Two-dimensional vibrational spectroscopy is applied to investigate the dilution process of 1-ethyl-3-methyl-imidazolium tetrafluoroborate ([Emim][BF4]) in water. With increasing water content in ionic liquid (IL)/water mixtures, the C-H stretching vibration of the imidazolium cation showed systematic blue-shifts, which reflect the weakening of the cohesion between the cation and anion of ILs. The two-dimensional IR results reveal that the ILs sense quite different environments during the whole dilution process. First, the three-dimensional network structure of pure ILs was destroyed gradually into ionic clusters, then the clusters were further dissociated into ionic pairs surrounded by water molecules, and finally the latter became the dominant form in bulk water. Within the concentration range we investigated (0.02

During the last few years, the preparation of novel fluorescent probes for the selective detection of chemical species inside mitochondria has attracted considerable attention because of their wide applications in chemistry, biology, and medical science. This feature article focuses on the recent advances in the design principles and recognition mechanisms of these kinds of fluorescent probes. In addition, their applications for the detection of reactive oxygen species (ROS), nitric oxide, reactive sulfur species (RSS), thioredoxin (Trx), metal ions, anions, etc. in the mitochondrion is discussed as well.

This work focuses on developing diketopyrrolopyrrole (DPP)-based small molecular nonfullerene acceptors for bulk heterojunction (BHJ) organic solar cells. The materials, SF-DPP s, have an X-shaped geometry arising from four DPP units attached to a spirobifl uorene (SF) center. The spiro-dimer of DPP-fl uorene-DPP is highly twisted, which suppresses strong intermolecular aggregation. Branched 2-ethylhexyl (EH), linear n -octyl (C8), and n -dodecyl (C12) alkyl sides are chosen as substituents to functionalize the N , N -positions of the DPP moiety to tune molecular interactions. SF-DPPEH , the best candidate in SF-DPP s family, when blended with poly(3-hexylthiophene) (P3HT) showed a moderate crystallinity and gives a J sc of 6.96 mA cm −2 , V oc of 1.10 V, a fi ll factor of 47.5%, and a power conversion effi ciency of 3.63%. However, SF-DPPC8 and SF-DPPC12 exhibit lower crystallinity in their BHJ blends, which is responsible for their reduced J sc . Coupling DPP units with SF using an acetylene bridge yields SF-A-DPP molecules. Such a small modification leads to drastically different morphological features and far inferior device performance. These observations demonstrate a solid structureproperty relationship by topology control and material design. This work offers a new molecular design approach to develop effi cient small molecule nonfullerene acceptors.

The blue-shifted C-D stretching vibrations (nu(CD)) of deuteriated dimethyl sulfoxide (DMSO-d(6)) in mixtures of DMSO-d(6)/ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF(4)]) were carefully investigated and compared with those in DMSO-d(6)/water. Results from FTIR studies indicate that the direct interaction of C-D...F between DMSO-d(6) and the anion [BF(4)(-)] plays a minor role in the blue-shift of nu(CD) in the mixtures of DMSO-d(6)/IL. They also show that the indirect influence of the hydrogen bond formed by the nearby functional group SO with C(2)-H of the cation significantly contributes to the blue-shift of nu(CD), as can be inferred from the significant differences of the blue-shift in [Bmim][BF(4)] and 1-butyl-2,3-dimethylimidazolium tetrafluoroborate ([Bm(2)im][BF(4)]). In contrast, in the case of DMSO-d(6)/water mixtures, direct hydration of C-H...O between the methyl groups of DMSO-d(6) with the oxygen atom of water is mainly responsible for the blue shift of nu(CD). Furthermore, theoretical calculations revealed that charge migrations as well as rehybridization have a dominant effect on the blue-shift in both mixtures.