Younbong Park

Excimers Beyond Pyrene: A Far‐Red Optical Proximity Reporter and its Application to the Label‐Free Detection of DNA

A family of organic chromophores that, like pyrene, forms emissive excimers is reported. Their chemical and photophysical properties are superior to pyrene for the design of chemo- and biosensors. Unlike hydrophobic pyrene, which requires excitation by cell-damaging UV irradiation, these polar dyes absorb strongly in the visible range, and their excimers emit brightly in the red to far-red region of the electromagnetic spectrum. The intensity of the emission signal is greatly increased upon formation of a preassociated dimer that is triggered upon aggregation or crystallization. In demonstration of the potential of this new family of excimer-forming dyes, a probe that is capable of detecting label-free DNA in water down to 10 pM and also doubles as a visualization agent for DNA in gel electrophoresis is reported.

Synthesis and structure of ansa-cyclopentadienyl pyrrolyl titanium complexes: [(η5-C5H4)CH2(2-C4H3N)]Ti(NMe2)2 and [1,3-{CH2(2-C4H3N)}2(η5-C5H3)]Ti(NMe2)

Abstract Reaction of ansa-cyclopentadienyl pyrrolyl ligand (C5H5)CH2(2-C4H3NH) (2) with Ti(NMe2)4 affords bis(dimethylamido)titanium complex [(η5-C5H4)CH2(2-C4H3N)]Ti(NMe2)2 (3) via amine elimination. A cyclopentadiene ligand with two pendant pyrrolyl arms, a mixture of 1,3- and 1,4-{CH2(2-C4H3NH)}2C5H4 (4), undergoes an analogous reaction with Ti(NMe2)4 to give [1,3-{CH2(2-C4H3N)}2(η5-C5H3)]Ti(NMe2) (5). Molecular structures of 3 and 5 have been determined by single crystal X-ray diffraction studies.

Bis(2-phenyl-ethyl-ammonium) tetra-chloridocobaltate(II).

Crystals of the title compound, (C6H5CH2CH2NH3)2[CoCl4], were grown by the solvent-evaporation method. This inorganic–organic hybrid compound exhibits a layered structure in which isolated CoCl4 inorganic layers alternate with bilayers of phenylethylammonium cations. Although the inorganic anion is zero-dimensional, the layered structure is stabilized via N—H⋯Cl hydrogen bonds. The CoCl4 tetrahedra connect to the cations through N—H⋯Cl hydrogen bonds, building a two-dimensional network extending parallel to (010).

Crystal structure, and thermal and magnetic properties of 2,4-dinitrobenzoatoterbium(III) complex

The Tb(III) complex containing 2,4-dinitrobenzoate (2,4-DNB), Tb(2,4-DNB)3(H2O)2] · C2H5OH has been synthesized and its crystal structure analyzed by X-ray diffraction methods. The complex crystallizes in the triclinic space group P 1, as a linear polymeric chain in which terbium ions are bridged by carboxylate groups. The eight-coordinate Tb ion with six carboxylate groups and two water molecules forms a slightly distorted square antiprism. Thermal and magnetic properties of the terbium complex were also studied.