Tailoring personalized cancer nanomedicines demands detailed understanding of the tumor microenvironment. In recent years, smart upconversion nanoparticles with the ability to exploit the unique characteristics of the tumor microenvironment for precise targeting have been designed. To activate upconversion nanoparticles, various bio‐physicochemical characteristics of the tumor microenvironment, namely, acidic pH, redox reactants, and hypoxia, are exploited. Stimuli‐responsive upconversion nanoparticles also utilize the excessive presence of adenosine triphosphate (ATP), riboflavin, and Zn2+ in tumors. An overview of the design of stimulus‐responsive upconversion nanoparticles that precisely target and respond to tumors via targeting the tumor microenvironment and intracellular signals is provided. Detailed understanding of the tumor microenvironment and the personalized design of upconversion nanoparticles will result in more effective clinical translation.

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Highly fluorescent nitrogen and phosphorus-doped carbon dots with a quantum yield 59% have been successfully synthesized from citric acid and di-ammonium hydrogen phosphate by single step hydrothermal method. The synthesized carbon dots have high solubility as well as stability in aqueous medium. The as-obtained carbon dots are well monodispersed with particle sizes 1.5-4 nm. Owing to a good tunable fluorescence property and biocompatibility, the carbon dots were applied for intercellular sensing of Fe(3+) ions as well as cancer cell imaging.

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The development of light harvesting systems based on heterostructures for efficient conversion of solar energy to renewable energy is an emerging area of research. Here, we have designed heterostructures by using carbon dots (C-dots) and zinc oxide nanoparticles (ZnO NP) to develop an efficient light harvesting system. Interestingly, the conduction band and the valence band positions of ZnO NP are lower than the LUMO and HOMO positions of C-dots in this type II heterostructure of C dot-ZnO NP, which causes efficient charge separation and photocurrent generation. Steady state and time resolved spectroscopic studies reveal that an efficient photoinduced electron transfer occurs from C dots to ZnO NP and a simultaneous hole transfer occurs from the valence band of ZnO NP to the HOMO of C dots. The calculated rate of electron transfer is found to be 3.7 × 10 s and the rate of hole transfer is found to be 3.6 × 10 s. The enhancement of photocurrent (11 fold) under solar light irradiation of the C dot-ZnO NP heterostructure opens up new possibilities to design efficient light harvesting systems.

ctc-Ru(L)2(Cl)2, 1 [L = pyridine-2-azobenzene], reacts with EtOCS2K to give an unusual product, 3, where the ortho-carbon atom of the pendant phenyl ring of each L is selectively thiolated. Crystal structure and spectra of compound 3 are reported.

Ruthenium(II) Phenolates. Synthesis and Characterization of A Novel Four-Membered Metallacycle Ruthenium phenolates constitute a small family of interesting complexes.1 While 4-methy!-2,6-diformylphenol (1) was studied as a potential binucleating ligand for the metal, complexes of composition Ru(/?-XC6H4L)(CO)(PPh3)2Cl, incorporating 2, were discovered. The X = Me complex 3, described here, is representative of the family.2 Reaction of Ru(PPh3)3Cl2 (100 mg, 0.10 mmol), 1 (26 mg, 0.15 mmol), and p-MeC6H4NH2 (17 mg, 0.15 mmol) in boiling ethanol (30 mL) for 0.5 h (the reaction does not proceed in the absence of the amine) affords a violet solution, which, upon cooling, deposits 3 as dark violet crystals in nearly quantitative yield.3 The same results are obtained when 1 + />MeC6H4NH2 is replaced by an equivalent amount of the preformed Schiff base 4 (40 mg, 0.15 mmol), which is thus the active reagent in the synthesis. Benzene can replace ethanol as the solvent without loss of synthetic efficacy.The X-ray structure4,5 of 3 is shown in Figure 1. The ru-