Band 86, Heft 1

One-to-one capture and confinement of a molecule within a finely designed synthetic scaffold is a highly topical field of research that aims to control the functions, properties, and stabilities of trapped molecules. In this account, a brief history of molecular encapsulation, for the design and synthesis of suitable molecular cages for large molecules, summarizes the daunting synthetic challenge associated with increasing molecular weight, and the attendant challenge to encapsulate macromolecules like proteins by synthetic hosts. Recent approaches toward the overall objective of large molecular encapsulation are discussed, and a personal account is given of the design and assembly of an advanced scaffolding system, which offers the promise of unprecedented progress toward this goal.

The solar power received by Earth far exceeds global power demands. Despite this, infrastructure shortages and high capital costs prevent the wide-scale adoption of photovoltaics to displace conventional energy technologies relying on carbon-based fuels. In response, new concepts and materials have been explored to develop next-generation solar cells capable of operating more efficiently and cheaply. Over the past decade, single semiconductor nanowire (NW) and NW array devices have emerged as promising platforms with which to examine new concepts. Small distances in NWs allow for efficient charge separation while tunable photonic modes permit light absorption properties distinct from bulk materials. Furthermore, the synthesis and fabrication of NW devices presents new opportunities such as with incorporation of complex heterostructures or use of cheaper substrates. Here, we present a critical discussion of the benefits and remaining challenges related to utilization of NWs for solar energy conversion and emphasize the synthetic advances leading towards significant improvement in the electrical and optical performance of NW devices. We conclude by articulating the unique capabilities of solar cells assembled from multiple, distinct NWs.

Thiolate-protected Au nanoclusters with core diameters smaller than 2 nm have captured considerable attention in recent years due to their diverse applications ranging from biological labeling to photovoltaics and catalysis. This new class of nanomaterials exhibits discrete electronic structure and molecular-like properties, such as HOMO-LUMO electronic transition, intrinsic magnetism, chiroptical properties, and enhanced catalytic properties. This review focuses on the research into thiolate-protected Au 38 (SR) 24 – one of the most representative nanoclusters, including its identification, size-focusing synthesis, structure determination, and intrinsic chirality. The properties of two size-adjacent Au nanoclusters [Au 40 (SR) 24 and Au 36 (SR) 24 ] are also discussed. The experimental and theoretical methodologies developed in studies of the Au 38 (SR) 24 model nanocluster open up new opportunities in the synthesis and properties investigation of other atomically precise Au n (SR) m nanoclusters.

This article reviews the origin and progress of inorganic/nanocarbon hybrid material research in my Ph.D. career. Building chemical bonds between inorganic active materials and nanocarbon substrates is the key to controlled hybrid material synthesis that allows for controlling the size and morphology of the materials and enhancing electron transport within the electrodes. Our inorganic/nanocarbon hybrid materials manifest superior electrochemical performance for asymmetrical supercapacitors, ultrafast nickel-iron batteries, lithium ion batteries, lithium-sulfur batteries, and electrocatalysis of oxygen reduction and evolution reactions. X-ray absorption near edge structure (XANES) spectroscopy has been utilized to characterize the chemical bonding and charge transfer at the interface of inorganic nanocrystals and nanocarbon substrates. Probing the physical and chemical states of the hybrid materials under electrochemical reaction conditions is an important future direction in this area.

Heterogeneous catalysis utilizing metal particles plays an essential role in the industrial applications. Design and fabrication of highly active catalysts in an efficient and cost-effective way is thus an important topic. The emergence of nanotechnology provides an excellent opportunity for developing new catalysts. In this critical review, we present our efforts and perspective on the recent advances in engineering nanomaterials for catalysis, including synthesis, stabilization, and catalytic applications of nanoparticles. We first briefly summarize the advanced colloidal synthesis of metal nanoparticles using Ag nanoplates as the model system, and then discuss the strategies for stabilization of metal nanoparticles using both chemical and physical approaches. And finally, for practical applications, we have designed and synthesized a highly efficient, stable, and cost-effective TiO 2 -based photocatalyst by combining both non-metal doping and noble metal decoration.

The report and results of an IUPAC Task Group (TG) formed in 2004 on “A Database of Water Transitions from Experiment and Theory” (Project No. 2004-035-1-100) are presented. Energy levels and recommended labels involving exact and approximate quantum numbers for the main isotopologues of water in the gas phase, H 2 16 O, H 2 18 O, H 2 17 O, HD 16 O, HD 18 O, HD 17 O, D 2 16 O, D 2 18 O, and D 2 17 O, are determined from measured transition frequencies. The transition frequencies and energy levels are validated using first-principles nuclear motion computations and the MARVEL (measured active rotational–vibrational energy levels) approach. The extensive data including lines and levels are required for analysis and synthesis of spectra, thermochemical applications, the construction of theoretical models, and the removal of spectral contamination by ubiquitous water lines. These datasets can also be used to assess where measurements are lacking for each isotopologue and to provide accurate frequencies for many yet-to-be measured transitions. The lack of high-quality frequency calibration standards in the near infrared is identified as an issue that has hindered the determination of high-accuracy energy levels at higher frequencies. The generation of spectra using the MARVEL energy levels combined with transition intensities computed using high accuracy ab initio dipole moment surfaces are discussed. A recommendation of the TG is for further work to identify a single, suitable model to represent pressure- (and temperature-) dependent line profiles more accurately than Voigt profiles.