The synthesis and photophysical evaluation of two enatiomerially pure dimetallic lanthanide luminescent triple-stranded helicates is described. The two systems, formed from the chiral (R,R) ligand 1 and (S,S) ligand 2, were produced as single species in solution, where the excitation of either the naphthalene antennae or the pyridiyl units gave rise to Eu(III) emission in a variety of solvents. Excitation of the antennae also gave rise to circularly polarized Eu(III) luminescence emissions for Eu(2):1(3) and Eu(2):2(3) that were of equal intensity and opposite sign, confirming their enantiomeric nature in solution providing a basis upon which we were able to assign the absolute configurations of Eu(2):1(3) and Eu(2):2(3).
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http://dx.doi.org/10.1021/ja9032204 | DOI Listing |
Chemistry
December 2021
Max-Planck-Institut für Kohlenforschung, 45470, Mülheim an der RuhrMülheim/Ruhr, Germany.
Alkynyl-B(aam) (aam=anthranilamidato) derivatives are readily available bench-stable compounds that undergo remarkably selective reactions with Bu SnH in the presence of [Cp*RuCl] as the catalyst. The addition follows a stereochemically unorthodox trans-selective course; in terms of regioselectivity, the Bu Sn- unit is delivered with high fidelity to the C-atom of the triple bond adjacent to the boracyclic head group ("alpha,trans-addition"). This outcome is deemed to reflect a hydrogen bonding interaction between the protic -NH groups of the benzo-1,3,2-diazaborininone ring system and the polarized [Ru-Cl] bond in the loaded catalyst, which locks the substrate in place in a favorable orientation relative to the incoming reagent.
View Article and Find Full Text PDFInorg Chem
March 2020
School of Chemistry and Trinity Biomedical Science Institute, Trinity College Dublin, Dublin 2 D02 PN40, Ireland.
Ditopic helicate ligands and were synthesized for the formation of dinuclear Eu luminescent chiral helical assemblies (Eu·L) in competitive organic and protic solvent media. Spectroscopic analysis revealed formation of the 2:3 (Eu·L) and 2:2 (Eu·L) species in methanolic solutions. Circular dichroism and circularly polarized luminescence (CPL) spectroscopy confirmed the chiral purity of the helical systems, while scanning electron microscopy imaging demonstrated the formation of hierarchical self-assemblies with spherical morphologies.
View Article and Find Full Text PDFJ Am Chem Soc
February 2018
School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
Magnetic exchange interactions within the asymmetric dimetallic compounds [hqH][Ln(hq)(NO)]·MeOH, (Ln = Er(III) and Yb(III), hqH = 8-hydroxyquinoline) have been directly probed with EPR spectroscopy and accurately modeled by spin Hamiltonian techniques. Exploitation of site selectivity via doping experiments in Y(III) and Lu(III) matrices yields simple EPR spectra corresponding to isolated Kramers doublets, allowing determination of the local magnetic properties of the individual sites within the dimetallic compounds. CASSCF-SO calculations and INS and far-IR measurements are all employed to further support the identification and modeling of the local electronic structure for each site.
View Article and Find Full Text PDFInorg Chem
December 2014
Grup de Química Bioinorgànica, Supramolecular i Catàlisi (QBIS-CAT), Institut de Química Computacional i Catàlisi (IQCC), Departament de Química, Universitat de Girona, Campus Montilivi, E17071 Girona, Catalonia, Spain.
A novel unsymmetric dinucleating ligand (L(N3N4)) combining a tridentate and a tetradentate binding sites linked through a m-xylyl spacer was synthesized as ligand scaffold for preparing homo- and dimetallic complexes, where the two metal ions are bound in two different coordination environments. Site-selective binding of different metal ions is demonstrated. L(N3N4) is able to discriminate between Cu(I) and a complementary metal (M' = Cu(I), Zn(II), Fe(II), Cu(II), or Ga(III)) so that pure heterodimetallic complexes with a general formula [Cu(I)M'(L(N3N4))](n+) are synthesized.
View Article and Find Full Text PDFChemistry
December 2013
Foundation for Advancement of International Science (FAIS), Tsukuba, Ibaraki 305-0821 (Japan); Department of Chemistry, Tokyo Gakugei University, Koganei, Tokyo 184-8501 (Japan); Life Science Center of Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan).
Although all the pure-carbon fullerene isomers above C60 reported to date comply with the isolated pentagon rule (IPR), non-IPR structures, which are expected to have different properties from those of IPR species, are obtainable either by exohedral modification or by endohedral atom doping. This report describes the isolation and characterization of a new endohedral metallofullerene (EMF), La2@C76, which has a non-IPR fullerene cage. The X-ray crystallographic result for the La2@C76/[Ni(II)(OEP)] (OEP=octaethylporphyrin) cocrystal unambiguously elucidated the C(s)(17,490)-C76 cage structure, which contains two adjacent pentagon pairs.
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