Quantitative Analysis of Self-Assembly Process of a Pd L Cage Consisting of Rigid Ditopic Ligands.

The self-assembly process of a Pd L cage complex consisting of rigid ditopic ligands, in which two 3-pyridyl groups are connected to a benzene ring through acetylene bonds and Pd ions was revealed by a recently developed quantitative analysis of self-assembly process (QASAP), with which the self-assembly process of coordination assemblies can be investigated by monitoring the evolution with time of the average composition of all the intermediates. QASAP revealed that the rate-determining steps of the cage formation are the intramolecular ligand exchanges in the final stage of the self-assembly: [Pd L Py* ] →[Pd L Py* ] +Py* and [Pd L Py* ] →[Pd L ] +Py* (Py*: 3-chloropyridine, which was used as a leaving ligand on the metal source). The energy barriers for the two reactions were determined to be 22.

The Effect of Solvent and Coordination Environment of Metal Source on the Self-Assembly Pathway of a Pd(II)-Mediated Coordination Capsule.

The effect of reaction environment on the self-assembly process of an octahedron-shaped PdL capsule was investigated. Quantitative analysis of self-assembly process with H NMR spectroscopy revealed that the self-assembly pathway of the capsule was altered by solvent and a leaving ligand coordinating to the metal source, which are not the components of the final self-assembly. Solvents definitively determine the pathway of the self-assembly at a very early stage of the self-assembly.

Emergence of fluoroquinolone-resistant Propionibacterium acnes caused by amino acid substitutions of DNA gyrase but not DNA topoisomerase IV.

With the aim of elucidating the mechanisms of fluoroquinolones resistance in Propionibacterium acnes, we determined the susceptibility of fluoroquinolones in 211 isolates from patients with acne vulgaris. We identified five isolates (2.4%) with reduced susceptibility to nadifloxacin (minimum inhibitory concentration ≥ 4 μg/ml).