Assembly of strongly phosphorescent hetero-bimetallic and -trimetallic [2]catenane structures based on a coinage metal alkynyl system.

Homo-metallic metal alkynyl complexes exhibit interesting catenane structures, but their hetero-metallic catenane counterparts are under-developed. In this work, we report rare examples of bimetallic Au-Cu (DtbpC[triple bond, length as m-dash]C ligand; Dtbp = 3,5-di--butylphenyl), Au-Ag ( BuC[triple bond, length as m-dash]C ligand), and Au-Cu, Au-Ag (C6-FluoC[triple bond, length as m-dash]C ligand; C6-Fluo = 9,9-dihexyl-9-fluoren-2-yl) complexes as well as a trimetallic Au-Ag-Cu (C6-FluoC[triple bond, length as m-dash]C ligand) complex, which feature [2]catenane structures. The formation of the [2]catenane structure is significantly affected by the coinage metal ion(s) and change of the structure of the alkynyl ligand.

From Cluster to Polymer: Ligand Cone Angle Controlled Syntheses and Structures of Copper(I) Alkynyl Complexes.

Copper(I) alkynyl complexes have attracted tremendous attention in structural studies, as luminescent materials, and in catalysis, and homoleptic complexes have been reported to form polymers or large clusters. Herein, six unprecedented structures of Cu(I) alkynyl complexes and a procedure to measure the cone angles of alkynyl ligands based on the crystal structures of these complexes are reported. An increase of the alkynyl cone angle in the complexes leads to a modulation of the structures from polymeric [((PhC≡CC≡C)Cu)2 (NH3 )]∞ , to a large cluster [(TripC≡CC≡C)Cu]20 (MeCN)4 , to a relatively small cluster [(TripC≡C)Cu]8 (Trip=2,4,6-iPr3 -C6 H2 ).

Identification of "sarsasapogenin-aglyconed" timosaponins as novel Aβ-lowering modulators of amyloid precursor protein processing.

The inhibition of amyloid β (Aβ) peptide production is a key approach in the development of therapeutics for the treatment of Alzheimer's disease (AD). We have identified that timosaponins consisting of sarsasapogenin (SSG) as the aglycone can effectively lower the production of Aβ peptides and stimulate neurite outgrowth in neuronal cell cultures. Structure-activity relationship studies revealed that the -fused AB ring, 3β-configuration, spiroketal F-ring and 25-configuration of SSG are the essential structural features responsible for the Aβ-lowering effects and neurite-stimulatory activity.