Zwitterionic amidinates as effective ligands for platinum nanoparticle hydrogenation catalysts

Abstract

Pt NPs covered with zwitterionic amidinates as ligands exhibit an exciting ligand effect in the hydrogenation of carbonyl groups when electron donor/acceptor groups are introduced in the N-substituents.

Novel nickel nanoparticles stabilized by imidazolium-amidinate ligands for selective hydrogenation of alkynes

“…Zwitterionic imidazolium-amidinate ligands ICy• (Ar) NCN (L1, L2 and L3) were synthesized according to the literature. 11 The AAS analyses of Ni@L1, Ni@L2 and Ni@L3 were performed by Kolbe (Mülheim, Germany), using a Perkin Elmer Analyst 200 atomic absorption spectrometer. The samples were prepared with an acid digestion procedure.…”

“…It has been already shown in the literature that the catalytic properties of MNPs can be tuned by the use of polymeric stabilizers, surface active agents, solid supports, but notably by ligands, which in turn also provide stability and solubility to the MNPs. 9 Imidazolium-amidinate ligands demonstrated to be a good stabilizer for Ru NPs 10 and Pt NPs, 11 enabling the synthesis of very small nanoparticles but until now they have never been used on nickel NPs. Due to the zwitterionic structure of the imidazolium-amidinate ligands, the nitrogen atoms exhibit a large electron-donor capability and coordinate strongly to transition metals without adding electric charges to the system.…”

“…Furthermore, a large influence of the substituents of the ligands on catalytic activity of the Pt NPs in the hydrogenation of activated ketones was found. 11 Here, we describe novel Ni NPs stabilized by three different imidazolium-amidinate ligands, ICy-(Ar) NCN (L1: Ar = p-tol, L2: Ar = p-anisyl and L3: Ar = p-ClC 6 H 4 ). The three systems were fully characterized by multiple techniques ((HR)TEM, XRD, WAXS, AAS, XPS and VSM).…”

Amidinate Aluminium Complexes as Catalysts for Carbon Dioxide Fixation into Cyclic Carbonates

“…Amidinate metal complexes have been shown to catalyse important reactions including: polymerisations, hydrogenations, hydrosilylations, Kharasch reactions, amidations and hydrophosphination reactions . In our efforts to investigate and take advantage of the catalytic properties of amidinate systems as described above, recently we have reported the application of a series of aluminium bisamidinates towards ring‐opening polymerisation (ROP) of cyclic esters .…”

Platinum nanoparticles stabilized by N-heterocyclic thiones. Synthesis and catalytic activity in mono- and di-hydroboration of alkynes

“…This is in stark contrast to the acquired knowledge that we have in molecular chemistry, for which a vast library of ligands have been used over the years to tune the properties of their corresponding platinum complexes. In recent years, some efforts have been made to transfer this knowledge to the realm of the metal nanoparticles, with some relevant illustrative examples in the use of the now prevalent N-heterocyclic carbenes (still under-developed in the field of metal nanoparticles), 10 zwitterionic amidinates 11 or other type of reactive (non-innocent) carbenes and vinyli-denes. 12 These ligands modify the properties of the surface of the metal nanoparticle both electronically and sterically, and thus open the door for controlling their stability and catalytic performance.…”