Molecular bowls for inclusion complexation of toxic anticancer drug methotrexate.

We describe the preparation and study of novel cavitands, molecular bowls 1 and 2, as good binders of the anticancer drug methotrexate (MTX). Molecular bowls are comprised of a curved tribenzotriquinacene (TBTQ) core conjugated to three macrocyclic pyridinium units at the top. The cavitands are easily accessible two synthetic steps from hexabromo-tribenzotriquinacene in 25% yield.

The photoactivated dynamics of dGpdC and dCpdG sequences in DNA: a comprehensive quantum mechanical study.

Study of alternating DNA GC sequences by different time-resolved spectroscopies has provided fundamental information on the interaction between UV light and DNA, a process of great biological importance. Multiple decay paths have been identified, but their interplay is still poorly understood. Here, we characterize the photophysics of GC-DNA by integrating different computational approaches, to study molecular models including up to 6 bases described at a full quantum mechanical level.

Design and Synthesis of Cubic K Ba SbSe Solid Electrolytes for K-O Batteries.

Developing K-ion conducting solid-state electrolytes (SSEs) plays a critical role in the safe implementation of potassium batteries. In this work, a chalcogenide-based potassium ion SSE is reported, K SbSe , which adopts a trigonal structure at room temperature. Single-crystal structural analysis reveals a trigonal-to-cubic phase transition at the low temperature of 50 °C, which is the lowest among similar compounds and thus provides easy access to the cubic phase.

Tackling antimicrobial stewardship through synergy and antimicrobial peptides.

The unrestricted use of antibiotics has led to rapid development of antibiotic resistance (AR) and renewed calls to address this serious problem. This review summarizes the most common mechanisms of antibiotic action, and in turn antibiotic resistance, as well as pathways to mitigate the harm. Focus is then turned to emerging antibiotic strategies, including antimicrobial peptides (AMPs), with a discussion of their modes of action, biochemical features, and potential challenges for their use as antibiotics.

Ultrafast spectral hole burning reveals the distinct chromophores in eumelanin and their common photoresponse.

Eumelanin, the brown-black pigment found in organisms from bacteria to humans, dissipates solar energy and prevents photochemical damage. While the structure of eumelanin is unclear, it is thought to consist of an extremely heterogeneous collection of chromophores that absorb from the UV to the infrared, additively producing its remarkably broad absorption spectrum. However, the chromophores responsible for absorption by eumelanin and their excited state decay pathways remain highly uncertain.

A perspective on physical organic chemistry.

A perspective on the development of mechanistic carbene chemistry is presented. The author will point out questions that have been answered, and a next generation of questions will be proposed.

Two approaches to diverting the course of a free-radical cyclization: application of cyclopropylcarbinyl radical fragmentations and allenes as radical acceptors.

Free radical cyclization of 4 and 7 gave the expected cyclization-reduction products (5 and 8) along with considerable amounts of products derived from a cyclization-atom transfer-secondary cyclization process (6 and 9). Two approaches to avoiding these unexpected products were explored. Use of a cyclopropylcarbinyl fragmentation avoided the secondary cyclization reaction (25 or 43 --> 26 or 44), whereas use of an allene as a radical acceptor avoided the atom-transfer reaction altogether (49 --> 52).