The challenges of developing sustainable methods of carbon-carbon bond formation remains a topic of considerable importance in synthetic chemistry. Capitalizing on the highly reactive nature of the nitrile imine 1,3-dipole, we have developed a novel metal-free coupling of this species with aryl boronic acids. Photochemical generation of a nitrile imine intermediate and trapping with a palette of boronic acids enabled rapid and facile access to a broad library of more than 25 hydrazone derivatives in up to 92% yield, forming a carbon-carbon bond in a metal free fashion. This represents the first reported example of direct reaction between boronic acids and a 1,3-dipole. This journal is © The Royal Society of Chemistry 2019.Changes of molecular spin are ubiquitous in chemistry and biology. Among spin flip processes, one of the fastest is intersystem crossing (ISC) in transition metal complexes. Here, we investigate the spin relaxation dynamics and emission spectrum of [Re(CO)3(im)(phen)]+ (im = imidazole, phen = phenanthroline) using extensive full-dimensional excited-state dynamics simulations in explicit aqueous solution. Contrary to what has been observed in other transition metal complexes, the transition from the singlet to triplet states occurs via a two-step process, with clearly separable electronic and nuclear-driven components with two different time scales. The initially excited electronic wave function is a "molecular spin-orbit wave packet" that evolves almost instantaneously, with an 8 fs time constant, into an approximate 25  75 singlet-to-triplet equilibrium. Surprisingly, this ISC process is an order of magnitude faster than it was previously documented for this and other rhenium(i) carbonyl diimine complexes from emission spectra. Simulations including explicit laser field interactions evidence that few-cycle UV laser pulses are required to follow the creation and evolution of such molecular spin-orbit wave packets. The analysis of the dynamics also reveals a retarded ISC component, with a time constant of 420 fs, which can be explained invoking intramolecular vibrational energy redistribution. The emission spectrum is shown to be characterized by ISC convoluted with internal conversion and vibrational relaxation. These results provide fundamental understanding of ultrafast intersystem crossing in transition metal complexes. This journal is © The Royal Society of Chemistry 2019.Flavin adenine dinucleotide (FAD) as a cofactor is involved in numerous important metabolic pathways where the biological function is intrinsically related to its transient conformations. The confined space of enzymes requires FAD set in its specific intermediate conformation. However, conventional methods only detect stable conformations of FAD molecules, while transient intermediates are hidden in ensemble measurements. There still exists a challenge to uncover the transient conformation of each FAD molecule, which hinders the understanding of the structure-activity relationship of the FAD mechanism. Here, we employ the electrochemically confined space of an aerolysin nanopore to directly characterize a series of transient conformations of every individual FAD. Based on distinguishable current blockages, the "stack", "open", and four quasi-stacked FADs are clearly determined in solution, which is further confirmed by temperature-dependent experiments and mutant aerolysin assay. Combined with molecular dynamics simulations, we achieved a direct correlation between the residual current ratio (I/I 0) and FAD backbone angle. These results would facilitate further understanding of the structure-activity relationship in the flavoprotein. This journal is © The Royal Society of Chemistry 2019.Adenylation enzymes selecting substrates for ribosomal and nonribosomal protein and peptide biosynthesis have been popular targets of enzyme engineering. Previous standard assays for adenylation specificity have been cumbersome and failed to reflect the competition conditions inside a cell because they measure substrates one at a time. We have developed an adenylation assay based on hydroxamate quenching and LC-MS/MS detection of hydroxamate products testing dozens of competing amino acid substrates in parallel. Streamlined specificity profiling of adenylation enzymes will facilitate engineering and directed evolution of ribosomal and nonribosomal peptide synthesis. This journal is © The Royal Society of Chemistry 2019.A bottom-up self-assembly approach is developed for the synthesis of ABC type heterotrimeric nanoparticles, which can be converted into secondary Janus-type silica derivatives. Compared to spherical ones, Janus silica nanoparticles stimulate stronger phagocytosis and transcytosis through intestinal epithelial microfold cells and exhibit higher cargo transport across an in vitro epithelial monolayer model mimicking the human intestinal epithelium. learn more This journal is © The Royal Society of Chemistry 2019.Inspired by the successful synthesis of Fe/Cu-5,5'-bis(4-pyridyl)(2,2'-bipirimidine) (PBP), a family of two-dimensional (2D) metal-organic frameworks (MOFs) with the Shastry-Sutherland lattice, i.e., transition metal (TM)-PBP (TM = Cr, Mn, Fe, Co, Ni, Cu, Zn) has been systematically investigated by means of first-principles density functional theory calculations and Monte Carlo simulations. Mn-PBP is discovered to be the first ferromagnetic 2D MOF with the Shastry-Sutherland lattice and the Curie temperature is predicted to be about 105 K, while Fe-PBP, TM-PBP (TM = Cr, Co, Ni) and TM-PBP (TM = Cu, Zn) are found to be stripe-order antiferromagnetic, magnetic-dimerized and nonmagnetic, respectively. The electronic structure calculations reveal that TM-PBP MOFs are semiconductors with band gaps ranging from 0.12 eV to 0.85 eV, which could be easily modulated by various methods. Particularly, Mn-PBP would exhibit half-metallic behavior under compressive strain or appropriate electron/hole doping and a Mn-PBP based spintronic device has been proposed. This study not only improves the understanding of the geometric, electronic and magnetic properties of the 2D TM-PBP MOF family, but also provides a novel spin lattice playground for the research of 2D magnetic systems, which has diverse modulating possibilities and rich potential applications. This journal is © The Royal Society of Chemistry 2019.