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Articles 1 - 10 of 10
Full-Text Articles in Materials Chemistry
Uses Of Diaryliodonium Salts And Methods For Their Synthesis, Jordan M. Veness
Uses Of Diaryliodonium Salts And Methods For Their Synthesis, Jordan M. Veness
Department of Chemistry: Dissertations, Theses, and Student Research
Diaryliodonium salts have been studied continuously since the first report of their synthesis in 1894. Diaryliodonium salts are I(III) derivatives that are air- and moisturestable. The reactivity of these compounds resembles the organometallic chemistry of heavy transition metal ions such as Pb(IV), Hg(II), Th(III), and Pd(II). A significant advantage of diaryliodonium salts is that they can carry undergo many of the aryl functionalization reactions of heavy metal organometallic complexes, yet they have little to no toxicity and they are relatively inexpensive to prepare. The DiMagno laboratory uses diaryliodonium salts as precursors in the final synthetic step of radiopharmaceuticals; given that …
Three-Dimensional Scaffolds Of Graphene, Carbon Nanotubes And Transition-Metal Oxides For Applications In Electronics, Sensors And Energy Storage, Gilbert N. Mbah
Three-Dimensional Scaffolds Of Graphene, Carbon Nanotubes And Transition-Metal Oxides For Applications In Electronics, Sensors And Energy Storage, Gilbert N. Mbah
Department of Chemistry: Dissertations, Theses, and Student Research
Electronics, sensors and energy storage devices are the new waves behind economic development, security and communication1. Engineering small sizes of electronic, sensors and energy storage devices is the hurdle limiting efficient, portable and vast applications of Nano-devices for economic, security and communication advancement2. Silicon the major material used in transistors has approached its limit to fabricated Nano-devices3. The discovery of free standing, one atomic layer thick and two-dimensional graphene sheets with high conductivity, inert, high specific surface area, stable and high tensile strength material in 2004 has shown capabilities to replaced silicon in electronics, …
Titanium Trisulfide Monolayer: Theoretical Prediction Of A New Direct-Gap Semiconductor With High And Anisotropic Carrier Mobility, Jun Dai, Xiao Cheng Zeng
Titanium Trisulfide Monolayer: Theoretical Prediction Of A New Direct-Gap Semiconductor With High And Anisotropic Carrier Mobility, Jun Dai, Xiao Cheng Zeng
Xiao Cheng Zeng Publications
A new two-dimensional (2D) layered material, namely, titanium trisulfide (TiS3) monolayer, is predicted to possess novel electronic properties. Ab initio calculations show that the perfect TiS3 monolayer is a direct-gap semiconductor with a bandgap of 1.02 eV, close to that of bulk silicon, and with high carrier mobility. More remarkably, the in-plane electron mobility of the 2D TiS3 is highly anisotropic, amounting to about 10,000 cm2 V−1 s−1 in the b direction, which is higher than that of the MoS2 monolayer, whereas the hole mobility is about two orders of magnitude lower. …
Unraveling Structures Of Protection Ligands On Gold Nanoparticle Au68(Sh)32, Wen Wu Xu, Yi Gao, Xiao Cheng Zeng
Unraveling Structures Of Protection Ligands On Gold Nanoparticle Au68(Sh)32, Wen Wu Xu, Yi Gao, Xiao Cheng Zeng
Xiao Cheng Zeng Publications
New low-energy atomic structures of the thiolate-protected gold nanoparticle Au68(SH)32 are uncovered, where the atomic positions of the Au atoms are taken from the recent single-particle transmission electron microscopy measurement by Kornberg and co-workers, whereas the pattern of thiolate ligands on the gold core is attained on the basis of the generic formulation (or rule) of the “divide and protect” concept. Four distinct low-energy isomers, Iso1 to Iso4, whose structures all satisfy the generic formulation, are predicted. Density-functional theory optimization indicates that the four isomers are all lower in energy by 3 to 4 eV than the …
Bio-Crosslinking Of Starch Films With Oxidized Sucrose, Hazal Canisag
Bio-Crosslinking Of Starch Films With Oxidized Sucrose, Hazal Canisag
Department of Textiles, Merchandising, and Fashion Design: Dissertations, Theses, and Student Research
In this work, corn starch films were crosslinked with a novel bio-based agent; oxidized sucrose and their strength and stability were improved. Although starch is an inexpensive, biodegradable and abundant source, industrial applications of starch films are limited due to their poor mechanical properties. Crosslinking is one of the most common methods to enhance the mechanical properties of starch films. However, most of the available crosslinkers, such as gluteraldehyde, phosphorus oxychloride, sodium trimetaphosphate, and epichlorohydrin, are either toxic, expensive or with low crosslinking efficiencies. Oxidized sucrose, which is derived by periodate cleavage, has aldehyde groups in the structure and this …
B27−: Appearance Of The Smallest Planar Boron Cluster Containing A Hexagonal Vacancy, Wei-Li Li, Rhitankar Pal, Zachary A. Piazza, Xiao Cheng Zeng, Lai-Sheng Wang
B27−: Appearance Of The Smallest Planar Boron Cluster Containing A Hexagonal Vacancy, Wei-Li Li, Rhitankar Pal, Zachary A. Piazza, Xiao Cheng Zeng, Lai-Sheng Wang
Xiao Cheng Zeng Publications
Photoelectron spectroscopy and ab initio calculations have been carried out to probe the structures and chemical bonding of the B27− cluster. Comparison between the experimental spectrum and the theoretical results reveals a two-dimensional (2D) global minimum with a triangular lattice containing a tetragonal defect (I) and two low-lying 2D isomers (II and III), each with a hexagonal vacancy. All three 2D isomers have 16 peripheral boron atoms and 11 inner boron atoms. Isomer I is shown to be mainly responsible for the observed photoelectron spectrum with isomers II and III as minor contributors. Chemical bonding analyses of these …
Unraveling The Mechanism Of Selective Ion Transport In Hydrophobic Subnanometer Channels, Hui Li, Joseph S. Francisco, Xiao Cheng Zeng
Unraveling The Mechanism Of Selective Ion Transport In Hydrophobic Subnanometer Channels, Hui Li, Joseph S. Francisco, Xiao Cheng Zeng
Xiao Cheng Zeng Publications
Recently reported synthetic organic nanopore (SONP) can mimic a key feature of natural ion channels, i.e., selective ion transport. However, the physical mechanism underlying the K+/Na+ selectivity for the SONPs is dramatically different from that of natural ion channels. To achieve a better understanding of the selective ion transport in hydrophobic subnanometer channels in general and SONPs in particular, we perform a series of ab initio molecular dynamics simulations to investigate the diffusivity of aqua Na+ and K+ ions in two prototype hydrophobic nanochannels: (i) an SONP with radius of 3.2 Å, and (ii) single-walled …
Electronic Structures And Electronic Spectra Of All-Boron Fullerene B40, Rongxing He, Xiao Cheng Zeng
Electronic Structures And Electronic Spectra Of All-Boron Fullerene B40, Rongxing He, Xiao Cheng Zeng
Xiao Cheng Zeng Publications
This study is motivated by the recent discovery of the first all-boron fullerene analogue, a B40 cluster with D2d point-group symmetry, dubbed borospherene (Nat. Chem., 2014, 6, 727). Insight into the electronic structures and spectral properties of B40 is timely and important to understand the borospherene and the transition from open-ended plate or ribbon-like structures to a hollow-cage structure at B40. Optimized geometries of borospherene B40 for both the ground state and the first excited state allow us to compute spectral properties including UV-vis absorption, infrared (IR) and Raman spectra. Highly resolved absorption and …
Medium-Sized Au40(Sr)24 And Au52(Sr)32 Nanoclusters With Distinct Gold-Kernel Structures And Spectroscopic Features, Wen Wu Xu, Yadong Li, Yi Gao, Xiao Cheng Zeng
Medium-Sized Au40(Sr)24 And Au52(Sr)32 Nanoclusters With Distinct Gold-Kernel Structures And Spectroscopic Features, Wen Wu Xu, Yadong Li, Yi Gao, Xiao Cheng Zeng
Xiao Cheng Zeng Publications
We have analyzed the structures of two medium-sized thiolateprotected gold nanoparticles (RS-AuNPs) Au40(SR)24 and Au52(SR)32 and identified the distinct structural features in their Au kernels [Sci. Adv., 2015, 1, e1500425]. We find that both Au kernels of the Au40(SR)24 and Au52(SR)32 nanoclusters can be classified as interpenetrating cuboctahedra. Simulated X-ray diffraction patterns of the RS-AuNPs with the cuboctahedral kernel are collected and then compared with the X-ray diffraction patterns of the RS-AuNPs of two other prevailing Au-kernels identified from previous experiments, namely the Ino-decahedral kernel and icosahedral kernel. …
Extremely Strong Tubular Stacking Of Aromatic Oligoamide Macrocycles, Mark A. Kline, Xiaoxi Wei, Ian J. Horner, Rui Liu, Shuang Chen, Si Chen, Ka Yi Yung, Kazuhiro Yamato, Zhonghou Cai, Frank V. Bright, Xiao Cheng Zeng, Bing Gong
Extremely Strong Tubular Stacking Of Aromatic Oligoamide Macrocycles, Mark A. Kline, Xiaoxi Wei, Ian J. Horner, Rui Liu, Shuang Chen, Si Chen, Ka Yi Yung, Kazuhiro Yamato, Zhonghou Cai, Frank V. Bright, Xiao Cheng Zeng, Bing Gong
Xiao Cheng Zeng Publications
As the third-generation rigid macrocycles evolved from progenitor 1, cyclic aromatic oligoamides 3, with a backbone of reduced constraint, exhibit extremely strong stacking with an astoundingly high affinity (estimated lower limit of Kdimer > 1013 M–1 in CHCl3), which leads to dispersed tubular stacks that undergo further assembly in solution. Computational study reveals a very large binding energy (–49.77 kcal mol–1) and indicates highly cooperative local dipole interactions that account for the observed strength and directionality for the stacking of 3. In the solid-state, X-ray diffraction (XRD) confirms that the aggregation of 3 results …