Jinshi Ma

Self-complementary hydrogen-bonded duplexes and helices based on bis(pyrrolyl)carbohydrazide derivatives

A series of novel bis(pyrrolyl)carbohydrazide derivatives have been designed and synthesized. X-Ray structural analysis confirmed the formation of self-complementary hydrogen-bonded duplexes in all cases. Multiple intermolecular N–H⋯O hydrogen bonds play crucial roles in the formation of the duplexes and the evolution of meso-suprahelical structures in the solid state.

Ultrasensitive reversible chromophore reaction of BODIPY functions as high ratio double turn on probe

Chromophore reactions with changes to conjugation degree, especially those between the conjugated and unconjugated state, will bring a large spectral variation. To realize such a process, a meso-naked BODIPY (MNBOD) with two electron-withdrawing groups around the core is designed and synthesized. The resulting system is extremely sensitive to bases. The red, highly fluorescent solution readily becomes colorless and non-fluorescent after base addition; however, the color and fluorescence can be totally and instantly restored by addition of acid or formaldehyde. Analyses show that two identical MNBODs are connected by a C–C single bond (sp3) at the meso-position through a radical reaction that results in an unconjugated, colorless dimer complexed with bases. When the bases are consumed, the dimer immediately dissociates into the red, highly fluorescent, conjugated MNBOD monomer. With 260u2009nm spectral change and over 120,000 turn-on ratio, this chromophore-reaction can be utilized as a sensitive reaction-based dual-signal probe.BODIPY dyes, though widely explored, have not been pursued as chromophore reaction based chemical probes. Here, the authors synthesize a meso-naked BODIPY core flanked with two electron-withdrawing groups, which undergoes a reversible change in conjugated structure in the presence of base and functions as a dual signal and ultrahigh turn-on ratio chemical probe.

Syntheses and crystal structures of nickel(II), copper(II), and zinc(II) complexes with a biphenyl-bridged bis(pyrrole-2-yl-methyleneamine) ligand

The reactions of nickel(II), copper(II), and zinc(II) acetate salts with a potentially tetradentate biphenyl-bridged bis(pyrrole-2-yl-methyleneamine) ligand yielded three complexes with different coordination geometries. X-ray crystal structural analysis reveals that in the nickel(II) complex each nickel is five-coordinate, distorted trigonal bipyramid. In the copper(II) complex, each copper is four-coordinate, between square planar and tetrahedral. In the zinc(II) complex, each zinc is four-coordinate with a distorted tetrahedral geometry and the molar ratio of the zinc and ligand is 1 : 2.