A mitochondria-targeted colorimetric and ratiometric fluorescent probe for biological SO2 derivatives in living cells
DOI: 10.1039/C5CC03055B, Communication
A novel mitochondria-targeted ratiometric fluorescent probe for SO2 derivatives was presented, which could selectively respond to HSO3- over other thiol compounds in living cells.
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Balancing the Rate of Cluster Growth and Etching for Gram-Scale Synthesis of Thiolate-Protected Au25 Nanoclusters with Atomic Precision
We report a NaOH-mediated NaBH4 reduction method for the synthesis of mono-, bi-, and tri-thiolate-protected Au25 nanoclusters (NCs) with precise control of both the Au core and thiolate ligand surface. The key strategy is to use NaOH to tune the formation kinetics of Au NCs, i.e., reduce the reduction ability of NaBH4 and accelerate the etching ability of free thiolate ligands, leading to a well-balanced reversible reaction for rapid formation of thermodynamically favorable Au25 NCs. This protocol is facile, rapid (≤3 h), versatile (applicable for various thiolate ligands), and highly scalable (>1 g Au NCs). In addition, bi- and tri-thiolate-protected Au25 NCs with adjustable ratios of hetero-thiolate ligands were easily obtained. Such ligand precision in molecular ratios, spatial distribution and uniformity resulted in richly diverse surface landscapes on the Au NCs consisting of multiple functional groups such as carboxyl, amine, and hydroxy. Analysis based on NMR spectroscopy revealed that the hetero-ligands on the NCs are well distributed with no ligand segregation. The unprecedented synthesis of multi-thiolate-protected Au25 NCs may further promote the practical applications of functional metal NCs.
One, two … many: A novel NaOH-mediated NaBH4 reduction method was developed for the synthesis of mono-, bi-, and tri-thiolate-protected Au25 nanoclusters. Both the Au core and thiolate ligand surface can be precisely controlled.
Dual-Organocatalyst-Promoted Asymmetric Cascade Reaction: Highly Efficient Construction of Enantiopure Fully Substituted Tetrahydro-1,2-oxazines
Hydrogenation was only the beginning: Hantzsch esters have now been used to transfer alkyl groups to imines under mild catalytic conditions to provide a variety of amines (see scheme). Benzyl, secondary alkyl, and tertiary alkyl groups containing ether, ester, and hydroxy functionalities were transferred successfully. The use of Hantzsch esters as alkylation reagents offers a practical and complementary alternative to organometallic processes.