Search for: All records

Mn(III)– and Co(III)–salen complexes (Mn-1 and Co-2) have been synthesized by a simple one-pot procedure through oxidation of Mn(II) and Co(II) precursors in air. X-ray structural analysis reveals that both complexes adopt similar coordination modes, including a typical square planar metal/salen coordination sphere, which is further occupied by two axial ligands, i.e., an acetate anion and a water molecule. Despite their structural similarity, they are not isomorphous given their distinct cell parameters. In the solid-state structures, both complexes exist as hydrogen-bonded dimers through hydrogen bonding interactions between the axially coordinating water molecules and outer O4 cavity from another molecule of the complex. The reductive activity of both complexes has been explored. While the reaction of Mn-1 with potassium triethylborohydride was unsuccessful, leading to a complicated mixture, the use of Co-2 furnished the formation of a novel product (CoK-3) that was isolated as red crystals in reasonable yield. CoK-3 was characterized as a heterometallic dimer involving the coordination of a K+ ion within the O4 cavity of a semi-hydrogenated salen/cobalt complex while the cobalt center has been reduced from Co(III) to Co(II). In addition, an attempt at reducing Co-2 with pinacolborane resulted in the isolation of crystals of Co-4, whose structure was determined as a simple square planar CoII–salen complex. Finally, three complexes (Mn-1, Co-2 and CoK-3) have been investigated for their cytotoxic activities against two human breast cancer cell lines (MCF-7 and MDA-MB 468) and a normal breast epitheliel cell line (MCF-10A), with cisplatin used as a reference in order to discover potential drug candidates that may compete with cisplatin. The results reveal that Co-2 can be a promising drug candidate, specifically for the MCF-7 cancer cells, with minimal damage to healthy cells. 

Bioactive indium(iii)–terpyridine complexes are synthesized and structurally characterized. These compounds demostrated antifungal activity against variousCandidaspecies, as well as antiproliferative activity against human breast cancer cells. 

The purinyl nitrogen atom is an effective metalation director, which in the presence of Pd(OAc)₂,t-BuOOH, and aryl aldehydes, leads to acylation of the aryl ring at the C6 position of the purine. 

Biological systems, including proteins, employ water-mediated supramolecular interactions to adopt specific conformations for their functions. However, current solid-state supramolecular materials are typically stiff and fail to capture the dynamic behaviors observed in proteins. Here, we present dynamic crystal-hydrates of aliphatic dipeptides with sequence-isomers of leucine (L) and isoleucine (I). These crystals exhibit shallow conformational energy landscapes, with various reconfigurable crystal nano-architectures accessible through small changes in relative humidity and temperature. Specifically, for LI crystals, as water content changes, the solid-state supramolecular architecture rapidly and reversibly transitions between perpendicular and parallel honeycomb nano-architectures, as well as layered van der Waals structures, leading to significant and distinct variations in mechanical and photophysical properties. Our findings demonstrate the potential of leveraging aliphatic hydrophobic domains inspired by protein architectures to create dynamic solid-state materials with context-adaptive properties. 

Synthesis of the COVID drug β-d-N⁴-hydroxycytidine (NHC) and its prodrug, molnupiravir, has been achievedviatwo chemical routes. 

Monoprotonated homoleptic complex of cobalt(ii) with 4′-pyridyl-2,2′;6′,2′′-terpyridine ligand is an efficient precatalyst for hydroboration of styrene derivatives with Markovnikov selectivity, displaying turnover frequencies up to 47 000 h⁻¹. 

A facile epoxide ring-opening hydroboration reaction catalysed by an active vanadium complex supported by a redox-active terpyridine ligand is reported for the synthesis of secondary alcohols under mild conditions. 

An ionic metal–organic-framework (MOF) containing nanoscale channels was readily assembled from ditopic 4′-pyridyl-2,2′:6′,2′′-terpyridine (pytpy) and a simple iron( ii ) salt. X-ray structural analysis revealed a two-dimensional grid-like framework assembled by classic octahedral (pytpy) 2 Fe II cations as linkers (with pytpy as a new ditopic pyridyl ligand) and octa-coordinate FeCl 2 centers as nodes. The layer-by-layer assembly of the 2-D framework resulted in the formation of 3-D porous materials consisting of nano-scale channels. The charges of the cationic framework were balanced with anionic Cl 3 FeOFeCl 3 in its void channels. The new Fe-based MOF material was employed as a precatalyst for syn -selective hydroboration of alkynes under mild, solvent-free conditions in the presence of an activator, leading to the synthesis of a range of trans -alkenylboronates in good yields. The larger scale applicability and recyclability of the new MOF catalyst was further explored. This represents a rare example of an ionic MOF material that can be utilized in hydroboration catalysis. 

A new diplumbane, namely [Pb(CH 2 SiMe 3 ) 3 ] 2 , was synthesized and structurally characterized. This group 14 element compound was found to catalyse the hydroboration of ketones and aldehydes under mild conditions without the use of additives and solvents, leading to the synthesis of a range of alcohols in high yields after hydrolysis.