Ion-Pairing Stereodynamic Probes for Circular Dichroism Chiral Sensing of Amines.

Tris(2-pyridylmethyl)amine () and tris(2-phenolmethyl)amine () metal complexes have been extensively used for catalysis and molecular recognition applications. In particular, due to their ability to form stereodynamic complexes through the helical arrangement of the ligand around the metal in a propeller shape, chiroptical sensing has been extensively investigated. In particular, the capability of the analyte, usually a Lewis base, to bind the metal complex has been the predominant recognition motif.

Sandwich d/f Heterometallic Complexes [(Ln(hfac))M(acac)] (Ln = La, Pr, Sm, Dy and M = Co; Ln = La and M = Ru).

Sandwich d/f heterometallic complexes [(Ln(hfac))M(acac)] (Ln = La, Pr, Sm, Dy and M = Co; Ln = La and M = Ru) were prepared in strictly anhydrous conditions reacting the formally unsaturated fragment [Ln(hfac)] and [M(acac)] in a 2-to-1 molar ratio. These heterometallic complexes are highly sensitive to moisture. Spectroscopic observation revealed that on hydrolysis, these compounds yield dinuclear heterometallic compounds [Ln(hfac)M(acac)], prepared here for comparison purposes only.

Understanding Stabilization Factors in Heterodinuclear Ln-Al Complexes from DFT Simulations on Thermochemistry Data: A Counterintuitive Conclusion.

This study validates a computational protocol to predict the stability of heterodinuclear complexes by varying ligands on both moieties and analyzing the reaction Gibbs free energy (Δ) values. To this purpose, a series of Eu-Al complexes with the general formula [Eu()Al()], where is the ligand of europium and is an oxygen donor ligand of aluminum, is used. The nature of the bridging bonds and thermochemical characteristics (Δ, enthalpy, and entropy) of the complexes were evaluated via DFT calculations.

Mononuclear Rare-Earth Metalloligands Exploiting a Divergent Ligand.

Rare-earth tris-diketonato [RE(dike)pyterpy] metalloligands can be prepared reacting at room temperature [RE(dike)dme] (dme = 1,2-dimethoxyethane; dike = tta with Htta = 2-thenoyltrifluoroacetone and RE = La, ; Y, ; Eu, ; Dy, ; or dike = hfac with Hhfac hexafluoroacetylacetone, and RE = Eu, ; Tb, ; Yb ) with 4'-(4‴-pyridil)-2,2':6',2″-terpyridine (pyterpy). The molecular structures of , , , and have been studied through single-crystal X-ray diffraction showing mononuclear neutral complexes with the rare-earth ion in coordination number nine and with a muffin-like coordination geometry. [RE(tta)pyterpy] promptly reacts with [M(tta)dme] with formation of [Mpyterpy][RE(tta)] (M = Zn, RE = Y, ; M = Co, RE = Dy, ).

Aluminium 8-Hydroxyquinolinate -Oxide as a Precursor to Heterometallic Aluminium-Lanthanide Complexes.

A reaction in anhydrous toluene between the formally unsaturated fragment [Ln(hfac)] (Ln = Eu, Gd and Er; Hhfac = hexafluoroacetylacetone) and [Al(qNO)] (HqNO = 8-hydroxyquinoline -oxide), here prepared for the first time from [Al(OBu)] and HqNO, affords the dinuclear heterometallic compounds [Ln(hfac)Al(qNO)] (Ln = Eu, Gd and Er) in high yields. The molecular structures of these new compounds revealed a dinuclear species with three phenolic oxygen atoms bridging the two metal atoms. While the europium and gadolinium complexes show the coordination number (CN) 9 for the lanthanide centre, in the complex featuring the smaller erbium ion, only two oxygens bridge the two metal atoms for a resulting CN of 8.