Unravelling the correlation between metal induced aggregation and cellular uptake/subcellular localization of Znsalen: an overlooked rule for design of luminescent metal probes.

Unravelling the unique effects of metal coordination on biological behaviours is of importance to design metal based therapeutic and diagnostic agents. In this work, we chose luminescent Znsalen ( ) as a case study to demonstrate that metal induced aggregation arising from the intermolecular Zn···O interaction influences its cellular uptake and subcellular localization. Comparative studies with the free bases ( and ) show that undergoes cellular uptake through caveolae-mediated endocytosis and internalizes in endosomal/lysosomal compartments, in contrast to the localization of and in the mitochondria.

Effect of distal histidines on hydrogen peroxide activation by manganese reconstituted myoglobin.

Myoglobins provide an opportunity to investigate the effect of the secondary coordination sphere on the functionality and reactivity of non-native metal porphyrins inside well-defined protein scaffolds. In this work, we reconstituted myoglobin by the replacement of natural heme with manganese(iii) protoporphyrin IX and firstly investigated the effect of distal histidine on the reaction of Mn(III) porphyrin with H2O2 and one-electron oxidation of ABTS. We have prepared L29H, F43H, H64F, L29H/H64F, F43H/H64F, L29H/F43H and L29H/F43H/H64F mutants and reconstituted apo-myoglobins with manganese(iii) protoporphyrin IX.

μ-Hydroxyl trinuclear copper(II) clusters: reactivity and unusual formation in the three-component synthesis of 1,2,3-triazoles in aqueous media.

μ-Hydroxyl trinuclear copper(II) compounds, with core structures closely resembling the central moieties in multicopper oxidases, have been extensively investigated and the importance of the prototypes in the oxidation of C-H bonds has been confirmed. In the course of study for the Cu(II) salens catalyzing the three-component (sodium azide, epoxide and non-activated terminal alkyne) 1,3-Huisgen cycloaddition, we observed the unusual formation of a μ-OH bridging trinuclear copper cluster supported by three (R,R)-N-(5-sulfonatosalicylidene)-1,2-diaminocyclohexane ligands (Cu-6) during the catalytic process. More interestingly, through comparative studies for the activity of the mononuclear copper(II) complexes (Cu-1 and Cu-5), we found that the μ-OH trinuclear copper(II) complex (Cu-6) was the active catalyst precursor.

π-π interaction assisted hydrodefluorination of perfluoroarenes by gold hydride: a case of synergistic effect on C-F bond activation.

"Synergistic effect" is prevalent in natural metalloenzymes in activating small molecules, and the success has inspired the development of artificial catalysts capable of unprecedented organic transformations. In this work, we found that the attractive π-π interaction between organic additives (as electron-donors) and the perfluorinated arenes (as electron acceptors) is effective in gold hydride catalyzed activation of C-F bonds, specifically hydrodefluorination (HDF) of perfluoroarenes catalyzed by the Sadighi's gold hydrides [(NHC)AuH] (NHC = N-heterocyclic carbene). Although a weak interaction between [(NHC)AuH] and perfluoroarenes was observed from (1)H NMR and UV-vis spectroscopies, low reactivity of [(NHC)AuH] toward HDF was found.

Molecular assembly directed by metal-aromatic interactions: control of the aggregation and photophysical properties of Zn-salen complexes by aromatic mercuration.

There is widespread interest in non-covalent bonding and weak interactions, such as electrostatic interactions, hydrogen bonding, solvophobic/hydrophobic interactions, metal-metal interactions, and π-π stacking, to tune the molecular assembly of planar π-conjugated organic and inorganic molecules. Inspired by the roles of metal-aromatic interaction in biological systems, such as in ion channels and metalloproteins, herein, we report the first example of the use of Hg(2+) -aromatic interactions to selectively control the assembly and disassembly of zinc-salen complexes in aqueous media; moreover, this process exhibited significant "turn on" fluorescent properties. UV/Vis and fluorescence spectroscopic analysis of the titration of Hg(2+) ions versus complex ZnL(1) revealed that the higher binding affinity of Hg(2+) ions (compared to 13 other metal ions) was ascribed to specific interactions between the Hg(2+) ions and the phenyl rings of ZnL(1); this result was also confirmed by (1)H NMR spectroscopy and HRMS (ESI).