Photoelectron Imaging Signature for Selective Formation of Icosahedral Anionic Silver Cages Encapsulating Group 5 Elements: M@Ag₁₂^– (M = V, Nb, and Ta)

An assembly of 13 atoms can form highly symmetric architectures like those belonging to D3h, Oh, D5h, and Ih point groups. Here, using photoelectron imaging spectroscopy in combination with density functional theory (DFT) calculations, we present a simple yet convincing experimental signature for the selective formation of icosahedral cages of anionic silver clusters encapsulating a dopant atom of group 5 elements: M@Ag12– (M = V, Nb, and Ta). Their photoelectron images obtained at 4 eV closely resemble one another: only a single ring is observed, which is assignable to photodetachment signals from a 5-fold degenerate superatomic 1D electronic shell in the 1S21P61D10 configuration of valence electrons. The perfect degeneracy represents an unambiguous fingerprint of an icosahedral symmetry, which would otherwise be lifted in all of the other structural isomers. DFT calculations confirm that Ih forms are the most stable and that D5h, Oh, and D3h structures are not found even in metastable states

Photoelectron Imaging Signature for Selective Formation of Icosahedral Anionic Silver Cages Encapsulating Group 5 Elements: M@Ag₁₂^– (M = V, Nb, and Ta)

An assembly of 13 atoms can form highly symmetric architectures like those belonging to D3h, Oh, D5h, and Ih point groups. Here, using photoelectron imaging spectroscopy in combination with density functional theory (DFT) calculations, we present a simple yet convincing experimental signature for the selective formation of icosahedral cages of anionic silver clusters encapsulating a dopant atom of group 5 elements: M@Ag12– (M = V, Nb, and Ta). Their photoelectron images obtained at 4 eV closely resemble one another: only a single ring is observed, which is assignable to photodetachment signals from a 5-fold degenerate superatomic 1D electronic shell in the 1S21P61D10 configuration of valence electrons. The perfect degeneracy represents an unambiguous fingerprint of an icosahedral symmetry, which would otherwise be lifted in all of the other structural isomers. DFT calculations confirm that Ih forms are the most stable and that D5h, Oh, and D3h structures are not found even in metastable states

DataSheet_1_A Bcl11bN797K variant isolated from an immunodeficient patient inhibits early thymocyte development in mice.pdf

BCL11B is a transcription factor with six C2H2-type zinc-finger domains. Studies in mice have shown that Bcl11b plays essential roles in T cell development. Several germline heterozygous BCL11B variants have been identified in human patients with inborn errors of immunity (IEI) patients. Among these, two de novo mis-sense variants cause asparagine (N) to lysine (K) replacement in distinct zinc-finger domains, BCL11BN441K and BCL11BN807K. To elucidate the pathogenesis of the BCL11BN807K variant, we generated a mouse model of BCL11BN807K by inserting the corresponding mutation, Bcl11bN797K, into the mouse genome. In Bcl11b+/N797K mice, the proportion of immature CD4−CD8+ single-positive thymocytes was increased, and the development of invariant natural killer cells was severely inhibited in a T-cell-intrinsic manner. Under competitive conditions, γδT cell development was outcompeted by control cells. Bcl11bN797K/N797K mice died within one day of birth. Recipient mice reconstituted with Bcl11bN797K/N797K fetal liver cells nearly lacked CD4+CD8+ double-positive thymocytes, which was consistent with the lack of their emergence in culture from Bcl11bN797K/N797K fetal liver progenitors. Interestingly, Bcl11bN797K/N797K progenitors gave rise to aberrant c-Kit+ and CD44+ cells both in vivo and in vitro. The increase in the proportion of immature CD8 single-positive thymocytes in the Bcl11bN797K mutants is caused, in part, by the inefficient activation of the Cd4 gene due to the attenuated function of the two Cd4 enhancers via distinct mechanisms. Therefore, we conclude that immunodeficient patient-derived Bcl11bN797K mutant mice elucidated a novel role for Bcl11b in driving the appropriate transition of CD4−CD8− into CD4+CD8+ thymocytes.</p

Effects of Carbon–Metal–Carbon Linkages on the Optical, Photophysical, and Electrochemical Properties of Phosphametallacycle-Linked Coplanar Porphyrin Dimers

5-(Diphenylphosphanyl)-10,15,20-triarylporphyrins (<i>meso</i>-phosphanylporphyrins) underwent complexations with palladium­(II) and platinum­(II) salts to afford phosphapalladacycle- and phosphaplatinacycle-fused coplanar porphyrin dimers, respectively, via regioselective peripheral β-C–H activation of the <i>meso</i>-phosphanylporphyrin ligands. The optical and electrochemical properties of these metal-linked porphyrin dimers as well as their porphyrin monomer/dimer references were investigated by means of steady-state UV–vis absorption/fluorescence spectroscopy, cyclic and differential pulse voltammetry, time-resolved spectroscopy (fluorescence and transient absorption lifetimes and spectra), and magnetic circular dichroism spectroscopy. All the observed data clearly show that the palladium­(II) and platinum­(II) linkers play crucial roles in the electronic communication between two porphyrin chromophores at the one-electron oxidized state and in the singlet–triplet intersystem-crossing process at the excited state. It has also been revealed that the C–Pt–C linkage makes more significant impacts on these fundamental properties than the C–Pd–C linkage. Furthermore, density functional theory calculations on the metal-linked porphyrin dimers have suggested that the antibonding dπ–pπ orbital interaction between the peripherally attached metal and adjacent pyrrolic β-carbon atoms destabilizes the highest occupied molecular orbitals of the porphyrin π-systems and accounts for the observed unique absorption properties. On the basis of these experimental and theoretical results, it can be concluded that the linear carbon–metal–carbon linkages weakly but definitely perturb the optical, photophysical, and electrochemical properties of the phosphametallacycle-linked coplanar porphyrin dimers