Joseph Jankolovits

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Near-infrared (NIR) luminescent lanthanide complexes hold great promise for practical applications, as their optical properties have several complementary advantages over organic fluorophores and semiconductor nanoparticles. The fundamental challenge for lanthanide luminescence is their sensitization through suitable chromophores. The use of the(More)
Two intermediates in the assembly of lanthanide metallacrowns (MCs) of divalent transition metals and ligands in the picoline hydroxamic acid (picHA)/α-amino hydroxamic acid family were synthesized and crystallographically characterized. Structures of the elusive M(II)[12-MC(M(II),L)-4](2+) were obtained with M = Ni, Zn and L = picHA, quinaldic hydroxamic(More)
Solvent dependence in the assembly of coordination driven macrocycles is a poorly understood phenomenon. This work presents the solvent dependent assembly of 8 lanthanide metallacrowns (LnMCs) in solution using picoline hydroxamic acid (picHA), Zn(II), and Ln(III) ions. ESI-MS and single-crystal X-ray crystallography reveal the selective assembly of(More)
A novel competitive binding assay was implemented to monitor the binding of a redox inactive substrate to a redox inactive metallacrown host based on its competition with ferrocene carboxylate (FcC(-)) using cyclic voltammetry (CV). First, the binding of FcC(-) to Ln(III)[15-MC(Cu(II),N,L-pheHA)-5] (LnMC) hosts was characterized by cyclic voltammetry. It(More)
Polyanion dispersants stabilize aqueous dispersions of hydrophilic (native) inorganic oxide particles, including pigments currently used in paints, which are used at an annual scale of 3 million metric tons. While obtaining stable aqueous dispersions of hydrophobically modified particles has been desired for the promise of improved film performance and(More)
Chiral Ln(III)[15-metallacrown-5] complexes with phenyl side chains have been shown to encapsulate aromatic carboxylates reversibly in their hydrophobic cavities. Given the importance of selective guest binding for applications of supramolecular containers in synthesis, separations, and materials design, the affinity of Gd(III)[15-metallacrown(Cu(II),(More)
Secondary sphere interactions from proximal phenyl side chains control the anion selectivity of dimeric Ln(III)[15-MC(Cu(II),α-aminoHA)-5](3+) metallocavitands. CH-O interactions, which are only possible with certain side chains, are sufficient for overcoming an intrinsic energy barrier to binding saturated dicarboxylates in hydrophobic compartments.
Dimeric Ln(3+)[15-metallacrown-5] compartments selectively recognize carboxylates through guest binding to host metal ions and intermolecular interactions with the phenyl side chains. A systematic study is presented on how the size, selectivity, and number of encapsulated guests in the dimeric containers is influenced by the(More)