Science in China Series B: Chemistry

A type of high visible-light active titanium oxinitride (TiO2−x Nx) powder was prepared by a simple process: the calcination of the hydrated titanium dioxide at the atmosphere of ammonia-argon using a tubular electric furnace at high temperatures. The hydrated titanium dioxide was synthesized as the precursor of TiO2−x Nx using titanic acid as raw material, which came from sulfate technique of producing titanium white. The effects of temperature and reaction time on the nitrogen content, grain size and crystal structure were studied. The visible-light activity and photocatalysis capability of the powder were also investigated.

Tribological properties of the TiO2, doped TiO2, Al2O3 and SiO2 thin films prepared by different sol-gel processes are reported. The results indicate that doping deteriorates the wear resistance of TiO2; organic modifier can improve the tribological property of Al2O3 significantly; and the SiO2 film prepared from inorganic salt sodium silicate registers much better wear resistance than that from ethyl orthosilicate.

Due to the strong crystallinity and anisotropy of small molecules, matched molecular photoelectric properties and morphologies between small molecules and non-fullerene acceptors are especially important in all-small-molecule organic solar cells (OSCs). Introducing fluorine atoms has been proved as an effective strategy to achieve a high device performance through tuning molecular energy levels, absorption and assembly properties. Herein, we designed a novel benzodithiophene-based small molecule donor BDTF-CA with deep highest occupied molecular orbital (HOMO) energy level. All-small-molecule OSCs were fabricated by combing non-fullerene acceptor IDIC with different fluorine-atom numbers. Two or four fluorine atoms were introduced to the end-capped acceptor of IDIC, which are named as IDIC-2F and IDIC-4F, respectively. With the increase of fluorination from IDIC to IDIC-4F, the open circuit voltage (Voc) of the devices decreased, while hole and electron mobilities of the active layers increased by one order of magnitude. Contributed to the most balanced Voc, short-circuit current (Jsc) and fill factor (FF), the device based on BDTF-CA/IDIC-2F achieved the highest power conversion efficiency of 9.11%.

It is well known that the estuarine research in China has got great achievements since the past 50 years. The development of estuarine research in China and progress in fundamental study are presented firstly in this paper. Especially in the aspect of theoretic studies, a distinctive feature is the combination studies of dynamics, sedimentology and geomorphology, which obtain a series of achievements, such as estuarine diluted water, estuarine fronts, turbidity maximum, sediment movement, formation of mouth bar, estuarine discontinuity phenomena, estuarine development, etc. Then some successful applications are introduced taking the Qiantang River Estuary and Yangtze Estuary as examples. Finally, main directions of estuarine research are discussed on fundamental study, the impacts of human activities on estuaries, estuarine material flux, sediment movement, prediction of estuarine erosion and accretion, estuarine discontinuity, artificial estuaries, land reclamation and wetland protection.

The two-state mechanism of the reaction of Nb(NH2)3 with N2O on the singlet and triplet potential energy surfaces has been investigated at the B3LYP level. Crossing points between the potential energy surfaces have been located using different methods. Analysis of the strain model shows that the singlet state of the four-coordinate (N2O)Nb(NH2)3 complex with N2O bonded via terminal N atom coordination (1 2) is more stable in the initial stage of reaction, since the bending of the N2O fragment [E def(N2O) = 86.1 kcal mol−1] results in an energy splitting of the doubly degenerate LUMO; the low-energy LUMO can now strongly couple with the occupied Nb-localized d orbitals, forming a back-bond and transferring charge (q = 0.82 e) from Nb(NH2)3 to the N2O ligand. Going from 3 2 to 1 2, the reacting system changes spin multiplicity near the MECP (minimal energy crossing point) region, which takes place with a spin crossing barrier of 9.6–10.0 kcal mol−1. Analysis of spin-orbit coupling (SOC) indicates that MECP will produce a significant SOC matrix element. The value of SOC is 111.52 cm−1, due to the electron shift between two perpendicular ϕ orbitals with the same rotation direction, and the magnitude of the spin-multi-plicity mixing increases in the small energy gap between high- and low-spin states, greatly enhancing the probability of intersystem crossing. The probabilities of single (P 1 ISC ) and double (P 2 ISC ) passes estimated at MECP (SOC = 111.52 cm−1) are approximately 1.17×10−2 and 2.32×10−2, respectively.

Three guests with two moiety probes for different Cucurbit[n = 6-8]urils have been synthesized. They are N-(2-methylenethiophen)-adamataneamine, N-(2-methylene pyrrole)-adamataneamine and N-(2-methylenefurfuran)-adamataneamine. The probes are methyle-nepyridyl typically for Q[6] and adamataneamine typically for Q[7]. The host-guest complexes of Cucurbit[n = 6-8]urils with these guests have been investigated by using NMR techniques and ESMS method. Also, thermoanalysis has been used for exploring relationship of enthalpy and stability of the host-guest complexes.

We report an ultrasensitive protocol for electrochemical sensing using the hydroxyl-rich C-dots assisted synthesis of gold nanoparticles (C-dots@AuNP) as labels with copper depositon reaction. The C-dots catalyzing copper deposition reaction was implemented for the first time. We constructed a sandwich-type immunosensor on the chitosan modified glassy carbon electrode (GCE) by glutaraldehyde (GA) crosslinking, with C-dots@AuNP as biolabels. Copper was deposited on the catalytic surfaces of second antibody-conjugated C-dots@AuNP nanoparticles through CuSO4-ascorbic acid reduction, because both C-dots and AuNPs could strongly catalyze the CuSO4 and ascorbic acid to form Cu particles, which amplified the detection signal. Then the corresponding antigen was quantified based on simultaneous chemical-dissolution/cathodic-preconcentration of copper for in-situ analysis using anodic stripping square wave voltammetry (ASSWV) directly on the modified electrode. Under optimized conditions, these electrodes were employed for sandwich-type immunoanalysis, pushing the lower limits of detection (LODs) down to the fg mL−1 level for human immunoglobulin G (IgG) and cardiac troponin I (cTnI), a cardiac biomarker. These novel sensors have good stability and acceptable accuracy and reproducibility, suggesting potential applications in clinical diagnostics.

Metal iodates with a lone-pair containing I(V) that is in an asymmetric coordination geometry can form a diversity of unusual structures and many of them are promising new second homonic generation (SHG) materials. They exhibit wide transparency wavelength regions, large SHG coefficients and high optical-damage thresholds as well as moderately high thermal stability. In this paper, the structures and properties of the metal iodates are reviewed. The combination of d0 transition-metal cations with the iodate groups afforded a large number of metal iodates, with cations covering alkali metal, alkaline earth and lanthanide elements. Many of them are noncentrosymmetric (NCS) and display excellent SHG properties due to the additive effects of polarizations from both types of the asymmetric units. Some lanthanide iodates are able to emit strong luminescence in the visible or near-IR regions. The use of transition metal ions with d n (n ≠ 0) electronic configuration into iodate systems can also induce the formation of NCS compounds when the lone pairs of the iodate groups are properly aligned. The d n transition metal cations are normally octahedrally coordinated or in a square-planar coordination geometry. Furthermore, the combination of two different types of lone-pair-containing cations is also an effective strategy to design new SHG materials.