An all-in-one approach for synthesis and functionalization of nano colloidal gold with acetylacetone

Controllable synthesis, proper dispersion, and feasible functionalization are crucial requirements for the application of nanomaterials in many scenarios. Here, we report an all-in-one approach for the synthesis and functionalization of gold nanoparticles (AuNPs) with the simplest β-diketone, acetylacetone (AcAc). With this approach, the particle size of the resultant AuNPs was tunable by simply adjusting the light intensity or AcAc dosage. Moreover, owing to the capping role of AcAc, the resultant AuNPs could be stably dispersed in water for a year without obvious change in morphology and photochemical property. Formation of ligand to metal charge transfer complexes was found to play an important role in the redox conversion of Au with AcAc. Meanwhile, the moderate complexation ability enables the surface AcAc on the AuNPs to undergo ligand exchange reactions. With the aid of Ag+, the AuNPs underwent ligand exchange reaction with glutathione and exhibited enhanced photoluminescence (PL) with a maximum of 22-fold increase in PL intensity. The PL response was linear to the concentration of glutathione in the range of 0~500 μM. Such a ligand exchange reaction makes the obtained AuNPs being good imaging probes. To the best of our knowledge, this is the first work on illustrating the roles of AcAc as a multifunctional ligand in fabrication of NPs, which sheds new light on the surface modulation in synthesis of nanomaterials.

Band Gap Narrowed P Doped 1T@2H MoS2 Nanosheets Towards Synergistically Enhanced Visible Light Photochemical Property

The weak transport charge efficiency and great band gap energy of layered MoS2 hamper its further commercial application. To overcome these deficiencies, we report a simple, controlled and handy hydrothermal process for realizing 2H MoS2 to 1T MoS2 transition with P source. Due to the more conductive ability and larger surface area, P-doped 1T@2H MoS2 nanosheets show an outstanding catalytic activity. Noticeably, P-doped 1T@2H MoS2 nanosheets with narrowed bandgap exhibits a remarkable optical photochemical performance. It fully eliminates 50 ml of 20 mg L–1 RhB in 70 minutes with outstanding recycling and structural stability by using 10 mg catalyst.

Crystal structure and photochemical property of 1,8-bis(p-tolylthio)pyrene, C30H22S2

C30H22S2, triclinic, P1̄ (no. 2), a = 7.604(4) Å, b = 11.556(5) Å, c = 13.090(7) Å, α = 93.964(8)°, β = 93.209(8)°, γ = 90.619(9)°, V = 1145.7(10) Å3, Z = 2, Rgt(F) = 0.0497, wRref(F2) = 0.1295, T = 296(2) K.

Photochemical property of a Ru(ii) compound based on 3-(2-pyridyl)pyrazole and 2,2′-bipyridine for ablation of cancer cells

Ru(ii) compounds are potential candidates for photodynamic therapy (PDT).

Photoactivation mechanism of a carotenoid-based photoreceptor

Photoprotection is essential for efficient photosynthesis. Cyanobacteria have evolved a unique photoprotective mechanism mediated by a water-soluble carotenoid-based photoreceptor known as orange carotenoid protein (OCP). OCP undergoes large conformational changes in response to intense blue light, and the photoactivated OCP facilitates dissipation of excess energy via direct interaction with allophycocyanins at the phycobilisome core. However, the structural events leading up to the OCP photoactivation remain elusive at the molecular level. Here we present direct observations of light-induced structural changes in OCP captured by dynamic crystallography. Difference electron densities between the dark and illuminated states reveal widespread and concerted atomic motions that lead to altered protein–pigment interactions, displacement of secondary structures, and domain separation. Based on these crystallographic observations together with site-directed mutagenesis, we propose a molecular mechanism for OCP light perception, in which the photochemical property of a conjugated carbonyl group is exploited. We hypothesize that the OCP photoactivation starts with keto–enol tautomerization of the essential 4-keto group in the carotenoid, which disrupts the strong hydrogen bonds between the bent chromophore and the protein moiety. Subsequent structural changes trapped in the crystal lattice offer a high-resolution glimpse of the initial molecular events as OCP begins to transition from the orange-absorbing state to the active red-absorbing state.