Isolation and Structures of Polyarene Palladium Nanoclusters.

We report that surrounding coordination of neutral six-membered arene rings affords molecularly well-defined organotransition metal nanoclusters. With the use of [2.2]paracyclophane as the face-capping arene ligand, we have isolated two polyarene palladium nanoclusters, one consisting of a hexakis-arene ligand shell and a hexagonal close-packed Pd13 anticuboctahedron trichloride core, and the other consisting of an octakis-arene ligand shell and a non-close-packed Pd17 square gyrobicupola dichloride core, both with Pd-Pd direct bonding. The µ4-facial coordination mode of arene was discovered through the structural characterization of the Pd13 cluster. Their Pd13 and Pd17 cores, which are distinct from the previously identified face-centered-cubic Pd13 core surrounded by seven-membered cycloheptatrienyl, are explained by stereochemical and theoretical analyses.

Terahertz Spectroscopy of Tetrameric Peptides.

Determining the sequence and structure of peptides is crucial for understanding their structure-property relationships. Among many techniques, structures are typically elucidated using nuclear magnetic resonance spectroscopy and single crystal X-ray diffraction measurements. In this study, we present terahertz time-domain spectroscopy (THz-TDS) as a complementary, nondestructive technique that is sensitive to both the primary and secondary structures of tetrapeptides. Using only a few milligrams of peptide, THz-TDS spectra have been measured, some of which have been supported by density functional theory (DFT) calculations, to distinguish six tetrameric peptides with similar primary and secondary structures.

[Effect of consensus on punitive behavior].

In addition to the cost of punishment, the fear that others would evaluate punishers negatively can be a major obstacle for resolving the second-order social dilemma or failure of providing sanctions useful for solving a social dilemma problem. In an experiment with 81 participants, we tested whether providing information that other participants were in favor of punishing non-cooperators in a social dilemma situation would enhance cooperation in the second-order dilemma (i.e., punishment of non-cooperators). Participants received feedback of three bogus "participants" choices in a four-person social dilemma, in which one bogus participant defected and two others cooperated, and then received a chance to punish the sole non-cooperator. The hypothesis was supported among those who were motivated to punish the non-cooperator. They punished the non-cooperator when they were informed that the other participants also wanted to punish the non-cooperator. The feedback information that the other participants wanted to punish the non-cooperator induced the participants who were not motivated to punish the non-cooperator to punish less.