Organoruthenium(II) compounds with pyridyl benzoxazole/benzthiazole moiety: studies on DNA/protein binding and enzyme mimetic activities

<p>We report herein synthesis and characterization of four new organoruthenium(II) complexes of the type [RuH(CO)(PPh₃)₂(<b>L</b>_<b>1,2</b>)]Cl (<b>1</b>, <b>3</b>) and [Ru(CO)(Cl)₂(AsPh₃)(<b>L</b>_<b>1,2</b>)] (<b>2</b>, <b>4</b>) derived from the reaction of [RuHCl(CO)(EPh₃)₃] (E = P or As) with 2-(pyridine-2yl)benzoxazole (<b>L</b>_<b>1</b>) and 2-(pyridine-2yl)benzthiazole (<b>L</b>_<b>2</b>). Single-crystal X-ray diffraction data of <b>2</b> proved octahedral geometry of the complexes with a 1 : 1 ratio between the metal and the coordinated ligands. The binding affinities of <b>1</b>–<b>4</b> toward calf-thymus DNA (CT-DNA) and BSA were thoroughly studied by various spectroscopic techniques. Furthermore, the coordination compounds exhibit catecholase-like activities in the aerial oxidation of 3,5-di-tert-butylcatechol to the corresponding <i>o</i>-quinone and phosphatase-like activities in the hydrolysis of 4-nitrophenyl phosphate to 4-nitrophenolate ion. The kinetic parameters have been determined using Michaelis–Menten approach. The highest <i>k</i>_cat values suggested that coordination compounds exhibit higher rates of catalytic efficacy.</p

BINOl‑Based Chiral Receptors as Fluorescent and Colorimetric Chemosensors for Amino Acids

Three representative BINOL derivatives were examined for their chiral recognitions with d- and l-<i>t</i>-Boc-amino acid anions: an open system 1, which bears two urea groups and two pyrene groups; a closed ring system 2, which bears two urea groups with a closed ring system; and a dimeric system 3, which bears two benzylic amine groups and two pyrene groups. Dimeric system 3 displayed a Δ<i>I</i>_D/Δ<i>I</i>_L of 12.95 for <i>t</i>-Boc-alanine