexes of phosphorus ylides based on fullerene C60 (FC60) were synthesized and utilized as the first fullerene‐based heterogeneous nano‐catalysts for H/D exchange reaction. Four new palladacyclopropa‐[60]fullerene complexes 1–4, [(η2‐C60)Pd(Y1–4)2] (Y1 = PPh3CHC(O)C6H4‐p‐NO2, Y2 = PPh3CHC(O)C6H4‐p‐CH3, Y3 = (p‐tolyl)3P‐CHC(O)C6H4‐p‐NO2, and Y4 = (p‐tolyl)3P‐CHC(O)C6H4‐p‐CH3), were prepared through dissolving the related α‐keto stabilized phosphorus ylide in toluene solution in the presence of FC60 and Pd (dba)2 (dba = dibenzylideneacetone). All of the complexes were characterized using Nuclear magnetic resonance (NMR) (1H, 13C, and 31P), Infrared spectroscopy (IR), Ultraviolet‐visible spectroscopy (UV‐visible), fluorescence, Electrospray Ionisation Mass Spectrometry (ESI‐MS), and Energy‐dispersive X‐ray spectroscopy (EDX) spectroscopies, and scanning electron microscopy (SEM) and TEM techniques. The data proved that FC60 and two ylides were coordinated to Pd(0) center through two hexagons and two ylidic carbon atoms, respectively. An evaluation was also performed to compare the catalytic activity of synthesized Pd complex 1 and a conventional heterogeneous catalyst, 10% Pd on carbon, in H/D exchange reaction. The results indicate that the process of H/D exchange reaction in aromatic rings of benzoic acid derivatives progressed more efficiently by Pd complex 1.

A series of nanoscaled Pt(0)‐phosphorus ylide complexes based on [60]fullerene: Synthesis, characterization, and in vitro biological assessments

“…Such coordination through the methinic carbon causes the modernization of the P‐C single bond from the P=C double bond, which leads to a large downfield shift for the phosphorus atom of the PCH group (see supporting file). [ 23 ] It is turned out by all IR and NMR analyses that the proposed structures of newly synthesized Pt(0)‐C 60 nanocomplexes are correct. It must be also noted that O‐coordination leads to a different set of signals in all NMR spectra.…”

“…The downfield shift for methinic proton signal in nanocomplexes (around 5) with respect to free ligands signal (around 4) is in agreement with coordination of ylidic carbon to Pt center. [ 23 ] As seen in 1 H NMR, it should also be considered that the coupling of 195 Pt makes satellites in methinic proton (see supporting file). Also, two spectral shifts can be also seen for methine carbon and carbonyl group signals in 13 C NMR spectra indicated the coordination of phosphorus ylides through the ylidic CH.…”

“…Coordination of Platinum atom to the C 60 also leads to split 13 C NMR signal of pure C 60 (143 ppm) into many more peaks around 140–150 ppm, which confirms the presence of fullerene in the Pt(0) nanocomplexes (see supporting file). [ 23 ] Analogously, the best way for proving the coordination is electronic changes in the phosphorus nuclei environment in 31 P NMR spectra. Such coordination through the methinic carbon causes the modernization of the P‐C single bond from the P=C double bond, which leads to a large downfield shift for the phosphorus atom of the PCH group (see supporting file).…”

“…These peaks are different than those found in pure C 60, which are in agreement with η 2 ‐coordination of metal center to the C 60 cage in such η 2 ‐C 60 ML 2 nanocomplexes (M = Pd, Pt and L = phosphine ligand). [ 23 ]…”

“…Also, two spectral shifts can be also seen for methine carbon and carbonyl group signals in 13 ). [23] Analogously, the best way for proving the coordination is electronic changes in the phosphorus nuclei environment in 31 P NMR spectra. Such coordination through the methinic carbon causes the modernization of…”