Design and synthesis of ordered, metal-free layered materials is intrinsically difficult due to the limitations of vapor deposition processes that are used in their making. Mixed-dimensional (2D/3D) metal-free van der Waals (vdW) heterostructures based on triazine (C N ) linkers grow as large area, transparent yellow-orange membranes on copper surfaces from solution. The membranes have an indirect band gap (E = 1.91 eV, E = 1.84 eV) and are moderately porous (124 m g ). The material consists of a crystalline 2D phase that is fully sp hybridized and provides structural stability, and an amorphous, porous phase with mixed sp -sp hybridization. Interestingly, this 2D/3D vdW heterostructure grows in a twinned mechanism from a one-pot reaction mixture: unprecedented for metal-free frameworks and a direct consequence of on-catalyst synthesis. Thanks to the efficient type I heterojunction, electron transfer processes are fundamentally improved and hence, the material is capable of metal-free, light-induced hydrogen evolution from water without the need for a noble metal cocatalyst (34 µmol h g without Pt). The results highlight that twinned growth mechanisms are observed in the realm of "wet" chemistry, and that they can be used to fabricate otherwise challenging 2D/3D vdW heterostructures with composite properties.

The resistance among microbes has brought an urgent need for new drugs. Thus, we synthesized a series of Schiff bases derived from the sulfa drug sulfadiazine and various salicylaldehydes. The resulting 4-[(2-hydroxybenzylidene)amino]-N-(pyrimidin-2-yl)benzene-sulfonamides were characterized and evaluated against Gram-positive and Gram-negative bacteria, yeasts, moulds, Mycobacterium tuberculosis, nontuberculous mycobacteria (M. kansasii, M. avium) and their cytotoxicity was determined. Among bacteria, the genus Staphylococcus, including methicillin-resistant S. aureus, showed the highest susceptibility, with minimum inhibitory concentration values from 7.81 µM. The growth of Candida sp. and Trichophyton interdigitale was inhibited at concentrations starting from 1.95 µM. 4-[(2,5-Dihydroxybenzylidene)amino]-N-(pyrimidin-2-yl)-benzenesulfonamide was identified as the most selective Schiff base for these strains with no apparent cytotoxicity and a selectivity index higher than 16. With respect to M. tuberculosis and M. kansasii that were inhibited within the range of 8 to 250 µM, unsubstituted 4-[(2-hydroxy-benzylidene)amino]-N-(pyrimidin-2-yl)benzenesulfonamide meets the selectivity requirement. In general, dihalogenation of the salicylic moiety improved the antibacterial and antifungal activity but also increased the cytotoxicity, especially with an increasing atomic mass. Some derivatives offer more advantageous properties than the parent sulfadiazine, thus constituting promising hits for further antimicrobial drug development.

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Thirteen known (1–12 and 16) and three previously undescribed Amaryllidaceae alkaloids of belladine structural type, named carltonine A-C (13–15), were isolated from bulbs of Narcissus pseudonarcissus cv. Carlton (Amaryllidaceae) by standard chromatographic methods. Compounds isolated in sufficient amounts, and not tested previously, were evaluated for their in vitro acetylcholinesterase (AChE; E.C. 3.1.1.7), butyrylcholinesterase (BuChE; E.C. 3.1.1.8) and prolyl oligopeptidase (POP; E.C. 3.4.21.26) inhibition activities. Significant human BuChE (hBUChE) inhibitory activity was demonstrated by newly described alkaloids carltonine A (13) and carltonine B (14) with IC50 values of 913 ± 20 nM and 31 ± 1 nM, respectively. Both compounds displayed a selective inhibition pattern for hBuChE with an outstanding selectivity profile over AChE inhibition, higher than 100. The in vitro data were further supported by in silico studies of the active alkaloids 13 and 14 in the active site of hBuChE.