A convenient and waste-free synthesis of indene-based tertiary carbinamines by rhodium-catalyzed imine/alkyne [3+2] annulation is described. Under the optimized conditions of 0.5-2.5 mol % [{(cod)Rh(OH)}(2)] (cod=1,5-cyclooctadiene) catalyst, 1,3-bis(diphenylphosphanyl)propane (DPPP) ligand, in toluene at 120 degrees C, N-unsubstituted aromatic ketimines and internal alkynes were coupled in a 1:1 ratio to form tertiary 1H-inden-1-amines in good yields and with high selectivities over isoquinoline products. A plausible catalytic cycle involves sequential imine-directed aromatic C-H bond activation, alkyne insertion, and a rare example of intramolecular ketimine insertion into a Rh(I)-alkenyl linkage.

Manganese ion (Mn2+) bonded nitrogen-doped graphene quantum dots (Mn(ii)-NGQDs) with water solubility have been successfully synthesized by a simple, one-pot hydrothermal carbonization, using sodium citrate, glycine and manganese chloride as raw materials.

Poly(ethylene glycol) passivated graphene quantum dots (PEG-GQDs) were synthesized based on a green and effective strategy of the hydrothermal treatment of cane molasses. The prepared PEG-GQDs, with an average size of 2.5 nm, exhibit a brighter blue fluorescence and a higher quantum yield (QY) (up to approximately 21.32%) than the QY of GQDs without surface passivation (QY = 10.44%). The PEG-GQDs can be used to detect and quantify paramagnetic transition-metal ions including Fe 3+ , Cu 2+ , Co 2+ , Ni 2+ , Pb 2+ , and Mn 2+ . In the case of ethylenediaminetetraacetic acid (EDTA) solution as a masking agent, Fe 3+ ions can be well selectively determined in a transition-metal ion mixture, following the lowest limit of detection (LOD) of 5.77 μM. The quenching mechanism of Fe 3+ on PEG-GQDs belongs to dynamic quenching. Furthermore, Fe 3+ in human serum can be successfully detected by the PEG-GQDs, indicating that the green prepared PEG-GQDs can be applied as a promising candidate for the selective detection of Fe 3+ in clinics.

Carbon dots have attracted much attention due to their high fluorescence intensity, easy modification, good stability, and biocompatibility. However, the realization of low‐cost mass production of high‐quality carbon dots still faces great challenges. Biomass is of non‐toxic and environmentally friendly organism, but a lot of biomass is treated as waste for burning and landfill at present, causing irreparable pollution to the environment. In fact, many biomass resources are ideal candidates for preparing carbon dots. This review focuses on carbon dots including carbon quantum dots (CQDs) and graphene quantum dots (GQDs) which using biomass as carbon source on the aspects of plants and their derivatives, animals and their derivatives and municipal waste. The characterization of the structure and composition of biomass carbon dots, the regulation of fluorescence color and the methods of improving quantum yield (QY) including heteroatom doping and surface modification are introduced in detail. Moreover, biomass carbon dots for detecting metal ions and non‐metal molecules and their quenching mechanism are emphatically introduced in addition to summarizing the luminescence mechanism, and some promising prospects and challenges in this uplifting field are discussed.